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PART 85— CONTROL OF AIR POLLUTION FROM MOBILE SOURCES

49. The authority citation for part 85 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart F—[Amended]

50. Section 85.510 is amended by revising paragraph (b)(9) to read as follows:

§ 85.510 Exemption provisions for new and relatively new vehicles/engines.

* * * * *

(b) * * *

(9) OBD requirements. (i) The OBD system must properly detect and identify 

malfunctions in all monitored emission-related powertrain systems or components 

including any new monitoring capability necessary to identify potential emission 

problems associated with the new fuel.

(ii) Conduct all OBD testing necessary to demonstrate compliance with 40 CFR 86.010-

18 or 86.1806-05.

(iii) Submit the applicable OBD reporting requirements set forth in 40 CFR part 86, 

subparts A and S, and submit the following statement of compliance if the OEM 

vehicles/engines were required to be OBD-equipped: 

The test group/engine family converted to an alternative fuel has fully functional 

OBD systems and therefore meets the OBD requirements specified in 40 CFR 

part 86 when operating on the alternative fuel.

* * * * *

51. Section 85.515 is amended by revising paragraph (b)(9)(iii) to read as follows:

§ 85.515 Exemption provisions for intermediate age vehicles/engines.

* * * * *

(b) * * *

(9) * * *

(iii) In addition to conducting OBD testing described in this paragraph (b)(9), you must 

submit to EPA the following statement of compliance if the OEM vehicles/engines were 

required to be OBD-equipped:

The test group/engine family converted to an alternative fuel has fully functional 

OBD systems and therefore meets the OBD requirements specified in 40 CFR part 86 

when operating on the alternative fuel.

* * * * *

52. Section 85.520 is amended by revising paragraph (b)(4)(iii) to read as follows:

§ 85.520 Exemption provisions for outside useful life vehicles/engines.

* * * * *

(b) * * *

(4) * * *

(iii) In addition to conducting OBD testing described in this paragraph (b)(4), you must 

submit to EPA the following statement of compliance if the OEM vehicles/engines were 

required to be OBD-equipped: 
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The test group/engine family converted to an alternative fuel has fully functional 

OBD systems and therefore meets the OBD requirements specified in 40 CFR 

part 86 when operating on the alternative fuel.

* * * * *

Subpart P—[Amended]

53. Section 85.1515 is revised to read as follows:

§ 85.1515 Emission standards and test procedures applicable to imported 

nonconforming motor vehicles and motor vehicle engines.

(a) Notwithstanding any other requirements of this subpart, any motor vehicle or motor 

vehicle engine conditionally imported pursuant to §85.1505 or §85.1509 and required to 

be emission tested shall be tested using the FCT at 40 CFR part 86 applicable to current 

model year motor vehicles and motor vehicle engines at the time of testing or reduced 

testing requirements as follows:

(1) ICIs are eligible for reduced testing under this paragraph (a) subject to the 

following conditions:

(i) The OEM must have a valid certificate of conformity covering the vehicle.

(ii) The vehicle must be in its original configuration as certified by the OEM. 

This applies for all emission-related components, including the electronic control 

module, engine calibrations, and all evaporative/refueling control hardware. It 

also applies for OBD software and hardware, including all sensors and actuators. 

(iii) The vehicle modified as described in paragraph (a)(1)(ii) of this section must 

fully comply with all applicable emission standards and requirements.

(iv) Vehicles must have the proper OBD systems installed and operating. When 

faults are present, the ICI must test and verify the system’s ability to find the 

faults (such as disconnected components), set codes, and illuminate the light, and 

set readiness codes as appropriate for each vehicle. When no fault is present, the 

ICI must verify that after sufficient prep driving (typically one FTP test cycle), all 

OBD readiness codes are set and the OBD system does not indicate a malfunction 

(i.e., no codes set and no light illuminated).

(v) The ICI may not modify more than 300 vehicles in any given model year 

using reduced testing provisions in this paragraph (a). 

(vi) The ICI must state in the application for certification that it will meet all the 

conditions in this paragraph (a)(1).

(2) The following provisions allow for ICIs to certify vehicles with reduced testing:

(i) In addition to the test waivers specified in 40 CFR 86.1829, you may provide a 

statement in the application for certification, supported by engineering analysis, 

that vehicles comply with any of the following standards that apply instead of 

submitting test data:

(A) Cold temperature CO and NMHC emission standards specified in 40 CFR 

86.1811.

(B) SFTP emission standards specified in 40 CFR 86.1811 and 86.1816 for all 

pollutants.

(C) For anything other than diesel-fueled vehicles, PM emission standards 

specified in 40 CFR 86.1811 and 86.1816.
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(D) Any running loss, refueling, spitback, bleed emissions, and leak standards 

specified in 40 CFR part 86, subparts A and S. 

(ii) You must perform testing and submit test data as follows to demonstrate 

compliance with emission standards:

(A) Exhaust and fuel economy tests. You must measure emissions over the 

FTP driving cycle and the highway fuel economy driving cycle as specified in 

40 CFR 600.109 to meet the fuel economy requirements in 40 CFR part 600 

and demonstrate compliance with the exhaust emission standards in 40 CFR 

part 86 (other than PM). Measure exhaust emissions and fuel economy with 

the same test procedures used by the original manufacturer to test the vehicle 

for certification. However, you must use an electric dynamometer meeting 

the requirements of §86.108 or 40 CFR part 1066, subpart B, unless we 

approve a different dynamometer based on excessive compliance costs. If you 

certify based on testing with a different dynamometer, you must state in the 

application for certification that all vehicles in the emission family will 

comply with emission standards if tested on an electric dynamometer. 

(B) Evaporative emission test. You may measure evaporative emissions as 

specified in this paragraph (a)(2)(ii)(B) to demonstrate compliance with the 

evaporative emission standards in 40 CFR part 86 instead of the otherwise 

specified procedures. Use measurement equipment for evaporative 

measurements specified in 40 CFR part 86, subpart B, except that the 

evaporative emission enclosure does not need to accommodate varying 

ambient temperatures. The evaporative measurement procedure is integral to 

the procedure for measuring exhaust emissions over the FTP driving cycle as 

described in paragraph (a)(ii)(2)(A) of this section. Perform canister 

preconditioning using the same procedure used by the original manufacturer 

to certify the vehicle; perform this canister loading before the initial 

preconditioning drive. Perform a diurnal emission test at the end of the 

stabilization period before the exhaust emission test by heating the fuel from 

60 to 84°F, either by exposing the vehicle to increasing ambient temperatures 

or by applying heat directly to the fuel tank. Measure hot soak emissions as 

described in 40 CFR 86.138-96(k). We may approve alternative measurement 

procedures that are equivalent to or more stringent than the specified 

procedures if the specified procedures are impractical for particular vehicle 

models or measurement facilities. The sum of the measured diurnal and hot 

soak values must meet the appropriate emission standard as specified in this 

section. 

(b) The emission standards applicable to nonconforming light-duty vehicles and lightduty trucks imported pursuant to this subpart are outlined in tables 1 and 2 of this section, 

respectively. The useful life as specified in tables 1 and 2 of this section is applicable to 

imported light-duty vehicles and light-duty trucks, respectively.

(c)(1) Nonconforming motor vehicles or motor vehicle engines of 1994 OP year and later 

conditionally imported pursuant to §85.1505 or §85.1509 shall meet all of the 

emission standards specified in 40 CFR part 86 for the OP year of the vehicle or 

motor vehicle engine. The useful life specified in 40 CFR part 86 for the OP year of 
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the motor vehicle or motor vehicle engine is applicable where useful life is not 

designated in this subpart.

(2)(i) Nonconforming light-duty vehicles and light light-duty trucks (LDV/LLDTs) 

originally manufactured in OP years 2004, 2005 or 2006 must meet the FTP 

exhaust emission standards of bin 9 in Tables S04–1 and S04–2 in 40 CFR 

86.1811–04 and the evaporative emission standards for light-duty vehicles and 

light light-duty trucks specified in 40 CFR 86.1811–01(e)(5).

(ii) Nonconforming LDT3s and LDT4s (HLDTs) and medium-duty passenger 

vehicles (MDPVs) originally manufactured in OP years 2004 through 2006 must 

meet the FTP exhaust emission standards of bin 10 in Tables S04–1 and S04–2 in 

40 CFR 86.1811–04 and the applicable evaporative emission standards specified 

in 40 CFR 86.1811–04(e)(5). For 2004 OP year HLDTs and MDPVs where 

modifications commence on the first vehicle of a test group before December 21, 

2003, this requirement does not apply to the 2004 OP year. ICIs opting to bring 

all of their 2004 OP year HLDTs and MDPVs into compliance with the exhaust 

emission standards of bin 10 in Tables S04–1 and S04–2 in 40 CFR 86.1811–04, 

may use the optional higher NMOG values for their 2004–2006 OP year LDT2s 

and 2004–2008 LDT4s.

(iii) Nonconforming LDT3s and LDT4s (HLDTs) and medium-duty passenger 

vehicles (MDPVs) originally manufactured in OP years 2007 and 2008 must meet 

the FTP exhaust emission standards of bin 8 in Tables S04–1 and S04–2 in 40 

CFR 86.1811–04 and the applicable evaporative standards specified in 40 CFR 

86.1811–04(e)(5).

(iv) Nonconforming LDV/LLDTs originally manufactured in OP years 2007 

through 2021 and nonconforming HLDTs and MDPVs originally manufactured in 

OP year 2009 through 2021 must meet the FTP exhaust emission standards of bin 

5 in Tables S04–1 and S04–2 in 40 CFR 86.1811–04, and the evaporative 

standards specified in 40 CFR 86.1811-04(e)(1) through (4).

(v) ICIs are exempt from the Tier 2 and the interim non-Tier2 phase-in 

intermediate percentage requirements for exhaust, evaporative, and refueling 

emissions described in 40 CFR 86.1811–04.

(vi) In cases where multiple standards exist in a given model year in 40 CFR part 

86 due to phase-in requirements of new standards, the applicable standards for 

motor vehicle engines required to be certified to engine-based standards are the 

least stringent standards applicable to the engine type for the OP year.

(vii) Nonconforming LDV/LLDTs originally manufactured in OP years 2009 

through 2021 must meet the evaporative emission standards in Table S09–1 in 40 

CFR 86.1811–09(e). However, LDV/LLDTs originally manufactured in OP years 

2009 and 2010 and imported by ICIs who qualify as small-volume manufacturers 

as defined in 40 CFR 86.1838–01 are exempt from the LDV/LLDT evaporative 

emission standards in Table S09–1 in 40 CFR 86.1811–09(e), but must comply

with the Tier 2 evaporative emission standards in Table S04–3 in 40 CFR 

86.1811–04(e).

(viii) Nonconforming HLDTs and MDPVs originally manufactured in OP years 

2010 through 2021 must meet the evaporative emission standards in Table S09–1 

in 40 CFR 86.1811–09(e). However, HLDTs and MDPVs originally 
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manufactured in OP years 2010 and 2011 and imported by ICIs, who qualify as 

small-volume manufacturers as defined in 40 CFR 86.1838–01, are exempt from 

the HLDTs and MDPVs evaporative emission standards in Table S09–1 in 40 

CFR 86.1811–09(e), but must comply with the Tier 2 evaporative emission 

standards in Table S04–3 in 40 CFR 86.1811–04(e).

(ix) Nonconforming LDVs, LDTs, MDPVs, and complete heavy-duty vehicles at 

or below 14,000 pounds GVWR originally manufactured in OP years 2022 and 

later must meet the Tier 3 exhaust and evaporative emission standards in 40 CFR 

86.1811-17, 86.1813-17, and 86.1816-18.

(3)(i) As an option to the requirements of paragraph (c)(2) of this section, 

independent commercial importers may elect to meet lower bins in Tables S04–1 

and S04–2 of 40 CFR 86.1811–04 than specified in paragraph (c)(2) of this 

section and bank or sell NOx credits as permitted in 40 CFR 86.1860–04 and 40 

CFR 86.1861–04. An ICI may not meet higher bins in Tables S04–1 and S04–2 of 

40 CFR 86.1811–04 than specified in paragraph (c)(2) of this section unless it 

demonstrates to the Administrator at the time of certification that it has obtained 

appropriate and sufficient NOx credits from another manufacturer, or has 

generated them in a previous model year or in the current model year and not 

transferred them to another manufacturer or used them to address other vehicles 

as permitted in 40 CFR 86.1860–04 and 40 CFR 86.1861–04.

(ii) Where an ICI desires to obtain a certificate of conformity using a bin higher 

than specified in paragraph (c)(2) of this section, but does not have sufficient 

credits to cover vehicles produced under such certificate, the Administrator may

issue such certificate if the ICI has also obtained a certificate of conformity for 

vehicles certified using a bin lower than that required under paragraph (c)(2) of 

this section. The ICI may then produce vehicles to the higher bin only to the 

extent that it has generated sufficient credits from vehicles certified to the lower 

bin during the same model year.

(4) [Reserved]

(5) Except for the situation where an ICI desires to bank, sell or use NOx credits as 

described in paragraph (c)(3) of this section, the requirements of 40 CFR 86.1811–04 

related to fleet average NOx standards and requirements to comply with such 

standards do not apply to vehicles modified under this subpart.

(6) ICIs using bins higher than those specified in paragraph (c)(2) of this section must 

monitor their production so that they do not produce more vehicles certified to the 

standards of such bins than their available credits can cover. ICIs must not have a 

credit deficit at the end of a model year and are not permitted to use the deficit 

carryforward provisions provided in 40 CFR 86.1860–04(e).

(7) The Administrator may condition the certificates of conformity issued to ICIs as 

necessary to ensure that vehicles subject to paragraph (c) of this section comply with 

the appropriate average NOx standard for each model year.

(8)(i) Nonconforming LDV/LLDTs originally manufactured in OP years 2010 and 

later must meet the cold temperature NHMC emission standards in Table S10–1 

in 40 CFR 86.1811–10(g).
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(ii) Nonconforming HLDTs and MDPVs originally manufactured in OP years 

2012 and later must meet the cold temperature NHMC emission standards in 

Table S10–1 in 40 CFR 86.1811–10(g).

(iii) ICIs, which qualify as small-volume manufacturers, are exempt from the cold 

temperature NMHC phase-in intermediate percentage requirements described in 

40 CFR 86.1811–10(g)(3). See 40 CFR 86.1811–04(k)(5)(vi) and (vii).

(iv) As an alternative to the requirements of paragraphs (c)(8)(i) and (ii) of this 

section, ICIs may elect to meet a cold temperature NMHC family emission level 

below the cold temperature NMHC fleet average standards specified in Table 

S10–1 of 40 CFR 86.1811–10 and bank or sell credits as permitted in 40 CFR 

86.1864–10. An ICI may not meet a higher cold temperature NMHC family 

emission level than the fleet average standards in Table S10–1 of 40 CFR 

86.1811–10 as specified in paragraphs (c)(8)(i) and (ii) of this section, unless it 

demonstrates to the Administrator at the time of certification that it has obtained 

appropriate and sufficient NMHC credits from another manufacturer, or has 

generated them in a previous model year or in the current model year and not 

traded them to another manufacturer or used them to address other vehicles as 

permitted in 40 CFR 86.1864–10.

(v) Where an ICI desires to obtain a certificate of conformity using a higher cold 

temperature NMHC family emission level than specified in paragraphs (c)(8)(i) 

and (ii) of this section, but does not have sufficient credits to cover vehicles 

imported under such certificate, the Administrator may issue such certificate if the 

ICI has also obtained a certificate of conformity for vehicles certified using a cold 

temperature NMHC family emission level lower than that required under 

paragraphs (c)(8)(i) and (ii) of this section. The ICI may then import vehicles to 

the higher cold temperature NMHC family emission level only to the extent that it 

has generated sufficient credits from vehicles certified to a family emission level 

lower than the cold temperature NMHC fleet average standard during the same 

model year.

(vi) ICIs using cold temperature NMHC family emission levels higher than the 

cold temperature NMHC fleet average standards specified in paragraphs (c)(8)(i) 

and (ii) of this section must monitor their imports so that they do not import more 

vehicles certified to such family emission levels than their available credits can 

cover. ICIs must not have a credit deficit at the end of a model year and are not 

permitted to use the deficit carryforward provisions provided in 40 CFR 86.1864–

10.

(vii) The Administrator may condition the certificates of conformity issued to 

ICIs as necessary to ensure that vehicles subject to this paragraph (c)(8) comply

with the applicable cold temperature NMHC fleet average standard for each 

model year.

(d) Except as provided in paragraph (c) of this section, ICI's must not participate in 

emission-related programs for emissions averaging, banking and trading, or 

nonconformance penalties.
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Table 1 to §85.1515—Emission Standards Applicable to Imported Light-Duty Motor 

Vehicles1,2,3

OP 

Year

Hydrocarbon Carbon

monoxide

Oxides of 

nitrogen

Diesel 

Particulate

Evaporative 

hydrocarbon

Useful life 

(years/miles)

1968–

76

1.5 gpm 15 gpm 3.1 gpm 6.0 g/test 5/50,000

1977–

79

1.5 gpm 15 gpm 2.0 gpm 6.0 g/test 5/50,000

1980 0.41 gpm 7.0 gpm 2.0 gpm 6.0 g/test 5/50,000

1981 0.41 gpm 3.4 gpm 1.0 gpm 2.0 g/test 5/50,000

1982–

86

0.41 gpm 3.4 gpm 1.0 gpm 0.60 gpm 2.0 g/test 5/50,000

1987–

93

0.41 gpm 3.4 gpm 1.0 gpm 0.20 gpm 2.0 g/test 5/50,000

1994 

and 

later

(

4

) (

4

) (

4

) (

4

) (

4

) (

4

)

1Diesel particulate standards apply only to diesel fueled light-duty vehicles. Evaporative hydrocarbon standards 

apply only to non-diesel fueled light-duty vehicles. For alternative fueled light-duty vehicles, the evaporative 

hydrocarbon standard is interpreted as organic material hydrocarbon equivalent grams carbon per test, as 

applicable.

2No crankcase emissions shall be discharged into the ambient atmosphere from any non-diesel fueled light-duty

vehicle.

3All light-duty vehicles shall meet the applicable emission standards at both low and high-altitudes according to 

the procedures specified in 40 CFR part 86 for current model year motor vehicles at the time of testing.

4

Specified in 40 CFR part 86 for the OP year of the vehicle, as described in paragraph (c) of this section.
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Table 2 to §85.1515—Emission Standards Applicable to Imported Light-Duty Trucks1,2,3,4,5

OP year Hydrocarbon Carbon 

monoxide

Oxides 

of 

nitrogen

Diesel 

Particulate

Evaporative 

hydrocarbon

Useful life 

(years/miles)

1968–78 2.0 gpm 20 gpm 3.1 gpm 6.0 g/test 5/50,000

1979–80 1.7 gpm 18 gpm 2.3 gpm 6.0 g/test 5/50,000

1981 1.7 gpm 18 gpm 2.3 gpm 2.0 g/test 5/50,000

1982–83 1.7 gpm

(2.0)

18 gpm

(26)

2.3 gpm

(2.3)

0.60 gpm

(0.60)

2.0 g/test

(2.6)

5/50,000

1984 0.80 gpm

(1.0)

10 gpm

(14)

2.3 gpm

(2.3)

0.60 gpm

(0.60)

2.0 g/test

(2.6)

5/50,000

1985–86 0.80 gpm

(1.0)

10 gpm

(14)

2.3 gpm

(2.3)

0.60 gpm

(0.60)

2.0 g/test

(2.6)

11/120,000

1987 0.80 gpm

(1.0)

10 gpm

(14)

2.3 gpm

(2.3)

0.26 gpm

(0.26)

2.0 g/test

(2.6)

11/120,000

1988–89 0.80 gpm

(1.0)

10 gpm

(14)

1.2 gpm6

(1.2)

0.26 gpm7

(2.0)

2.0 g/test

(2.6)

11/120,000

 1988–89 0.80 gpm

(1.0)

10 gpm

(14)

1.7 gpm6

(1.7)

0.45 gpm7

(0.26)

2.0 g/test

(2.6)

11/120,000

 1988–89 0.80 gpm

(1.0)

10 gpm

(14)

2.3 gpm6

(2.3)

0.45 gpm7

(0.26)

2.0 g/test

(2.6)

11/120,000

1990–93 0.80 gpm

(1.0)

10 gpm

(14)

1.2 gpm8

(1.2)

0.26 gpm7

(0.26)

2.0 g/test

(2.6)

11/120,000

 0.80 gpm

(1.0)

10 gpm

(14)

1.7 gpm8

(1.7)

0.45 gpm7

(0.26)

2.0 g/test

(2.6)

11/120,000

1994 and 

later

(

9

) (

9

) (

9

) (

9

) (

9

) (

9

)

1Diesel particulate standards apply only to diesel fueled light-duty trucks. Evaporative hydrocarbon standards 

apply only to non-diesel fueled light-duty trucks. For alternative fueled light-duty trucks, the evaporative 

hydrocarbon standard is interpreted as organic material hydrocarbon equivalent grams carbon per test, as 

applicable.

2No crankcase emissions shall be discharged into the ambient atmosphere from any non-diesel fueled light-duty

truck.

3A carbon monoxide standard of 0.50% of exhaust flow at curb idle is applicable to all 1984 and later model year 

light-duty trucks sold to, or owned by, an importer for principal use at other than a designated high-altitude 

location. This requirement is effective for light-duty trucks sold to, or owned by an importer for principal use at a 

designated high-altitude location beginning with the 1988 model year.

4All 1982 OP year and later light-duty trucks sold to, or owned by, an importer for principal use at a designated 

high-altitude location shall meet high-altitude emission standards according to the requirements specified in 40 

CFR part 86 for current model year light-duty trucks at the time of testing.

5

Standards in parentheses apply to motor vehicles sold to, or owned by, an importer for principal use at a 

designated high-altitude location. These standards must be met at high-altitude according to the procedures 

specified in 40 CFR part 86 for current model year motor vehicles at the time of testing.

6The oxides of nitrogen standard of 1.2 gpm applies to light-duty trucks at or below 3,750 pounds loaded vehicle 

weight and at or below 6,000 pounds GVWR. The 1.7 gpm standard applies to light-duty trucks above 3,750 

pound loaded vehicle weight and at or below 6,000 pounds GVWR; the 2.3 gpm standard applies to light-duty

trucks above 6,000 pounds GVWR.

7The diesel particulate standard of 0.26 gpm applies to light-duty trucks at or below 3,750 pounds loaded vehicle 

weight; the 0.45 gpm standard applies to light-duty trucks above 3,750 pounds loaded vehicle weight.

8The NOx standard of 1.2 gpm applies to light-duty trucks at or below 3,750 pounds loaded vehicle weight; the 

1.7 gpm standard applies to light-duty trucks above 3,750 pounds loaded vehicle weight.

9

Specified in 40 CFR part 86 for the OP year of the vehicle, as described in paragraph (c) of this section.
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54. Subpart W, is revised to consist of §§ 85.2201, 85.2207, 85.2222, 85.2223, and 

85.2231, to read as follows:

Subpart W—Emission Control System Performance Warranty Short Tests

Sec.

85.2201 Applicability. 

85.2207 Onboard diagnostic test standards.

85.2222 Onboard diagnostic test procedures.

85.2223 Onboard diagnostic test report.

85.2231 Onboard diagnostic test equipment requirements.

Subpart W—Emission Control System Performance Warranty Short Tests

§ 85.2201 Applicability. 

(a) This subpart describes the test provisions to be employed in conjunction with the 

Emissions Performance Warranty in subpart V of this part. These provisions generally 

rely on a vehicle’s onboard diagnostic system (OBD) to indicate whether a vehicle passes 

or fails the test.

(b) The provisions of this subpart may be used to establish warranty eligibility for lightduty vehicles, light-duty trucks, and medium-duty passenger vehicles when tested during 

the useful life as prescribed in subpart V of this part.

§ 85.2207 Onboard diagnostic test standards.

(a) A vehicle shall fail the OBD test if it is a 1996 or newer vehicle and the vehicle 

connector is missing, has been tampered with, or is otherwise inoperable.

(b) A vehicle shall fail the OBD test if the malfunction indicator light (MIL) is 

commanded to be illuminated and it is not visually illuminated according to visual 

inspection.

(c) A vehicle shall fail the OBD test if the MIL is commanded to be illuminated for one 

or more diagnostic trouble codes (DTCs), as described in 40 CFR 86.1806. 

§ 85.2222 Onboard diagnostic test procedures.

The test sequence for the OBD inspection shall consist of the following steps:

(a) The OBD inspection shall be conducted with the key-on/engine running, with the 

exception of inspecting for MIL illumination as required in paragraph (d)(4) of this 

section, during which the inspection shall be conducted with the key-on/engine off.

(b) The inspector shall locate the vehicle connector and plug the test system into the 

connector.

(c) The test system shall send a Mode $01, PID $01 request in accordance with 40 CFR 

86.1806 to determine the OBD evaluation status. The test system shall determine what 

monitors are supported by the OBD system, and perform the readiness evaluation for 

applicable monitors in accordance with the requirements and specifications in 40 CFR 

86.1806.

(1) Coincident with the beginning of mandatory testing, repair, and retesting based 

upon the OBD test, if the readiness evaluation indicates that any onboard tests are not 

complete, the customer shall be instructed to return after the vehicle has been run 

under conditions that allow completion of all applicable onboard tests. If the 
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readiness evaluation again indicates that any onboard test is not complete, the vehicle 

shall be failed.

(2) An exception to paragraph (c)(1) of this section is allowed for MY 1996 to MY 

2000 vehicles, inclusive, with two or fewer unset readiness monitors, and for MY 

2001 and newer vehicles with no more than one unset readiness monitor. Vehicles 

from those model years which would otherwise pass the OBD inspection, but for the 

unset readiness code in question, may be issued a passing certificate without being 

required to operate the vehicle in such a way as to activate those particular monitors. 

Vehicles from those model years with an unset readiness code that also have a DTC 

stored resulting in an illuminated MIL must be failed, though setting the unset 

readiness flag in question shall not be a prerequisite for passing the retest.

(d) The test system shall evaluate the MIL status bit and record status information in the 

vehicle test record.

(1) If the MIL status bit indicates that the MIL has been commanded to be 

illuminated, the test system shall send a Mode $03 request in accordance with 40 

CFR 86.1806 to determine the stored DTCs. The system shall repeat this cycle until 

the number of codes reported equals the number expected based on the Mode $01 

response. All DTCs resulting in MIL illumination shall be recorded in the vehicle test 

record and the vehicle shall fail the OBD inspection.

(2) If the MIL bit is not commanded to be illuminated the vehicle shall pass the OBD 

inspection, even if DTCs are present.

(3) If the MIL bit is commanded to be illuminated, the inspector shall visually inspect 

the MIL to determine if it is illuminated. If the MIL is commanded to be illuminated 

but is not, the vehicle shall fail the OBD inspection.

(4) If the MIL does not illuminate at all when the vehicle is in the key-on/engine-off 

condition, the vehicle shall fail the OBD inspection, even if no DTCs are present and 

the MIL has not been commanded on.

§ 85.2223 Onboard diagnostic test report.

(a) Motorists whose vehicles fail the OBD test described in §85.2222 shall be provided 

with the OBD test results, including the codes retrieved, the name of the component or 

system associated with each DTC, the status of the MIL illumination command, and the 

customer alert statement as stated in paragraph (b) of this section.

(b) In addition to any codes that were retrieved, the test report shall include the following 

language:

Your vehicle's computerized self-diagnostic system (OBD) registered the faults listed below. 

The faults are probably an indication of a malfunction of an emission component. However, 

multiple and/or seemingly unrelated faults may be an indication of an emission-related 

problem that occurred previously, but upon further evaluation by the OBD system was 

determined to be only temporary. Therefore, proper diagnosis by a qualified technician is 

required to positively identify the source of any emission-related problem.

§ 85.2231 Onboard diagnostic test equipment requirements.

(a) The test system interface to the vehicle shall include a plug that conforms to the 

requirements and specifications of 40 CFR 86.1806. 

(b) The test system shall be capable of communicating with the standard data link 

connector of vehicles with certified OBD systems.
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(c) The test system shall be capable of checking for OBD monitors and the evaluation 

status of supported monitors (test complete/test not complete) in Mode $01 PID $01, as 

well as be able to request the DTCs, consistent with the requirements and specifications 

of 40 CFR 86.1806. 

Part 86— Control of Emissions from New and In-use Highway Vehicles and Engines

55. The authority citation for part 86 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

56. Section 86.1 is revised to read as follows:

§ 86.1 Incorporation by reference.

(a) Certain material is incorporated by reference into this part with the approval of the 

Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. To enforce any 

edition other than that specified in this section, a document must be published in the 

Federal Register and the material must be available to the public. All approved material is 

available for inspection at U.S. EPA, Air and Radiation Docket and Information Center, 

1301 Constitution Ave., NW., Room B102, EPA West Building, Washington, DC 20460, 

(202) 202-1744, and is available from the sources listed below. It is also available for 

inspection at the National Archives and Records Administration (NARA). For information

on the availability of this material at NARA, call 202–741–6030, or go to

http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(b) ASTM International material. The following standards are available from ASTM 

International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA, 19428-

2959, (610) 832-9585, or http://www.astm.org/:

(1) ASTM C1549-09, Standard Test Method for Determination of Solar Reflectance 

Near Ambient Temperature Using a Portable Solar Reflectometer, approved August 

1, 2009, IBR approved for § 86.1869-12(b).

(2) ASTM D86-12, Standard Test Method for Distillation of Petroleum Products at 

Atmospheric Pressure, approved December 1, 2012, IBR approved for §§ 86.113-

04(a), 86.113-94(b), 86.213(a), and 86.513(a).

(3) ASTM D93-13, Standard Test Methods for Flash Point by Pensky- Martens 

Closed Cup Tester, approved July 15, 2013, IBR approved for §86.113-94(b).

(4) ASTM D445-12, Standard Test Method for Kinematic Viscosity of Transparent 

and Opaque Liquids (and Calculation of Dynamic Viscosity), approved April 15, 

2012, IBR approved for §86.113-94(b).

(5) ASTM D613-13, Standard Test Method for Cetane Number of Diesel Fuel Oil, 

approved December 1, 2013, IBR approved for §86.113-94(b).

(6) ASTM D975-13a, Standard Specification for Diesel Fuel Oils, approved 

December 1, 2013, IBR approved for § 86.1910(c).

(7) ASTM D976-06 (Reapproved 2011), Standard Test Method for Calculated Cetane 

Index of Distillate Fuels, approved October 1, 2011, IBR approved for §86.114-94(b).

(8) ASTM D1319-13, Standard Test Method for Hydrocarbon Types in Liquid 

Petroleum Products by Fluorescent Indicator Adsorption, approved May 1, 2013, IBR 

approved for §§ 86.113-04(a), 86.213(a), and 86.513(a).
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(9) ASTM D1945-03 (reapproved 2010), Standard Test Method for Analysis of 

Natural Gas by Gas Chromatography, approved January 1, 2010, IBR approved for 

§§ 86.113-94(e) and 86.513(d).

(10) ASTM D2163-07, Standard Test Method for Determination of Hydrocarbons in

Liquefied Petroleum (LP) Gases and Propane/Propene Mixtures by Gas 

Chromatography, approved December 1, 2007, IBR approved for §§ 86.113-94(f).

(11) ASTM D2622-10, Standard Test Method for Sulfur in Petroleum Products by

Wavelength Dispersive X-ray Fluorescence Spectrometry, approved February 15, 

2010, IBR approved for §§ 86.113-04(a), 86.113-94(b), 86.213(a), and 86.513(a).

(12) ASTM D2699-13b, Standard Test Method for Research Octane Number of 

Spark-Ignition Engine Fuel, approved October 1, 2013, IBR approved for §§ 86.113-

04(a) and 86.213(a).

(13) ASTM D2700-13b, Standard Test Method for Motor Octane Number of SparkIgnition Engine Fuel, approved October 1, 2013, IBR approved for §§ 86.113-04(a)

and 86.213(a).

(14) ASTM D3231-13, Standard Test Method for Phosphorus in Gasoline, approved 

June 15, 2013, IBR approved for §§ 86.113-04(a), 86.213(a), and 86.513(a).

(15) ASTM D3237-12, Standard Test Method for Lead in Gasoline By Atomic 

Absorption Spectroscopy, approved June 1, 2012, IBR approved for §§ 86.113-04(a),

86.213(a), and 86.513(a).

(16) ASTM D4052-11, Standard Test Method for Density, Relative Density, and API 

Gravity of Liquids by Digital Density Meter, approved October 15, 2011, IBR 

approved for §86.113-94(b).

(17) ASTM D5186-03 (Reapproved 2009), Standard Test Method for Determination 

of the Aromatic Content and Polynuclear Aromatic Content of Diesel Fuels and 

Aviation Turbine Fuels By Supercritical Fluid Chromatography, approved April 15, 

2009, IBR approved for § 86.113-94(b).

(18) ASTM D5191-13, Standard Test Method for Vapor Pressure of Petroleum 

Products (Mini Method), approved December 1, 2013, IBR approved for §§ 86.113-

04(a), 86.213(a), and 86.513(a).

(19) ASTM E29-93a, Standard Practice for Using Significant Digits in Test Data to 

Determine Conformance with Specifications, approved March 15, 1993, IBR 

approved for §§ 86.004-15(c), 86.007-11(a), 86.007-15(m), 86.1803-01, 86.1823-

01(a), 86.1824-01(c), 86.1825-01(c).

(20) ASTM E903-96, Standard Test Method for Solar Absorptance, Reflectance, and 

Transmittance of Materials Using Integrating Spheres, approved April 10, 1996, IBR 

approved for § 86.1869-12(b).

(21) ASTM E1918-06, Standard Test Method for Measuring Solar Reflectance of 

Horizontal and Low-Sloped Surfaces in the Field, approved August 15, 2006, IBR 

approved for § 86.1869-12(b).

(c) ANSI material. The following standards are available from American National 

Standards Institute, 25 W 43rd Street, 4th Floor, New York, NY 10036, (212) 642-4900,

or http://www.ansi.org:

(1) ANSI NGV1-2006, Standard for Compressed Natural Gas Vehicle (NGV) Fueling 

Connection Devices, 2

nd edition, reaffirmed and consolidated March 2, 2006, IBR 

approved for §86.1813-17(f).
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(2) [Reserved]

(d) California Air Resources Board. The following documents are available from the 

California Air Resources Board, 1001 I Street, Sacramento, CA, 95812, (916) 322–2884, 

or http://www.arb.ca.gov:

(1) California Requirements Applicable to the LEV III Program, including the 

following documents:

(i) LEV III exhaust emission standards are in Title 13 Motor Vehicles, Division 3 

Air Resources Board, Chapter 1 Motor Vehicle Pollution Control Devices, Article 

2 Approval of Motor Vehicle Pollution Control Devices (New Vehicles), §1961.2 

Exhaust Emission Standards and Test Procedures – 2015 and Subsequent Model 

Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles, effective as of 

December 31, 2012, IBR approved for §86.1803-01.

(ii) LEV III evaporative emission standards for model year 2015 and later 

vehicles are in Title 13 Motor Vehicles, Division 3 Air Resources Board, Chapter 

1 Motor Vehicle Pollution Control Devices, Article 2 Approval of Motor Vehicle 

Pollution Control Devices (New Vehicles) §1976 Standards and Test Procedures 

for Motor Vehicle Fuel Evaporative Emissions, effective as of December 31, 

2012, IBR approved for §86.1803-01.

(2) California Regulatory Requirements Applicable to the National Low Emission 

Vehicle Program, October 1996, IBR approved for § 86.113–04(a).

(3) California Regulatory Requirements known as Onboard Diagnostics II (OBD–II), 

Approved on April 21, 2003, Title 13, California Code of Regulations, Section 

1968.2, Malfunction and Diagnostic System Requirements for 2004 and Subsequent 

Model-Year Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and 

Engines (OBD–II), IBR approved for § 86.1806–05(j).

(4) California Regulatory Requirements known as Onboard Diagnostics II (OBD–II), 

Approved on November 9, 2007, Title 13, California Code of Regulations, Section 

1968.2, Malfunction and Diagnostic System Requirements for 2004 and Subsequent 

Model-Year Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and 

Engines (OBD–II), IBR approved for § 86.1806–05(j).

(5) California Regulatory Requirements known as Onboard Diagnostics II (OBD-II), 

Title 13, Motor Vehicles, Division 3, Air Resources Board, Chapter 1, Motor Vehicle 

Pollution Control Devices, Article 2, Approval of Motor Vehicle Pollution Control 

Devices (New Vehicles), §1968.2 Malfunction and Diagnostic System Requirements 

– 2004 and Subsequent Model-Year Passenger Cars, Light-Duty Trucks, and 

Medium-Duty Vehicles and Engines, effective as of July 31, 2013, IBR approved for 

§ 86.1806-17(a).

(e) ISO material. The following standards are available from International Organization 

for Standardization, Case Postale 56, CH-1211 Geneva 20, Switzerland, 41-22-749-01-

11, or http://www.iso.org:

(1) ISO 15765-4:2005(E), Road Vehicles—Diagnostics on Controller Area Networks 

(CAN)—Part 4: Requirements for emissions-related systems, January 15, 2005, IBR 

approved for §§ 86.010-18(k) and 86.1806-05(h).

(2) ISO 13837:2008(E), Road Vehicles—Safety glazing materials—Method for the 

determination of solar transmittance, First edition, April 15, 2008, IBR approved for 

§ 86.1869-12(b).
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(f) NIST material. The following documents are available from National Institute of 

Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, or

http://www.nist.gov:

(1) NIST Special Publication 811, 2008 Edition, Guide for the Use of the 

International System of Units (SI), March 2008, IBR approved for § 86.1901(d).

(2) [Reserved]

(g) SAE International material. The following standards are available from SAE 

International, 400 Commonwealth Dr., Warrendale, PA 15096-0001, (877) 606-7323 

(U.S. and Canada) or (724) 776-4970 (outside the U.S. and Canada), or

http://www.sae.org:

(1) SAE J1151, Methane Measurement Using Gas Chromatography, stabilized 

September 2011, IBR approved for § 86.111-94(b).(2) SAE J1349, Engine Power 

Test Code—Spark Ignition and Compression Ignition—As Installed Net Power 

Rating, revised September 2011, IBR approved for § 86.1803-01.

(3) SAE J1850, Class B Data Communication Network Interface, Revised May 2001, 

IBR approved for § 86.1806-05(h).

(4) SAE J1877, Recommended Practice for Bar-Coded Vehicle Identification Number 

Label, July 1994, IBR approved for § 86.095-35(i).

(5) SAE J1892, Recommended Practice for Bar-Coded Vehicle Emission 

Configuration Label, October 1993, IBR approved for § 86.095-35(i).

(6) SAE J1930, Electrical/Electronic Systems Diagnostic Terms, Definitions, 

Abbreviations, and Acronyms, Revised May 1998, IBR approved for §§ 86.1808-

01(f), 86.1808-07(f).

(7) SAE J1930, Electrical/Electronic Systems Diagnostic Terms, Definitions, 

Abbreviations, and Acronyms—Equivalent to ISO/TR 15031-2: April 30, 2002, 

Revised April 2002, IBR approved for §§ 86.010-18(k) and 86.1806-05(h).

(8) SAE J1939, Recommended Practice for a Serial Control and Communications 

Vehicle Network, Revised October 2007, IBR approved for § 86.010-18(k).

(9) SAE J1939-11, Physical Layer—250K bits/s, Shielded Twisted Pair, Revised 

October 1999, IBR approved for § 86.1806-05(h).

(10) SAE J1939-13, Off-Board Diagnostic Connector, July 1999, IBR approved for 

§ 86.1806-05(h).

(11) SAE J1939-13, Off-Board Diagnostic Connector, Revised March 2004, IBR 

approved for § 86.010-18(k).

(12) SAE J1939-21, Data Link Layer, Revised April 2001, IBR approved for 

§ 86.1806-05(h).

(13) SAE J1939-31, Network Layer, Revised December 1997, IBR approved for 

§ 86.1806-05(h).

(14) SAE J1939-71, Vehicle Application Layer (Through February 2007), Revised 

January 2008, IBR approved for §§ 86.010-38(j) and 86.1806-05(h).

(15) SAE J1939-73, Application Layer—Diagnostics, Revised September 2006, IBR 

approved for §§ 86.010-18(k), 86.010-38(j), and 86.1806-05(h).

(16) SAE J1939-81, Network Management, Revised May 2003, IBR approved for 

§§ 86.010-38(j) and 86.1806-05(h).

(17) SAE J1962, Diagnostic Connector Equivalent to ISO/DIS 15031-3; December 

14, 2001, Revised April 2002, IBR approved for §§ 86.010-18(k) and 86.1806-05(h).
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(18) SAE J1978, OBD II Scan Tool—Equivalent to ISO/DIS 15031-4; December 14, 

2001, Revised April 2002, IBR approved for §§ 86.010-18(k) and 86.1806-05(h).

(19) SAE J1979, E/E Diagnostic Test Modes, Revised September 1997, IBR 

approved for §§ 86.1808-01(f) and 86.1808-07(f).

(20) SAE J1979, (R) E/E Diagnostic Test Modes, Revised May 2007, IBR approved 

for §§ 86.010-18(k) and 86.1806-05(h).

(21) SAE J2012, (R) Diagnostic Trouble Code Definitions Equivalent to ISO/DIS 

15031-6: April 30, 2002, Revised April 2002, IBR approved for §§ 86.010-18(k) and

86.1806-05(h).

(22) SAE J2064 FEB2011, R134a Refrigerant Automotive Air-Conditioned Hose, 

Revised February 2011, IBR approved for § 86.1867-12(a) and (b).

(23) SAE J2284-3, High Speed CAN (HSC) for Vehicle Applications at 500 KBPS, 

May 2001, IBR approved for §§ 86.1808-01(f) and 86.1808-07(f).

(24) SAE J2403, Medium/Heavy-Duty E/E Systems Diagnosis Nomenclature—Truck 

and Bus, Revised August 2007, IBR approved for §§ 86.010-18(k), 86.010-38(j), and

86.1806-05(h).

(25) SAE J2534, Recommended Practice for Pass-Thru Vehicle Programming, 

February 2002, IBR approved for §§ 86.1808-01(f) and 86.1808-07(f).

(26) SAE J2727 FEB2012, Mobile Air Conditioning System Refrigerant Emission 

Charts for R-134a and R-1234yf, Revised February 2012, IBR approved for 

§ 86.1867-12(a) and (b).

(27) SAE J2765 OCT2008, Procedure for Measuring System COP [Coefficient of 

Performance] of a Mobile Air Conditioning System on a Test Bench, issued October 

2008, IBR approved for § 86.1868-12(h).

(h) Truck and Maintenance Council material. The following documents are available 

from the Truck and Maintenance Council, 950 North Glebe Road, Suite 210, Arlington, 

VA 22203-4181, or (703) 838-1754:

(1) TMC RP 1210B, Revised June 2007, WINDOWSTMCOMMUNICATION API, 

IBR approved for § 86.010-38(j).

(2) [Reserved]

Subpart A—[Amended]

57. Section 86.000-7 is amended as follows:

a. By revising the introductory text.

b. By removing and reserving paragraph (h)(1).

c. By revising paragraph (h)(6).

d. By removing paragraph (h)(7).

§ 86.000-7 Maintenance of records; submittal of information; right of entry.

Section 86.000–7 includes text that specifies requirements that differ from §86.091–7 or 

§86.094–7. Where a paragraph in §86.091–7 or §86.094–7 is identical and applicable to 

§86.000–7, this may be indicated by specifying the corresponding paragraph and the 

statement “[Reserved]. For guidance see §86.091–7.” or “[Reserved]. For guidance see 

§86.094–7.”

* * * * *

(h) * * *
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(6) EPA may void ab initio a certificate for a vehicle certified to Tier 1 certification 

standards or to the respective evaporative and/or refueling test procedure and 

accompanying evaporative and/or refueling standards as set forth or otherwise referenced 

in §86.098–10 for which the manufacturer fails to retain the records required in this 

section or to provide such information to the Administrator upon request.

* * * * *

§§86.000-8, 86.000-9, 86.000-16 [Removed]

58. Remove §§86.000-8, 86.000-9, and 86.000-16.

§86.000-24—[Amended]

59. Section 86.000-24 is amended as follows:

a. By removing the introductory text.

b. By removing and reserving paragraphs (a), (b)(1) introductory text, and (b)(1)(iii) 

through (f).

c. By removing and reserving paragraphs (g)(1) and (g)(2).

d. By removing paragraph (h).

§§86.000-26, 86.000-28, 86.001-9, 86.001-22 [Removed]

60. Remove §§86.000-26, 86.000-28, 86.001-9, and 86.001-22.

61. Section 86.001-23 is amended by revising the introductory text and adding a heading 

to paragraph (c), and removing and reserving paragraphs (c)(1), (f), and (g) to read as 

follows:

§ 86.001-23 Required data.

Section 86.001–23 includes text that specifies requirements that differ from §86.098–23. 

Where a paragraph in §86.098–23 is identical and applicable to §86.001–23, this may be 

indicated by specifying the corresponding paragraph and the statement “[Reserved]. For 

guidance see §86.098–23.”

* * * * *

(c) Emission data —

* * * * *

§§86.001-25, 86.001-26, 86.001-28, 86.001-30, 86.004-9 [Removed]

62. Remove §§86.001-25, 86.001-26, 86.001-28, 86.001-30, and 86.004-9.

63. Section 86.004-11 is amended by revising paragraphs (b)(3) introductory text and 

(b)(4) introductory text and adding paragraph (b)(4)(iv) to read as follows:

§ 86.004-11 Emission standards for 2004 and later model year diesel heavy-duty 

engines and vehicles.

* * * * *

(b) * * *

(3) This paragraph (b)(3) applies as specified in 40 CFR 1037.103. Evaporative 

emissions (total of non-oxygenated hydrocarbons plus methanol) from heavy-duty 

vehicles equipped with methanol-fueled diesel engines shall not exceed the following 

standards. The standards apply equally to certification and in-use vehicles. The spitback 

standard also applies to newly assembled vehicles.
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* * * * *

(4) This paragraph (b)(4) applies as specified in 40 CFR 1037.103. Evaporative 

emissions from 2004 and later model year heavy-duty vehicles equipped with natural gasfueled or liquefied petroleum gas-fueled HDEs shall not exceed the following standards. 

The standards apply equally to certification and in-use vehicles.

* * * * *

(iv) Compressed natural gas vehicles must meet the requirements for fueling connection 

devices as specified in §86.1813-17(f)(1). Vehicles meeting these requirements are 

deemed to comply with evaporative emission standards.

* * * * *

64. Section 86.004-21 is amended as follows:

a. By revising the introductory text

b. By removing and reserving paragraph (b)(4)(i).

c. By removing paragraph (b)(5)(v).

d. By removing and reserving paragraphs (k) and (l).

§ 86.004-21 Application for certification.

Section 86.004–21 includes text that specifies requirements that differ from §86.094–21. 

Where a paragraph in §86.094–21 is identical and applicable to §86.004–21, this may be 

indicated by specifying the corresponding paragraph and the statement “[Reserved]. For 

guidance see §86.094–21.”

* * * * *

§86.004-25—[Amended]

65. Section 86.004-25 is amended by removing and reserving paragraphs (b)(4)(ii) and 

(b)(4)(iv).

66. Section 86.004-26 is amended as follows:

a. By removing the introductory text.

b. By removing and reserving paragraphs (a) and (b).

c. By revising paragraph (d).

§86.004-26 Mileage and service accumulation; emission measurements.

* * * * *

(d)(1) This paragraph (d) applies for heavy-duty engines.

(2)(i) The results of all emission testing shall be supplied to the Administrator. The 

manufacturer shall furnish to the Administrator explanation for voiding any test. 

The Administrator will determine if voiding the test was appropriate based upon 

the explanation given by the manufacturer for the voided test. Tests between test 

points may be conducted as required by the Administrator. Data from all tests 

(including voided tests) may be submitted weekly to the Administrator, but shall 

be delivered to the Administrator within 7 days after completion of the test. In 

addition, all test data shall be compiled and provided to the Administrator in 

accordance with §86.007–23. Where the Administrator conducts a test on a 

durability data vehicle at a prescribed test point, the results of that test will be 

used in the calculation of the deterioration factor.
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(ii) The results of all emission tests shall be recorded and reported to the 

Administrator. These test results shall be rounded as specified in 40 CFR part 

1065 to the number of decimal places contained in the applicable emission 

standard expressed to one additional significant figure.

(3) Whenever a manufacturer intends to operate and test a vehicle (or engine) that 

may be used for emission data, the manufacturer shall retain in its records all 

information concerning all emission tests and maintenance, including vehicle (or 

engine) alterations to represent other vehicle (or engine) selections. This information 

shall be submitted, including the vehicle (or engine) description and specification 

information required by the Administrator, to the Administrator following the 

emission test.

(4) Emission testing of any type with respect to any certification vehicle or engine 

other than that specified in this subpart is not allowed except as such testing may be 

specifically authorized by the Administrator.

§86.004-28—[Amended]

67. Section 86.004-28 is amended by removing the introductory text and by removing 

and reserving paragraphs (a), (b), (f), and (g).

68. Section 86.004-30 is amended as follows:

a. By revising the introductory text.

b. By removing and reserving paragraphs (a)(4), (a)(5), (a)(10)(i), and (a)(11)(i) and 

(a)(12) through (a)(16).

c. By removing paragraphs (a)(19) through (a)(21).

d. By removing and reserving paragraphs (b)(1)(i) and (b)(1)(ii).

e. By removing paragraph (b)(1)(ii)(C) and (b)(1)(ii) (D).

f. By removing and reserving paragraph (b)(4).

§ 86.004-30 Certification.

Section 86.004–30 includes text that specifies requirements that differ from §86.094–30. 

Where a paragraph in §86.094–30 is identical and applicable to §86.004–30, this may be 

indicated by specifying the corresponding paragraph and the statement “[Reserved]. For 

guidance see §86.094–30.”

* * * * *

69. Section 86.004-38 is amended by removing the introductory text, removing and 

reserving paragraph (g), and adding paragraph (i) to read as follows:

§86.004-38 Maintenance instructions.

* * * * *

(i) For each new diesel-fueled engine subject to the standards prescribed in §86.007–11, 

as applicable, the manufacturer shall furnish or cause to be furnished to the ultimate 

purchaser a statement that “This engine must be operated only with ultra low-sulfur 

diesel fuel (meeting EPA specifications for highway diesel fuel, including a 15 ppm 

sulfur cap).”

70. Section 86.005-10 is amended by revising the introductory text and paragraph (c) to 

read as follows:
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§86.005-10 Emission standards for 2005 and later model year Otto-cycle heavyduty engines and vehicles.

Section 86.005–10 includes text that specifies requirements that differ from §86.099–10. 

Where a paragraph in §86.099–10 is identical and applicable to §86.005–10, this may be 

indicated by specifying the corresponding paragraph and the statement “[Reserved]. For 

guidance see §86.099–10.”

* * * * *

(c) No crankcase emissions shall be discharged into the ambient atmosphere from any 

new 1998 or later model year Otto-cycle heavy-duty engine.

* * * * *

§86.005-17 [Removed]

71. Remove §86.005-17.

72. Section 86.007-17 is revised to read as follows:

§ 86.007-17 Onboard diagnostics for engines used in applications less than or equal 

to 14,000 pounds GVWR.

Heavy-duty engines intended to be installed in heavy duty vehicles at or below 14,000 

pounds GVWR that are subject to standards under this subpart must meet onboard

diagnostic requirements as specified in §86.1806.

§86.007-21—[Amended]

73. Section 86.007-21 is amended as follows:

a. By removing and reserving paragraph (b)(4)(i).

b. By removing paragraphs (b)(9) and (b)(10).

c. By removing and reserving paragraphs (k) and (l).

74. Section 86.007-23 is amended by removing and reserving paragraphs (b)(2), (f), (g), 

and (l) and revising the introductory text and paragraph (c) to read as follows:

§ 86.007-23 Required data.

Section 86.007–23 includes text that specifies requirements that differ from §86.098–23 

or §86.001–23. Where a paragraph in §86.098–23 or §86.001–23 is identical and 

applicable to §86.007–23, this may be indicated by specifying the corresponding 

paragraph and the statement “[Reserved]. For guidance see §86.098–23.” or “[Reserved]. 

For guidance see §86.001–23.”.

* * * * *

(b) * * *

(2) [Reserved]

* * * * *

(c) Emission data from certification vehicles and engines. The manufacturer shall submit 

emission data for each applicable emission standard from vehicles and engines tested in 

accordance with applicable test procedures and in such numbers as specified. These data 

shall include zero-mile or zero-hour data, if generated, and emission data generated for 

certification as required under §86.004-26. However, manufacturers may provide a 

statement in the application for certification that vehicles and engines comply with the 

following standards instead of submitting test data, provided that the statement is 
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supported by previous emission tests, development tests, or other appropriate 

information, and good engineering judgment:

(1) Idle CO, smoke, or particulate matter emissions from methanol-fueled or gaseousfueled diesel-cycle certification engines.

(2) Particulate matter emissions from Otto-cycle certification engines or gaseousfueled certification engines.

(3) CO emissions from diesel-cycle certification engines.

(4) Formaldehyde emissions from petroleum-fueled engines. 

(5) Particulate matter and formaldehyde emissions when conducting Selective 

Enforcement Audit testing of Otto-cycle engines.

(6) Smoke from methanol-fueled or petroleum-fueled diesel-cycle certification 

engines.

(7) Smoke when conducting Selective Enforcement Audit testing of diesel-cycle 

engines.

(8) Evaporative emissions from vehicles fueled by natural gas, liquefied petroleum 

gas, or hydrogen. 

* * * * *

(f) through (g) [Reserved]

* * * * *

(l) [Reserved]

* * * * *

§86.007-30—[Amended]

75. Section 86.007-30 is amended as follows:

a. By removing and reserving paragraphs (a)(4), (a)(5), (a)(7), (a)(10)(i), (a)(11)(i), 

and (a)(12) through (a)(16).

b. By removing paragraphs (a)(19) through (a)(21).

c. By removing and reserving paragraphs (b)(1)(i), (b)(1)(ii), and (b)(4).

d. By removing paragraph (f).

76. Section 86.007-35 is amended as follows:

a. By revising paragraph (a) introductory text.

b. By removing and reserving paragraphs (a)(1) and (a)(2)

c. By revising paragraph (c).

d. By removing and reserving paragraphs (d), (f), and (i).

§86.007-35 Labeling.

* * * * *

(a) The manufacturer of any motor vehicle (or motor vehicle engine) subject to the 

applicable emission standards (and family emission limits, as appropriate) of this subpart, 

shall, at the time of manufacture, affix a permanent legible label, of the type and in the 

manner described below, containing the information hereinafter provided, to all 

production models of such vehicles (or engines) available for sale to the public and 

covered by a Certificate of Conformity under §86.007–30(a).

* * * * *

(c) Vehicles powered by model year 2007 through 2013 diesel-fueled engines must 

include permanent, readily visible labels on the dashboard (or instrument panel) and near 
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all fuel inlets that state “Use Ultra Low Sulfur Diesel Fuel Only”; or “Ultra Low Sulfur 

Diesel Fuel Only”.

* * * * *

§86.007-38 [Removed]

77. Remove §86.007-38.

78. Section 86.008-10 is amended as follows:

a. By removing the introductory text.

b. By revising paragraphs (b) introductory text.

c. By adding paragraph (b)(5).

d. By revising paragraph (e).

§86.008-10 Emission standards for 2008 and later model year Otto-cycle heavyduty engines and vehicles.

* * * * *

(b) This paragraph (b) applies as specified in 40 CFR 1037.103. Evaporative emissions 

from heavy-duty vehicles shall not exceed the following standards when measured using 

the test procedures specified in 40 CFR 1037.501. The standards apply equally to 

certification and in-use vehicles. The spitback standard also applies to newly assembled 

vehicles. For certification vehicles only, manufacturers may conduct testing to quantify a 

level of nonfuel background emissions for an individual test vehicle. Such a 

demonstration must include a description of the source(s) of emissions and an estimated 

decay rate. The demonstrated level of nonfuel background emissions may be subtracted 

from emission test results from certification vehicles if approved in advance by the 

Administrator.

* * * * *

(5) Compressed natural gas vehicles must meet the requirements for fueling connection 

devices as specified in § 86.1813-17(f)(1). Vehicles meeting these requirements are 

deemed to comply with evaporative emission standards.

* * * * *

(e) The standards described in this section do not apply to Otto-cycle medium-duty

passenger vehicles (MDPVs) that are subject to regulation under subpart S of this part, 

except as specified in subpart S of this part. The standards described in this section also 

do not apply to Otto-cycle engines used in such MDPVs, except as specified in subpart S 

of this part. The term “medium-duty passenger vehicle” is defined in §86.1803.

* * * * *

79. Section 86.010-38 is amended by revising paragraphs (g) and (i) to read as follows:

§ 86.010-38 Maintenance instructions.

* * * * *

(g) Manufacturers are subject to the service-information requirements of §86.1808-01(f) 

beginning in the 2005 model year for manufacturers of heavy-duty vehicles and heavyduty engines weighing 14,000 pounds gross vehicle weight (GVW) and less that are 

subject to the OBD requirements of this part.

* * * * *

(i) Through model year 2013, the manufacturer shall furnish or cause to be furnished to 

the ultimate purchaser the following statement for each new diesel-fueled engine subject 
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to the standards prescribed in §86.007–11, as applicable: “This engine must be operated 

only with ultra low-sulfur diesel fuel (meeting EPA specifications for highway diesel 

fuel, including a 15 ppm sulfur cap).”

* * * * *

80. Section 86.016-1 is amended by revising paragraphs (a), (b), and (c) and adding 

paragraphs (g) and (h) to read as follows:

§ 86.016-1 General applicability.

(a) Applicability. The provisions of this subpart apply for certain types of new heavyduty engines and vehicles as described in this paragraph (a). Note that this subpart does 

not apply for light-duty vehicles, light-duty trucks, or medium-duty passenger vehicles 

(see subpart S of this part for requirements that apply for those vehicles). In some cases, 

manufacturers of heavy-duty engines and vehicles can choose whether to meet the 

requirements of this subpart or the requirements of subpart S of this part; those provisions 

are therefore considered optional, but only to the extent that manufacturers comply with 

the other set of requirements. In cases where a provision applies only for a certain 

vehicle group based on its model year, vehicle class, motor fuel, engine type, or other 

distinguishing characteristics, the limited applicability is cited in the appropriate section. 

The provisions of this subpart apply for certain heavy-duty engines and vehicles as 

follows: 

(1) The provisions of this subpart related to exhaust emission standards apply for 

diesel-cycle and Otto-cycle heavy-duty engines installed in vehicles above 14,000 

pounds GVWR; however, these vehicles may instead be certified under subpart S of 

this part as specified in §86.1801. 

(2) The provisions of this subpart related to exhaust emission standards apply for 

engines that will be installed in incomplete vehicles at or below 14,000 pounds 

GVWR; however, these vehicles may instead be certified under subpart S of this part 

as specified in §86.1801.

(3) Diesel-cycle and Otto-cycle complete heavy-duty vehicles at or below 14,000 

pounds GVWR and the corresponding engines are not subject to the provisions of this 

subpart related to exhaust emission standards, except that these provisions are 

optional for diesel-cycle engines installed in such vehicles until those vehicles 

become subject to the Tier 3 standards under §86.1816-18.

(4) The provisions of this subpart related to evaporative emission standards apply for 

diesel-cycle and Otto-cycle heavy-duty vehicles as follows:

(i) These provisions do not apply for vehicles at or below 14,000 pounds GVWR.

(ii) Vehicles above 14,000 pounds GVWR must meet evaporative emission 

standards as specified in 40 CFR 1037.103. This involves meeting the standards

specified in §§86.008-10(b) and 86.007-11(b)(3) and (4) until the Tier 3 standards

in §86.1813 start to apply.

(iii) Note that diesel-fueled vehicles are not subject to evaporative emissions 

under this part.

(5) The provisions of this subpart related to onboard diagnostics apply for dieselcycle and Otto-cycle heavy-duty engines and vehicles as follows:

(i) Engines installed in vehicles above 14,000 pounds GVWR must meet the 

onboard diagnostic requirements specified in §86.010-18.
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(ii) Engines installed in vehicles at or below 14,000 pounds GVWR must meet the

the onboard diagnostic requirements specified in §86.1806.

(b) Relationship to subpart S of this part. Unless specified otherwise, if engines are not 

subject to provisions of this subpart or if manufacturers choose not to meet optional 

provisions of this subpart as described in paragraph (a) of this section, those engines must 

be installed in vehicles meeting the corresponding requirements under subpart S of this 

part. If a vehicle and its installed engine comply with a mix of provisions from this 

subpart and from subpart S of this part, the vehicle must be certified under subpart S of 

this part, and the engine does not need to be certified separately.

(c) Greenhouse gas emission standards. See 40 CFR parts 1036 and 1037 for greenhouse 

gas emission standards that apply for heavy-duty engines and vehicles.

* * * * *

(g) Clean alternative fuel conversions. The provisions of this subpart also apply for clean 

alternative fuel conversions as defined in 40 CFR 85.502 of all vehicles described in 

paragraph (a) of this section.

(h) Turbine engines. Turbine engines are deemed to be compression-ignition engines for 

purposes of this part.

§86.079-36 [Removed]

81. Remove §86.079-36.

82. Section 86.082-2 is amended by adding definitions for “Round” and “United States” 

in alphabetical order to read as follows. 

§ 86.082-2 Definitions.

* * * * *

Round has the meaning given in 40 CFR 1065.1001, unless otherwise specified.

* * * * *

United States has the meaning given in 40 CFR 1068.30. 

* * * * *

§86.085-2 [Amended]

83. Section 86.085-2 is amended by removing the definition for “Incomplete gasolinefueled heavy-duty vehicle”.

* * * * *

84. Section 86.085-20 is revised to read as follows:

§86.085-20 Incomplete vehicles, classification.

For purposes of this part:

(a) A heavy-duty gasoline-fueled vehicle is considered to be a complete vehicle if it has 

the primary load carrying device or container attached at the time the vehicle leaves the 

control of the manufacturer of the engine, and is considered to be an incomplete vehicle if 

it does not.

(b) For all other heavy-duty vehicles, a vehicle that has the primary load carrying device 

or container attached at the time the vehicle is introduced into U.S. commerce is 

considered to be a complete vehicle. Vehicles not considered to be complete vehicles are 

incomplete vehicles. For purposes of determining when a vehicle is introduced into U.S. 
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commerce, an assembly of motor vehicle parts is deemed to be a vehicle if either of the 

following applies: 

(1) A piece of equipment that is intended for self-propelled use on highways becomes 

a vehicle when it includes at least an engine, a transmission, and a frame. (Note: For 

purposes of this definition, any electrical, mechanical, and/or hydraulic devices 

attached to engines for the purpose of powering wheels are considered to be 

transmissions.)

(2) A piece of equipment that is intended for self-propelled use on highways becomes 

a vehicle when it includes a passenger compartment attached to a frame with axles.

§86.085-37—[Amended]

85. Section 86.085-37 is amended by removing paragraph (b). 

§86.087-2 [ Removed]

86. Remove §86.087-2.

§86.091-29—[Amended]

87. Section 86.091-29 is amended by removing and reserving paragraph (a). 

88. Section 86.094-7 is amended by adding paragraph (h)(6) to read as follows:

§ 86.094-7 Maintenance of records; submittal of information; right of entry.

* * * * *

(h) * * *

(6) EPA may void ab initio a certificate for a vehicle certified to Tier 1 certification 

standards or to the respective evaporative and/or refueling test procedure and 

accompanying evaporative and/or refueling standards as set forth or otherwise referenced 

in §86.098–10 for which the manufacturer fails to retain the records required in this 

section or to provide such information to the Administrator upon request.

* * * * *

§86.094-13 [Removed]

89. Remove §86.094-13.

§86.094-14—[Amended]

90. Section 86.094-14 is amended by removing and reserving paragraphs (c)(5) and 

(c)(7)(i)(A)(1). 

§86.094-16 [Removed]

91. Remove §86.094-16.

§86.094-21—[Amended]

92. Section 86.094-21 is amended by removing paragraph (b)(1)(i)(C) and by removing 

and reserving paragraphs (b)(4)(i), (b)(5)(iii)(B), (b)(8), (d), and (g).

§86.094-25—[Amended]

93. Section 86.094-25 is amended as follows:

a. By removing and reserving paragraphs (a), (b)(3)(i)(A), and (b)(3)(ii).
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b. By removing paragraphs (b)(3)(iii) through (b)(3)(vii).

c. By removing and reserving paragraphs (b)(4) through (b)(6), (d), and (g).

§§86.094-26 and 86.094-28 [Removed]

94. Remove §§86.094-26 and 86.094-28.

§86.094-30—[Amended]

95. Section 86.094-30 is amended as follows:

a. By removing and reserving paragraphs (a)(1)(ii), (a)(4), (a)(5), and (a)(7).

b. By removing paragraphs (a)(9) through (a)(14).

c. By removing and reserving paragraphs (b)(1)(i), (b)(1)(ii), and (b)(4).

d. By removing and reserving paragraph (d).

§§86.095-23, 86.095-26, and 86.095-30 [Removed]

96. Remove §§86.095-23, 86.095-26, and 86.095-30.

97. Section 86.095-35 is amended as follows:

a. By removing and reserving paragraphs (a)(1) and (a)(2).

b. By revising paragraph (a)(4) introductory text.

c. By removing and reserving paragraphs (d), (e), and (f).

d. By revising paragraph (g) introductory text.

§86.095-35 Labeling.

(a) * * *

(1) – (2) [Reserved]

* * * * *

(4) Heavy-duty vehicles employing a fuel or fuels covered by evaporative emission 

standards. This paragraph (a)(4) applies through model year 2014. See 40 CFR part 

1037 for provisions that apply in 2015 and later model years. 

* * * * *

(d) – (f) [Reserved]

(g) Incomplete vehicle fuel tank capacity. This paragraph (g) applies through model year 

2014. See 40 CFR part 1037 for provisions that apply in 2015 and later model years. 

* * * * *

§§86.096-7, 86.096-8, and 86.096-21 [Removed]

98. Remove §§86.096-7, 86.096-8, and 86.096-21.

§86.096-24—[Amended]

99. Section 86.096-24 is amended as follows:

a. By removing and reserving paragraphs (a)(8) through (a)(11)

b. By removing and reserving paragraphs (a)(14)(ii), (a)(14)(iii), and (a)(14)(vii).

c. By removing and reserving paragraphs (b)(1), (c)(1), (c)(2), and (d).

d. By removing paragraphs (g) and (h).

§§86.096-26, 86.096-30, 86.096-35, 86.096-38, and 86.097-9 [Removed]

100. Remove §§86.096-26, 86.096-30, 86.096-35, 86.096-38, and 86.097-9.
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§86.098-23—[Amended]

101. Section 86.098-23 is amended by removing and reserving paragraphs (b)(1)(i), 

(e)(2), and (e)(3). 

§§86.098-24, 86.098-25, 86.098-26, 86.098-28, 86.098-30, 86.098-35, 86.099-8, 86.099-

9, and 86.099-17 [Removed]

102. Remove §§86.098-24, 86.098-25, 86.098-26, 86.098-28, 86.098-30, 86.098-35, 

86.099-8, 86.099-9, and 86.099-17.

Subpart B—[Amended]

103. Section 86.101 is revised to read as follows: 

§ 86.101 General applicability.

(a) General provisions. This subpart describes test procedures for measuring exhaust, 

evaporative, and refueling emissions from motor vehicles subject to emission standards 

under subpart S of this part. This generally includes light-duty vehicles, light-duty 

trucks, and complete heavy-duty vehicles at or below 14,000 pounds GVWR. The 

following provisions apply for all testing under this subpart:

(1) Provisions of this subpart apply to tests performed by both the Administrator and 

manufacturers.

(2) References in this subpart to engine families and emission control systems apply

to durability groups and test groups as applicable.

(3) Except as noted, heavy-duty vehicles are subject to all the same provisions of this 

subpart that apply to light-duty trucks.

(4) The procedures in this subpart apply for testing vehicles powered by any fuel, 

except as specified in subpart S of this part.

(5) For exhaust emission testing, measure emissions for all pollutants with an 

applicable emission standard. 

(6) All emission control systems designed for production vehicles must be 

functioning during testing. Maintenance to correct component malfunction or failure 

must be authorized in accordance with §86.1834.

(7) The test sequence for the Federal Test Procedure (FTP) includes steps to 

precondition vehicles for evaporative emission measurements; these steps are 

required for exhaust testing whether or not testing includes evaporative emission 

measurements.

(8) Evaporative emission measurement procedures of this subpart include 

specifications for testing methanol-fueled vehicles. For vehicles fueled with other 

oxygenated fuels, use good engineering judgment to apply these procedures. For 

example, if you are testing an ethanol-fueled vehicle, perform diagnostics in your 

evaporative emission enclosure with ethanol and propane.

(9) For exhaust emission testing with ethanol-gasoline blends that have less than 

25% ethanol by volume, if you use NMHC-to-NMOG conversion factors instead of 

measuring oxygenates as described in 40 CFR 1066.635, the testing specifications 

and diagnostic requirements in this part 86 that are specific to ethanol-gasoline blends

do not apply. 
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(b) Migration to 40 CFR parts 1065 and 1066. This subpart transitions to rely on the test 

procedure specifications in 40 CFR parts 1065 and 1066 as follows:

(1) Through model year 2021, manufacturers may use the test procedures specified in 

paragraph (c) or (d) of this section or, using good engineering judgement, elements of 

both. For any EPA testing before model year 2022, EPA will use the manufacturer's 

selected procedures for determining road load parameters and applying acceptable 

speed-tolerance criteria. For any other parameters, EPA may conduct testing using 

either of the specified procedures. As allowed under this part, manufacturers may use 

carryover data from previous model years to demonstrate compliance with emission 

standards, without regard to the provisions of this section.

(2) Manufacturers must use the following procedures before model year 2022:

(i) For vehicles certified to any of the Tier 3 emission standards specified in 

subpart S of this part, determine overall driver accuracy based on driven cycle 

energy as described in 40 CFR 1066.425(j).

(ii) Equipment specifications and measurement procedures that are specific to PM 

emissions from 40 CFR part 1066 apply for any vehicles certified to the Tier 3 

PM emission standards specified in subpart S of this part.

(iii) Use 40 CFR 1066.635 to determine NMOG for any vehicles certified to the 

Tier 3 NMOG+NOx emission standards in subpart S of this part.

(3) For model years 2022 and later, manufacturers must use the test procedures 

specified in paragraph (d) of this section.

(c) Interim procedures. Test vehicles as described in this subpart for the appropriate 

model year, through model year 2021, as follows:

(1) Sections 86.106 through 86.115 set forth general testing specifications and 

equipment requirements. Sections 86.116 through 86.126 discuss calibration methods 

and frequency. Sections 86.127 through 86.145 describe procedures for measuring 

exhaust and evaporative emissions. Sections 86.146 through 86.157 lay out refueling 

test procedures. Sections 86.158 through 86.166 cover procedures related to the 

Supplemental Federal Test Procedure and testing related to air conditioning systems. 

The test procedure for measuring fuel system leaks is described in 40 CFR 1066.985.

(2) Alternate equipment, procedures, and calculation methods may be used if shown 

to yield equivalent or superior results, and if approved in advance by the 

Administrator.

(d) Long-term procedures. Test vehicles as described in 40 CFR parts 1065 and 1066. 

The following requirements from this subpart also apply:

(1) Use fuel for testing and service accumulation as specified in §86.113.

(2) Perform evaporative emission tests as follows:

(i) Use evaporative testing equipment meeting the specifications in §86.107. This 

equipment must meet calibration requirements as specified in §86.117.

(ii) Generate fuel test temperature profiles as described in §86.129-94(d).

(iii) Follow the general provisions and driving schedules described in 40 CFR part 

1066, subpart I. Evaporative testing consists of vehicle preconditioning as 

described in § 86.132, diurnal measurement as described in §86.133, running loss 

testing as described in §86.134, and hot soak testing as described in §86.138. 

(iv) Calculate emission results as described in §86.143.

(3) Keep records as described in §86.142
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(4) Perform refueling emission tests, calculate emission results, and keep associated 

records as described in §86.146 through 86.157.

104. Section 86.102 is revised to read as follows: 

§ 86.102 Definitions.

The definitions in §86.1803 apply to this subpart.

§ 86.106-00 [Removed]

105. Section 86.106-00 is removed.

106. Section 86.106-96 is amended by revising paragraph (a)(3) to read as follows: 

§86.106-96 Equipment required; overview.

(a) * * *

(3) Fuel, analytical gas, and driving schedule specifications. Fuel specifications for 

exhaust and evaporative emission testing and for mileage accumulation for petroleumfueled and methanol-fueled vehicles are specified in §86.113. Analytical gases are 

specified in §86.114. The Urban Dynamometer Driving Schedule (UDDS), US06, and 

SC03 driving schedules, for use in exhaust emission tests, and the New York City Cycle 

(NYCC), for use with the UDDS in running loss tests, are specified in §§86.115, 86.130, 

86.159, 86.160, and appendix I to this part.

* * * * *

§86.107-96—[Amended]

107. Section 86.107-96 is amended by removing and reserving paragraph (e). 

§§ 86.108-79, 86.110-90 [Removed]

108. Sections 86.108-79 and 86.110-90 are removed.

109. Section 86.110-94 is amended by revising paragraphs (b)(6)(i) and (d) to read as 

follows:

§ 86.110-94 Exhaust gas sampling system; diesel-cycle vehicles, and Otto-cycle 

vehicles requiring particulate emissions measurements.

* * * * *

(b) * * *

(6) * * *

(i) Sized to permit development of turbulent flow (Reynolds No. >>4000) and 

complete mixing of the exhaust and dilution air between the mixing orifice and each 

of the two sample probes (i.e., the particulate probe and the heated THC sample 

probe). It is recommended that uniform mixing be demonstrated by the user.

* * * * *

(d) Filters, particulate sampling. Use fluorocarbon-coated glass fiber filters or 

fluorocarbon-based (membrane) filters to collect particulate matter, as follows:

(1) Use primary and back-up test filters as follows for particulate measurements:

(i) During each phase of the UDDS, sample dilute exhaust simultaneously with 

paired primary and back-up test filters.
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(ii) Position the back-up filter holder 3 to 4 inches downstream of the primary

filter holder.

(iii) Determine the net weight of particulate material collected on each primary

test filter and each back-up test filter using the procedure described in § 86.139.

(iv) Determine a ratio of net weights using the following formula:

(v) If the ratio is greater than 0.95, base the particulate emission calculations on 

the net weight of the primary filter only.

(vi) If the ratio is less than 0.95, base the particulate emission calculations on the 

combined net weights of the back-up test filter and the primary test filter.

(2) The particulate filter must have a 47 mm diameter (37 mm stain area). 

§ 86.111-90 [Removed]

110. Section 86.111-90 is removed.

111. Section 86.111-94 is amended by revising paragraph (b)(3)(vii) to read as follows:

§86.111-94 Exhaust gas analytical system.

* * * * *

(b) * * *

(3) * * *

(vii) Using a methane analyzer consisting of a gas chromatograph combined with a FID, 

measure methane according to SAE J1151 (incorporated by reference in §86.1). 

* * * * *

112. Section 86.113-04 is amended by revising paragraphs (a)(1), (a)(2) and (a)(3)(i) to 

read as follows:

§ 86.113-04 Fuel specifications.

* * * * *

(a) * * *

(1) Gasoline meeting the following specifications, or substantially equivalent 

specifications approved by the Administrator, must be used for exhaust and evaporative 

testing: 
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Table 1 of §86.113-04–Test fuel specifications for gasoline without ethanol

Item Regular Reference 

Procedure1

Research octane, Minimum293 ASTM D2699

Octane sensitivity ASTM D2700 27.5

Distillation Range (°F):

 Evaporated initial boiling point3

 10% evaporated

 50% evaporated

 90% evaporated

 Evaporated final boiling point

75 – 95

120 - 135

200 - 230

300 - 325

415 Maximum

ASTM D86

Hydrocarbon composition (vol %):

 Olefins

 Aromatics

 Saturates

10% Maximum

35% Maximum

Remainder

ASTM D1319

Lead, g/gallon (g/liter), Maximum 0.050

(0.013) ASTM D3237

Phosphorous, g/gallon (g/liter), Maximum 0.005 

(0.0013) ASTM D3231

Total sulfur, wt. %40.0015 – 0.008 ASTM D2622

Dry Vapor Pressure Equivalent (DVPE), 

kPa (psi)

5

60.0-63.4 

(8.7-9.2)

ASTM D5191

1 ASTM procedures are incorporated by reference in §86.1.

2 Octane specifications are optional for manufacturer testing.

3

For testing at altitudes above 1,219 m (4000 feet), the specified range

is 75-105° F.

4

Sulfur concentration will not exceed 0.0045 weight percent for EPA testing.

5

For testing unrelated to evaporative emission control, the specified range is 

54.8-63.7 kPa (8.0-9.2 psi). For testing at altitudes above 1,219 m (4000 feet), 

the specified range is 52.0-55.4 kPa (7.6-8.0 psi). Calculate dry vapor pressure 

equivalent, DVPE, based on the measured total vapor pressure, pT, using the 

following equation: DVPE (kPa) = 0.956∙pT - 2.39 (or DVPE (psi) = 0.956∙pT –

0.347). DVPE is intended to be equivalent to Reid Vapor Pressure using a 

different test method.

(2) Manufacturers may use California test fuels, as follows:

(i) For model year 2014 and earlier vehicles certified for 50-state sale, manufacturers 

may perform exhaust emission tests using California Phase 2 gasoline as specified in 

Chapter 4 of the California Regulatory Requirements Applicable to the National Low 

Emission Vehicle Program, October 1996 (incorporated by reference in §86.1). 

However, the Administrator may use or require the use of test fuel meeting the 

specifications in paragraph (a)(1) of this section for confirmatory testing, selective 

enforcement auditing and in-use testing.

(ii) For model year 2015 and later, manufacturers may certify 50-state Tier 2 vehicles 

based on testing used to meet California’s LEV III standards, subject to the following 

provisions:

(A) Manufacturers may perform exhaust and evaporative emission tests using

California Phase 2 gasoline or California LEV III gasoline. The Administrator 

may use or require the use of test fuel meeting the specifications in paragraph 

(a)(1) of this section for confirmatory testing, selective enforcement auditing and 

in-use testing. 
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(B) All evaporative testing with California fuel must be conducted with 

temperatures meeting the specifications adopted by the California Air Resources 

Board.

(C) The vehicles must also meet exhaust and evaporative emission standards at 

high-altitude conditions as specified in §§86.1811-17 and 86.1813-17, except that 

testing is based on the fuel specified in paragraph (a)(1) of this section. 

(D) The vehicle must meet the applicable cold temperature standards using test 

fuel specified for cold temperature testing in §86.213 .

(3) * * *

(i) Unless otherwise approved by the Administrator, gasoline representative of 

commercial gasoline that will be generally available through retail outlets must be

used in service accumulation. Unless otherwise approved by the Administrator, where 

the vehicle is to be used for evaporative emission durability demonstration, such fuel 

must contain ethanol as required by §86.1824–08(f)(1).

* * * * *

§86.113-07—[Removed]

113. Remove §86.113-07.

114. A new §86.113-15 is added to subpart S to read as follows:

§86.113-15 Fuel specifications.

Section 86.113–15 includes text that specifies requirements that differ from §86.113–94. 

Where a paragraph in §86.113–94 is identical and applicable to §86.113–15, this may be 

indicated by specifying the corresponding paragraph and the statement “[Reserved]. For 

guidance see §86.113–94.”

(a) Gasoline fuel. This paragraph (a) describes how to transition to an ethanol-blend test 

fuel for vehicles certified under subpart S of this part. You may use the test fuels 

specified in §86.113-04(a) for vehicles that are not yet subject to testing with the new 

fuel. You may use the specified ethanol-blend test fuel anytime earlier than we specify as 

long as you use the corresponding procedures for measuring and calculating emission 

results. See 40 CFR 600.113 for special provisions that apply for emission measurements 

related to fuel economy and greenhouse gases. Manufacturers must certify using E10 test 

fuel as specified in 40 CFR 1065, subpart H, and service accumulation fuel meeting 

applicable specifications as follows::

(1) Except as allowed under paragraph (a)(2) of this section, Use E10 test fuel to 

demonstrate compliance with the Tier 3 exhaust emission standards as specified in 

§86.1811 and 86.1816, and to demonstrate compliance with the Tier 3 evaporative

emission standards as specified in §86.1813. 

(2) You may use California test fuels to demonstrate compliance with Tier 3 emission 

standards as follows:

(i) For vehicles certified for 50-state sale, you may instead use California Phase 3 

gasoline (E10) as adopted in California’s LEV III program for exhaust emission 

testing. Through model year 2019, we will also use this E10 fuel for any lowaltitude exhaust emission testing with such vehicles. Starting in model year 2020, 

we may use test fuel meeting either California Phase 3 gasoline (E10) or the 

gasoline (E10) test fuel specified in this paragraph (a). For cold temperature 

testing and for exhaust emission tests at high-altitude conditions, you may certify
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vehicles through model year 2019 based on testing with the gasoline (E0) test fuel 

specified in §86.113-04(a); for such vehicles, we may use test fuel meeting either 

the gasoline (E0) test fuel specified in §86.113-04(a) or the gasoline (E10) test 

fuel specified in this paragraph (a).

(ii) For vehicles that were certified to SULEV exhaust emission standards with a 

150,000 mile useful life under California’s LEV II program and that are eligible 

to use that carryover data for continued certification, you may use that carryover 

data to demonstrate compliance with the exhaust emission standards that apply for 

Bin 30 vehicles under §86.1811-17 for model years 2015 through 2019. The test 

fuel specifications that applied for the original emission measurements under the 

LEV II program also apply for any additional exhaust testing under the Tier 3 

program, including confirmatory testing, selective enforcement auditing, and inuse testing. For vehicles certified under this paragraph (a)(2)(ii), use the E10 test 

fuel specified in 40 CFR 1065.710 for cold temperature testing and high-altitude 

testing.

(iii) For vehicles certified for 50-state sale, you may instead use California test 

fuel for evaporative emission testing as follows:

(A) If you originally certified vehicles in California in model year 2015 or 

2016 to PZEV standards with California Phase 2 gasoline, you may use that 

data with carryover vehicles to certify to the Tier 3 evaporative emission 

standards through model year 2019. We will use this same fuel to measure 

diurnal, hot soak, running loss, and SHED rig emissions at low-altitude 

conditions for such vehicles. For refueling, spitback, and high-altitude testing, 

you may use test fuel meeting either the gasoline (E0) test fuel specified in 

§86.113-04(a) or the gasoline (E10) test fuel specified in this paragraph (a); 

we may use either of the specified fuels for our testing. For leak testing, you 

must use the gasoline (E10) test fuel specified in this paragraph (a).

(B) If you certify vehicles to LEV III standards with California Phase 3

gasoline (E10), you may use that collection of data to certify to the Tier 3 

evaporative emission standards. Through model year 2019, we will use this 

same fuel to measure diurnal, hot soak, running loss, SHED rig, and canister 

bleed emissions (as appropriate) at low-altitude conditions; starting in model 

year 2020, we may use either California Phase 3 gasoline (E10) or the 

gasoline (E10) test fuel specified in this paragraph (a) for our testing with 

such vehicles. For refueling, spitback, high-altitude, and leak testing, you 

must use the gasoline (E10) test fuel specified in this paragraph (a), except 

that you may instead use the the gasoline (E0) test fuel specified in §86.113-

04(a) for model year 2015 and 2016; we will use your selected fuel for our 

testing. Note that you may no longer certify vehicles to the Tier 3 standards 

based on California’s rig-testing procedures after model year 2021, as 

described in §86.1813-17(g). 

(C) For evaporative emission testing with California test fuels, perform tests 

based on the test temperatures specified by the California Air Resources 

Board.

(3) Except as specified in paragraph (a)(2)(iii) of this section and in this paragraph 

(a)(3), use E10 test fuel to demonstrate compliance with the refueling and spitback
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emission standards for any vehicles that must be certified to meet the diurnal plus hot 

soak standards with E10 test fuel under paragraphs (a)(1) and (2) of this section. You 

may delay using E10 test fuel until model year 2022 for incomplete heavy-duty

vehicles not certified to refueling emission standards.

(4) If a vehicle uses E10 test fuel for evaporative emission testing and E0 is the 

applicable test fuel for exhaust emission testing, exhaust measurement and reporting 

requirements apply over the course of the evaporative emission test, but the vehicle 

need not meet the exhaust emission standards during the evaporative emission test 

run. 

(5) For service accumulation, use a commercially available fuel, subject to the 

additional specification in §86.1824-08(f) for evaporative emissions. 

(b) through (g) [Reserved]. For guidance see §86.113–94.

115. Section 86.113-94 is amended by removing and reserving paragraphs (a) and (d) 

and revising paragraphs (b)(2), (b)(3), (e), and (f)(3) to read as follows:

§86.113-94— Fuel specifications.

* * * * *

(b) * * *

(2) A diesel fuel designated as “Type 2-D” grade meeting the following specifications, or 

substantially equivalent specifications approved by the Administrator, must be used for 

exhaust emission testing:

Property Unit Type 2-D

Reference 

Procedure1

(i) Cetane Number — 40-50 ASTM D613

(ii) Cetane Index — 40-50 ASTM D976

(iii) Distillation range: 

(A) IBP 

(B) 10 pct. point 

(C) 50 pct. point 

(D) 90 pct. point 

(E) EP 

°F (°C)

340-400 (171.1-204.4)

400-460 (204.4-237.8)

470-540 (243.3-282.2)

560-630 (293.3-332.2)

610-690 (321.1-365.6)

ASTM D86

(iv) Gravity °API 32-37 ASTM D4052

(v) Total sulfur ppm 7-15 ASTM D2622

(vi) Hydrocarbon composition: 

Aromatics, minimum (Remainder shall 

be paraffins, naphthenes, and olefins)

pct. 27 ASTM D5186

(vii) Flashpoint, min. °F (°C) 130 (54.4) ASTM D93

(viii) Viscosity centistokes 2.0-3.2 ASTM D445

1ASTM procedures are incorporated by reference in §86.1.

(3) A diesel fuel designated as “Type 2-D” grade meeting the following specifications, or 

substantially equivalent specifications approved by the Administrator, must be used for 

service accumulation:
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Property Unit Type 2-D

Reference 

Procedure1

(i) Cetane Number — 38-58 ASTM D613

(ii) Cetane Index, minimum — 40 ASTM D976

(iii) 90 percent distillation °F 540-630 ASTM D86

(iv) Gravity °API 30-39 ASTM D4052

(v) Total sulfur Ppm 7-15 ASTM D2622

(vi) Flashpoint, minimum °F (°C) 130 (54.4) ASTM D93

(vii) Viscosity centistokes 1.5-4.5 ASTM D445

1ASTM procedures are incorporated by reference in §86.1.

* * * * *

(e) Natural gas. (1) A natural gas fuel meeting the following specifications, or 

substantially equivalent specifications approved by the Administrator, must be used for 

exhaust and evaporative testing: 

Item Value1

Methane, CH4 Minimum, 89.0 mole percent 

Ethane, C2H6 Maximum, 4.5 mole percent 

C3 and higher Maximum, 2.3 mole percent

C6 and higher Maximum, 0.2 mole percent

Oxygen Maximum, 0.6 mole percent

Inert gases (sum of CO2 and N2) Maximum, 4.0 mole percent

1 All parameters are based on the reference procedures in ASTM D1945 

(incorporated by reference in §86.1).

(2) The natural gas at ambient conditions must have a distinctive odor potent enough 

for its presence to be detected down to a concentration in air of not over one-fifth of 

the lower limit of flammability.

(3) Natural gas representative of commercially available natural gas fuel generally 

available through retail outlets shall be used in service accumulation for natural gasfueled vehicles.

(4) A natural gas fuel meeting different specifications may be used for testing and 

service accumulation if all the following conditions are met:

(i) The alternate test fuel is commercially available.

(ii) Information acceptable to the Administrator is provided to show that only the 

designated fuel will be used in customer service.

(iii) The Administrator must provide advance written approval for the alternate 

test fuel.

(f) * * *

(3) The specification range of the fuel to be used under paragraphs (f)(1) and (2) of this 

section shall be measured in accordance with ASTM D2163 (incorporated by reference in 

§ 86.1).

* * * * *

§ 86.115-00 [Removed]
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116. Section 86.115-00 is removed.

117. Section 86.115-78 is amended by revising the section heading and paragraphs (a) 

and (b) introductory text to read as follows:

§86.115-78 EPA dynamometer driving schedules.

(a) The driving schedules for the Urban Dynamometer Driving Schedule, US06, SC03, 

and the New York City Cycles are specified in appendix I of this part. The driving 

schedules are defined by a smooth trace drawn through the specified speed vs. time 

relationships. They each consist of a distinct non-repetitive series of idle, acceleration, 

cruise, and deceleration modes of various time sequences and rates.

(b) The driver should attempt to follow the target schedule as closely as possible (refer to 

§86.128 for additional cycle driving instructions). The speed tolerance at any given time 

for these schedules, or for a driver's aid chart approved by the Administrator, are as 

follows: 

* * * * *

118. Section 86.117-96 is amended by revising the introductory text and paragraphs (c) 

introductory text, (c)(1)(vii), and (c)(1)(ix) to read as follows:

§ 86.117-96 Evaporative emission enclosure calibrations.

The calibration of evaporative emission enclosures consists of three parts: initial and 

periodic determination of enclosure background emissions (hydrocarbons and methanol); 

initial determination of enclosure internal volume; and periodic hydrocarbon and 

methanol retention check and calibration. Ethanol retention checks may be performed 

instead of methanol retention checks. Alcohol retentions may be omitted if no alcohol -

fueled vehicles will be tested in the evaporative enclosure. For evaporative and refueling 

emission tests with ethanol-gasoline blends that have less than 25% ethanol by volume, if 

you account for ethanol with a mathematical adjustment as described in §86.1813-

17(a)(1)(iv) instead of measuring ethanol, the testing specifications and diagnostic 

requirements in this part 86 that are specific to ethanol-gasoline blends do not apply.

Alternate calibration methods may be used if shown to yield equivalent or superior 

results, and if approved in advance by the Administrator; specifically, more extreme 

temperatures may be used for determining calibration without affecting the validity of 

test results.

* * * * *

(c) Hydrocarbon and methanol (organic gas) retention check and calibration. The 

hydrocarbon and methanol (if the enclosure is used for methanol-fueled vehicles) 

retention check provides a check upon the calculated volume and also measures the leak 

rate. The enclosure leak rate shall be determined prior to its introduction into service, 

following any modifications or repairs to the enclosure that may affect the integrity of the 

enclosure, and at least monthly thereafter. The methanol retention check must be 

performed only upon initial installation and after major maintenance, consistent with 

good engineering judgment. If six consecutive monthly retention checks are successfully

completed without corrective action, the enclosure leak rate may be determined quarterly

thereafter as long as no corrective action is required.

(1) * * *
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(vii) Inject into the enclosure 0.5 to 1.0 grams of pure methanol at a recommended 

temperature of at least 150 °F (65 °C) and/or 0.5 to 1.0 grams of pure propane at lab 

ambient temperature. The injected quantity may be measured by volume flow or by mass 

measurement. The method used to measure the quantity of methanol and propane must 

have an accuracy of ±0.5 percent of the measured value (less accurate methods may be 

used with the advance approval of the Administrator).

* * *

(ix) To verify the enclosure calibration, calculate the mass of propane and the mass of 

methanol using the measurements taken in paragraphs (c)(1)(vi) and (viii) of this section. 

See paragraph (d) of this section. This quantity must be within ±2 percent of that 

measured in paragraph (c)(1)(vii) of this section for propane and ±5 percent for methanol. 

Evaluate long-term trends using good engineering judgment to minimize measurement 

bias. Keep records to document such evaluations and make them available to EPA upon 

request.

* * * * *

§§86.118-78, 86.127-96, and 86.128-00 [Removed]

119. Sections 86.118-78, 86.127-96, and 86.128-00 are removed.

120. Section 86.128-79 is amended by revising paragraph (d) to read as follows: 

§86.128-79 Transmissions.

* * * * *

(d) The vehicle shall be driven with appropriate accelerator pedal movement necessary to 

achieve the speed versus time relationship prescribed by the driving schedule. Both 

smoothing of speed variations and excessive accelerator pedal perturbations are to be 

avoided.

* * * * *

§86.129-80—[Amended]

121. Section 86.129-80 is amended by removing and reserving paragraph (a). 

§86.130-00 [Removed]

122. Section 86.130-00 is removed.

123. Section 86.130-96 is amended by adding introductory text, revising paragraph (e),

and adding paragraph (f) to read as follows: 

§ 86.130-96 Test sequence; general requirements.

Paragraphs (a) through (d) of this section are applicable to vehicles tested for the FTP 

test. Paragraph (e) of this section is applicable to vehicles tested for the SFTP 

supplemental tests of air conditioning (SC03) and aggressive driving (US06). Paragraph 

(f) of this section is applicable to all emission testing.

* * * * *

(e) The supplemental tests for exhaust emissions related to aggressive driving (US06) and 

air conditioning (SC03) use are conducted as stand-alone tests as described in §§86.158 

through 86.160. These tests may be performed in any sequence that maintains the 

appropriate preconditioning requirements as specified in §86.132.
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(f) If tests are invalidated after collection of emission data from previous test segments, 

the test may be repeated to collect only those data points needed to complete emission 

measurements. Compliance with emission standards may be determined by combining 

emission measurements from different test runs. If any emission measurements are 

repeated, the new measurements supersede previous values.

§86.131-00 [Removed]

124. Section 86.131-00 is removed.

125. Section 86.131-96 is amended by adding paragraphs (f) and (g) to read as follows: 

§ 86.131-96 Vehicle preparation.

* * * * *

(f) For vehicles to be tested for aggressive driving emissions (US06), provide a throttle 

position sensing signal that is compatible with the test dynamometer. This signal provides 

the input information that controls dynamometer dynamic inertia weight adjustments (see 

§§ 86.108-00(b)(2)(ii) and 86.129-00(f)(2)). If a manufacturer chooses not to implement 

dynamic inertia adjustments for a portion or all of their product line, this requirement is 

not applicable.

(g) You may disable any AECDs that have been approved solely for emergency vehicle 

applications under paragraph (4) of the definition of defeat device in §86.1803. The 

emission standards do not apply when any of these AECDs are active.

§86.132-96—[Amended]

126. Section 86.132-96 is amended by removing and reserving paragraph (k). 

127. Section 86.134-96 is amended by revising paragraphs (g)(1)(vi), (g)(1)(xvi), and 

(g)(2)(vi), and adding paragraph (g)(4) to read as follows:

§ 86.134-96 Running loss test.

* * * * *

(g) * * *

(1) * * *

(vi) Set vehicle air conditioning controls as described in 40 CFR 1066.835. 

* * * * *

(xvi) Fuel tank pressure must not exceed 10 inches of water during the running loss test, 

except that temporary exceedances are allowed for vehicles whose tank pressure 

remained below 10 inches of water during the entire outdoor driving period specified in 

§ 86.129. These temporary pressure exceedances may not occur for more than 10 percent 

of the total driving time. 

* * * * *

(2) * * *

(vi) Set vehicle air conditioning controls as described in 40 CFR 1066.835. 

* * * * *

(4) High-altitude testing. For testing under high-altitude conditions, decrease the target 

ambient and fuel temperatures by 5°F. For example, the fuel temperature profile should 

be adjusted downward based on a nominal starting temperature of 90°F, and the nominal 

temperature in the enclosure should be 90°F.
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* * * * *

§86.135-00 [Removed]

128. Section 86.135-00 is removed.

129. Section 86.135-90 is amended by revising paragraphs (a) and (d) to read as 

follows: 

§86.135-90 Dynamometer procedure.

(a) The dynamometer run consists of two tests— a “cold” start test, after a minimum 12-

hour and a maximum 36-hour soak according to the provisions of §§86.132 and 86.133, 

and a “hot” start test following the “cold” start by 10 minutes. Engine startup (with all 

accessories turned off), operation over the UDDS and engine shutdown make a complete 

cold-start test. Engine startup and operation over the first 505 seconds of the driving 

schedule complete the hot start test. The exhaust emissions are diluted with ambient air in 

the dilution tunnel as shown in Figure B94-5 and Figure B94-6. A dilution tunnel is not 

required for testing vehicles waived from the requirement to measure particulate matter. 

Six particulate samples are collected on filters for weighing; the first sample plus backup 

is collected during the first 505 seconds of the cold-start test; the second sample plus 

backup is collected during the remainder of the cold-start test (including shutdown); the 

third sample plus backup is collected during the hot start test. Continuous or batch 

proportional samples of gaseous emissions are collected for analysis during each test 

phase. Use the following measurement procedures for each type of engine:

(1) For gasoline-fueled, natural gas-fueled and liquefied petroleum gas-fueled Otto-cycle 

vehicles, the composite samples collected in bags are analyzed for THC, CO, CO2, CH4, 

and NOx. 

(2) For petroleum-fueled diesel-cycle vehicles (optional for natural gas-fueled, liquefied 

petroleum gas-fueled and methanol-fueled diesel-cycle vehicles), THC is sampled and 

analyzed continuously according to the provisions of §86.110. Parallel samples of the 

dilution air are similarly analyzed for THC, CO, CO2, CH4, and NOx. 

(3) For natural gas-fueled, liquefied petroleum gas-fueled and methanol-fueled vehicles, 

bag samples are collected and analyzed for THC (if not sampled continuously), CO, CO2, 

CH4, and NOx. 

(4) For methanol-fueled vehicles, methanol and formaldehyde samples are taken for both 

exhaust emissions and dilution air (a single dilution air formaldehyde sample, covering 

the total test period may be collected). Parallel bag samples of dilution air are analyzed 

for THC, CO, CO2, CH4, and NOx. 

* * * * *

(d) Practice runs over the prescribed driving schedule may be performed at test point, 

provided an emission sample is not taken, for the purpose of finding the appropriate 

throttle action to maintain the proper speed-time relationship, or to permit sampling 

system adjustment. Both smoothing of speed variations and excessive accelerator pedal 

perturbations are to be avoided. When using two-roll dynamometers a truer speed-time 

trace may be obtained by minimizing the rocking of the vehicle in the rolls; the rocking 

of the vehicle changes the tire rolling radius on each roll. This rocking may be minimized 

by restraining the vehicle horizontally (or nearly so) by using a cable and winch.

* * * * *
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§86.135-94 and 86.137-90 [Removed]

130. Sections 86.135-94 and 86.137-90 are removed.

131. Section 86.137-94 is amended by revising paragraphs (b)(16) through (b)(24) to 

read as follows:

§ 86.137-94 Dynamometer test run, gaseous and particulate emissions.

* * * * *

(b) * * *

(16) Immediately after the end of the sample period, turn off the cooling fan and close the 

engine compartment cover.

(17) Turn off the CVS or disconnect the exhaust tube from the tailpipe(s) of the vehicle.

(18) Repeat the steps in paragraphs (b)(2) through (b)(12) of this section for the hot start 

test, except only two evacuated sample bags, two methanol sample impingers, two 

formaldehyde sample impingers, and one pair of particulate sample filters, as appropriate, 

are required. The step in paragraph (b)(9) of this section shall begin between 9 and 11 

minutes after the end of the sample period for the cold-start test.

(19) At the end of the deceleration scheduled to occur at 505 seconds, simultaneously

turn off gas flow measuring device No. 1 (and the petroleum-fueled diesel hydrocarbon 

integrator No. 1; mark the petroleum-fueled diesel hydrocarbon recorder chart and turn 

off the No. 1 particulate sample pump, if applicable) and position the sample selector 

valve to the “standby” position. (Engine shutdown is not part of the hot start test sample 

period.) Record the measured roll or shaft revolutions (and the No. 1 gas meter reading or 

flow measurement instrument). Carefully remove the third pair of particulate sample 

filters from the holder and place in a clean petri dish and cover, if applicable.

(20) As soon as possible, transfer the hot start “transient” exhaust and dilution air 

samples to the analytical system and process the samples according to § 86.140, 

obtaining a stabilized reading of the exhaust bag sample on all analyzers within 20 

minutes of the end of the sample collection phase of the test. Obtain methanol and 

formaldehyde sample analyses, if applicable, within 24 hours of the end of the sample 

period. If it is not possible to perform analysis on the methanol and formaldehyde 

samples within 24 hours, the samples should be stored in a dark, cold (4-10 °C) 

environment until analysis. Analyze the samples within fourteen days.

(21) As soon as possible, and in no case longer than one hour after the end of the hot start 

phase of the test, transfer the six particulate filters to the weighing chamber for post-test 

conditioning, if applicable.

(22) Disconnect the exhaust tube from the vehicle tailpipe(s) and drive the vehicle from 

dynamometer.

(23) The CVS or CFV may be turned off, if desired.

(24) Vehicles to be tested for evaporative emissions proceed according to §86.134; 

vehicles to be tested with the supplemental two-diurnal test sequence for evaporative 

emissions proceed according to §86.138-96(k). For all others, this completes the test 

sequence.

§86.137-96 [Removed]

132. Section 86.137-96 is removed.
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133. Section 86.142-90 is amended by revising paragraph (d) to read as follows:

§ 86.142-90 Records required.

* * * * *

(d) Test results. Also include a comparison of drive cycle energy and target cycle energy

relative to both inertia and road load forces as specified in 40 CFR 1066.425 for each 

drive cycle or test phase, as appropriate. 

* * * * *

134. Section 86.143-96 is amended by revising paragraph (c) to read as follows:

§ 86.143-96 Calculations; evaporative emissions.

* * * * *

(c) If the test fuel contains at least 25 % oxygenated compounds by volume, measure the 

concentration of oxygenated compounds directly using a photoacoustic analyzer specified 

in 40 CFR 1065.269 or using impingers as described in 40 CFR 1065.805(f). Calculate 

total hydrocarbon equivalent emissions with the following equation, using density values 

specified in 40 CFR 1066.1005(f):

 

OHCi

THCE THC THC OHCi[THC-FID]

1 OHCi

1

N

i

m

m m  RF

 

     

Where:

mTHCE = the sum of the mass of THCE in the SHED.

mTHC = the mass of THC and all oxygenated hydrocarbons in the SHED, as measured by 

the FID. Calculate THC mass based on ρTHC.

ρTHC = the effective C1-equivalent density of THC as specified in 40 CFR 1066.1005(f).

mOHCi = the mass of oxygenated species i in the SHED.

ρOHCi = the C1-equivalent density of oxygenated species i.

RFOHCi[THC-FID] = the response factor of a THC-FID to oxygenated species i relative to 

propane on a C1-equivalent basis as determined in 40 CFR 1065.845.

* * * * *

135. Section 86.153-98 is amended by adding paragraph (b)(3) to read as follows:

§86.153-98 Vehicle and canister preconditioning; refueling test.

* * * * *

(b) * * *

(3) Manufacturers may use the procedures described in this paragraph (b) to demonstrate 

compliance with the seal test for vehicles with fuel tanks exceeding 35 gallons nominal 

fuel tank capacity, and for any incomplete vehicles.

* * * * *

§§86.162-00 and 86.167-17 [Removed]

136. Sections 86.162-00 and 86.167-17 are removed.

137. Subpart C is revised to consist of §§ 86.201 and 86.213 to read as follows:
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Subpart C—Emission Regulations for 1994 and Later Model Year Gasoline-Fueled 

New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty 

Passenger Vehicles; Cold Temperature Test Procedures

Sec.

86.201 General applicability.

86.213 Fuel specifications.

Subpart C—Emission Regulations for 1994 and Later Model Year Gasoline-Fueled 

New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty 

Passenger Vehicles; Cold Temperature Test Procedures

§ 86.201 General applicability.

(a) Vehicles are subject to cold temperature testing requirements as described in subpart 

S of this part and 40 CFR part 600. Perform testing to measure CO and NMHC 

emissions and determine fuel economy as described in 40 CFR part 1066; see especially 

40 CFR 1066.710.

(b) Perform intermediate temperature testing as follows:

(1) For testing during ambient temperatures of less than 50 °F (10 °C), perform 

testing as described in 40 CFR part 1066, subpart H.

(2) For testing at temperatures of 50 °F (10 °C) or higher, perform FTP testing as 

described in 40 CFR part 1066.

(c) Through model year 2021, manufacturers may certify vehicles based on data collected 

according to previously published cold temperature and intermediate temperature testing

procedures. In addition, we may approve the use of previously published cold

temperature and intermediate temperature testing procedures for later model years as an 

alternative procedure under 40 CFR 1066.10(c).

(d) Section 86.213 describes special provisions related to test fuel specifications. 

§86.213 Fuel specifications.

(a) Gasoline. Use a gasoline test fuel with ethanol (low-level blend only) or without 

ethanol as follows:

(1) You must certify using service accumulation fuel and E10 test fuel as specified in 

§86.113 for any vehicles required to use a low-level ethanol-gasoline blend test fuel 

for measuring exhaust emissions. You may use this test fuel any time earlier than we 

specify. 

(2) You may use the test fuel specified in this paragraph (a)(2) for vehicles that are 

not yet subject to exhaust testing with an ethanol-blend test fuel under §86.113. 

Manufacturers may certify based on this fuel using carryover data until testing with 

the ethanol-blend test fuel is required. The following specifications apply for 

gasoline test fuel without ethanol:
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Table 1 of §86.213–Cold temperature test fuel specifications for gasoline without 

ethanol

Item Regular Premium Reference 

Procedure1

(RON+MON)/2287.8±0.3 92.3±0.5 ASTM D2699

Sensitivity ASTM D2700 37.5 7.5

Distillation Range (°F):

 Evaporated initial boiling point

 10% evaporated

 50% evaporated

 90% evaporated

 Evaporated final boiling point

76 – 96

98 - 118

179 - 214

316 - 346

413 Maximum

76 – 96

105 - 125

195 - 225

316 - 346

413 Maximum

ASTM D86

Hydrocarbon composition (vol %):

 Olefins

 Aromatics

 Saturates

12.5±0.5

26.4±4.0

Remainder

10.5±0.5

32.0±4.0

Remainder

ASTM D1319

Lead, g/gallon 0.01, 

Maximum

0.01, 

Maximum ASTM D3237

Phosphorous, g/gallon 0.005 

Maximum

0.005 

Maximum ASTM D3231

Total sulfur, wt. %30.0015 – 0.008 0.0015 – 0.008 ASTM D2622

RVP, psi 11.5±0.3 11.5±0.3 ASTM D5191

1 ASTM procedures are incorporated by reference in §86.1.

2 Octane specifications are optional for manufacturer testing. The premium fuel specifications apply 

for vehicles designed to use high-octane premium fuel.

3

Sulfur concentration will not exceed 0.0045 weight percent for EPA testing.

(3) Manufacturers may use the E0 gasoline test fuel specified in §86.113 for 

certification instead of the fuel specified in paragraph (a)(2) of this section, as long as 

the change in test fuel does not cause cold temperature NMHC, CO, or CO2 emissions 

to decrease; manufacturers must keep records documenting these emission effects and 

make them available to EPA upon request. 

(4) We may approve alternate fuel specifications that are substantially equivalent to 

those in paragraph (a)(2) of this section for a manufacturer’s testing.

(b) Diesel fuel. Diesel fuel for testing under this subpart must meet the specifications for 

low-temperature test fuel in 40 CFR 1065.703. 

Subpart D—[Removed and reserved]

138. Subpart D, consisting of §§ 86.301-79 through 86.348-79, is removed and 

resereved.

Subpart F—[Amended]

§ 86.505-78 – [Removed]

139. Remove § 86.505-78.

140. Section 86.513-94 is redesignated as §86.513, and the newly redesignated 

§86.513 is amended by revising paragraphs (a) and (d) to read as follows:

§ 86.513 Fuel and engine lubricant specifications.
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(a) Gasoline. (1) Gasoline meeting the following specifications, or substantially

equivalent specifications approved by the Administrator, must be used for exhaust and 

evaporative testing: 

Table 1 of § 86.513—Gasoline Test Fuel Specifications

Item Value Procedure1

Distillation Range:

1. Initial boiling point, °C

2. 10% point, °C

3. 50% point, °C

4. 90% point, °C

5. End point, °C

23.9—35.0 2

48.9—57.2

93.3—110.0

148.9—162.8

212.8 maximum

ASTM D86

Hydrocarbon composition:

1. Olefins, volume %

2. Aromatics, volume %

3. Saturates

10 maximum

35 maximum

Remainder

ASTM D1319

Lead (organic), g/liter 0.013 maximum ASTM D3237

Phosphorous, g/liter 0.0013 maximum ASTM D3231

Sulfur, weight % 0.008 maximum ASTM D2622

Dry Vapor Pressure 

Equivalent (DVPE), kPa 55.2 to 63.4 3 ASTM D5191

1 ASTM procedures are incorporated by reference in §86.1.

2

For testing at altitudes above 1,219 m, the specified initial boiling 

point range is (23.9 to 40.6) °C.

3

For testing at altitudes above 1,219 m, the specified volatility range is 

52 to 55 kPa. Calculate dry vapor pressure equivalent, DVPE, based on 

the measured total vapor pressure, pT, using the following equation: 

DVPE (kPa) = 0.956∙pT - 2.39 (or DVPE (psi) = 0.956∙pT – 0.347). DVPE

is intended to be equivalent to Reid Vapor Pressure using a different 

test method.

(2) The following specifications apply for fuels used during service accumulation for 

certification:

(i) Unleaded gasoline and engine lubricants representative of commercial fuels and 

engine lubricants which will be generally available through retail outlets shall be used in 

service accumulation.

(ii) The octane rating of the gasoline used shall be no higher than 4.0 Research octane 

numbers above the minimum recommended by the manufacturer.

(iii) The Reid Vapor Pressure of the gasoline used shall be characteristic of commercial 

gasoline fuel during the season in which the service accumulation takes place.

* * * * *

(d) Natural gas fuel. (1) Natural gas meeting the following specifications, or substantially

equivalent specifications approved by the Administrator, must be used for exhaust and 

evaporative testing:
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Table 2 of § 86.513—Natural Gas Test Fuel Specifications

Item Value1

Methane, CH4 Minimum, 89.0 mole percent 

Ethane, C2H6 Maximum, 4.5 mole percent 

C3 and higher Maximum, 2.3 mole percent

C6 and higher Maximum, 0.2 mole percent

Oxygen Maximum, 0.6 mole percent

Inert gases (sum of CO2 and N2) Maximum, 4.0 mole percent

1 All parameters are based on the reference procedures in ASTM D1945 

(incorporated by reference in §86.1).

(2) The natural gas at ambient conditions must have a distinctive odor potent enough for 

its presence to be detected down to a concentration in air of not over one-fifth of the 

lower limit of flammability.

(3) Natural gas fuel and engine lubricants representative of commercial fuels and engine 

lubricants generally available through retail outlets shall be used in service accumulation.

(4) A natural gas fuel meeting different specifications may be used for testing and service 

accumulation if all the following conditions are met:

(i) The alternate test fuel is commercially available.

(ii) Information, acceptable to the Administrator, is provided to show that only the 

designated fuel will be used in customer service.

(iii) The Administrator must provide advance written approval for the alternate test fuel.

* * * * *

141. Section 86.515-78 is amended by revising paragraphs (a) and (d) to read as 

follows: 

§ 86.515-78 EPA urban dynamometer driving schedule.

(a) The dynamometer driving schedules are listed in appendix I. The driving schedules 

are defined by a smooth trace drawn through the specified speed vs. time relationships. 

They consist of a nonrepetitive series of idle, acceleration, cruise, and deceleration modes 

of various time sequences and rates. Appropriate driving schedules are as follows:

(1) Class I—Appendix I(b).

(2) Class II—Appendix I(a)(2).

(3) Class III—Appendix I(a)(2).

* * * * *

(d) For motorcycles with an engine displacement less than 50 cc and a top speed less than 

58.7 km/hr (36.5 mph), the speed indicated for each second of operation on the applicable 

Class I driving trace (speed versus time sequence) specified in appendix I(b) shall be 

adjusted downward by the ratio of actual top speed to specified maximum test speed. 

Calculate the ratio with three significant figures by dividing the top speed of the 

motorcycle in km/hr by 58.7. For example, for a motorcycle with a top speed of 48.3 

km/hr (30 mph), the ratio would be 48.3/58.7 = 0.823. The top speed to be used under 

this section shall be indicated in the manufacturer's application for certification, and shall 

be the highest sustainable speed of the motorcycle with an 80 kg rider on a flat paved 

surface. If the motorcycle is equipped with a permanent speed governor that is unlikely to 

be removed in actual use, measure the top speed in the governed configuration; otherwise 

measure the top speed in the ungoverned configuration.
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Subpart G—[Amended]

142. Section 86.608-98 is amended by revising paragraph (a) to read as follows: 

§ 86.608-98 Test procedures.

(a) The prescribed test procedures are the Federal Test Procedure, as described in subpart 

B of this part, and the cold temperature CO test procedure as described in subpart C of 

this part. For purposes of Selective Enforcement Audit testing, the manufacturer shall 

not be required to perform any of the test procedures in subpart B of this part relating to 

evaporative emission testing, other than refueling emissions testing, except as specified in 

paragraph (a)(2) of this section.

(1) The Administrator may omit any of the testing procedures described in paragraph 

(a) of this section. Further, the Administrator may, on the basis of a written 

application by a manufacturer, approve optional test procedures other than those in 

subparts B and C of this part for any motor vehicle which is not susceptible to 

satisfactory testing using the procedures in subparts B and C of this part.

(2) The following exceptions to the test procedures in subpart B of this part are 

applicable to Selective Enforcement Audit testing:

(i) For mileage accumulation, the manufacturer may use test fuel meeting the 

specifications for mileage and service accumulation fuels of §86.113. Otherwise, 

the manufacturer may use fuels other than those specified in this section only with 

the advance approval of the Administrator.

(ii) The manufacturer may measure the temperature of the test fuel at other than 

the approximate mid-volume of the fuel tank, as specified in §86.131–96(a) with 

only a single temperature sensor, and may drain the test fuel from other than the 

lowest point of the tank, as specified in §§86.131–96(b) and 86.152–98(a), 

provided an equivalent method is used. Equivalency documentation shall be 

maintained by the manufacturers and shall be made available to the Administrator 

upon request. Additionally, for any test vehicle that has remained under 

laboratory ambient temperature conditions for at least 6 hours prior to testing, the 

vehicle soak described in §86.132–96(c) may be eliminated upon approval of the 

Administrator. In such cases, the vehicle shall be operated through the 

preconditioning drive described in §86.132–96(c) immediately following the fuel 

drain and fill procedure described in §86.132–96(b).

(iii) The manufacturer may perform additional preconditioning on Selective 

Enforcement Audit test vehicles other than the preconditioning specified in 

§86.132 only if the additional preconditioning was performed on certification test 

vehicles of the same configuration.

(iv) [Reserved] 

(v) The manufacturer may substitute slave tires for the drive wheel tires on the 

vehicle as specified in §86.135–90(e): Provided, that the slave tires are the same 

size.

(vi) [Reserved] 

(vii) In performing exhaust sample analysis under §86.140–94.

(A) When testing diesel vehicles, or methanol-fueled Otto-cycle vehicles, the 

manufacturer shall allow a minimum of 20 minutes warm-up for the HC 

analyzer, and for diesel vehicles, a minimum of two hours warm-up for the 

CO, CO2. and NOx analyzers. (Power is normally left on infrared and 
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chemiluminescent analyzers. When not in use, the chopper motors of the 

infrared analyzers are turned off and the phototube high voltage supply to the 

chemiluminescent analyzers is placed in the standby position.)

(B) The manufacturer shall exercise care to prevent moisture from condensing 

in the sample collection bags.

(viii) The manufacturer need not comply with §86.142 or §86.155, since the 

records required therein are provided under other provisions of this subpart G.

(ix) If a manufacturer elects to perform the background determination procedure 

described in paragraph (a)(2)(xi) of this section in addition to performing the 

refueling emissions test procedure, the elapsed time between the initial and final 

FID readings shall be recorded, rounded to the nearest second rather than minute 

as described in §86.154–98(e)(8). In addition, the vehicle soak described in 

§86.153–98(e) shall be conducted with the windows and luggage compartment of 

the vehicle open.

(x) The Administrator may elect to perform a seal test, described in §86.153–

98(b), of both integrated and non-integrated systems instead of the full refueling 

test. When testing non-integrated systems, a manufacturer may conduct the 

canister purge described in §86.153–98(b)(1) directly following the 

preconditioning drive described in §86.132–96(e) or directly following the 

exhaust emissions test described in §86.137–96.

(xi) In addition to the refueling test, a manufacturer may elect to perform the 

following background emissions determination immediately prior to the refueling 

measurement procedure described in §86.154, provided EPA is notified of this 

decision prior to the start of testing in an SEA.

(A) The SHED shall be purged for several minutes immediately prior to the 

background determination. Warning: If at any time the concentration of 

hydrocarbons, of methanol, or of methanol and hydrocarbons exceeds 15,000 

ppm C, the enclosure should be immediately purged. This concentration 

provides a 4:1 safety factor against the lean flammability limit.

(B) The FID (or HFID) hydrocarbon analyzer shall be zeroed and spanned 

immediately prior to the background determination. If not already on, the 

enclosure mixing fan and the spilled fuel mixing blower shall be turned on at 

this time.

(C) Place the vehicle in the SHED. The ambient temperature level 

encountered by the test vehicle during the entire background emissions 

determination shall be 80 °F ±3 °F. The windows and luggage compartment of 

the vehicle must be open and the gas cap must be secured.

(D) Seal the SHED. Immediately analyze the ambient concentration of 

hydrocarbons in the SHED and record. This is the initial background 

hydrocarbon concentration.

(E) Soak the vehicle for ten minutes ±1 minute.

(F) The FID (or HFID) hydrocarbon analyzer shall be zeroed and spanned 

immediately prior to the end of the background determination.

(G) Analyze the ambient concentration of hydrocarbons in the SHED and 

record. This is the final background hydrocarbon concentration.
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(H) The total hydrocarbon mass emitted during the background determination 

is calculated according to §86.156. To obtain a per-minute background 

emission rate, divide the total hydrocarbon mass calculated in this paragraph 

by the duration of the soak, rounded to the nearest second, described in 

paragraph (a)(2)(xi)(G) of this section.

(I) The background emission rate is multiplied by the duration of the refueling 

measurement obtained in paragraph (a)(2)(ix) of this section. This number is 

then subtracted from the total grams of emissions calculated for the refueling 

test according to §86.156–98(a) to obtain the adjusted value for total refueling 

emissions. The final results for comparison with the refueling emission 

standard shall be computed by dividing the adjusted value for total refueling 

mass emissions by the total gallons of fuel dispensed in the refueling test as 

described in §86.156–98(b).

(xii) In addition to the requirements of subpart B of this part, the manufacturer 

shall prepare gasoline-fueled and methanol-fueled vehicles as follows prior to 

emission testing:

(A) The manufacturer shall inspect the fuel system to ensure the absence of 

any leaks of liquid or vapor to the atmosphere by applying a pressure of 

14.5±0.5 inches of water (3.6±0.1 kPa) to the fuel system, allowing the 

pressure to stabilize, and isolating the fuel system from the pressure source. 

Following isolation of the fuel system, pressure must not drop more than 2.0 

inches of water (0.5 kPa) in five minutes. If required, the manufacturer shall 

perform corrective action in accordance with paragraph (d) of this section and 

report this action in accordance with §86.609–98(d).

(B) When performing this pressure check, the manufacturer shall exercise care 

to neither purge nor load the evaporative or refueling emission control 

systems.

(C) The manufacturer may not modify the test vehicle's evaporative or 

refueling emission control systems by component addition, deletion, or 

substitution, except to comply with paragraph (a)(2)(ii) of this section if 

approved in advance by the Administrator.

(3) The following exceptions to the test procedures in subpart C of this part are 

applicable to Selective Enforcement Audit testing:

(i) The manufacturer may measure the temperature of the test fuel at other than 

the approximate mid-volume of the fuel tank, as specified in §86. 107-96(e), and 

may drain the test fuel from other than the lowest point of the fuel tank, provided 

an equivalent method is used. Equivalency documentation shall be maintained by

the manufacturer and shall be made available to the Administrator upon request.

(ii) In performing exhaust sample analysis under §86.140, the manufacturer shall 

exercise care to prevent moisture from condensing in the sample collection bags.

(iii) The manufacturer need not comply with §86.142 since the records required 

therein are provided under other provisions of this subpart G.

(iv) In addition to the requirements of subpart C of this part, the manufacturer 

shall prepare gasoline-fueled vehicles as follows prior to exhaust emission testing:

(A) The manufacturer shall inspect the fuel system to ensure the absence of 

any leaks of liquid or vapor to the atmosphere by applying a pressure of 
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14.5±0.5 inches of water (3.6±0.1 kPa) to the fuel system allowing the 

pressure to stabilize and isolating the fuel system from the pressure source. 

Following isolation of the fuel system, pressure must not drop more than 2.0 

inches of water (0.5 kPa) in five minutes. If required, the manufacturer shall 

perform corrective action in accordance with paragraph (d) of this section and 

report this action in accordance with §86.609–98(d).

(B) When performing this pressure check, the manufacturer shall exercise care 

to neither purge nor load the evaporative or refueling emission control system.

(C) The manufacturer shall not modify the test vehicle's evaporative or 

refueling emission control system by component addition, deletion, or 

substitution, except if approved in advance by the Administrator, to comply 

with paragraph (a)(3)(i) of this section. 

* * * * *

143. Section 86.609-98 is amended by revising paragraphs (a), (b), and (c) to read as 

follows: 

§ 86.609-98 Calculation and reporting of test results.

(a) Initial test results are calculated following the test procedures specified in §86.608–

98(a). Round the initial test results to the number of decimal places contained in the 

applicable emission standard expressed to one additional significant figure. 

(b) Final test results for each test vehicle are calculated by summing the initial test results 

derived in paragraph (a) of this section for each test vehicle, dividing by the number of 

times that specific test has been conducted on the vehicle, and rounding to the same 

number of decimal places contained in the applicable standard expressed to one 

additional significant figure. 

(c) Final deteriorated test results —(1) For each test vehicle. The final deteriorated test 

results for each light-duty vehicle tested for exhaust emissions and/or refueling emissions 

according to subpart B, subpart C, or subpart R of this part are calculated by first 

multiplying or adding, as appropriate, the final test results by or to the appropriate 

deterioration factor derived from the certification process for the engine or 

evaporative/refueling family and model year to which the selected configuration belongs, 

and then by multiplying by the appropriate reactivity adjustment factor, if applicable, and 

rounding to the same number of decimal places contained in the applicable emission 

standard. For the purpose of this paragraph (c), if a multiplicative deterioration factor as 

computed during the certification process is less than one, that deterioration factor is one. 

If an additive deterioration factor as computed during the certification process is less than 

zero, that deterioration factor will be zero.

(2) Exceptions. There are no deterioration factors for light-duty vehicle emissions 

obtained during spitback testing in accordance with §86.146. Accordingly, for the fuel 

dispensing spitback test, the term “final deteriorated test results” means the final test 

results derived in paragraph (b) of this section for each test vehicle, rounded to the same 

number of decimal places contained in the applicable emission standard. 

* * * * *

§86.610-98—[Amended]

144. Section 86.610-98 is amended by removing and reserving paragraph (c)(2).
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145. Section 86.612-97 is revised to read as follows: 

§ 86.612-97 Suspension and revocation of certificates of conformity.

(a) The certificate of conformity is immediately suspended with respect to any vehicle 

failing pursuant to §86.610-98 (b) effective from the time that testing of that vehicle is 

completed.

(b) The Administrator may suspend the certificate of conformity for a configuration that 

does not pass a selective enforcement audit pursuant to §86.610–98(c) based on the first 

test, or all tests, conducted on each vehicle. This suspension will not occur before ten 

days after failure to pass the audit.

(c) If the results of vehicle testing pursuant to the requirements of this subpart indicates 

the vehicles of a particular configuration produced at more than one plant do not conform 

to the regulations with respect to which the certificate of conformity was issued, the 

Administrator may suspend the certificate of conformity with respect to that 

configuration for vehicles manufactured by the manufacturer in other plants of the 

manufacturer.

(d) The Administrator will notify the manufacturer in writing of any suspension or 

revocation of a certificate of conformity in whole or in part: Except, that the certificate of 

conformity is immediately suspended with respect to any vehicle failing pursuant to 

§86.610-98(b) and as provided for in paragraph (a) of this section.

(e) The Administrator may revoke a certificate of conformity for a configuration when 

the certificate has been suspended pursuant to paragraph (b) or (c) of this section if the 

proposed remedy for the nonconformity, as reported by the manufacturer to the 

Administrator, is one requiring a design change(s) to the engine and/or emission control 

system as described in the Application for Certification of the affected configuration.

(f) Once a certificate has been suspended for a failed vehicle as provided for in paragraph 

(a) of this section, the manufacturer must take the following actions:

(1) Before the certificate is reinstated for that failed vehicle—

(i) Remedy the nonconformity; and

(ii) Demonstrate that the vehicle's final deteriorated test results conform to the 

applicable emission standards or family particulate emission limits, as defined in 

this part 86 by retesting the vehicle in accordance with the requirements of this 

subpart.

(2) Submit a written report to the Administrator within thirty days after successful 

completion of testing on the failed vehicle, which contains a description of the 

remedy and test results for the vehicle in addition to other information that may be 

required by this subpart.

(g) Once a certificate has been suspended pursuant to paragraph (b) or (c) of this section, 

the manufacturer must take the following actions before the Administrator will consider 

reinstating such certificate:

(1) Submit a written report to the Administrator which identifies the reason for the 

noncompliance of the vehicles, describes the proposed remedy, including a 

description of any proposed quality control and/or quality assurance measures to be 

taken by the manufacturer to prevent the future occurrence of the problem, and states 

the date on which the remedies will be implemented.
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(2) Demonstrate that the engine family or configuration for which the certificate of 

conformity has been suspended does in fact comply with the requirements of this 

subpart by testing vehicles selected from normal production runs of that engine 

family or configuration at the plant(s) or the facilities specified by the Administrator, 

in accordance with: the conditions specified in the initial test order pursuant to 

§86.603 for a configuration suspended pursuant to paragraph (b) or (c) of this section. 

(3) If the Administrator has not revoked the certificate pursuant to paragraph (e) of 

this section and if the manufacturer elects to continue testing individual vehicles after 

suspension of a certificate, the certificate is reinstated for any vehicle actually

determined to have its final deteriorated test results in conformance with the 

applicable standards through testing in accordance with the applicable test 

procedures.

(h) Once a certificate for a failed engine family or configuration has been revoked under 

paragraph (e) of this section and the manufacturer desires to introduce into commerce a 

modified version of that engine family or configuration, the following actions will be 

taken before the Administrator may issue a certificate for the new engine family or 

configuration:

(1) If the Administrator determines that the proposed change(s) in vehicle design may

have an effect on emission performance deterioration and/or fuel economy, he/she 

shall notify the manufacturer within five working days after receipt of the report in 

paragraph (g)(1) of this section whether subsequent testing under this subpart will be 

sufficient to evaluate the proposed change(s) or whether additional testing will be 

required.

(2) After implementing the change(s) intended to remedy the nonconformity, the 

manufacturer shall demonstrate, if the certificate was revoked pursuant to paragraph 

(e) of this section, that the modified vehicle configuration does in fact conform with 

the requirements of this subpart by testing vehicles selected from normal production 

runs of that modified vehicle configuration in accordance with the conditions 

specified in the initial test order pursuant to §86.603. The Administrator shall 

consider this testing to satisfy the testing requirements of §86.079–32 or §86.079–33 

if the Administrator had so notified the manufacturer. If the subsequent testing results 

in a pass decision pursuant to the criteria in §86.610–98(c), the Administrator shall 

reissue or amend the certificate, if necessary, to include that configuration: Provided, 

that the manufacturer has satisfied the testing requirements specified in paragraph 

(h)(1) of this section. If the subsequent audit results in a fail decision pursuant to the

criteria in §86.610-98(c), the revocation remains in effect. Any design change 

approvals under this subpart are limited to the modification of the configuration 

specified by the test order.

(i) A manufacturer may at any time subsequent to an initial suspension of a certificate of 

conformity with respect to a test vehicle pursuant to paragraph (a) of this section, but not 

later than fifteen (15) days or such other period as may be allowed by the Administrator 

after notification of the Administrator's decision to suspend or revoke a certificate of 

conformity in whole or in part pursuant to paragraph (b), (c) or (e) of this section, request 

that the Administrator grant such manufacturer a hearing as to whether the tests have 

been properly conducted or any sampling methods have been properly applied.
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(j) After the Administrator suspends or revokes a certificate of conformity pursuant to 

this section or notifies a manufacturer of his intent to suspend, revoke or void a certificate 

of conformity under §86.007-30(e) or §86.1850, and prior to the commencement of a 

hearing under §86.614, if the manufacturer demonstrates to the Administrator's 

satisfaction that the decision to suspend, revoke or void the certificate was based on 

erroneous information, the Administrator shall reinstate the certificate.

(k) To permit a manufacturer to avoid storing non-test vehicles when conducting testing 

of an engine family or configuration subsequent to suspension or revocation of the 

certificate of conformity for that engine family or configuration pursuant to paragraph 

(b), (c), or (e) of this section, the manufacturer may request that the Administrator 

conditionally reinstate the certificate for that engine family or configuration. The 

Administrator may reinstate the certificate subject to the condition that the manufacturer 

consents to recall all vehicles of that engine family or configuration produced from the 

time the certificate is conditionally reinstated if the engine family or configuration fails 

the subsequent testing and to remedy any nonconformity at no expense to the owner.

Subpart H—[Removed and reserved]

146. Subpart H, consisting of §§ 86.701-94 through 86.709-99, is removed and 

reserved.

Subpart L—[Amended]

147. Section 86.1102-87 is amended by adding a definition of “Round” to paragraph 

(b) in alphabetical order to read as follows:

§ 86.1102-87 Definitions.

* * * * *

Round has the meaning given in 40 CFR 1065.1001.

* * * * *

148. Section 86.1105-87 is amended by revising paragraph (e) to read as follows:

§ 86.1105-87 Emission standards for which nonconformance penalties are 

available.

* * * * *

(e) The values of COC50 , COC90 , and MC50 in paragraphs (a) and (b) of this section are 

expressed in December 1984 dollars. The values of COC50 , COC90 , and MC50 in 

paragraphs (c) and (d) of this section are expressed in December 1989 dollars. The values 

of COC50 , COC90 , and MC50 in paragraph (f) of this section are expressed in December 

1991 dollars. The values of COC50 , COC90 , and MC50 in paragraphs (g) and (h) of this 

section are expressed in December 1994 dollars. The values of COC50 , COC90 , and 

MC50 in paragraph (i) of this section are expressed in December 2001 dollars. The values 

of COC50 , COC90 , and MC50 in paragraph (j) of this section are expressed in December 

2011 dollars. These values shall be adjusted for inflation to dollars as of January of the 

calendar year preceding the model year in which the NCP is first available by using the 

change in the overall Consumer Price Index, and rounded to the nearest whole dollar.

* * * * *
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Subpart M—[Removed and reserved]

149. Subpart M, consisting of §§ 86.1201-90 through 86.1246-96, is removed and 

reserved.

Subpart N--Exhaust Test Procedures for Heavy-duty Engines

150. The heading of subpart N is revised to read as set forth above. 

151. Section 86.1305-2010 is redesignated as § 86.1305, and newly redesignated § 

86.1305 is revised to read as follows:

§ 86.1305 Introduction; structure of subpart.

(a) This subpart specifies the equipment and procedures for performing exhaust-emission 

tests on Otto-cycle and diesel-cycle heavy-duty engines. Subpart A of this part sets forth 

the emission standards and general testing requirements to comply with EPA certification 

procedures.

(b) Use the applicable equipment and procedures for spark-ignition or compressionignition engines in 40 CFR part 1065 to determine whether engines meet the duty-cycle 

emission standards in subpart A of this part. Measure the emissions of all regulated 

pollutants as specified in 40 CFR part 1065. Use the duty cycles and procedures specified 

in §§ 86.1333, 86.1360, and 86.1362. Adjust emission results from engines using 

aftertreatment technology with infrequent regeneration events as described in § 86.004–

28.

(c) The provisions in §§86.1370 and 86.1372 apply for determining whether an engine 

meets the applicable not-to-exceed emission standards.

(d) Measure smoke using the procedures in subpart I of this part for evaluating whether 

engines meet the smoke standards in subpart A of this part.

(e) Use the fuels specified in 40 CFR part 1065 to perform valid tests, as follows:

(1) For service accumulation, use the test fuel or any commercially available fuel that 

is representative of the fuel that in-use engines will use.

(2) For diesel-fueled engines, use the ultra low-sulfur diesel fuel specified in 40 CFR 

part 1065 for emission testing.

(3) For gasoline-fueled engines, use the appropriate E10 fuel specified in 40 CFR part 

1065; however, through model year 2021 you may instead use the appropriate E0 fuel 

specified in 40 CFR part 1065, with the exception that the E0 fuel must have sulfur 

concentration between 0.0015 and 0.008 weight percent and research octane of at 

least 93. Starting in model year 2022, you may certify up to 5 percent of your 

nationwide sales volume of engines certified under subpart A of this part in a given 

model year based on this E0 test fuel if those engines are certified with carryover 

data.

(f) You may use special or alternate procedures to the extent we allow them under 40 

CFR 1065.10. In addition, for 2010 and earlier model year engines, you may use 

modified test procedures as needed to conform to the procedures that were specified at 

the time of emission testing for the model year in question.

(g) This subpart applies to you as a manufacturer, and to anyone who does testing for 

you.
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(h) For testing conducted with engines installed in vehicles, including field testing 

conducted to measure emissions under Not-To-Exceed test procedures, use the test 

procedures and equipment specified in 40 CFR part 1065, subpart J.

§§ 86.1305-90, 86.1305-2004, 86.1306-07, 86.1306-96, 86.1308-84, 86.1309-90, 

86.1310-90, 86.1310-2007, 86.1311-94, 86.1312-88, 86.1312-2007, 86.1313-94, 

86.1313-98, 86.1313-2004, 86.1313-2007, 86.1314-94, 86.1316-94, 86.1318-84, 

86.1319-90, 86.1320-90, 86.1321-94, 86.1322-84, 86.1323-84, 86.1323-2007, 86.1324-

84, 86.1325-94, 86.1326-90, 86.1327-96, 86.1327-98, 86.1330-90, and 86.1332-90

[Removed]

152. Remove §§ 86.1305-90, 86.1305-2004, 86.1306-07, 86.1306-96, 86.1308-84, 

86.1309-90, 86.1310-90, 86.1310-2007, 86.1311-94, 86.1312-88, 86.1312-2007, 

86.1313-94, 86.1313-98, 86.1313-2004, 86.1313-2007, 86.1314-94, 86.1316-94, 

86.1318-84, 86.1319-90, 86.1320-90, 86.1321-94, 86.1322-84, 86.1323-84, 86.1323-

2007, 86.1324-84, 86.1325-94, 86.1326-90, 86.1327-96, 86.1327-98, 86.1330-90, and 

86.1332-90.

153. Section 86.1333-2010 is redesignated as § 86.1333, and newly redesignated § 

86.1333 is amended by revising paragraphs (a)(1), (c), and (d) to read as follows:

§ 86.1333 Transient test cycle generation.

(a) * * *

(1) To unnormalize rpm, use the following equations:

(i) For diesel engines:

%  

112

rpm MaxTest Speed Curb Idle Speed

Actualrpm Curb Idle Speed

 

 

Where:

Max Test Speed = the maximum test speed as calculated in 40 CFR part 1065.

(ii) For Otto-cycle engines:

%  

100

rpm MaxTest Speed Curb Idle Speed

Actualrpm Curb Idle Speed

 

 

Where:

Max Test Speed = the maximum test speed as calculated in 40 CFR part 1065.

* * * * *

(c) Clutch operation. Manual transmission engines may be tested with a clutch. If used, 

the clutch shall be disengaged at all zero percent speeds, zero percent torque points, but 

may be engaged up to two points preceding a non-zero point, and may be engaged for 

time segments with zero percent speed and torque points of durations less than four 

seconds. 

(d) Determine idle speeds as specified in 40 CFR 1065.510.

§§ 86.1333-90, 86.1334-84, 86.1335-90, 86.1336-84, 86.1337-96, 86.1337-2007, 

86.1338-84, 86.1338-2007, 86.1339-90, 86.1340-90, 86.1340-94, 86.1341-90, 86.1341-

98, 86.1342-90, 86.1342-94, 86.1343-88, and 86.1344-94 [Removed]
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154. Remove §§ 86.1333-90, 86.1334-84, 86.1335-90, 86.1336-84, 86.1337-96, 

86.1337-2007, 86.1338-84, 86.1338-2007, 86.1339-90, 86.1340-90, 86.1340-94, 

86.1341-90, 86.1341-98, 86.1342-90, 86.1342-94, 86.1343-88, and 86.1344-94.

155. Section 86.1360-2007 is redesignated as § 86.1360, and newly redesignated § 

86.1360 is amended by revising paragraphs (b)(1), (c), and (f)(3) to read as follows:

§ 86.1360 Supplemental emission test; test cycle and procedures.

* * * * *

(b) * * *

(1) Perform testing as described in §86.1362 for determining whether an engine meets the 

applicable standards when measured over the supplemental emission test.

* * * * *

(c) The engine speeds A, B and C, referenced in the table in paragraph (b)(1) of this 

section, must be determined as follows:

Speed A = nlo+ 0.25 × (nhi−nlo)

Speed B = nlo+ 0.50 × (nhi−nlo)

Speed C = nlo+ 0.75 × (nhi−nlo)

Where: nhi= High speed as determined by calculating 70% of the maximum power. The 

highest engine speed where this power value occurs on the power curve is defined as nhi.

nlo= Low speed as determined by calculating 50% of the maximum power. The lowest 

engine speed where this power value occurs on the power curve is defined as nlo.

Maximum power = the maximum observed power calculated according to the engine 

mapping procedures defined in 40 CFR 1065.510.

* * * * *

(f) * * *

(3) If the Maximum Allowable Emission Limit for any point, as calculated under 

paragraphs (f)(1) and (2) of this section, is greater than the applicable Not-to-Exceed 

limit (if within the Not-to-Exceed control area defined in §86.1370(b)), then the 

Maximum Allowable Emission Limit for that point shall be defined as the applicable 

Not-to-Exceed limit.

* * * * *

156. Section 86.1362-2010 is redesignated as § 86.1362, and newly redesignated § 

86.1362 is revised to read as follows:

§ 86.1362 Steady-state testing with a ramped-modal cycle.

This section describes how to test engines under steady-state conditions. 

(a) Measure emissions by testing the engine on a dynamometer with the following 

ramped-modal duty cycle to determine whether it meets the applicable steady-state 

emission standards:

RMC

mode

Time in mode

(seconds)

Engine

speed 1,2

Torque

(percent) 2,3

1a Steady-state 170 Warm Idle 0

1b Transition 20 Linear Transition Linear Transition.

2a Steady-state 173 A 100

2b Transition 20 Linear Transition Linear Transition.
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3a Steady-state 219 B 50

3b Transition 20 B Linear Transition.

4a Steady-state 217 B 75

4b Transition 20 Linear Transition Linear Transition.

5a Steady-state 103 A 50

5b Transition 20 A Linear Transition.

6a Steady-state 100 A 75

6b Transition 20 A Linear Transition.

7a Steady-state 103 A 25

7b Transition 20 Linear Transition Linear Transition.

8a Steady-state 194 B 100

8b Transition 20 B Linear Transition.

9a Steady-state 218 B 25

9b Transition 20 Linear Transition Linear Transition.

10a Steady-state 171 C 100

10b Transition 20 C Linear Transition.

11a Steady-state 102 C 25

11b Transition 20 C Linear Transition.

12a Steady-state 100 C 75

12b Transition 20 C Linear Transition.

13a Steady-state 102 C 50

13b Transition 20 Linear Transition Linear Transition.

14 Steady-state 168 Warm Idle 0

1

Speed terms are defined in 40 CFR part 1065.

2Advance from one mode to the next within a 20-second transition phase. During the transition phase, 

command a linear progression from the speed or torque setting of the current mode to the speed or torque 

setting of the next mode.

3The percent torque is relative to maximum torque at the commanded engine speed.

(b) Perform the ramped-modal test as described in 40 CFR part 1065.

(c) For 2007 through 2010 model years, manufacturers may follow the mode order 

described in this paragraph (c) instead of the mode order specified in paragraph (a) of this 

section. Any EPA testing with these engines will rely on the same procedure used by the 

manufacturer for certification.
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RMC

mode

Time in mode

(seconds)

Engine

speed1,2

Torque

(percent) 2,3

1a Steady-state 170 Warm Idle 0

1b Transition 20 Linear Transition Linear Transition

2a Steady-state 170 A 100

2b Transition 20 A Linear Transition

3a Steady-state 102 A 25

3b Transition 20 A Linear Transition

4a Steady-state 100 A 75

4b Transition 20 A Linear Transition

5a Steady-state 103 A 50

5b Transition 20 Linear Transition Linear Transition

6a Steady-state 194 B 100

6b Transition 20 B Linear Transition

7a Steady-state 219 B 25

7b Transition 20 B Linear Transition

8a Steady-state 220 B 75

8b Transition 20 B Linear Transition

9a Steady-state 219 B 50

9b Transition 20 Linear Transition Linear Transition

10a Steady-state 171 C 100

10b Transition 20 C Linear Transition

11a Steady-state 102 C 25

11b Transition 20 C Linear Transition

12a Steady-state 100 C 75

12b Transition 20 C Linear Transition

13a Steady-state 102 C 50

13b Transition 20 Linear Transition Linear Transition

14 Steady-state 168 Warm Idle 0

1

Speed terms are defined in 40 CFR part 1065.

2 Advance from one mode to the next within a 20-second transition phase. During the transition phase, 

command a linear progression from the speed or torque setting of the current mode to the speed or torque 

setting of the next mode.

3 The percent torque is relative to maximum torque at the commanded engine speed.

§§ 86.1362-2007 and 86.1363-2007 [Removed]

157. Remove §§ 86.1362-2007 and 86.1363-2007.

158. Section 86.1370-2007 is redesignated as § 86.1370, and newly redesignated § 

86.1370 is amended by revising paragraphs (a), (b)(3), (b)(6), and (f) introductory text to 

read as follows:

§ 86.1370 Not-To-Exceed test procedures. 

(a) General. The purpose of this test procedure is to measure in-use emissions of heavyduty diesel engines while operating within a broad range of speed and load points (the 

Not-To-Exceed Control Area) and under conditions which can reasonably be expected to 

be encountered in normal vehicle operation and use. Emission results from this test 

procedure are to be compared to the Not-To-Exceed Limits specified in §86.007–

11(a)(4), or to later Not-To-Exceed Limits. The Not-To-Exceed Limits do not apply for 

engine-starting conditions. Tests conducted using the procedures specified in this subpart 

are considered valid Not-To-Exceed tests (Note: duty cycles and limits on ambient 

conditions do not apply for Not-To-Exceed tests).
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(b) * * *

(3) Notwithstanding the provisions of paragraphs (b)(1) and (2) of this section, all 

operating speed and load points with brake specific fuel consumption (BSFC) values 

within 5% of the minimum BSFC value of the engine. For the purposes of this 

requirement, BFSC must be calculated under the general test cell conditions specified in 

40 CFR part 1065. The manufacturer may petition the Administrator at certification to 

exclude such points if the manufacturer can demonstrate that the engine is not expected to 

operate at such points in normal vehicle operation and use. Engines equipped with 

drivelines with multi-speed manual transmissions or automatic transmissions with a finite 

number of gears are not subject to the requirements of this paragraph (b)(3).

* * * * *

(6)(i) For petroleum-fueled diesel cycle engines, the manufacturer may identify particular 

engine-vehicle combinations and may petition the Administrator at certification to 

exclude operating points from the Not-to-Exceed Control Area defined in paragraphs 

(b)(1) through (5) of this section if the manufacturer can demonstrate that the engine is 

not capable of operating at such points when used in the specified engine-vehicle 

combination(s).

(ii) For diesel cycle engines that are not petroleum-fueled, the manufacturer may petition 

the Administrator at certification to exclude operating points from the Not-to-Exceed 

Control Area defined in paragraphs (b)(1) through (5) of this section if the manufacturer 

can demonstrate that the engine is not expected to operate at such points in normal 

vehicle operation and use.

* * * * *

(f) NTE cold temperature operating exclusion. Engines equipped with exhaust gas 

recirculation (EGR) whose operation within the NTE control area specified in paragraph 

(b) of this section when operating during cold temperature conditions as specified in 

paragraph (f)(1) of this section are not subject to the NTE emission limits during the 

specified cold temperature conditions.

* * * * *

§86.1372-2007 ]Redesignated as § 86.1372]

159. Section 86.1372-2007 is redesignated as § 86.1372.

§§86.1375-2007 and 86.1380-2004 [Removed]

160. Remove §§86.1375-2007 and 86.1380-2004.

Subpart O—[Removed and reserved]

161. Subpart O, consisting of §§ 86.1401 through 86.1442, is removed and reserved.

Subpart R—[Removed and reserved]

162. Subpart R, consisting of §§ 86.1701-99 through 86.1780-99, is removed and 

reserved.

Subpart S – [Amended]

163. Section 86.1801-12 is amended by revising paragraphs (a) through (d) and adding 

paragraphs (e), (f), and (g) to read as follows:
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§ 86.1801-12 Applicability.

(a) Applicability. The provisions of this subpart apply to certain types of new vehicles as 

described in this paragraph (a). Where the provisions apply for a type of vehicle, they 

apply for vehicles powered by any fuel, unless otherwise specified. In some cases, 

manufacturers of heavy-duty engines and vehicles can choose whether to meet the 

requirements of this subpart or the requirements of subpart A of this part; those 

provisions are therefore considered optional, but only to the extent that manufacturers 

comply with the other set of requirements. In cases where a provision applies only to a 

certain vehicle group based on its model year, vehicle class, motor fuel, engine type, or 

other distinguishing characteristics, the limited applicability is cited in the appropriate

section. References in this subpart to 40 CFR part 86 generally apply to Tier 2 and older 

vehicles, while references to 40 CFR part 1066 generally apply to Tier 3 and newer 

vehicles; see 40 CFR 86.101 for detailed provisions related to this transition. The 

provisions of this subpart apply to certain vehicles as follows:

(1) The provisions of this subpart apply for light-duty vehicles and light-duty trucks.

(2) The provisions of this subpart apply for medium-duty passenger vehicles. The 

provisions of this subpart also apply for other complete heavy-duty vehicles at or 

below 14,000 pounds GVWR, except as follows:

(i) The provisions of this subpart are optional for diesel-cycle vehicles through 

model year 2017; however, if you are using the provisions of §86.1811-17(b)(9) 

or §86.1816-18(b)(8) to transition to the Tier 3 exhaust emission standards, the 

provisions of this subpart are optional for those diesel-cycle vehicles until the start 

of the Tier 3 phase-in for those vehicles.

(ii) Greenhouse gas emission standards apply as specified in 40 CFR parts 1036 

and 1037 instead of the standards specified in this subpart.

(3) The provisions of this subpart generally do not apply to incomplete heavy-duty 

vehicles or to complete vehicles above 14,000 pounds GVWR (see subpart A of this 

part and 40 CFR part 1037). However, this subpart applies to such vehicles in the 

following cases:

(i) Heavy duty vehicles above 14,000 pounds GVWR and all sizes of incomplete 

heavy-duty vehicles may be optionally certified to the exhaust emission standards 

in this subpart that apply for heavy-duty vehicles.

(ii) The evaporative emission standards apply for incomplete heavy-duty vehicles 

at or below 14,000 pounds GVWR. Evaporative emission standards also apply

for complete and incomplete heavy-duty vehicles above 14,000 pounds GVWR as 

specified in 40 CFR 1037.103.

(iii) Refueling emission standards apply for complete heavy-duty vehicles above 

14,000 pounds GVWR as specified in 40 CFR 1037.103. All sizes of incomplete 

heavy-duty vehicles may be optionally certified to the refueling emission

standards in this subpart.

(iv) The onboard diagnostic requirements in this subpart apply for incomplete 

vehicles at or below 14,000 pounds GVWR, but not for any vehicles above 

14,000 pounds GVWR.

(4) The provisions of this subpart are optional for diesel-fueled Class 3 heavy-duty 

vehicles in a given model year if those vehicles are equipped with engines certified to 

the appropriate standards in §86.007-11 for which less than half of the engine 
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family’s sales for the model year in the United States are for complete Class 3 heavyduty vehicles. This includes engines sold to all vehicle manufacturers. If you are the 

original manufacturer of the engine and the vehicle, base this showing on your sales 

information. If you manufacture the vehicle but are not the original manufacturer of 

the engine, you must use your best estimate of the original manufacturer's sales 

information.

(5) If you optionally certify vehicles to standards under this subpart, those vehicles 

are subject to all the regulatory requirements as if the standards were mandatory.

(b) Relationship to subpart A of this part. Unless specified otherwise, if heavy-duty

vehicles are not subject to provisions of this subpart or if manufacturers choose not to 

meet optional provisions of this subpart as described in paragraph (a) of this section, the 

engines installed in those vehicles must meet the corresponding requirements under 

subpart A of this part. If a vehicle and its installed engine comply with a mix of 

provisions from this subpart and from subpart A of this part, the vehicle must be certified 

under this subpart, and the engine does not need to be certified separately.

(c) Clean alternative fuel conversions. The provisions of this subpart also apply to clean 

alternative fuel conversions as defined in 40 CFR 85.502 of all vehicles described in 

paragraph (a) of this section.

(d) Small-volume manufacturers. Special certification procedures are available for smallvolume manufacturers as described in §86.1838.

(e) You. The term “you” in this subpart refers to manufacturers subject to the emission 

standards and other requirements of this subpart.

(f) Vehicle. The term “vehicle”, when used generically, does not exclude any type of 

vehicle for which the regulations apply (such as light-duty trucks). 

(g) Complete and incomplete vehicles. Several provisions in this subpart, including the 

applicability provisions described in this section, are different for complete and 

incomplete vehicles. We differentiate these vehicle types as described in §86.085-20.

* * * * *

164. Section 86.1803-01 is amended as follows:

a. By removing the definition for “Certification Short Test (CST)”.

b. By adding definitions for “Class 2b” and “Class 3” in alphabetical order.

c. By removing the definition for “Complete heavy-duty vehicle”.

d. By revising the definitions for “Family emission limit (FEL)”, “Heavy-duty

vehicle”, and “Hybrid electric vehicle (HEV)”.

e. By removing the definitions for “Incomplete heavy-duty vehicle” and “Incomplete 

truck”.

f. By adding definitions for “LEV III” and “Low-altitude conditions” in alphabetical 

order.

g. By removing the definition for “Low altitude conditions”.

h. By adding a definition for “Rated power” in alphabetical order.

i. By removing the definition for “Round, rounded or rounding”.

j. By adding definitions for “Round (rounded, rounding)”, “Section 177 states”, “Tier 

3”, and “United States” in alphabetical order.

k. By revising the definition for “U.S. sales”.
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l. By adding definitions for “Volatile liquid fuel” and “We (us, our)” in alphabetical 

order.

§86.1803-01 Definitions. 

* * * * *

Class 2b means relating to heavy-duty vehicles at or below 10,000 pounds GVWR.

Class 3 means relating to heavy-duty vehicles above 10,000 pounds GVWR and at or 

below 14,000 pounds GVWR.

* * * * *

Emergency vehicle means one of the following:

(1) For the greenhouse gas emission standards in §86.1818, emergency vehicle means a 

motor vehicle manufactured primarily for use as an ambulance or combination 

ambulance-hearse or for use by the U.S. Government or a State or local government for 

law enforcement.

(2) For the OBD requirements in §86.1806, emergency vehicle means a motor vehicle 

manufactured primarily for use in medical response or for use by the U.S. Government or 

a State or local government for law enforcement or fire protection.

* * * * *

Family emission limit (FEL) means a bin standard or emission level selected by the 

manufacturer that serves as the applicable emission standard for the vehicles in the family

or test group in the context of fleet-average standards or emission credits. 

* * * * *

Heavy-duty vehicle means any motor vehicle rated at more than 8,500 pounds GVWR 

or that has a vehicle curb weight of more than 6,000 pounds or that has a basic vehicle 

frontal area in excess of 45 square feet. Note that MDPVs are heavy-duty vehicles that 

are in many cases subject to requirements that apply for light-duty trucks.

* * * * *

Hybrid electric vehicle (HEV) means a motor vehicle which draws propulsion energy

from onboard sources of stored energy that are both an internal combustion engine or 

heat engine using consumable fuel, and a rechargeable energy storage system such as a 

battery, capacitor, hydraulic accumulator, or flywheel. This includes plug-in hybrid 

electric vehicles.

* * * * *

LEV III means relating to the LEV III emission standards in Title 13, §§1961.2 and 

1976 of the California Code of Regulations, as adopted by the California Air Resources 

Board (incorporated by reference in §86.1). 

* * * * *

Low-altitude conditions means a test altitude less than 549 meters (1,800 feet).

* * * * *

Rated power means an engine’s maximum power output in an installed configuration, 

as determined by using SAE J1349 (incorporated by reference in §86.1).

* * * * *

Round (rounded or rounding) has the meaning given in 40 CFR 1065.1001, unless 

otherwise specified.

* * * * *
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Section 177 states means the states that have adopted California’s motor vehicle 

standards for a particular model year under section 177 of the Clean Air Act (42 U.S.C. 

7507).

* * * * *

Tier 3 means relating to the Tier 3 emission standards described in §§86.1811-17, 

86.1813-17, and 86.1816-18. 

* * * * *

United States has the meaning given in 40 CFR 1068.30. 

* * * * *

U.S. sales means, unless otherwise specified, sales in any state or territory of the 

United States except for California or the section 177 states. Sale location is based on the 

point of first sale to a dealer, distributor, fleet operator, broker, or other entity. 

* * * * *

Volatile liquid fuel means any fuel other than diesel or biodiesel that is a liquid at 

atmospheric pressure and has a Reid Vapor Pressure higher than 2.0 pounds per square 

inch.

* * * * *

We (us, our) means the Administrator of the Environmental Protection Agency and 

any authorized representatives.

* * * * *

§ 86.1805-01 [Removed]

165. Remove § 86.1805-01.

166. A new §86.1805-17 is added to subpart S to read as follows:

§ 86.1805-17 Useful life.

(a) General provisions. The useful life values specified in this section apply for all 

exhaust, evaporative, refueling, and OBD emission requirements described in this 

subpart, except for standards that are specified to apply only at certification. These useful 

life requirements also apply to all air conditioning leakage credits, air conditioning 

efficiency credits, and other credit programs used by the manufacturer to comply with the 

fleet-average CO2 emission standards in §86.1818. Useful life values are specified as a 

given number of calendar years and miles of driving, whichever comes first.

(b) Greenhouse gas pollutants. The emission standards in §86.1818 apply for a useful life 

of 10 years or 120,000 miles for LDV and LLDT and 11 years or 120,000 miles for 

HLDT and HDV. Manufacturers may alternatively certify based on a longer useful life 

as specified in paragraph (d) of this section.

(c) Cold temperature emission standards. The cold temperature NMHC emission 

standards in §86.1811 apply for a useful life of 10 years or 120,000 miles for vehicles at 

or below 6,000 pounds GVWR, and 11 years or 120,000 miles for vehicles above 6,000 

pounds GVWR. The cold temperature CO emission standards in §86.1811 apply for a 

useful life of 5 years or 50,000 miles.

(d) Criteria pollutants. The useful life provisions of this paragraph (d) apply for all 

emission standards not covered by paragraph (b) or (c) of this section. Except as 

specified in paragraph (f) of this section and in §§ 86.1811, 86.1813, and 86.1816, the 

useful life for LDT2, HLDT, MDPV, and HDV is 15 years or 150,000 miles. The useful 
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life for LDV and LDT1 is 10 years or 120,000 miles. Manufacturers may optionally

certify LDV and LDT1 to a useful life of 15 years or 150,000 miles, in which case the 

longer useful life would apply for all the standards and requirements covered by this 

paragraph (d). 

(e) Intermediate useful life. Where exhaust emission standards are specified for an 

intermediate useful life, these standards apply for five years or 50,000 miles.

(f) Interim provisions. The useful life provisions of §86.1805-12 apply for vehicles not 

yet subject to Tier 3 requirements. For example, vehicles above 6,000 pounds GVWR 

are not subject to the useful life provisions in this section until model year 2019 unless 

manufacturers voluntarily certify to the Tier 3 requirements earlier than the regulations 

require. Also, where the transition to Tier 3 standards involves a phase-in percentage for 

a given standard, vehicles not included as part of the phase-in portion of the fleet 

continue to be subject to the useful life provisions of §86.1805-12 with respect to that 

standard. The useful life values for a set of vehicles may be different for exhaust and 

evaporative emission standards in 2021 and earlier model years; if vehicles have different 

useful life values for evaporative and exhaust emission standards, the evaporative useful 

life applies for the OBD requirements related to the leak standard and the exhaust useful 

life applies for all other OBD requirements.

§§ 86.1806-01 and 86.1806-04 [Removed]

167. Remove §§ 86.1806-01 and 86.1806-04.

168. Section 86.1806-05 is amended by revising the section heading and paragraphs 

(b) introductory text, (h), and (j) and adding paragraph (k)(7) to read as follows:

§ 86.1806-05 Onboard diagnostics.

* * * * *

(b) Malfunction descriptions. The OBD system must detect and identify malfunctions in 

all monitored emission-related powertrain systems or components according to the 

following malfunction definitions as measured and calculated in accordance with test 

procedures set forth in subpart B of this part (chassis-based test procedures), excluding 

those test procedures defined as “Supplemental” test procedures in §86.004–2 and 

codified in §§86.158, 86.159, and 86.160. For clean alternative fuel conversion 

manufacturers, your OBD system is expected to detect and identify malfunctions in all 

monitored emission-related powertrain systems or components according to the 

malfunction definitions described in this paragraph (b) as measured and calculated in 

accordance with the chassis-based test procedures set forth in subpart B of this part to the 

extent feasible, excluding the elements of the Supplemental FTP (see §86.1803). 

However, at a minimum, systems must detect and identify malfunctions as described in 

paragraph (k)(7) of this section.

* * * * *

(h) The following additional requirements apply based on industry standard 

specifications, which are incorporated by reference in § 86.1:

(1) The following requirements apply for standardized on-board to off-board 

communications:
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(i) Starting in model year 2008, light-duty vehicles and light-duty trucks must comply

with ISO 15765-4:2005(E), “Road Vehicles-Diagnostics on Controller Area Network 

(CAN)—Part 4: Requirements for emission-related systems”, January 15, 2005. 

(ii) Starting in model year 2008, heavy-duty vehicles must comply with the protocol 

described in paragraph (h)(1)(i) of this section, or the following set of SAE standards: 

SAE J1939-11, Revised October 1999; SAE J1939-13, July 1999; SAE J1939-21, 

Revised April 2001; SAE J1939-31, Revised December 1997; SAE J1939-71, 

Revised January 2008; SAE J1939-73, Revised September 2006; SAE J1939-81, May

2003.

(iii) Note that for model years 1996 through 2007 manufacturers could instead 

comply with the protocols specified in SAE J1850, ISO 9141-2, or ISO 14230-4.

(2) Light-duty vehicles and light-duty trucks must meet the following additional 

specifications:

(i) Basic diagnostic data (as specified in §§ 86.094-17(e) and (f)) shall be 

provided in the format and units in SAE J1979 “E/E Diagnostic Test Modes—

Equivalent to ISO/DIS 15031-5: Revised, May 2007.

(ii) Diagnostic trouble codes shall be consistent with SAE J2012 “Diagnostic 

Trouble Code Definitions—Equivalent to ISO/DIS 15031-6: April 30, 2002”, 

(Revised, April 2002).

(iii) The connection interface between the OBD system and test equipment and 

diagnostic tools shall meet the functional requirements of SAE J1962 “Diagnostic 

Connector—Equivalent to ISO/DIS 15031-3: December 14, 2001” (Revised, 

April 2002).

(iv) SAE J1930, Revised April 2002. All acronyms, definitions and abbreviations 

shall be formatted according to this industry standard. Alternatively, 

manufacturers may use SAE J2403, Revised August 2007.

(v) All equipment used to interface, extract, and display OBD-related information 

shall meet SAE J1978 “OBD II Scan Tool” Equivalent to ISO 15031-4: 

December 14, 2001”, (Revised, April 2002).

* * * * *

(j) California OBDII compliance option. Manufacturers may comply with California’s 

OBD requirements instead of meeting the requirements of this section as follows:

(1) Through the 2006 model year, demonstration of compliance with California OBDII 

requirements (Title 13 California Code of Regulations § 1968.2 (13 CCR 1968.2)), as 

modified, approved and filed on April 21, 2003 (incorporated by reference, see § 86.1), 

shall satisfy the requirements of this section, except that compliance with 13 CCR 

1968.2(e)(4.2.2)(C), pertaining to 0.02 inch evaporative leak detection, and 13 CCR 

1968.2(d)(1.4), pertaining to tampering protection, are not required to satisfy the 

requirements of this section. Also, the deficiency provisions of 13 CCR 1968.2(i) do not 

apply. In addition, demonstration of compliance with 13 CCR 1968.2(e)(16.2.1)(C), to 

the extent it applies to the verification of proper alignment between the camshaft and 

crankshaft, applies only to vehicles equipped with variable valve timing. 

(2) For 2007 through 2012 model year vehicles, demonstration of compliance with 

California OBD II requirements (Title 13 California Code of Regulations § 1968.2 (13 

CCR 1968.2)), approved on November 9, 2007 (incorporated by reference, see § 86.1), 

shall satisfy the requirements of this section, except that compliance with 13 CCR 
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1968.2(e)(4.2.2)(C), pertaining to 0.02 inch evaporative leak detection, and 13 CCR 

1968.2(d)(1.4), pertaining to tampering protection, are not required to satisfy the 

requirements of this section. Also, the deficiency provisions of 13 CCR 1968.2(k) do not 

apply. In addition, demonstration of compliance with 13 CCR 1968.2(e)(15.2.1)(C), to 

the extent it applies to the verification of proper alignment between the camshaft and 

crankshaft, applies only to vehicles equipped with variable valve timing. 

(3) Beginning with the 2013 model year, manufacturers may demonstrate compliance 

with California’s 2013 OBD requirements as described in §86.1806-17(a). 

(4) For all model years, the deficiency provisions of paragraph (i) of this section and the 

evaporative leak detection requirement of paragraph (b)(4) of this section, if applicable, 

apply to manufacturers selecting this paragraph for demonstrating compliance.

(k) * * *

(7) For clean alternative fuel conversion manufacturers (e.g., natural gas, liquefied 

petroleum gas, methanol, ethanol), in lieu of the requirements specified for other 

manufacturers in this paragraph (k), you may demonstrate that the malfunction indicator 

light will illuminate, at a minimum, under any of the following circumstances when the 

vehicle is operated on the applicable alternative fuel:

(i) Otto-cycle. A catalyst is replaced with a defective catalyst system where the 

catalyst brick for the monitored volume has been removed (i.e., empty catalyst 

system) resulting in an increase of 1.5 times the NMOG (or NMOG+NOx) standard 

or FEL above the NMOG (or NMOG+NOx) emission level measured using a 

representative 4000 mile catalyst system. 

(ii)(A) Diesel. If monitored for emissions performance—a catalyst is replaced with a 

defective catalyst system where the catalyst brick for the monitored volume has 

been removed (i.e., empty catalyst can) resulting in exhaust emissions exceeding 

1.5 times the applicable standard or FEL for NOX (or NMOG+NOx) or PM.

(B) If monitored for performance—a particulate trap is replaced with a trap that 

has catastrophically failed.

(iii) (A) Otto-cycle. An engine misfire condition is induced that completely disables 

one or more cylinders, either through mechanical or electrical means, resulting in 

exhaust emissions exceeding 1.5 times the applicable standards or FEL for CO, 

NMOG, or NOX (or NMOG+NOx).

(B) Diesel. An engine misfire condition resulting in complete lack of cylinder 

firing is induced and is not detected.

(iv) If so equipped, any oxygen sensor is replaced with a completely defective oxygen 

sensor, or an electronic simulation of such, resulting in exhaust emissions exceeding 

1.5 times the applicable standard or FEL for CO, NMOG, or NOX (or NMOG+NOx).

(v) If so equipped and applicable, a vapor leak is introduced in the evaporative and/or 

refueling system (excluding the tubing and connections between the purge valve and 

the intake manifold) greater than or equal in magnitude to a leak caused by a 0.040 

inch diameter orifice, or the evaporative purge air flow is blocked or otherwise 

eliminated from the complete evaporative emission control system. At a minimum, 

gas cap removal or complete venting of the evaporative and/or refueling system may

be introduced resulting in a gross leak of the complete evaporative emission control 

system.
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(vi) A malfunction condition is induced resulting in complete disablement in any

emission-related powertrain system or component, including but not necessarily

limited to, the exhaust gas recirculation (EGR) system, if equipped, the secondary air 

system, if equipped, and the fuel control system, singularly resulting in exhaust 

emissions exceeding 1.5 times the applicable emission standard or FEL for PM, CO, 

NMOG, or NOX (or NMOG+NOx).

(vii) A malfunction condition is induced that completely disables an electronic 

emission-related powertrain system or component not otherwise described in this 

paragraph (k) that either provides input to or receives commands from the onboard

computer resulting in a measurable impact on emissions. At a minimum, 

manufacturers may be required to perform this disablement on critical inputs and 

outputs where lack of the input and output disables an entire monitor as described in 

this paragraph (k)(7)(vii), disables multiple monitors (e.g., two or more) used by the 

onboard computer, or renders the entire onboard computer and its functions 

inoperative.

(viii) Clean alternative fuel conversion manufacturers must use good engineering 

judgment to induce malfunctions and may perform more stringent malfunction 

demonstrations than described in this paragraph (k)(7). In addition, the Administrator 

reserves the right to request a clean alternative fuel conversion manufacturer to 

perform stricter demonstration requirements, to the extent feasible, on clean 

alternative fuel conversions.

* * * * *

169. A new § 86.1806-17 is added to subpart S to read as follows:

§ 86.1806-17 Onboard diagnostics.

Model year 2017 and later vehicles must have onboard diagnostic (OBD) systems as 

described in this section. OBD systems must generally detect malfunctions in the 

emission control system, store trouble codes corresponding to detected malfunctions, and 

alert operators appropriately.

(a) Vehicles must comply with the 2013 OBD requirements adopted for California as 

described in this paragraph (a). California’s 2013 OBD-II requirements are part of Title 

13, §1968.2 of the California Code of Regulations, approved on July 31, 2013

(incorporated by reference in §86.1). The following clarifications and exceptions apply 

for vehicles certified under this subpart:

(1) For vehicles not certified in California, references to vehicles meeting certain 

California Air Resources Board emission standards are understood to refer to the 

corresponding EPA emission standards for a given family, where applicable. Use 

good engineering judgment to correlate the specified standards with the bin standards 

that apply under this subpart. 

(2) Vehicles must comply with OBD requirements throughout the useful life as 

specified in §86.1805. If the specified useful life is different for evaporative and 

exhaust emissions, the useful life specified for evaporative emissions applies for 

monitoring related to fuel-system leaks and the useful life specified for exhaust 

emissions applies for all other parameters.

(3) The purpose and applicability statements in 13 CCR 1968.2(a) and (b) do not 

apply.
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(4) The anti-tampering provisions in 13 CCR 1968.2(d)(1.4) do not apply.

(5) The requirement to verify proper alignment between the camshaft and crankshaft 

described in 13 CCR 1968.2(e)(15.2.1)(C) applies only for vehicles equipped with 

variable valve timing.

(6) The deficiency provisions described in paragraph (c) of this section apply instead 

of 13 CCR 1968.2(k).

(7) For emergency vehicles only, the provisions of 13 CCR 1968.2(e)(6.2.1) related to 

monitoring and identification of air-fuel ratio cylinder imbalance, as part of the fuel 

system monitoring, do not apply until model year 2020, unless the vehicle met the 

requirements in 2016 or earlier model years.

(8) Apply thresholds for exhaust emission malfunctions from Tier 3 vehicles based on 

the thresholds calculated for the corresponding bin standards in the California LEV II 

program as prescribed for the latest model year in CCR 1968.2(e)(1) through (3). For 

example, for Tier 3 Bin 160 standards, apply the threshold that applies for the LEV 

standards. For cases involving Tier 3 standards that have no corresponding bin 

standards from the California LEV II program, use the next highest LEV II bin. For 

example, for Tier 3 Bin 50 standards, apply the threshold that applies for the ULEV 

standards. You may apply thresholds that are more stringent than we require under 

this paragraph (a)(8).

(b) The following additional provisions apply:

(1) Model year 2017 and later vehicles must meet the OBD system requirements 

described in this paragraph (b)(1). When monitoring conditions are satisfied, test 

vehicles must detect the presence of a leak with an effective leak diameter at or above 

0.020 inches, illuminate the MIL, and store the appropriate confirmed diagnostic 

trouble codes (DTCs) (13 CCR1968.2 refers to these as fault codes). For a 0.020 inch 

leak, the DTC(s) shall be a generic SAE J2012 DTC that is specific to an EVAP 

system very small leak (e.g., P0456, P04EE, or P04EF) or an equivalent 

manufacturer-specific DTC that we approve. Conduct testing using an O’Keefe 

Controls Co. metal “Type B” orifice with a diameter of 0.020 inches or an alternate 

orifice diameter approved under 13 CCR 1968.2(e)(4.2.3) or (e)(4.2.4).

(i) Use the methodology specified in 13 CCR 1968.2(h)(2.2) to select test vehicles 

to demonstrate that the OBD system is capable of detecting a 0.020 inch leak 

installed in the evaporative system, except that the manufacturer may use 

production-representative vehicles instead of the vehicle options specified in 13 

CCR 1968.2(h)(2.3). 

(ii) Perform tests in the laboratory, with or without a dynamometer, or on an 

outdoor road surface, as necessary to exercise the vehicle’s ability to detect leaks 

in the evaporative system.

(iii) Perform at least two tests to evaluate the OBD system for leaks that are 

installed near the fuel fill pipe and near the canister. The implanted leak near the 

fuel fill pipe must be at the fuel cap or between the fuel cap and the fuel tank. 

The implanted leak near the canister must be in the vapor line between the 

canister and the fuel tank, or between the canister and the purge valve). If a

vehicle has multiple canisters or fuel fill pipes, repeat the testing to evaluate the 

system for implanted leaks corresponding to each canister and fuel fill pipe. You 

may propose to implant leaks in different locations (e.g., near the purge valve); 
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we will approve your alternate leak location if it more effectively demonstrates 

leak detection for your particular fuel system design.

(iv) If vehicle operation is needed to fulfill preconditioning (i.e., when engine-off 

tests require driving before vehicle shutdown to enable the engine-off monitor) or 

monitoring conditions for leak detection under this paragraph (b)(1) utilize an

FTP cycle, Unified cycle, or some other specified operating cycle that will satisfy

the approved monitoring or preconditioning conditions without the interference of 

approved deficiencies. Continue vehicle operation as needed to illuminate the 

MIL and store the appropriate DTCs.

(v) Emission measurements are not required during this OBD evaporative system 

leak monitoring demonstration testing.

(vi) For test groups not selected for testing in a given model year, you may instead 

provide a statement in the application for certification, consistent with good 

engineering judgment, that vehicles meet leak-detection requirements based on 

previous OBD tests, development tests, or other appropriate information. For any 

untested test groups, the statement specified in §86.1844-01(d)(8) applies with 

regard to the leak monitoring requirement. We may ask you to provide the data 

and other information that formed the basis for your statement. Select test groups 

in later model years such that testing will rotate to cover your whole product line 

over time.

(vii) Submit the following information in the application for certification:

(A) Describe the test sequence.

(B) Identify the driving cycle used and the time expired and distance driven 

before the MIL illuminated.

(C) Identify the ranges of in-use environmental and vehicle operating 

conditions for which the vehicle will not meet the leak-detection 

specifications described in this paragraph (b)(1). To meet this requirement, 

you may give us the same information you gave the California Air Resources 

Board regarding enable conditions for the evaporative system leak monitor. 

(D) Identify the confirmed and permanent DTCs set by the OBD system

during testing.

(E) Include the freeze frame information stored at the point the fault is 

detected.

(F) Include the SAE J1979 test results (e.g., Mode/Service $06) corresponding 

to the DTCs that were stored during the test.

(viii) If you have one or more vehicle models in model year 2016 that do not 

comply with the leak requirements in 13 CCR 1968.2(e)(4), you may comply with 

the requirements of this paragraph (b)(1) in model year 2017 by substituting 

model year 2016 vehicles on an equal-percentage basis. Demonstrate this by

calculating the percentage of vehicles subject to OBD requirements under this

subpart that meet the requirements of this paragraph (b)(1) in model years 2016 

and 2017; the sum of these two percentage values must be at or above 100 

percent. Any model year 2017 vehicles not meeting the requirements of this 

paragraph (b)(1), as allowed by this paragraph (b)(1)(viii), may not be counted as 

compliant Tier 3 vehicles under the alternative phase-in specified in §86.1813-

17(g)(2)(ii).
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(2) For vehicles subject to the leak standard in §86.1813, OBD systems must record 

in computer memory the result of the most recent successfully completed diagnostic 

check for a 0.020 inch leak. Someone must be able to use the data to determine the 

miles driven since the last check occurred, the pass/fail result, and whether there has 

been a check since the computer memory was last cleared (e.g., from a scan tool 

command or battery disconnect). The system may be designed to keep data only

from the previous 750 miles of driving. (Note: This 750 mile requirement is related 

to the use of the OBD evaporative leak monitor in the leak test and should not be 

confused with either the minimum or maximum distance values specified in Table G19 of SAE J1979.) The data must be reported in a standardized format consistent 

with other data required for the OBD system. The results must be scan-readable.

(3) For vehicles with fuel tanks exceeding 25 gallons nominal fuel tank capacity, you 

may request our approval for a leak threshold greater than 0.020 inches, up to a 

maximum value of 0.040 inches. We will generally approve a leak threshold equal to 

the standard that applies under §86.1813.

(c) You may ask us to accept as compliant a vehicle that does not fully meet specific 

requirements under this section. Such deficiencies are intended to allow for minor 

deviations from OBD standards under limited conditions. We expect vehicles to have 

functioning OBD systems that meet the objectives stated in this section. The following 

provisions apply regarding OBD system deficiencies:

(1) Except as specified in paragraph (d) of this section, we will not approve a 

deficiency that involves the complete lack of a major diagnostic monitor, such as 

monitors related to exhaust aftertreatment devices, oxygen sensors, air-fuel ratio 

sensors, NOx sensors, engine misfire, evaporative leaks, and diesel EGR (if 

applicable). 

(2) We will approve a deficiency only if you show us that full compliance is 

infeasible or unreasonable considering any relevant factors, such as the technical 

feasibility of a given monitor, or the lead time and production cycles of vehicle 

designs and programmed computing upgrades. 

(3) Our approval for a given deficiency applies only for a single model year, though 

you may continue to ask us to extend a deficiency approval in renewable one-year 

increments. We may approve an extension if you demonstrate an acceptable level of 

effort toward compliance and show that the necessary hardware or software 

modifications would pose an unreasonable burden. 

(d) For alternative-fuel vehicles, manufacturers may request a waiver from specific 

requirements for which monitoring may not be reliable for operation with the alternative 

fuel. However, we will not waive requirements that we judge to be feasible for a 

particular manufacturer or vehicle model.

(e) For alternative-fuel conversions, manufacturers may meet the requirements of 

§86.1806-05 instead of the requirements of this section. 

(f) You may ask us to waive certain requirements in this section for emergency vehicles. 

We will approve your request for an appropriate duration if we determine that the OBD 

requirement in question could harm system performance in a way that would impair a 

vehicle’s ability to perform its emergency functions.

(g) The following interim provisions describe an alternate implementation schedule for 

the requirements of this section in certain circumstances:
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(1) Manufacturers may delay complying with all the requirements of this section, and 

instead meet all the requirements that apply under §86.1806-05, for any heavy-duty 

vehicles that are not yet subject to the Tier 3 standards in §86.1816.

(2) Except as specified in this paragraph (g)(2), small-volume manufacturers may

delay complying with all the requirements of this section until model year 2022, and 

instead meet all the requirements that apply under §86.1806-05 during those years. 

This provision does not apply for a vehicle model if it is identical to a 2016 vehicle 

model that was certified to meet California’s OBD requirements under §86.1806-

05(j)(3). A vehicle model is considered identical to one from model year 2016 if it is 

certified in the current year based on the same test data for exhaust or evaporative 

emissions under the carryover data provisions of this subpart. 

(3) Manufacturers may disregard the requirements of this section that apply above 

8,500 pounds GVWR before model year 2019 and instead meet all the requirements 

that apply under §86.1806-05. This also applies for model year 2019 vehicles from a

test group with vehicles that have a Job 1 date on or before [INSERT DATE FOUR 

YEARS AFTER FRM SIGNATURE] (see 40 CFR 85.2304).

§86.1807-01—[Amended]

170. Section 86.1807-01 is amended by removing and reserving paragraph (a)(3)(ix).

171. Section 86.1808-01 is amended as follows:

a. By revising paragraphs (f)(1), (f)(3) introductory text, (f)(6)(ii)(D), (f)(7)(i) 

introductory text, (f)(7)(ii)(B), (f)(10)(ii), (f)(13) introductory text, (f)(13)(iv), and 

(f)(16)(i). 

b. By adding paragraph (g).

§ 86.1808-01 Maintenance instructions.

* * * * *

(f) * * *

(1) Applicability. Manufacturers are subject to the provisions of this paragraph (f) for 

1996 model year for and later light-duty vehicles and light-duty trucks.Manufacturers are 

subject to the provisions of this paragraph (f) for 2005 model year and later heavy-duty 

vehicles at or below 14,000 pounds GVWR and the corresponding engines that are 

subject to the OBD requirements of this part.

* * * * *

(3) Information dissemination. Each manufacturer shall provide or cause to be provided 

to the persons specified in paragraph (f)(2)(i) of this section and to any other interested 

parties a manufacturer-specific website containing the information specified in paragraph 

(f)(2)(i) of this section for vehicles identified in paragraph (f)(1) of this section that have 

been offered for sale; this requirement does not apply to indirect information, including 

the information specified in paragraphs (f)(12) through (f)(16) of this section. Each 

manufacturer website shall:

* * * * *

(6) * * *

(ii) * * *
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(D) Any alternative means proposed by a manufacturer must be available to aftermarket 

technicians at a fair and reasonable price.

* * * * *

(7) * * *

(i) All information required to be made available by this section shall be made available 

at a fair and reasonable price. In determining whether a price is fair and reasonable, 

consideration may be given to relevant factors, including, but not limited to, the 

following:

* * * * *

(ii) * * *

(B) The Administrator will act on the request within 180 days following receipt of a 

complete request or following receipt of any additional information requested by the 

Administrator.

* * * * *

(10) * * *

(ii) Provide on the manufacturer’s website an index of all emissions-related training 

information available for purchase by aftermarket service providers for 1994 and newer 

vehicles. The required information must be made available for purchase within 3 months 

of model introduction and then must be made available at the same time it is made 

available to manufacturer-franchised dealerships, whichever is earlier. The index shall 

describe the title of the course or instructional session, the cost of the video tape or 

duplicate, and information on how to order the item(s) from the manufacturer website. 

All of the items available must be shipped within 24 hours of the order being placed and 

are to be made available at a fair and reasonable price as described in paragraph (f)(7) of 

this section. Manufacturers unable to meet the 24 hour shipping requirement under 

circumstances where orders exceed supply and additional time is needed by the 

distributor to reproduce the item being ordered may exceed the 24 hour shipping 

requirement, but in no instance can take longer than 14 days to ship the item.

* * * * *

(13) Generic and enhanced information for scan tools. Manufacturers shall make 

available to equipment and tool companies all generic and enhanced service information 

including bi-directional control and data stream information as defined in paragraph 

(f)(2)(ii) of this section. This requirement applies for 1996 and later model year vehicles.

* * * * *

(iv) Manufacturers can satisfy the requirement of paragraph (f)(13)(iii) of this section by

making available diagnostic trouble trees on their websites in full-text.

* * * * *

(16) * * *

(i) Manufacturers who have developed special tools to extinguish the malfunction 

indicator light (MIL) for Model Years 1994 through 2003 shall make available the

necessary information to equipment and tool companies to design a comparable generic 

tool. 

* * * * *

(g) Through model year 2013, the manufacturer shall furnish or cause to be furnished to 

the purchaser the following statement for each new diesel-fueled Tier 2 vehicle (certified 

using a test fuel with 15 ppm sulfur or less): “This vehicle must be operated only with 
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ultra low sulfur diesel fuel (that is, diesel fuel meeting EPA specifications for highway

diesel fuel, including a 15 ppm sulfur cap).”

§86.1808-07 [Removed]

172. Remove §86.1808-07.

173. Section 86.1809-12 is amended by revising paragraph (c) introductory text to read 

as follows:

§86.1809-12 Prohibition of defeat devices.

* * * * *

(c) For cold temperature CO and cold temperature NMHC emission control, the 

Administrator will use a guideline to determine the appropriateness of the CO and 

NMHC emission control at ambient temperatures between 25 °F (the upper bound of the 

FTP test temperature range) and 68 °F (the lower bound of the FTP test temperature 

range). The guideline for CO emission congruity across the intermediate temperature 

range is the linear interpolation between the CO standard applicable at 25 °F and the CO 

standard applicable at 68 °F. The guideline for NMHC emission congruity across the 

intermediate temperature range is the linear interpolation between the NMHC FEL pass 

limit (e.g., 0.3499 g/mi for a 0.3 g/mi FEL) applicable at 20 °F and the Tier 2 NMOG 

standard or the Tier 3 NMOG+NOx bin standard to which the vehicle was certified at 68 

°F, where the intermediate temperature NMHC level is rounded to the nearest hundredth 

for comparison to the interpolated line. For vehicles that exceed this CO emissions 

guideline or this NMHC emissions guideline upon intermediate temperature testing:

* * * * *

174. Section 86.1810-01 is amended by removing and reserving paragraph (m), and 

revising paragraphs (f) and (k)(3) to read as follows:

§ 86.1810-01 General standards; increase in emissions; unsafe condition; waivers.

* * * * *

(f) Altitude requirements. Unless otherwise specified, emission standards apply at lowaltitude conditions and at high-altitude conditions. The following exceptions apply:

(1) The supplemental exhaust emission standards as described in § 86.1811–04(f) apply 

only at low-altitude conditions;

(2) The cold temperature NMHC emission standards as described in § 86.1811–10(g) 

apply only at low-altitude conditions;

(3) The evaporative emission standards specified in § 86.1811-09(e) apply at low-altitude 

conditions. The evaporative emission standards specified in § 86.1811-04(e) continue to 

apply at high-altitude conditions for 2009 and later model year vehicles. 

* * * * *

(k) * * *

(3) Refueling receptacle requirements. Compressed natural gas vehicles must meet the 

requirements for fueling connection devices as specified in §86.1813-17(f)(1). 

175. A new §86.1810-17 is added to subpart S to read as follows:

§ 86.1810-17 General requirements.

The following provisions apply to all vehicles certified under this subpart:
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(a) Any device, system or element of design installed on or incorporated in a new motor 

vehicle to enable such vehicle to conform to the standards imposed by this subpart:

(1) Shall not in its operation or function cause the emission into the ambient air of any

noxious or toxic substance that would not be emitted in the operation of such vehicle 

without such system, except as specifically permitted by regulation; and

(2) Shall not in its operation, function or malfunction result in any unsafe condition 

endangering the vehicle, its occupants, or persons or property in close proximity to 

the vehicle.

(b) In establishing the physically adjustable range of each adjustable parameter on a new 

motor vehicle, the manufacturer shall ensure that, taking into consideration the 

production tolerances, safe vehicle drivability characteristics are available within that 

range.

(c) Unless otherwise specified, the emission standards of this subpart apply equally for 

certification and for in-use vehicles throughout the specified useful-life period. Also, 

manufacturers must use good engineering judgment to determine that all of a vehicle’s 

emission-related components are designed to operate properly throughout the specified 

useful-life period.

(d) Vehicles may not discharge crankcase emissions into the ambient atmosphere.

(e) All vehicles must have an onboard diagnostic system as described in §86.1806.

(f) Emission standards apply at low-altitude conditions and at high-altitude conditions, 

except as noted in this subpart. 

(g) The cold temperature CO and NMHC standards in this subpart refer to test procedures 

set forth in subpart C of this part and 40 CFR part 1066, subpart H. All other emission 

standards in this subpart rely on test procedures set forth in subpart B of this part. These 

procedures rely on the test specifications in 40 CFR parts 1065 and 1066 as described in 

subparts B and C of this part.

(h) Multi-fueled vehicles (including dual-fueled and flexible-fueled vehicles) must 

comply with all the requirements established for each consumed fuel (and blend of fuels 

for flexible-fueled vehicles). The following specific provisions apply for flexible-fueled 

vehicles that operate on ethanol and gasoline:

(1) For exhaust emissions, we may identify the worst-case fuel blend for testing in 

addition to what is required for gasoline-fueled vehicles. The worst-case fuel blend 

may be the fuel specified in 40 CFR 1065.725, or it may consist of a combination of 

the fuels specified in 40 CFR 1065.710(b) and 1065.725. We may waive testing with 

the worst-case blended fuel for US06 and/or SC03 duty cycles; if we waive only

SC03 testing, substitute the SC03 emission result using the standard test fuel for 

gasoline-fueled vehicles to calculate composite SFTP emissions.

(2) For refueling emissions, we may identify the worst-case fuel blend for testing in 

addition to what is required for gasoline-fueled vehicles. The worst-case fuel blend 

may consist of a combination of the fuels specified in 40 CFR 1065.710(c) and 

1065.725. This is generally expected to be a fuel blend with 10 percent ethanol and a 

nominal Dry Vapor Pressure Equivalent of 10 psi. You may prepare such a worstcase fuel blend by mixing it before dispensing into the vehicle’s fuel tank, or by

consecutively dispensing appropriate amounts of the two specified fuels into a fuel 

tank.
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(3) No additional spitback or evaporative emission testing is required beyond the 

emission measurements with the gasoline test fuel specified in 40 CFR 1065.710.

(i) Where we specify requirements based on a percentage of total sales volume in a given 

model year, you may instead ask us to calculate the percentage based on production 

volumes instead of sales volumes.

§86.1811-01 [Removed]

176. Remove §86.1811-01.

177. Section 86.1811-04 is revised as follows:

a. By revising paragraph (e)(3)(i).

b. By removing and reserving paragraph (h).

c. By revising paragraphs (j) and (n) to read as follows:

§ 86.1811-04 – Emission standards for light-duty vehicles, light-duty trucks and 

medium-duty passenger vehicles.

* * * * *

(e) * * *

(3) * * *

(i) For gasoline-fueled and methanol-fueled LDV, LDT and MDPV: 0.20 grams 

hydrocarbon per gallon (0.053 grams per liter) of fuel dispensed. This standard also 

applies for diesel-fueled LDV.

* * * * *

(j) Highway NOX exhaust emission standard. The NOx emissions measured on the federal 

Highway Fuel Economy Test in 40 CFR part 600, subpart B, must not be greater than 

1.33 times the applicable FTP NOx standard to which the manufacturer certifies the test 

group. Both the measured emissions and the product of the NOx standard and 1.33 must 

be rounded to the nearest 0.01 g/mi before being compared. 

* * * * *

(n) Requirements for vehicles with rechargeable energy storage systems. Manufacturers 

must measure emissions from hybrid electric vehicles (including plug-in hybrid electric 

vehicles) as described in 40 CFR part 1066, subpart F, except that these procedures do 

not apply for plug-in hybrid electric vehicles during charge-depleting operation.

* * * * *

178. A new §86.1811-17 is added to subpart S to read as follows:

§ 86.1811-17 Exhaust emission standards for light-duty vehicles, light-duty trucks 

and medium-duty passenger vehicles.

(a) Applicability and general provisions. This section describes exhaust emission 

standards that apply for model year 2017 and later light-duty vehicles, light-duty trucks, 

and medium-duty passenger vehicles. MDPVs are subject to all the same provisions of 

this section that apply to LDT4. Some of the provisions of this section also apply to 

heavy-duty vehicles as specified in §86.1816. See §86.1818 for greenhouse gas emission 

standards. See §86.1813 for evaporative and refueling emission standards. This section 

may apply to vehicles from model years earlier than 2017 as specified in paragraph 

(b)(11) of this section. 

(b) Tier 3 exhaust emission standards. Exhaust emissions may not exceed the Tier 3 
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exhaust emission standards, as follows: 

(1) Measure emissions using the chassis dynamometer procedures of 40 CFR part 

1066, as follows:

(i) Establish appropriate load settings based on loaded vehicle weight (see 

§86.1803). 

(ii) Use appropriate driving schedules. Measurements involve testing over 

multiple driving schedules. The Federal Test Procedure (FTP) is based on testing 

with the Urban Dynamometer Driving Schedule (UDDS). The Supplemental 

Federal Test Procedure (SFTP) involves testing with the UDDS, the US06 driving 

schedule, and the SC03 driving schedule. See 40 CFR 1066.801 for further 

information on these test cycles.

(iii) Calculate SFTP emissions as a composite of test results over the driving 

schedules identified in paragraph (b)(1)(ii) of this section based on the following 

calculation:

SFTP (g/mi) = 0.35∙FTP + 0.28∙US06 + 0.37∙SC03

(A) For test vehicles that do not have air conditioning, you may omit SC03 

testing. To calculate composite SFTP emissions for such vehicles, use FTP 

emission results to substitute for the SC03 value in the equation. 

(B) You may also use FTP emission results to substitute for the SC03 value in 

the equation for the types of vehicles identified in 40 CFR 600.115 that 

automatically qualify for the derived 5-cycle method for determining fuel 

economy label values. Such vehicles remain subject to the SFTP standard

when tested over the SC03 driving schedule. Other vehicles remain subject to 

the litmus-test provisions in 40 CFR 600.115.

(iv) Use E10 test fuel as required in §86.113, except as specified in this section.

(v) Hydrocarbon emission standards are expressed as NMOG; however, for 

certain vehicles you may measure exhaust emissions based on nonmethane 

hydrocarbon instead of NMOG as described in 40 CFR 1066.635.

(vii) Measure emissions from hybrid electric vehicles (including plug-in hybrid 

electric vehicles) as described in 40 CFR part 1066, subpart F, except that these 

procedures do not apply for plug-in hybrid electric vehicles during chargedepleting operation.

(2) Table 1 of this section describes fully phased-in Tier 3 standards that apply as 

specified in this paragraph (b) for the identified driving schedules. The FTP 

standards for NMOG+NOx apply on a fleet-average basis using discrete bin standards 

as described in paragraph (b)(4) of this section. The bin standards include additional 

emission standards for high-altitude testing and for CO emissions when testing over 

the FTP driving schedule. The SFTP standards for NMOG+NOx apply on a fleetaverage basis as described in paragraph (b)(5) of this section. Table 1 follows:
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Table 1 of §86.1811-17–

Fully Phased-in Tier 3 Exhaust Emission Standards (g/mile)

NMOG+NOx PM CO Formaldehyde

FTP1SFTP FTP US06 SFTP FTP

0.030 0.050 0.003 0.006 4.2 0.004

1 The fleet-average FTP emission standard for NMOG+NOx is 

0.026 g/mile for any LDV or LDT1 test group certified to standards 

based on a useful life of 120,000 miles or 10 years in a given model 

year.

(3) The FTP standards specified in this section apply for testing at low-altitude 

conditions and high-altitude conditions as specified in paragraph (b)(4) of this 

section. The SFTP standards specified in paragraph (b)(2) of this section apply only 

for testing at low-altitude conditions. 

(4) The FTP emission standard for NMOG+NOx is based on a fleet average for a 

given model year. You must specify a family emission limit (FEL) for each test 

group. The FEL serves as the emission standard for the test group with respect to all 

required FTP testing. Calculate your fleet-average emission level as described in 

§86.1860 based on the FEL that applies for low-altitude testing to show that you meet 

the specified standard. For multi-fueled vehicles, calculate fleet-average emission 

levels based only on emission levels for testing with gasoline or diesel fuel. You may 

generate emission credits for banking and trading and you may use banked or traded 

credits as described in §86.1861 for demonstrating compliance with the FTP emission 

standard for NMOG+NOx. You comply with the emission standard for a given 

model year if you have enough credits to show that your fleet-average emission level 

is at or below the applicable standard. You may exchange FTP credits between or 

among any test groups subject to standards under this section. You may not exchange 

FTP and SFTP credits.

(i) Specify one of the identified values from Table 2 of this section as the FEL for 

demonstrating that your fleet-average emission level complies with the FTP 

emission standard for NMOG+NOx under low-altitude conditions. These FEL 

values define emission bins that also determine corresponding emission standards 

for NMOG+NOx emissions under high-altitude conditions, and for CO emissions, 

as follows:
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Table 2 of §86.1811-17—

Tier 3 FTP Bin Standards (g/mile)

FEL Name NMOG+NOx 

FELs for Low 

Altitude 

NMOG+NOx 

for High 

Altitude

CO for Low

and High 

Altitude

Bin 160 0.160 0.160 4.2

Bin 125 0.125 0.160 2.1

Bin 70 0.070 0.105 1.7

Bin 50 0.050 0.070 1.7

Bin 30 0.030 0.050 1.0

Bin 20 0.020 0.030 1.0

Bin 0 0.000 0.000 0.0

(ii) Manufacturers earn a compliance credit of 0.005 g/mile NMOG+NOx for 

vehicles that are certified for a useful life of 150,000 miles or 15 years and that 

are covered by an extended warranty over the same period for all components 

whose failure triggers MIL illumination. Manufacturers may apply the 

compliance credit as follows:

(A) You may reduce your official FTP emission result for certification by the 

amount of the compliance credit if that allows you to certify to a more 

stringent bin. In that case, you may use the more stringent bin standard for 

calculating the fleet-average NMOG+NOx emission level. For any 

compliance testing with these vehicles, the applicable FTP bin standard for 

NMOG+NOx is higher than the specified bin standard by the amount of the 

compliance credit. For example, if the official FTP emission result for 

NMOG+NOx is 0.052 g/mile, this qualifies for an FEL of 0.050 g/mile for 

calculating the fleet average and the vehicle is subject to an FTP bin standard 

of 0.055 g/mile. 

(B) If the amount of the compliance credit does not allow you to certify to a 

more stringent bin, calculate the fleet-average NMOG+NOx emission level 

using an FEL for these vehicles that is smaller than the bin standard by the 

amount of the compliance credit. For any compliance testing with these 

vehicles, the specified bin standard applies. For example, if the official FTP 

emission result for NMOG+NOx is 0.038 g/mile, calculate the fleet-average 

NMOG+NOx emission level by specifying an FEL of 0.045 g/mile; these 

vehicles are subject to the specified FTP bin standard of 0.050 g/mile. 

(iii) If you qualify for a compliance credit for direct ozone reduction under the 

LEV III program, you may apply the compliance credit approved for California 

vehicles as described in paragraphs (b)(4)(ii)(A) and (B) of this section. 

(iv) You may combine the adjustments in paragraphs (b)(4)(ii) and (iii) of this 

section if you qualify for them separately. 

(5) The SFTP emission standard for NMOG+NOx is also based on a fleet average in 

a given model year. You must specify FELs as described in paragraph (b)(4) of this 

section and calculate a fleet-average emission level to show that you meet the SFTP 

emission standard for NMOG+NOx, except that you may specify FELs in any even 

increment of 0.010 g/mile up to a maximum value of 0.180 g/mile. You may

generate emission credits for banking and trading and you may use banked or traded 

credits as described in §86.1861 for demonstrating compliance with the SFTP 
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emission standard for NMOG+NOx. You comply with the emission standard for a 

given model year if you have enough credits to show that your fleet-average emission 

level is at or below the applicable standard. You may exchange SFTP credits 

between or among any test groups subject to standards under this section. You may 

not exchange FTP and SFTP credits. The SFTP standards described in this section 

apply only for testing at low-altitude conditions.

(6) The full Tier 3 program includes new emission standards for NMOG+NOx, PM, 

CO, and formaldehyde; it also includes measurement with a new test fuel and a 

longer useful life (for some vehicles). Vehicles meeting all these requirements are 

considered Final Tier 3 vehicles. Vehicles that do not meet all the Tier 3 

requirements are considered Interim Tier 3 vehicles. Paragraphs (b)(7) through (13) 

of this section describe how to comply with standards during a phase-in period.

(7) The Tier 3 PM standards phase in over several years. The following provisions 

describe the primary approach for phasing in the Tier 3 PM standards:

(i) You must meet the FTP and the US06 PM standards with 20, 20, 40, 70, and 

100 percent of your projected nationwide sales of all vehicles subject to this 

section in model years 2017 through 2021, respectively. In model years 2017 and 

2018, an interim US06 PM standard of 0.010 g/mile applies. Each vehicle 

meeting the Tier 3 FTP standard for PM must also meet the Tier 3 US06 standard 

for PM. In model year 2017, the phase-in requirement applies only for vehicles at 

or below 6,000 pounds GVWR; however, you may meet an alternative phase-in 

requirement of 10 percent in model year 2017 based on your full production of 

vehicles subject to standards under this section. 

(ii) You may disregard the phase-in percentages specified in paragraph (b)(7)(i) of 

this section if you instead comply with an indexed PM phase-in schedule as 

described in this paragraph (b)(7)(ii). To do this, you must notify us of your 

intent before January 1, 2017, and include a detailed plan for complying with the 

indexed phase-in schedule. You comply with the indexed phase-in schedule by

calculating a PM phase-in index at or above 540 using the following equation for 

model years 2017 through 2021:

PM phase-in index = 5∙APP2017 + 4∙APP2018 + 3∙APP2019 + 2∙APP2020 + 

APP2021

Where:

APP = The phase-in percentage of vehicles meeting the Tier 3 PM standards 

for the indicated model year, based on actual sales, as described in paragraph 

(b)(7)(i) of this section.

(iii) Vehicles meeting the Tier 3 PM standards must meet those standards over the 

useful life as specified in §86.1805. Note that Interim Tier 3 vehicles may have 

different useful life values for PM emission standards than for other emission 

standards.

(iv) Any vehicles not included for demonstrating compliance with the Tier 3 PM 

phase-in requirement must instead comply with an FTP emission standard for PM 

of 0.010 g/mile, and a composite SFTP emission standard for PM of 0.070 g/mile.

(v) Measure PM emissions from all vehicles using the same test fuel specified in 

paragraph (b)(8) of this section for measuring NMOG+NOx emissions. 

(vi) You may certify Interim Tier 3 vehicles based on carryover data.
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(vii) You may use the alternative phase-in provisions described in paragraph 

(b)(9) of this section to transition to the Tier 3 exhaust emission standards on a 

different schedule. 

(8) The following provisions describe the primary approach for phasing in the Tier 3 

standards other than PM in 2025 and earlier model years:

(i) FTP phase-in. The fleet-average FTP emission standard for NMOG+NOx 

phases in over several years as described in this paragraph (b)(8)(i). You must 

identify FELs as described in paragraph (b)(4) of this section and calculate a fleetaverage emission level to show that you meet the FTP emission standard for 

NMOG+NOx that applies for each model year. For model year 2017, do not 

include vehicles above 6,000 pounds GVWR. Through model year 2019, you 

may also certify to transitional Bin 85 or Bin 110 standards, which consist of allaltitude FTP emission standards for NMOG+NOx of 0.085 or 0.110 g/mile, 

respectively; additional FTP standards for PM, CO, and formaldehyde apply as 

specified in this section for vehicles certified to Bin 125 standards. Fleet-average 

FTP emission standards decrease through the phase-in period as shown in the 

following table:

Table 3 of §86.1811-17—

Declining Fleet-Average Tier 3 FTP 

Emission Standards for NMOG+NOx (g/mile)

Model Year LDV, LDT11 LDT2, HLDT

2017 20.086 0.101

2018 0.079 0.092

2019 0.072 0.083

2020 0.065 0.074

2021 0.058 0.065

2022 0.051 0.056

2023 0.044 0.047

2024 0.037 0.038

2025 0.030 0.030

1 Calculate the adjusted fleet-average standard for LDV and 

LDT1 test groups certified to standards based on a useful life of 

120,000 miles or 10 years in a given model year by multiplying 

the specified value by 0.85 and rounding to the nearest 0.001 

g/mile. Through model year 2019, apply this adjustment only if 

one or more test groups is certified to Bin 70 or lower standards 

based on a useful life of 120,000 miles or 10 years.

2 Vehicles above 6,000 pounds GVWR must meet the Tier 3 

standards starting with model year 2018.

(ii) SFTP phase-in. The fleet-average SFTP emission standard for NMOG+NOx

phases in over several years as described in this paragraph (b)(8)(ii). You must 

identify FELs as described in paragraph (b)(5) of this section and calculate a fleetaverage emission level to show that you meet the SFTP emission standard for 

NMOG+NOx that applies for each model year. 

(A) Calculate the fleet-average emission level together for all your light-duty

vehicles and light-duty trucks, except for those certified using the provisions 

of paragraph (b)(8)(ii)(C) of this section. For model year 2017, do not include 
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vehicles above 6,000 pounds GVWR (in the numerator or denominator). 

(B) Fleet-average FTP emission standards decrease through the phase-in 

period as shown in the following table:

Table 4 of §86.1811-17—

Declining Fleet-Average Tier 3

SFTP Emission Standards 

Model

Year

NMOG+NOx 

(g/mile)

201710.103

2018 0.097

2019 0.090

2020 0.083

2021 0.077

2022 0.070

2023 0.063

2024 0.057

2025 0.050

1 Vehicles above 6,000 pounds GVWR 

must meet the Tier 3 standards starting 

with model year 2018.

(C) You may use the Option 1 provisions specified in the LEV III program to 

demonstrate compliance with EPA’s SFTP standards. Do not include any 

such test groups when demonstrating compliance with the phased-in fleetaverage SFTP standards specified in this paragraph (b)(8)(ii). Note that this 

option is not available for vehicles certified to the transitional bins described 

in paragraph (b)(8)(i) of this section.

(iii) Interim provisions. (A) For LDT2 and HLDT certified to bins higher than Bin 

70 under this section through model year 2019, the Tier 2 useful life period 

applies as specified in §86.1805-12 for all criteria pollutants other than PM.

A similar provisions applies for LDV and LDT1, as described in Table 3 of 

this section.

(B) You may use the E0 test fuel specified in §86.113 through model year 

2019 for gasoline-fueled vehicles certified to bins higher than Bin 70. You 

may not certify these vehicles using carryover data after model year 2019.

(iv) You may use the alternative phase-in provisions described in paragraph (b)(9) 

of this section to transition to the Tier 3 exhaust emission standards on a different 

schedule. 

(9) This paragraph (b)(9) describes an alternative approach to phasing in the Tier 3 

emission standards for vehicles above 6,000 pounds GVWR. If you choose this 

approach, you must phase in the Tier 3 standards for all your vehicles above 6,000 

pounds GVWR that are subject to this section according to this schedule. Under this 

alternative phase-in, you must meet the fully phased-in standards specified in this 

paragraph (b) with 40, 70, and 100 percent of your projected nationwide sales of all 

vehicles above 6,000 pounds GVWR that are subject to this section in model years 

2019 through 2021, respectively. Any vehicles not subject to Tier 3 standards during 

the phase-in period must continue to comply with the Tier 2 standards in §86.1811-

04(c) and (f), including the Tier 2 SFTP emission standards for NMHC+NOx and CO 
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for 4,000-mile testing as specified in §86.1811-04(f)(1). Vehicles subject to Tier 2 

standards under this paragraph (b)(9) are subject to the useful life provisions in 

§86.1805-12 relative to exhaust emission standards. Each vehicle counting toward 

the phase-in percentage under this paragraph (b)(9) must meet all the standards that 

apply throughout the useful life as specified in §86.1805-17, and must use the Tier 3 

test fuel specified in §86.113-07. The following exceptions and special provisions 

apply under this paragraph (b)(9):

(i) For model year 2019, you may exclude from the phase-in calculation any test 

groups with vehicles above 6,000 pounds GVWR that have a Job 1 date on or 

before [INSERT DATE FOUR YEARS AFTER FRM SIGNATURE] (see 40 

CFR 85.2304).

(ii) The FTP and SFTP emission standards for NMOG+NOx are fleet-average 

standards. Calculate your fleet-average values based on all the vehicles that are 

subject to the standard in a given year. You may not generate credits for banking 

or trading in model years 2019 or 2020, and you may not use banked or traded 

credits to demonstrate compliance with the standards in those years. 

(iii) The US06 emission standard for PM is 0.010 g/mile in model years 2019 

through 2021, and 0.006 g/mile starting in model year 2022. The other standards 

described in this paragraph (b)(9) apply to all your vehicles above 6,000 pounds 

GVWR in model years 2022 through 2024. 

(10) You may not use credits generated from Tier 2 vehicles for demonstrating 

compliance with the Tier 3 standards except as specified in this paragraph (b)(10). 

You may generate early credits with U.S. sales of Tier 2 vehicles in the two model 

years before the Tier 3 standards start to apply for a given vehicle model. Vehicles 

certified to the Tier 2 standards must meet all the Tier 2 requirements in §86.1811-10, 

including the fleet-average Tier 2 standards. Calculate early Tier 3 emission credits 

as described in §86.1861 by subtracting the appropriate Tier 2 fleet-average value for 

FTP emissions of NMOG+NOx from 0.160 g/mile. Calculate your fleet-average 

value for the model year based on vehicles at or below 6,000 pounds GVWR in 2015, 

on all sizes of vehicles in 2016, and on vehicles above 6,000 pounds GVWR in 2017. 

You may use these early credits as described in §86.1861 for demonstrating 

compliance with the FTP emission standard for NMOG+NOx starting in model year

2017. For model years 2018 and later, you may use these early credits for banking or 

trading subject to a limitation based on credits generated in California, as follows:

(i) For the applicable model years in which you generate emission credits relative 

to California’s LEV III fleet-average NMOG+NOx standard, determine the actual 

California sales of light-duty vehicles and light-duty trucks and the actual 

nationwide sales of those same vehicles. In 2015, count sales only from vehicle 

models at or below 6,000 pounds GVWR. For each model year, multiply the 

credits generated under the California program by the ratio of nationwide vehicle 

sales to LEV III vehicle sales to calculate an effective nationwide quantity. Sum 

these results for model years 2015 through 2017. Note that this calculation results 

in a maximum credit quantity based on vehicle sales in all states, even though the 

initial credit calculation does not include vehicle sales in California or the section 

177 states. If you comply with the LEV III standards based on pooled emission 

credits for California and the section 177 states, use those pooled emission credits 
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and corresponding sales for calculating the maximum credit quantity under this 

paragraph (b)(10)(i). 

(ii) You may not use more early credits generated under this paragraph (b)(10) for 

banking or trading to demonstrate compliance with Tier 3 emission standards than 

the calculated value of the effective nationwide credit quantity summed in 

paragraph (b)(10)(i) of this section. If your generated credits are greater than this 

threshold, determine the percentage of your generated early credits that exceed the 

threshold. Calculate an adjusted quantity of early credits generated under this 

paragraph (b)(10) by decreasing the generated quantity from each model year by 

the calculated percentage that exceed the applicable threshold. This adjusted 

quantity of credits may be used for banking or trading relative to the Tier 3 

standards, subject to the five-year credit life described in §86.1861. 

(11) You may certify vehicles to the Tier 3 standards starting in model year 2015. To 

do this, you may either sell all your LEV III vehicles models nationwide, or you may

certify a subset of your fleet to alternate fleet-average emission standards as follows:

(i) The alternate fleet-average FTP emission standards for NMOG+NOx are 0.100 

g/mile in 2015 and 0.093 g/mile in 2016 for LDV and LDT1.

(ii) The alternate fleet-average FTP emission standards for NMOG+NOx are 

0.119 g/mile in 2015, 0.110 g/mile in 2016, and 0.101 g/mile in 2017 for LDT2 

and HLDT. 

(iii) The alternate fleet-average SFTP emission standards for NMOG+NOx are 

0.140 in 2015 for LDV and LDT1, 0.110 in 2016 for all vehicles, and 0.103 in 

2017 for LDT2 and HLDT. 

(iv) The vehicles must meet FTP and SFTP standards for PM as specified in 

§86.1811-04. The PM testing provisions of §86.1829-01(b)(1)(iii)(B) apply for 

these vehicles.

(v) Vehicles not certified to the Tier 3 standards in a given model year must meet 

all the requirements that apply for Tier 2 vehicles in that model year.

(vi) For cold temperature testing and for high-altitude testing, you may use the E0 

fuel specified in §86.113-04(a) or §86.213 instead of the E10 test fuel specified in 

§86.113-07.

(vii) For vehicles certified under this paragraph (b)(11), you may generate 

emission credits and use those credits for demonstrating compliance with Tier 3 

standards as described in paragraph (b)(10) of this section. 

(12) The following alternate standards apply for in-use testing:

(i) Alternate in-use FTP standards for NMOG+NOx apply for 2021 and earlier 

model year vehicles certified to Bin 70 and lower. Calculate these alternate 

standards by multiplying the applicable FEL by 1.4. These alternate standards 

apply only for testing at low-altitude conditions.

(ii) The alternate in-use FTP standard for PM is 0.006 g/mile for 2021 and earlier 

model year vehicles. 

(iii) The in-use US06 standard for PM is 0.010 g/mile for 2023 and earlier model 

year vehicles.

(13) Keep records as needed to show that you meet the requirements specified in this 

paragraph (b) for phasing in standards and for complying with declining fleet-average 

average standards.
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(c) Highway NMOG+NOx exhaust emission standard. NMOG+NOx emissions measured 

on the federal Highway Fuel Economy Test in 40 CFR part 600, subpart B, may not 

exceed the applicable FTP bin standard for NMOG+NOx. Demonstrate compliance with 

this standard for low-mileage vehicles by applying the appropriate deterioration factor. 

For vehicles not certified to any Tier 3 emission standards specified in paragraph (b) of 

this section, the provisions of §86.1811-04(j) apply instead of this paragraph (c). 

(d) Special provisions for Otto-cycle engines. The special provisions described in this 

paragraph (d) apply for vehicles with Otto-cycle engines. For vehicles not certified to 

any Tier 3 emission standards, the provisions of §86.1810-01(i)(6), (i)(13), and (i)(14) 

apply instead of this paragraph (d).

(1) Enrichment limits. The nominal air-fuel ratio throughout the US06 cycle may not 

be richer than the leanest air-fuel mixture required for lean best torque, except as 

allowed under paragraph (d)(2) of this section. Unless we approve otherwise in 

advance, lean best torque is the leanest air-fuel ratio required at any speed and load 

point with a fixed spark advance to make peak torque. The allowable tolerance 

around the nominal value for any given speed and load point over the US06 cycle for 

a particular vehicle is 4 percent, which is calculated as the nominal mass-based airfuel ratio for lean best torque divided by 1.04. 

(2) Engine protection. AECDs that use commanded enrichment to protect the engine 

or emission control hardware must not use enrichment more frequently or to a greater 

degree than is needed for this purpose. For purposes of this section, commanded 

enrichment includes intended engine operation at air-fuel ratios rich of stoichiometry, 

except the following:

(i) Cycling back and forth in a narrow window between rich and lean operation as 

a result of feedback controls targeted to maintain overall engine operation at 

stoichiometry.

(ii) Small changes in the target air-fuel ratio to optimize vehicle emissions or 

drivability. This may be called “closed-loop biasing.”

(iii) Temporary enrichment in response to rapid throttle motion.

(iv) Enrichment during cold-start and warm-up conditions.

(v) Temporary enrichment for running OBD checks to comply with §86.1806.

(3) A/C-on specific calibrations. (i) A/C-on specific calibrations (e.g., air-fuel ratio, 

spark timing, and exhaust gas recirculation) that differ from A/C-off calibrations may

be used for a given set of engine operating conditions (e.g., engine speed, manifold 

pressure, coolant temperature, air charge temperature, and any other parameters). 

Such calibrations must not unnecessarily reduce emission control effectiveness during 

A/C-on operation when the vehicle is operated under conditions that may reasonably 

be expected during normal operation and use. If emission control effectiveness 

decreases as a result of such calibrations, the manufacturer must describe in the 

Application for Certification the circumstances under which this occurs and the 

reason for using these calibrations.

(ii) For AECDs involving commanded enrichment, these AECDs must not 

operate differently for A/C-on operation than for A/C-off operation, except as 

provided under paragraph (d)(2) of this section. This includes both the sensor 

inputs for triggering enrichment and the degree of enrichment employed. 
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(4) “Lean-on-cruise” calibration strategies. Manufacturers may use “lean-on-cruise” 

strategies subject to the following specifications:

(i) A “lean-on-cruise” strategy is defined as the use of an air-fuel ratio

significantly leaner than stoichiometry during non-deceleration conditions at 

speeds above 40 mph.

(ii) You must not employ “lean-on-cruise” strategies during vehicle operation in 

normal driving conditions, including A/C usage, unless at least one of the 

following conditions is met:

(A) Such strategies are substantially employed during the FTP, US06, or 

SC03 duty cycle.

(B) Such strategies are demonstrated not to significantly reduce vehicle 

emission control effectiveness over the operating conditions in which they are 

employed.

(C) Such strategies are demonstrated to be necessary to protect the vehicle 

occupants, engine, or emission control hardware.

(iii) If you propose to use a “lean-on-cruise” strategy, you must describe in the 

application for certification the circumstances under which such a calibration 

would be used and the reasons for using it.

(e) through (f) [Reserved]

(g) Cold temperature exhaust emission standards. The following standards apply for 

vehicles tested over the test procedures specified in subpart C of this part:

(1) Cold temperature CO standards. These cold temperature CO standards are 

applicable only to gasoline-fueled vehicles. These standards apply for testing at lowaltitude conditions and high-altitude conditions. Cold temperature CO exhaust 

emission standards apply when measured using the test procedures specified in 

subpart C of this part, as follows:

(i) For LDV and LDT1, the standard is 10.0 g/mile CO.

(ii) For LDT2, LDT3 and LDT4, the standard is 12.5 grams per mile CO.

(2) Cold temperature NMHC standards. Fleet average cold temperature NMHC 

standards are applicable only to gasoline-fueled vehicles, and apply equally to 

certification and in-use except as otherwise specified in §86.1811-10(u) for in-use 

standards for applicable phase-in models. Testing with other fuels such as a highlevel ethanol-gasoline blend, or testing on diesel vehicles, is not required. Multi-fuel, 

bi-fuel or dual-fuel vehicles must comply with requirements using gasoline only. 

(i) The standards are shown in the following table:

Table 5 of §86.1811-17—Fleet Average Cold Temperature 

NMHC Exhaust Emission Standards

Vehicle weight category Cold temperature NMHC 

sales-weighted fleet average 

standard (g/mile)

LDV and LLDT 0.3

HLDT 0.5

(ii) The manufacturer must calculate its fleet average cold temperature NMHC 

emission level(s) as described in §86.1864–10(m).
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(iii) The standards specified in this paragraph (g)(2) apply only for testing at lowaltitude conditions. However, manufacturers must submit an engineering 

evaluation indicating that common calibration approaches are utilized at high 

altitudes. Any deviation from low altitude emission control practices must be 

included in the auxiliary emission control device (AECD) descriptions submitted 

at certification. Any AECD specific to high altitude must require engineering 

emission data for EPA evaluation to quantify any emission impact and validity of 

the AECD.

(h) Small-volume manufacturers. Small-volume manufacturers may use the following 

Tier 3 phase-in provisions: 

(1) Instead of the fleet-average FTP standards for NMOG+NOx specified in this 

section, small-volume manufacturers may meet alternate fleet-average standards of 

0.125 g/mile through model year 2021, and 0.051 g/mile for model years 2022 

through 2027. The following additional provisions apply for vehicles certified under 

this paragraph (h)(1):

(i) Vehicles are subject to exhaust emission standards over the useful life as 

specified in §86.1805-12 through model year 2021, and as specified in this section

starting in model year 2022.

(ii) Gasoline-fueled vehicles may use the E0 test fuel specified in §86.113-04 for 

vehicles certified to bins higher than Bin 70 through model year 2021.

(iii) Vehicles certified under this paragraph (h)(1) may generate emission credits 

and they may use banked or traded emission credits relative to the alternate fleetaverage FTP standard for NMOG+NOx only in model years 2022 through 2027. 

(iv) Vehicles are subject to all the other requirements specified in this section. 

(2) Small-volume manufacturers may delay complying with all the requirements of 

this section until model year 2022, and instead meet all the requirements that apply to 

Tier 2 vehicles under §86.1811-10 for 2021 and earlier model years. 

(3) If meeting the Tier 3 standards would cause severe economic hardship, smallvolume manufacturers may ask us to approve an extended compliance deadline under 

the provisions of 40 CFR 1068.250, except that the solvency criterion does not apply

and there is no maximum duration of the hardship relief. 

§§86.1812-01 and 86.1813-01 [Removed]

179. Remove §§86.1812-01 and 86.1813-01.

180. A new §86.1813-17 is added to subpart S to read as follows:

§ 86.1813-17 Evaporative and refueling emission standards.

Vehicles must meet evaporative and refueling emission standards as specified in this 

section. These standards apply for heavy duty vehicles above 14,000 pounds GVWR as 

specified in §86.1801. The emission standards apply for total hydrocarbon equivalent 

(THCE) measurements using the test procedures specified in subpart B of this part, as 

appropriate. Note that § 86.1829 allows you to certify without testing in certain 

circumstances. Except as specified in paragraph (b) of this section, evaporative and 

refueling emission standards do not apply for diesel-fueled vehicles. Unless otherwise 

specified, MDPVs are subject to all the same provisions of this section that apply to 

LDT4.
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(a) Tier 3 evaporative emission standards. Vehicles may not exceed the Tier 3 

evaporative emission standards, as follows:

(1) Measure emissions using the test procedures of subpart B of this part, as follows:

(i) Follow the vehicle preconditioning and exhaust testing procedures as described 

in subpart B of this part.

(ii) Measure diurnal, running loss, and hot soak emissions as shown in §86.130. 

This includes separate measurements for the two-diurnal test sequence and the 

three-diurnal test sequence; however, gaseous-fueled vehicles are not subject to 

evaporative emission standards using the two-diurnal test sequence.

(iii) For gasoline-fueled vehicles, use E10 test fuel as required in §86.113, except 

as specified in this section.

(iv) Emissions are generally measured with a flame ionization detector (FID). In 

the case of diurnal, hot soak, and running loss testing with E10 test fuel, multiply

measured (unspeciated) FID values by 1.08 to account for the FID’s reduced 

response to ethanol. You may instead determine total hydrocarbon equivalent for 

E10 testing based on speciated measurements as described in § 86.143-96(c). 

You must use the same method (with or without speciation) for all of the specified

evaporative testing for a given evaporative/refueling family. Similarly, any

evaporative/refueling families certified in later model years using carryover data 

must use the same method that was used for the original testing. We may do 

testing with or without speciation, but we will apply the 1.08 correction factor to 

unspeciated measurements only if you also use it to determine your final test 

results.

(2) Diurnal and hot soak emissions may not exceed the Tier 3 emission standards, as 

follows:

(i) The emission standard for the sum of diurnal and hot soak measurements from 

the two- diurnal test sequence and the three- diurnal test sequence is based on a 

fleet average in a given model year. You must specify a family emission limit 

(FEL) for each evaporative family. The FEL serves as the emission standard for 

the evaporative family with respect to all required diurnal and hot soak testing. 

Calculate your fleet average emission level as described in §86.1860 based on the 

FEL that applies for low-altitude testing to show that you meet the specified 

standard. For multi-fueled vehicles, calculate fleet-average emission levels based 

only on emission levels for testing with gasoline. You may generate emission 

credits forbanking and trading and you may use banked or traded credits for 

demonstrating compliance with the diurnal plus hot soak emission standard for 

vehicles required to meet the Tier 3 standards, other than electric vehicles and 

gaseous-fueled vehicles, as described in §86.1861 starting in model year 2017. 

You comply with the emission standard for a given model year if you have 

enough credits to show that your fleet-average emission level is at or below the 

applicable standard. You may exchange credits between or among evaporative 

families within an averaging set as described in §86.1861. Separate diurnal plus 

hot soak emission standards apply as shown for high-altitude conditions. The 

sum of diurnal and hot soak measurements may not exceed the following fleetaverage Tier 3 standards:
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Table 1 of §86.1813-17—

Tier 3 Diurnal Plus Hot Soak Emission Standards (grams per test)

Vehicle category Low-altitude 

conditions

High-altitude 

conditions

LDV, LDT1 0.300 0.65

LDT2 0.400 0.85

HLDT 0.500 1.151

HDV 0.600 1.75

1

1.25 g/test for MDPVs.

(ii) Specify FELs as follows:

(A) You may specify the low-altitude FEL in increments of 0.025 g above or 

below the otherwise applicable Tier 3 diurnal plus hot soak standard, up to the 

maximum values specified in the following table:

Table 2 of §86.1813-17—

Tier 3 FEL Caps for Low-Altitude Testing

Vehicle category FEL caps

LDV 0.500

LLDT 0.650

HLDT 0.900

MDPV 1.000

HDV 1.4

(B) Calculate the FEL for testing at high-altitude conditions based on the 

difference between the low-altitude FEL and the standard. For example, if a 

light-duty vehicle was certified with an FEL of 0.400 g instead of the 0.300 g 

standard, the FEL for testing under high-altitude conditions would be 0.75 g 

(0.65+0.10). 

(iii) Hydrocarbon emissions must not exceed 0.020 g for LDV and LDT and 

0.030 g for HDV when tested using the Bleed Emission Test Procedure adopted 

by the California Air Resources Board as part of the LEV III program. This 

procedure quantifies diurnal emissions without measuring hot soak emissions. 

The standards in this paragraph (a)(2)(iii) do not apply for testing at high-altitude 

conditions. For vehicles with non-integrated refueling canisters, the bleed 

emission test and standard do not apply to the refueling canister. You may

perform the Bleed Emission Test Procedure using the analogous test temperatures 

and the E10 test fuel specified in subpart B of this part.

(3) Running losses may not exceed 0.05 g per mile when measured using the test 

procedures specified in § 86.134. This standard does not apply for gaseous-fueled

vehicles.

(4) Fuel systems for vehicles operating on one or more volatile liquid fuels may not 

exceed an effective leak diameter of 0.02 inches when measured using the procedure 

specified in 40 CFR 1066.985. For vehicles with fuel tanks exceeding 25 gallons 

nominal fuel tank capacity, you may request our approval for a leak standard greater 

than 0.020 inches, up to a maximum value of 0.040 inches. 

(5) The Tier 3 evaporative emission standards start to phase in with model year 2017 

for vehicles at or below 6,000 pounds GVWR and with model year 2018 for vehicles 
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above 6,000 pounds GVWR. Table 3 of this section specifies the minimum 

percentage of each manufacturer’s sales in each model year that must be certified to 

the Tier 3 evaporative emission standards. Calculate annual percentages based on 

actual nationwide sales of all vehicles subject to standards under this paragraph (a) 

for the applicable model year; however, if all your FELs for Tier 3 evaporative 

families are at the applicable standard (neither generating nor using emission credits), 

the phase-in requirements are based on projected sales. Also, if you certify vehicles 

above 6,000 pounds GVWR to the Tier 3 evaporative emission standards in model 

year 2017, you may count projected U.S. sales of those vehicles toward your 

calculation for meeting the 40 percent requirement in 2017 (numerator only). 

Manufacturers may meet this requirement using the additional alternative phase-in 

provisions in paragraph (g) of this section. Vehicles from the identified model years 

not certified to the Tier 3 evaporative emission standards continue to be subject to the 

evaporative emission standards specified in § 86.1811-09(e) or § 86.1816-08(d) , 

including the useful life provisions of §86.1805-12. Note that this subjects LDV and 

LDT1 to a 150,000 mile useful life for evaporative emissions if the vehicles are 

subject to a 150,000 mile useful life for exhaust emissions. Keep records as needed 

to show that you meet the phase-in requirements specified in this section. See 

paragraph (g) of this section for additional provisions that apply for model year 2017 

and the rest of the phase-in. 

Table 3 of §86.1813-17—

Default Phase-in Schedule for Tier 3 

Evaporative Emission Standards

Model year Minimum percentage of vehicles 

subject to the Tier 3 standards

2017 40%1,2

2018 60%

2019 60%

2020 80%

2021 80%

2022 100%

1 The phase-in percentage for model year 2017 applies 

only for vehicles at or below 6,000 pounds GVWR.

2 The leak standard specified in paragraph (a)(4) of this 

section does not apply for model year 2017.

(6) For model year 2017, exclude vehicle sales from California and section 177 states 

from the calculation to demonstrate compliance with the phase-in schedule in 

paragraph (a)(5) or (g) of this section, and from the credit calculation in §86.1860. 

(b) Refueling emissions. Light-duty vehicles, light-duty trucks, and complete heavy-duty 

vehicles must meet the refueling emission standards in this paragraph (b) when measured 

over the procedure specified in §86.150. These standards apply starting with model year 

2018 for vehicles above 10,000 pounds GVWR. The following refueling standards 

apply:

(1) 0.20 g THCE per gallon of fuel dispensed for vehicles using volatile liquid fuels. 

This standard also applies for diesel-fueled LDV.
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(2) 0.15 g THC per gallon of fuel dispensed for liquefied petroleum gas-fueled 

vehicles and natural gas-fueled vehicles.

(c) Fuel spitback. For vehicles fueled by volatile liquid fuels, fuel spitback emissions 

may not exceed 1.0 g THCE when measured using the test procedures specified in § 

86.146. The fuel spitback standard applies only to newly assembled vehicles. 

(d) [Reserved]

(e) Auxiliary engines and separate fuel systems. The provisions of 40 CFR 1037.103(g) 

apply for vehicles with auxiliary engines. This includes any engines installed in the final 

vehicle configuration that contribute no motive power through the vehicle’s transmission.

(f) Refueling provisions for gaseous-fueled vehicles. The following provisions apply

specifically for gaseous-fueled vehicles:

(1) Compressed natural gas vehicles must meet the requirements for fueling 

connection devices as specified in ANSI NGV1-2006 (incorporated by reference in 

§86.1). 

(2) [Reserved]

(3) With our advance approval, liquefied petroleum gas-fueled vehicles with gauges 

or valves that can be opened to release fuel or fuel vapor during refueling (such as 

fixed liquid level gauges) may be tested for refueling emissions without opening such 

gauges or valves, as outlined in §86.157–98(d)(2). We will approve your request if

you can show that such gauges or valves will not be open during in-use refueling due 

to inaccessibility or other design features that would prevent them from opening or 

make this very unlikely.

(g) Alternative phase-in options for Tier 3 evaporative emission standards. You may use 

any of the following alternative methods to transition to the Tier 3 evaporative emission 

standards:

(1) Starting in model year 2015, you may earn an “allowance” for each vehicle that 

you certify early under this paragraph (g)(1). For each allowance you earn, you may

count it as one compliant vehicle in a later model year during the phase-in period. 

Calculate the total phase-in percentage in each model year by adding the allowances 

to the number of compliant vehicles (in the numerator), without increasing total sales 

(in the denominator). For each allowance you earn, you may alternatively count it as 

one compliant vehicle under the phase-in schedule described in paragraph (g)(5) of 

this section, except that you may not use those allowances to increase the value of the 

phase-in index from any model year by more than 10 percentage points. Vehicles 

earning allowances under this paragraph (g)(1) may not have an FEL above the 

applicable Tier 3 standard, and may not generate emission credits for banking or 

trading. Allowances may not be traded to another company. You may earn 

allowances under this paragraph (g)(1) for early-compliant vehicles as follows:

(i) Model year 2015 and 2016 vehicles at or below 6,000 pounds GVWR meeting 

the Tier 3 standards in paragraph (a) of this section or the equivalent California 

standards as specified in paragraph (g)(4) of this section earn allowances, as long 

as the vehicles are not sold in California or any of the section 177 states. 

(ii) Model year 2015 through 2017 LDV and LDT above 6,000 pounds GVWR 

meeting the Tier 3 standards in paragraph (a) of this section or the equivalent 

California standards as specified in paragraph (g)(4) of this section earn 
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allowances, as long as the vehicles are not sold in California or any of the section 

177 states. 

(iii) Model year 2015 through 2017 MDPV and HDV meeting the Tier 3 

standards in paragraph (a) of this section or the equivalent California standards as 

specified in paragraph (g)(4) of this section earn allowances for vehicles sold in 

any state.

(iv) To the extent that you over-comply with the 40-percent phase-in requirement 

in model year 2017, you may count your actual U.S. sales exceeding the required 

number of Tier 3 vehicles as allowances toward meeting the phase-in requirement 

in 2018 and later model years.

(v) For HDV above 10,000 pounds GVWR and at or below 14,000 pounds 

GVWR that you certify to the refueling emission standards in paragraph (b) of 

this section in model years 2015 through 2017 and sell outside of California and 

the section 177 states, a single vehicle may produce two allowances if it is 

certified to the Tier 3 diurnal plus hot soak standard. Allowances earned under 

this paragraph (g)(1)(v) may alternatively be used in model years 2018 through 

2022 to phase in the refueling standard, except that a single early-compliant 

vehicle produces only a single allowance.

(vi) Complete HDV above 14,000 pounds GVWR and all sizes of incomplete 

HDV earn allowances as described in pargraph (g)(1)(v) of this section if they are 

certified to the refueling emission standards in paragraph (b) of this section in 

model years 2015 through 2021.

(2) The following alternative phase-in options apply for model year 2017:

(i) You may disregard the percentage phase-in specified in paragraph (a)(5) of this 

section for 2017 if you choose 50-state certification for all your vehicles meeting 

the LEV III PZEV evaporative standards in 2017. Under this option, you may not 

produce a higher-emitting version of those vehicle models for sale outside of 

California or the section 177 states. Such vehicles may be certified using 

carryover data under the California program, but they may not generate or use 

emission credits. LDV and LDT1 that comply under this paragraph (g)(2)(i) may

not generate allowances under paragraph (g)(1) of this section, regardless of the 

calculated percentage of compliant vehicles in model year 2017.

(ii) You may comply with the phase-in requirement for model year 2017 by

meeting the Tier 3 emission standards for diurnal plus hot soak, running loss, and 

bleed emissions (or the equivalent set of California standards as allowed in this 

section) with 20 percent of vehicles at or below 6,000 pounds GVWR, and by

meeting the leak standard in paragraph (a)(2)(iii) of this section with 20 percent of 

vehicles at or below 6,000 pounds GVWR. You may optionally include vehicles 

above 6,000 pounds GVWR under this paragraph (g)(2)(ii) to calculate the 

percentage (numerator only) if they meet the leak and/or evaporative emission 

standards in model year 2017. Vehicles complying with Tier 3 evaporative 

emission standards may generate or use emission credits relative to the diurnal 

plus hot soak standard as specified in this section, but they may not generate 

allowances. You may apply this option and use the alternative phase-in 

calculation in paragraph (g)(4) of this section, subject to the following conditions:
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(A) You must meet or exceed the 20 percent threshold for both evaporative 

emissions and the leak standard.

(B) All the vehicles meeting the leak standard must also meet the Tier 3 

evaporative emission standards and the OBD requirements in §86.1806-

17(b)(1).

(C) Determine the appropriate percentage for calculating compliance under 

paragraph (g)(4) of this section by adding 20 to the percentage of vehicles 

meeting the Tier 3 evaporative emission standards to account for vehicles 

meeting the leak standard. Do not increase the percentage based on meeting 

the leak standard with more than 20 percent of your vehicles in model year 

2017.

(3) If you certify model year 2021 or earlier vehicles to the LEV III evaporative 

emission standards in California, you may certify those as Tier 3 vehicles that count 

toward meeting the phase-in requirements of this section. Such vehicles must still be 

certified to the high-altitude standards in paragraph (a)(2) of this section and the leak 

standard specified in paragraph (a)(4) of this section. You may not certify vehicles 

under this paragraph (g)(3) after model year 2021. Vehicles meeting the LEV III 

standards may also generate allowances under paragraph (g)(1) of this section; 

however, these vehicles may generate or use emission credits under this subpart only

if they are not used to generate allowances and if they are certified using the Option 2 

procedures under the LEV III program (including the bleed emission test). Vehicles 

may be certified under this paragraph (g)(3) based on the rig test (“Option 1”) if they

are certified to LEV III standards based on the rig test before model year 2017; this 

certification option applies through model year 2021. Include these Option 1 vehicles 

in the calculation of fleet average emissions by using the appropriate Tier 3 emission 

standard as the FEL. Note that the rig test is considered a diurnal test with respect to 

the provisions to account for ethanol emissions as described in paragraph (a)(1)(iv) of 

this section.

(4) If you fall short of the phase-in percentage specifications in paragraph (a)(5) of 

this section, you may designate the requisite number of Tier 2 vehicles as Tier 3 

vehicles for purposes of demonstrating compliance with the Tier 3 standards in this 

section. To do this, factor those Tier 2 vehicles into the Tier 3 fleet-average emission 

calculation using an FEL that is equal to the applicable diurnal plus hot soak standard 

from the two-day test sequence. The Tier 3 emission standards do not apply to these 

Tier 2 vehicles. In addition, you may disregard the phase-in percentages specified in 

paragraph (a)(5) of this section if you instead comply based on one of the following 

alternative measures: 

(i) You may comply with an alternate phase-in schedule described in this 

paragraph (g)(4)(i). To do this, you must give us a detailed plan for describing 

how you will meet the alternate phase-in schedule. You comply with the alternate 

phase-in schedule by calculating an evaporative phase-in index using the 

following equation that is at or above 1,280 for model years 2017 through 2022 

(or 1,040 for model years 2018 through 2022 if you use the provisions of 

paragraph (g)(2)(i) of this section):

Evaporative phase-in index = 6∙APP2017 + 5∙APP2018 + 4∙APP2019 + 3∙APP2020

+ 2∙APP2021 + APP2022
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Where:

APP = The phase-in percentage of vehicles meeting the Tier 3 evaporative 

emission standards for the indicated model year, based on actual sales, as 

described in paragraph (a)(5) of this section.

(ii) You may comply with an alternate phase-in schedule described in this 

paragraph (g)(4)(ii). To do this, you must give us a detailed plan for describing 

how you will meet the alternate phase-in schedule. You comply with the alternate 

phase-in schedule by calculating an evaporative phase-in index using the 

following equation that is at or above 420 for model years 2017 through 2022 (or 

380 for model years 2018 through 2022 if you use the provisions of paragraph 

(g)(2)(i) of this section):

Evaporative phase-in index = APP2017 + APP2018 + APP2019 + APP2020 + 

APP2021 + APP2022

Where:

APP = The phase-in percentage of vehicles meeting the Tier 3 evaporative emission 

standards for the indicated model year, based on actual sales, as described in 

paragraph (a)(5) of this section.(5) This paragraph (g)(5) describes an alternative 

approach to phasing in the evaporative and refueling emission standards for gaseousfueled vehicles above 8,500 pounds GVWR. Under this alternative phase-in, you 

may disregard the requirements of this section related to evaporative emission 

standards that apply for these vehicles before model year 2019. Similarly, you may 

disregard the refueling emission standards of this section before model year 2019 for 

vehicles above 10,000 pounds GVWR. For model year 2019, you may exclude from 

the phase-in calculation any evaporative families with vehicles that have a Job 1 date 

on or before [INSERT DATE FOUR YEARS AFTER FRM SIGNATURE] (see 40 

CFR 85.2304). Any vehicles not subject to Tier 3 evaporative emission standards 

during this phase-in period must continue to comply with the evaporative emission 

standards in §86.1816-08(d); such vehicles are subject to the useful life provisions in 

§86.1805-12 relative to evaporative emission standards. Each vehicle counting 

toward the phase-in percentage under this paragraph (g)(5) must meet all the 

standards that apply throughout the useful life as specified in §86.1805-17.

(h) Small-volume manufacturers. Small-volume manufacturers meeting the eligibility

requirements in § 86.1838 may delay complying with the requirements in this section 

until model year 2022. If meeting the Tier 3 standards would cause severe economic 

hardship, such manufacturers may ask us to approve an extended compliance deadline 

under the provisions of 40 CFR 1068.250, except that the solvency criterion does not 

apply and there is no maximum duration of the hardship relief. 

§§86.1814-01, 86.1814-02, 86.1815-01, and 86.1815-02 [Removed]

181. Remove §§86.1814-01, 86.1814-02, 86.1815-01, and 86.1815-02.

182. A new §86.1816-18 is added to subpart S to read as follows:

§ 86.1816-18 Emission standards for heavy-duty vehicles.

(a) Applicability and general provisions. This section describes exhaust emission 

standards that apply for model year 2018 and later complete heavy-duty vehicles. These 

standards are optional for incomplete heavy-duty vehicles and for heavy duty vehicles 
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above 14,000 pounds GVWR as described in §86.1801. Greenhouse gas emission 

standards are specified in §86.1818 for MDPVs and in 40 CFR 1037.104 for other HDV. 

See §86.1813 for evaporative and refueling emission standards. This section may apply

to vehicles before model year 2018 as specified in paragraph (b)(11) of this section. 

Separate requirements apply for MDPVs as specified in §86.1811. See subpart A of this 

part for requirements that apply for incomplete heavy-duty vehicles and for heavy-duty 

engines certified independent of the chassis. The following general provisions apply:

(1) Test all vehicles as described in this section using a chassis dynamometer; 

establish appropriate load settings based on adjusted loaded vehicle weight (see 

§86.1803).

(2) Some provisions apply differently depending on the vehicle’s power-to-weight 

ratio. Determine a vehicle’s power-to-weight ratio by dividing the engine’s rated 

power by the vehicle’s GVWR (in hp/pound). For purposes of this section, if a test 

group includes multiple configurations, use the vehicle with the highest power-toweight ratio to characterize the test group.

(3) Use E10 test fuel as required in §86.113, except as specified in this section.

(4) Measure emissions from hybrid electric vehicles (including plug-in hybrid electric 

vehicles) as described in 40 CFR part 1066, subpart F, except that these procedures

do not apply for plug-in hybrid electric vehicles during charge-depleting operation.

(b) Tier 3 exhaust emission standards. Exhaust emissions may not exceed the Tier 3 

exhaust emission standards, as follows:

(1) Measure emissions using the procedures of subpart B of this part, using specific 

driving schedules and additional procedures as follows:

(i) The Federal Test Procedure (FTP) is based on testing with the Urban 

Dynamometer Driving Schedule (UDDS) specified in paragraph (a) of Appendix I

of this part. 

(ii) The Heavy-Duty Supplemental Federal Test Procedure (HD-SFTP) involves 

testing with the UDDS, the SC03 driving schedule specified in paragraph (h) of 

Appendix I of this part, and one of the following additional driving schedules:

(A) For Class 2b vehicles, the US06 driving schedule specified in paragraph 

(g) of Appendix I of this part.

(B) For Class 2b vehicles with a power-to-weight ratio at or below 0.024 

hp/pound that are certified to optional standards under paragraphs (b)(2) and 

(4) of this section, the highway portion of the US06 driving schedule 

characterized as the “second bag” in §86.159-08(a).

(C) For Class 3 vehicles, the LA-92 driving schedule as specified in paragraph 

(c) of Appendix I of this part. 

(iii) HD-SFTP emissions are calculated as a composite of test results over these 

driving schedules based on the following calculation:

HD-SFTP (g/mi) = 0.35∙FTP + 0.28∙HDSIM + 0.37∙SC03

Where: 

HDSIM = the appropriate driving schedule specified in paragraph 

(b)(1)(ii)(A) through (C) of this section.

(iv) You may alternatively use FTP emission results to substitute for the SC03 

value in the calculation under paragraph (b)(1)(iii) of this section for a given 
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vehicle for any testing under this section. Such vehicles remain subject to the 

SFTP standard when tested over the SC03 driving schedule.

(v) Hydrocarbon emission standards are expressed as NMOG; however, you may

measure exhaust emissions based on nonmethane hydrocarbon instead of NMOG 

as described in 40 CFR 1066.635.

(2) Table 1 of this section describes fully phased-in Tier 3 standards that apply as 

specified in this paragraph (b) for the identified driving schedules. The FTP 

standards for NMOG+NOx apply on a fleet-average basis using discrete bin standards 

as described in paragraph (b)(4) of this section. The bin standards include additional 

emission standards for CO emissions, and for NMOG+NOx standards when testing 

over the HD-SFTP driving schedule. Table 1 follows:

Table 1 of §86.1816-18

Fully Phased-in Tier 3 HDV Exhaust Emission Standards (g/mile)

HDV Class

Fleet-average

NMOG+NOx PM Formaldehyde

FTP FTP HD-SFTP FTP

2b 0.178 0.008 0.01010.006

3 0.247 0.010 0.007 0.006

1

For vehicles with a power-to-weight ratio at or below 0.024 hp/pound that are 

certified using the driving schedule described in paragraph (b)(1)(ii)(B) of this 

section, the HD-SFTP standard for PM is 0.007 g/mile instead of the value 

specified in the table.

(3) The FTP standards specified in this section apply equally for testing at lowaltitude conditions and high-altitude conditions. The HD-SFTP standards described 

in this section apply only for testing at low-altitude conditions. 

(4) The FTP emission standard for NMOG+NOx is based on a fleet average in a 

given model year. You must specify a family emission limit (FEL) for each test 

group. The FEL serves as the emission standard for the test group with respect to all 

required FTP testing. Calculate your fleet-average emission level as described in 

§86.1860 to show that you meet the specified standard. For multi-fueled vehicles, 

calculate fleet-average emission levels based only on emission levels for testing with 

gasoline or diesel fuel. You may generate or use emission credits forbanking and

trading and you may use banked or traded credits for demonstrating compliance with 

the FTP emission standard for NMOG+NOx as described in §86.1861. You comply

with the emission standard for a given model year if you have enough credits to show 

that your fleet-average emission level is at or below the applicable standard. You 

may exchange credits between or among any test groups subject to standards under 

this section. Specify one of the identified values from Table 2 or Table 3 of this 

section as the FEL for demonstrating that your fleet-average emission level complies 

with the FTP emission standard for NMOG+NOx. These FEL values define emission 

bins that also determine corresponding emission standards for NMOG+NOx 

emissions over the HD-SFTP driving schedule and for CO emissions, as follows:
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Table 2 of §86.1816-18

Tier 3 Bin Standards—Class 2b (g/mile)

FEL 

Name

NMOG+NOx CO

FTP (FEL) HD-SFTP1FTP HD-SFTP

Bin 250 0.250 0.800 6.4 22.0

Bin 200 0.200 0.800 4.2 22.0

Bin 170 0.170 0.450 4.2 12.0

Bin 150 0.150 0.450 3.2 12.0

Bin 020.000 0.000 0.0 0.0

1 Vehicles with a power-to-weight ratio at or below 0.024 

hp/pound that are certified using the driving schedule 

described in paragraph (b)(1)(ii)(B) of this section, the 

following HD-SFTP bin standards for NMOG+NOx apply 

instead of those identified in the table: 0.350 g/mile for Bin 

150 and Bin 170; and 0.550 g/mile for Bin 200 and Bin 250.

2 Vehicles certified to Bin 0 must also meet PM and 

formaldehyde standards of 0.000 g/mile instead of the 

standards specified in paragraph (b)(2) of this section.

Table 3 of §86.1816-18

Tier 3 Bin Standards—Class 3 (g/mile)

FEL 

Name

NMOG+NOx CO

FTP (FEL) HDSFTP FTP HD-SFTP

Bin 400 0.400 0.550 7.3 6.0

Bin 270 0.270 0.550 4.2 6.0

Bin 230 0.230 0.350 4.2 4.0

Bin 200 0.200 0.350 3.7 4.0

Bin 010.000 0.000 0.0 0.0

1 Vehicles certified to Bin 0 must also meet PM and 

formaldehyde standards of 0.000 g/mile instead of the 

standards specified in paragraph (b)(2) of this section.

(5) [Reserved]

(6) The full Tier 3 program includes new emission standards for NMOG+NOx, PM, 

CO, and formaldehyde; it also includes measurement with a new test fuel and a 

longer useful life. Vehicles meeting all these requirements are considered Final Tier 

3 vehicles. Vehicles that do not meet all the Tier 3 requirements are considered 

Interim Tier 3 vehicles. The Tier 3 PM standards phase in over several years. Any

vehicles not subject to Tier 3 PM standards during the phase-in period must continue 

to comply with the PM standards in §86.1816-08. Paragraph (b)(7) of this section 

describes how to transition to Tier 3 standards for emissions other than PM. The 

following provisions describe the primary approach for phasing in the Tier 3 PM 

standards:

(i) You must meet the FTP emission standard for PM with 20, 40, 70, and 100 

percent of your projected nationwide sales of all vehicles subject to this section in 

model years 2018 through 2021, respectively. Each vehicle meeting the Tier 3 

FTP standard for PM must also meet the Tier 3 HD-SFTP standard for PM.

(ii) You may disregard the phase-in percentages specified in paragraph (b)(6)(i) of 
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this section if you instead comply with an indexed PM phase-in schedule as 

described in this paragraph (b)(6)(ii). To do this, you must notify us of your 

intent before January 1, 2018, and include a detailed plan for complying with the 

indexed phase-in schedule. You comply with the indexed phase-in schedule by

calculating a PM phase-in index at or above 440 using the following equation for 

model years 2018 through 2021:

PM phase-in index = 4∙APP2018 + 3∙APP2019 + 2∙APP2020 + APP2021

Where:

APP = The phase-in percentage of vehicles meeting the Tier 3 PM standards 

for the indicated model year, based on actual sales.

(iii) Vehicles meeting the Tier 3 PM standards must meet those standards over the 

useful life as specified in §86.1805. Note that Interim Tier 3 vehicles may have 

different useful life values for PM emission standards than for other emission 

standards.

(iv) Measure PM emissions from all vehicles using the same test fuel used for 

measuring NMOG+NOx emissions.

(v) You may certify Interim Tier 3 vehicles based on carryover data.

(vi) You may use the alternative phase-in provisions described in paragraph (b)(8) 

of this section to transition to the Tier 3 exhaust emission standards on a different 

schedule. 

(7) The following provisions describe the primary approach for phasing in the Tier 3 

standards other than PM in 2022 and earlier model years:

(i) The fleet-average FTP emission standard for NMOG+NOx phases in over 

several years as described in this paragraph (b)(7)(i). You must identify FELs as 

described in paragraph (b)(4) of this section and calculate a fleet-average 

emission level to show that you meet the FTP emission standard for NMOG+NOx 

that applies for each model year. You may certify using transitional bin standards 

specified in Table 5 of this section through model year 2021; these vehicles are 

subject to FTP emission standards for PM and formaldehyde as described in 

paragraph (b)(2) of this section. You may use the E0 test fuel specified in 

§86.113 for gasoline-fueled vehicles certified to the transitional bins; the useful 

life period for these vehicles is 120,000 miles or 11 years. Fleet-average FTP 

emission standards decrease as shown in the following table:
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Table 4 of §86.1816-18

Declining Fleet-Average FTP 

Emission Standards for NMOG+NOx (g/mile)

Model

Year Class 2b Class 3

201610.333 0.548

201710.310 0.508

2018 0.278 0.451

2019 0.253 0.400

2020 0.228 0.349

2021 0.203 0.298

2022 0.178 0.247

1

Fleet-average standards are shown for 2016 and 

2017 for purposes of voluntary early compliance 

as described in paragraph (b)(11) of this section.

Table 5 of §86.1816-18

Transitional Tier 3 FTP Bin Standards (g/mile)1

Class FEL Name NMOG+NO

x

NOx2 CO

2b Bin 395 0.395 0.2 6.4

Bin 340 0.340 0.2 6.4

3

Bin 630 0.630 0.4 7.3

Bin 570 0.570 0.4 7.3

1 Vehicles certified to Transitional Tier 3 FTP bins are not subject to HDSFTP standards.

2 The NOx standard applies only for certification testing with emission-data 

vehicles.

(ii) You may use the alternative phase-in provisions described in paragraph (b)(8) 

of this section to transition to the Tier 3 exhaust emission standards on a different 

schedule. 

(8) This paragraph (b)(8) describes an alternative approach to phasing in the Tier 3 

emission standards. If you choose this approach, you must phase in the Tier 3 

standards for all your vehicles subject to this section according to this schedule. 

Under this alternative phase in, you must meet all the standards specified in paragraph 

(b)(2) of this section according to the phase-in schedule specified in Table 6 of this 

section based on the indicated percentage of your projected nationwide sales in each 

model year. These vehicles must meet the applicable FTP emission standard for CO 

and the HD-SFTP emission standards for NMOG+NOx and CO that apply for Class 

2b Bin 170 and Class 3 Bin 230 as described in paragraph (b)(4) of this section. Any

vehicles not subject to Tier 3 standards during the phase-in period must continue to 

comply with the gaseous exhaust emission standards in §86.1816-08. Each vehicle 

counting toward the PM phase-in percentage under this paragraph (b)(8) in model 

years 2019 and 2020 must also be included in the portion of the fleet meeting the Tier 

3 standards for pollutants other than PM. Each vehicle counting toward the phase-in 

percentage for any pollutant must use the Tier 3 test fuel specified in §86.113-07. 

The following exceptions and special provisions apply under this paragraph (b)(8): 
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(i) For model year 2019, you may exclude from the phase-in calculation any test 

groups that have a Job 1 date on or before [INSERT DATE FOUR YEARS 

AFTER FRM SIGNATURE] (see 40 CFR 85.2304).

(ii) You may generate Tier 3 emission credits during the phase-in period if all 

your pre-Tier 3 vehicles in a given model year have FELs at or below the NOx 

and NMHC standards in §86.1816-08. Determine emission credits by calculating 

fleet-average emission levels for Tier 3 and pre-Tier 3 vehicles together; for preTier 3 vehicles use an NMOG+NOx equivalent FEL of 0.395 g/mile for Class 2b 

vehicles and 0.630 g/mile for Class 3 vehicles. 

Table 6 of §86.1816-18

Alternative Phase-in Schedule 

Model

Year

Class 2b Class 3

PM Other 

than PM PM Other than PM

2019 40% 65% 40% 60%

2020 70% 77% 70% 73%

2021 100% 88% 100% 87%

2022 100% 100% 100% 100%

(9) You may not use credits generated from vehicles certified under §86.1816-08 for 

demonstrating compliance with the Tier 3 standards. 

(10) [Reserved] 

(11) You may voluntarily certify your vehicles under this section in model years 2016 

and 2017. If you do this, the fleet-average FTP emission standards for NMOG+NOx 

apply to all your heavy-duty vehicles under this section as specified in paragraph 

(b)(7)(i) of this section. Use any of the available bin standards as described in this 

section. Vehicles certified under this paragraph (b)(11) must comply with the PM 

standards specified in §86.1816-08 instead of the Tier 3 PM standards specified in 

this section.

(12) Alternate standards apply for in-use testing with 2022 and earlier model year 

vehicles as described in this paragraph (b)(12). These alternate standards apply in the 

the first model year that a test group is certified to Tier 3 FTP or HD-SFTP standards 

for NMOG+NOx or PM under this section. The alternate in-use standards also apply

in the following model year (but not beyond 2022) for carryover test groups certified 

to the same bin standards. If you certify a test group to more stringent bin standards 

under this section in a given model year, the alternate in-use standards apply as if that 

were the first model year of certifying to the Tier 3 standards. The provisions of this 

section apply separately for NMOG+NOx and PM. This paragraph (b)(12) does not 

apply for Bin 0 vehicles.

(i) The alternate in-use FTP standards for PM are 0.016 g/mile for Class 2b 

vehicles and 0.020 g/mile for Class 3 vehicles. 

(ii) The alternate in-use HD-SFTP standards for PM are 0.012 g/mile for Class 2b 

vehicles with a power-to-weight ratio at or below 0.024 hp/pound that are 

certified to optional standards under paragraphs (b)(2) and (4) of this section, and 

0.015 g/mile for other Class 2b vehicles. The alternate in-use HD-SFTP standard 

for PM is 0.012 g/mile for Class 3 vehicles. Alternate in-use HD-SFTP standards 
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do not apply for vehicles certified to the transitional bins described in paragraph 

(b)(7) of this section.

(iii) Alternate in-use FTP and HD-SFTP standards for NMOG+NOx apply as 

specified in the following table: 

Table 7 of §86.1816-18

Alternate In-use NMOG+NOx Standards (g/mile)

Class FEL Name FTP HD-SFTP1

2b

Bin 250 0.370 1.120

Bin 200 0.300 1.120

Bin 170 0.250 0.630

Bin 150 0.220 0.630

3

Bin 400 0.600 0.770

Bin 270 0.400 0.770

Bin 230 0.340 0.490

Bin 200 0.300 0.490

1

For Class 2b vehicles with a power-to-weight ratio at or below 0.024 

hp/pound that are certified to optional standards under paragraphs (b)(2) 

and (4) of this section, the following alternate in-use FTP standards for 

NMOG+NOx apply instead of those identified in the table: 0.490 g/mile 

for Bin 150 and Bin 170; and 0.770 g/mile for Bin 200 and Bin 250. Note 

that vehicles certified to transitional Tier 3 FTP bins are not subject to HDSFTP standards.

(13) Keep records as needed to show that you meet the requirements specified in this 

paragraph (b) for phasing in standards and for complying with declining fleet-average 

average standards.

(c) Highway NMOG+NOx exhaust emission standard. For vehicles certified to any of the 

Tier 3 standards specified in paragraph (b) of this section, NMOG+NOx emissions 

measured on the highway test cycle in 40 CFR part 600, subpart B, may not exceed the 

applicable NMOG+NOx bin standard for FTP testing. Demonstrate compliance with this 

standard for low-mileage vehicles by applying the appropriate deterioration factor.

(d) Provisions for Otto-cycle engines. The special provisions described in §86.1811-17(d) 

apply to vehicles with Otto-cycle engines that are certified under this section.

(e) Small-volume manufacturers. Small-volume manufacturers meeting the eligibility

requirements in § 86.1838 may delay complying with the requirements in this section 

until model year 2022. This also applies for continuing to use the E0 test fuel specified in 

§86.113 through model year 2021. If meeting the Tier 3 standards would cause severe 

economic hardship, such manufacturers may ask us to approve an extended compliance 

deadline under the provisions of 40 CFR 1068.250, except that the solvency criterion 

does not apply and there is no maximum duration of the hardship relief. 

183. Section §86.1817-08 is amended by revising the introductory text to read as 

follows:

§ 86.1817-08 Complete heavy-duty vehicle averaging, trading, and banking 

program.

Section 86.1817–08 includes text that specifies requirements that differ from §86.1817–

05. Where a paragraph in §86.1817–05 is identical and applicable to §86.1817–08, this 

may be indicated by specifying the corresponding paragraph and the statement 

“[Reserved]. For guidance see §86.1817–05.” This section does not apply for NOx or 
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NMOG+NOx emissions for vehicles certified to the Tier 3 standards in §86.1816-18, 

including those vehicles that certify to the Tier 3 standards before model year 2018. See 

§§86.1860 and 86.1861 for provisions that apply for vehicles certified to the Tier3 

standards.

* * * * *

184. Section 86.1818-12 is amended by revising paragraph (a) to read as follows:

§ 86.1818-12 Greenhouse gas emission standards for light-duty vehicles, light-duty 

trucks, and medium-duty passenger vehicles.

(a) Applicability. (1) This section contains standards and other regulations applicable to 

the emission of the air pollutant defined as the aggregate group of six greenhouse gases: 

Carbon dioxide, nitrous oxide, methane, hydrofluorocarbons, perfluorocarbons, and 

sulfur hexafluoride. This section applies to 2012 and later model year LDV, LDT and 

MDPV, including multi-fuel vehicles, vehicles fueled with alternative fuels, hybrid 

electric vehicles, plug-in hybrid electric vehicles, electric vehicles, and fuel cell vehicles. 

Unless otherwise specified, multi-fuel vehicles must comply with all requirements 

established for each consumed fuel. The provisions of this section, except paragraph (c), 

also apply to clean alternative fuel conversions as defined in 40 CFR 85.502, of all model 

year light-duty vehicles, light-duty trucks, and medium-duty passenger vehicles. 

Manufacturers that qualify as a small business according to the requirements of 

§86.1801–12(j) are exempt from the emission standards in this section. Manufacturers 

that have submitted a declaration for a model year according to the requirements of 

§86.1801–12(k) for which approval has been granted by the Administrator are 

conditionally exempt from the emission standards in paragraphs (c) through (e) of this 

section for the approved model year.

(2) The standards specified in this section apply only for testing at low-altitude 

conditions. However, manufacturers must submit an engineering evaluation indicating 

that common calibration approaches are utilized at high altitude. Any deviation from low 

altitude emission control practices must be included in the auxiliary emission control 

device (AECD) descriptions submitted at certification. Any AECD specific to high 

altitude requires engineering emission data for EPA evaluation to quantify any emission 

impact and determine the validity of the AECD.

* * * * *

185. Section §86.1821-01 is amended by revising paragraphs (a) and (b) introductory

text an adding paragraphs (b)(10) and (f) to read as follows:

§ 86.1821-01 Evaporative/refueling family determination.

(a) The gasoline-, ethanol-, methanol-, liquefied petroleum gas-, and natural gas-fueled 

vehicles described in a certification application will be divided into groupings expected to 

have similar evaporative and/or refueling emission characteristics (as applicable) 

throughout their useful life. Each group of vehicles with similar evaporative and/or 

refueling emission characteristics shall be defined as a separate evaporative/refueling 

family. Manufacturers shall use good engineering judgment to determine 

evaporative/refueling families.

(b) For vehicles that operate on volatile liquid fuels to be classed in the same 

evaporative/refueling family, they must be similar with respect to all the following items:
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* * * * *

(10) Evaporative emission standard or family emission limit (FEL).

* * * * *

(f) For vehicles to be classed in the same leak family, they must be similar with respect to 

the items listed in paragraph (b) of this section and use the same OBD method for 

detecting leaks.

186. Section §86.1823-08 is amended as follows:

a. By revising the introductory text.

b. By removing and reserving paragraph (g).

c. By adding paragraph (n).

§ 86.1823-08 Durability demonstration procedures for exhaust emissions.

This section describes durability demonstration procedures for exhaust emissions. 

Eligible small-volume manufacturers or small-volume test groups may optionally meet 

the requirements of §§ 86.1826 and 86.1838 instead of the requirements of paragraphs 

(a) through (m) of this section. A separate durability demonstration is required for each 

durability group.

* * * * *

(g) [Reserved]* * * * *

(n) Emission component durability. [Reserved]. For guidance see 40 CFR 86.1823-01(e). 

187. Section §86.1824-08 is amended as follows:

a. By revising the introductory text.

b. By revising paragraphs (a) and (f)(1).

c. By removing and reserving paragraph (h).

d. By adding paragraph (k).

§ 86.1824-08 Durability demonstration procedures for evaporative emissions.

This section describes durability demonstration procedures for evaporative emissions. 

Eligible small-volume manufacturers or small-volume test groups may optionally meet 

the requirements of §§ 86.1826 and 86.1838 instead of the requirements of paragraphs (a) 

through (j) of this section. A separate durability demonstration is required for each 

evaporative/refueling family.

(a) Durability program objective. The durability program must predict an expected in-use 

emission deterioration rate and emission level that effectively represents a significant 

majority of the distribution of emission levels and deterioration in actual use over the full 

useful life of candidate in-use vehicles of each vehicle design which uses the durability

program. This requirement applies for all SHED-based measurements except the bleed 

emission test. The standard for bleed emissions applies for the full useful life, but 

manufacturers do not need to establish deterioration factors for bleed emissions. The 

requirements of this section do not apply for spitback or leak standards.

* * * * *

(f) * * *

(1) For gasoline fueled vehicles certified to meet the evaporative emission standards set 

forth in this subpart, any mileage accumulation method for evaporative emissions must 

employ gasoline fuel for the entire mileage accumulation period which contains ethanol 

in, at least, the highest concentration permissible in gasoline under federal law and that is 
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commercially available in any state in the United States. Unless otherwise approved by

the Administrator, the manufacturer must determine the appropriate ethanol concentration 

by selecting the highest legal concentration commercially available during the calendar 

year before the one in which the manufacturer begins its mileage accumulation. The 

manufacturer must also provide information acceptable to the Administrator to indicate 

that the mileage accumulation method is of sufficient design, duration and severity to 

stabilize the permeability of all non-metallic fuel and evaporative system components to 

the mileage accumulation fuel constituents.

* * * * *

(h) [Reserved]

* * * * *

(k) Emission component durability. [Reserved]. For guidance see 40 CFR 86.1824-01(d).

188. Section §86.1826-01 is revised to read as follows:

§ 86.1826-01 Assigned deterioration factors for small-volume manufacturers and 

small-volume test groups.

(a) Applicability. This program is an option available for small-volume manufacturers 

and small-volume test groups as described in §86.1838. 

(b) Determination of deterioration factors. No service accumulation method or 

vehicle/component selection method is required. Deterioration factors for all types of 

regulated emissions are assigned using the provisions in this paragraph (b). A separate 

assigned deterioration factor is required for each durability group. Manufacturers shall 

use good engineering judgment in applying deterioration factors. Manufacturers may use 

assigned deterioration factors that the Administrator determines and prescribes.

(1) The deterioration factors will be the Administrator's estimate, periodically

updated and published in a guidance document, of the 70th percentile deterioration 

factors calculated using the industry-wide database of previously completed 

durability data vehicles or engines used for certification.

(2) The Administrator may use discretion to develop assigned deterioration factors 

using alternative methods if there is insufficient information to calculate an 

appropriate industry-wide deterioration factor (for example: a new engine technology

coupled with a proven emission control system). These methods may include the use 

of assigned deterioration factors based on similar durability vehicles.

(3) Alternatively, with advance approval from the Administrator, a manufacturer may

use deterioration factors developed by another manufacturer. The manufacturer 

seeking to use these deterioration factors must—

(i) Demonstrate that the engines from the two manufacturers share technical 

parameters to the degree that would support the conclusion that a common 

deterioration factor should apply for both vehicle configurations as defined in 

§86.1803. 

(ii) Provide supporting information, such as histograms of exhaust temperature 

data, comparisons of vehicle weight and road load horsepower, or comparisons of 

powertrains and emission control systems.

189. Section 86.1828-01 is amended by removing and reserving paragraph (d) and 

adding paragraph (g) to read as follows: 
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§ 86.1828-01 Emission data vehicle selection.

* * * * *

(g) Cold temperature NMHC testing. For cold temperature NMHC exhaust emission 

compliance for each durability group, the manufacturer must select the vehicle expected 

to emit the highest NMHC emissions at 20 °F on candidate in-use vehicles from the test 

vehicles specified in paragraph (a) of this section. When the expected worst-case cold 

temperature NMHC vehicle is also the expected worst-case cold temperature CO vehicle 

as selected in paragraph (c) of this section, then cold temperature testing is required only 

for that vehicle; otherwise, testing is required for both the worst-case cold temperature 

CO vehicle and the worst-case cold temperature NMHC vehicle.

§86.1828-10 [Removed]

190. Remove §86.1828-10.

191. Section 86.1829-01 is amended as follows:

a. By removing and reserving paragraph (b)(1)(iii)(C).

b. By revising paragraph (b)(2)(i).

c. By adding paragraph (b)(2)(iv).

d. By revising paragraph (b)(4).

f. By removing and reserving paragraph (d).

§ 86.1829-01 Durability and emission testing requirements; waivers. 

* * * * *

(b) * * *

(2) * * *

(i) Testing at low altitude. One EDV in each evaporative/refueling family and 

evaporative/refueling emission control system combination must be tested in 

accordance with the evaporative/refueling test procedure requirement of subpart B of 

this part. The configuration of the EDV will be determined under the provisions of 

§86.1828–01. The EDV must also be tested for exhaust emission compliance using 

the FTP and SFTP procedures of subpart B of this part. In lieu of testing natural gas 

or hydrogen fueled vehicles to demonstrate compliance with the evaporative and 

refueling emission standards specified in this subpart, a manufacturer may provide a 

statement in its application for certification that, based on the manufacturer's 

engineering evaluation of appropriate testing and/or design parameters, all light-duty 

vehicles, light-duty trucks, and complete heavy-duty vehicles comply with applicable 

emission standards. This same testing exemption applies for vehicles fueled by

liquefied petroleum gas, except that refueling tests are required for systems that allow 

venting during the refueling operation.

* * * * *

(iv) For diesel-fueled light-duty vehicles, a manufacturer may provide a statement in 

the application for certification that vehicles comply with the refueling emission 

standard instead of submitting test data. Such a statement must be based on previous 

emission tests, development tests, or other appropriate information, and good 

engineering judgment.

* * * * *
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(4) Electric vehicles and fuel cell vehicles. For electric vehicles and fuel cell vehicles, 

manufacturers may provide a statement in the application for certification that vehicles 

comply with all the requirements of this subpart instead of submitting test data. Such a 

statement must be based on previous emission tests, development tests, or other 

appropriate information, and good engineering judgment.

* * * * *

192. A new §86.1829-15 is added to subpart S to read as follows:

§86.1829-15 Durability and emission testing requirements; waivers.

This section describes general testing requirements for certifying vehicles under this 

subpart, and includes several provisions allowing for statements of compliance instead of 

testing in certain circumstances. Where a manufacturer provides a statement instead of 

test data under this section, it must be based on previous emission tests, development 

tests, or other appropriate information, and on good engineering judgment.

(a) One durability demonstration is required for each durability group. The configuration 

of the DDV is determined according to §86.1822. The DDV shall be tested and 

accumulate service mileage according to the provisions of §§86.1823, 86.1824, 86.1825, 

and 86.1831. Small-volume manufacturers and small-volume test groups may optionally 

use the alternative durability provisions of §86.1838.

(b) The manufacturer must test EDVs as follows to demonstrate compliance with 

emission standards:

(1) Test one EDV in each durability group using the test procedures in 40 CFR part 

1066 to demonstrate compliance with cold temperature CO and NMHC exhaust 

emission standards. 

(2) Test one EDV in each test group using the FTP and SFTP test procedures in 40 

CFR part 1066 and the HFET test procedures of 40 CFR part 600, subpart B, to 

demonstrate compliance with other exhaust emission standards. 

(3) Test one EDV in each evaporative/refueling family and evaporative/refueling 

emission control system combination using the test procedures in subpart B of this 

part to demonstrate compliance with evaporative and refueling emission standards.

(c) The manufacturer must demonstrate compliance with emission standards at lowaltitude conditions as described in paragraph (b) of this section. For standards that apply

at high-altitude conditions, the manufacturer may either perform the same tests or provide 

a statement in the application for certification that, based on an engineering evaluation of 

appropriate testing to measure or simulate high-altitude emissions, all vehicles comply

with applicable emission standards at high altitude.

(d) Manufacturers may omit exhaust testing for certification in certain circumstances as 

follows: 

(1) For vehicles subject to the Tier 3 PM standards in §§86.1811, a manufacturer may

provide a statement in the application for certification that vehicles comply with 

applicable PM standards instead of submitting PM test data for a certain number of 

vehicles. However, each manufacturer must test vehicles from a minimum number of

durability data groups as follows:

(i) Manufacturers with a single durability data group subject to the Tier 3 PM 

standards in §86.1811 must submit PM test data for that group. 
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(ii) Manufacturers with two to eight durability data groups subject to the Tier 3 

PM standards in §86.1811 must submit PM test data for at least two durability

data groups each model year. EPA will work with the manufacturer to select 

durability data groups for testing, with the general expectation that testing will 

rotate to cover a manufacturer’s whole product line over time. If a durability data 

group has been certified in an earlier model year based on submitted PM data, and 

that durability data group is eligible for certification using carryover test data, that 

carryover data may count toward meeting the requirements of this paragraph 

(d)(1), subject to the selection of durability data groups. 

(iii) Manufacturers with nine or more durability data groups subject to the Tier 3 

PM standards in §86.1811 must submit PM test data for at least 25 percent of 

those durability data groups each model year. We will work with the 

manufacturer to select durability data groups for testing as described in paragraph 

(d)(1)(ii) of this section.

(2) Small-volume manufacturers may provide a statement in the application for 

certification that vehicles comply with the applicable PM standard instead of 

submitting test data.

(3) Manufacturers may omit PM measurements for fuel economy and GHG testing 

conducted in addition to the testing needed to demonstrate compliance with the PM 

emission standards.

(4) Manufacturers may provide a statement in the application for certification that 

vehicles comply with the applicable formaldehyde standard instead of submitting test 

data.

(5) When conducting Selective Enforcement Audit testing, a manufacturer may

petition the Administrator to waive the requirement to measure PM emissions and 

formaldehyde emissions.

(e) Manufacturers may omit evaporative or refueling testing for certification in certain 

circumstances as follows: 

(1) For diesel-fueled vehicles, a manufacturer may provide a statement in the 

application for certification that vehicles comply with the refueling emission standard 

instead of submitting test data.

(2) For vehicles fueled by natural gas, a manufacturer may provide a statement in the 

application for certification that vehicles comply with evaporative emission standards 

instead of submitting test data. Compressed natural gas vehicles meeting the 

requirements for fueling connection devices in §86.1813-17(f)(1) are deemed to 

comply with evaporative and refueling emission standards.

(3) For vehicles fueled by liquefied petroleum gas, a manufacturer may provide a 

statement in the application for certification that vehicles comply with evaporative

and refueling emission standards instead of submitting test data, except that refueling 

tests are required for systems that allow venting during the refueling operation.

(4) Manufacturers may provide a statement in the application for certification that 

vehicles comply with the leak standard in §86.1813 instead of submitting test data.

(5) For vehicles certified to the refueling emission standards in §§86.1811 or 86.1813, 

a manufacturer may provide a statement in the application for certification that 

vehicles comply with the fuel dispensing spitback standard instead of submitting test 

data.
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(6) In lieu of testing vehicles for the supplemental two-diurnal test sequence, a 

manufacturer may optionally provide a statement of compliance in its application for 

certification that, based on the manufacturer's good engineering judgment, all 

vehicles in the evaporative/refueling emission family comply with the evaporative 

emission standard for the supplemental two-diurnal test sequence.

(i) The option to provide a statement of compliance in lieu of 2-diurnal 

evaporative certification test data is limited to vehicles with conventional 

evaporative emission control systems (as determined by the Administrator). EPA 

may perform confirmatory 2-diurnal evaporative emission testing on test vehicles 

certified using this option. If data shows noncompliance, it will be addressed 

through §86.1851. Also, if data shows noncompliance, EPA will generally 

disallow subsequent waivers for the applicable evaporative family.

(ii) Manufacturers shall supply information if requested by EPA in support of the 

statement of compliance described in this paragraph (e)(6). This information shall 

include evaporative calibration information for the emission-data vehicle and for 

other vehicles in the evaporative/refueling family, including, but not limited to, 

canister type, canister volume, canister working capacity, canister shape and 

internal configuration, fuel tank volume, fuel tank geometry, the type of fuel 

delivery system (return, returnless, variable flow fuel pump, etc.), a description of 

the input parameters and software strategy used to control the evaporative canister 

purge, the nominal purge flow volume (in bed volumes) when vehicles are driven 

over the 2-diurnal (FTP) driving cycle, the nominal purge flow volume (in bed 

volumes) when vehicles are driven over the 3-diurnal (FTP + running loss) 

driving cycle, and other supporting information as necessary to demonstrate that 

the purge flow rate calibration on the 2-diurnal test sequence is adequate to 

comply with the evaporative emission standard for the supplemental two-diurnal 

test sequence.

(7) Where a California evaporative emission standard is at least as stringent as a 

comparable federal evaporative emission standard for a vehicle, we may accept test 

data demonstrating compliance with the California standard as demonstrating 

compliance with the comparable standard under this subpart. We may require you to 

provide test data clearly demonstrating that a vehicle tested using the Californiaspecified test procedures will meet the comparable standard under this subpart when 

tested using the test procedures specified in this part.

(8) Through model year 2019, we may accept test data demonstrating compliance 

with the California refueling emission standard as demonstrating compliance with the 

analogous refueling emission standard under this subpart if all the following 

conditions apply:

(i) You certified the vehicles in model year 2016 to California’s refueling 

emission standards.

(ii) You are certifying the vehicles to refueling standards for the new model year 

based on carryover data instead of performing new testing.

(iii) You are also certifying the vehicles for evaporative emissions based on 

California test procedures under the provisions of paragraph (e)(6) of this section.

(9) For vehicles with fuel tanks exceeding 35 gallons nominal fuel tank capacity, and 

for any incomplete vehicles, a manufacturer may provide a statement in the 
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application for certification that vehicles comply with refueling emission standards 

instead of submitting test data, consistent with 40 CFR 1037.103(c).

(f) For electric vehicles and fuel cell vehicles, manufacturers may provide a statement in 

the application for certification that vehicles comply with all the requirements of this 

subpart instead of submitting test data. Tailpipe emissions of regulated pollutants from

vehicles powered solely by electricity are deemed to be zero.

193. Section 86.1837-01 is amended by revising paragraph (a) to read as follows:

§ 86.1837-01 Rounding of emission measurements.

(a) Unless otherwise specified, the results of all emission tests shall be rounded to the 

number of places to the right of the decimal point indicated by expressing the applicable 

emission standard of this subpart to one additional significant figure, in accordance with 

40 CFR 1065.20. 

* * * * *

194. Section 86.1838-01 is amended by revising paragraphs (a), (b), (c), and (d) 

introductory text to read as follows:

§ 86.1838-01 Small-volume manufacturer certification procedures.

(a) Overview. The small-volume manufacturer certification procedures described in 

paragraphs (b) and (c) of this section are optional. Small-volume manufacturers may use 

these optional procedures to demonstrate compliance with the general standards and 

specific emission requirements contained in this subpart.

(b) Eligibility requirements —(1) Small-volume manufacturers. (i) Optional smallvolume manufacturer certification procedures apply for vehicles produced by

manufacturers with the following number of combined sales of vehicles subject to 

standards under this subpart in all states and territories of the United States in the 

model year for which certification is sought, including all vehicles and engines 

imported under the provisions of 40 CFR 85.1505 and 85.1509:

(A) 5,000 units for the Tier 3 standards described in §§ 86.1811, 86.1813, and 

86.1816. This volume threshold applies for phasing in the Tier 3 standards 

and for determining the corresponding deterioration factors. This is based on 

average nationwide sales volumes for model years 2012 through 2014 for 

manufacturers that sell vehicles in model year 2012. The provision allowing 

delayed compliance with the Tier 3 standards applies for qualifying 

companies even if sales after model year 2014 increase beyond 5,000 units. 

Manufacturers with no sales in model year 2012 may instead rely on projected 

sales volumes; however, if nationwide sales exceed an average value of 5,000 

units in any three consecutive model years, the manufacturer is no longer 

eligible for provisions that apply to small-volume manufacturers after two 

additional model years. For example, if actual sales in model years 2015 

through 2017 exceed 5,000 units, the small-volume provisions would no 

longer apply starting in model year 2020.

(B) 15,000 units for all other requirements. See §86.1845 for separate 

provisions that apply for in-use testing.

(ii) If a manufacturer’s aggregated sales in the United States, as determined in 

paragraph (b)(3) of this section are fewer than the number of units specified in 
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paragraph (b)(1)(i) of this section, the manufacturer (or each manufacturer in the 

case of manufacturers in an aggregated relationship) may certify under the 

provisions of paragraph (c) of this section.

(iii) A manufacturer that qualifies as a small business under the Small Business 

Administration regulations in 13 CFR part 121 is eligible for all the provisions 

that apply for small-volume manufacturers under this subpart. See §86.1801-12(j) 

to determine whether companies qualify as small businesses.

(iv) The sales volumes specified in this section are based on actual sales, unless 

otherwise specified. 

(v) Except for delayed implementation of new emission standards, an eligible 

manufacturer must transition out of the special provisions that apply for smallvolume manufacturers as described in §86.1801-12(k)(2)(i) through (iii) if sales 

volumes increase above the applicable threshold. 

(2) Small-volume test groups. (i) If the aggregated sales in all states and territories 

of the United States, as determined in paragraph (b)(3) of this section are equal to 

or greater than 15,000 units, then the manufacturer (or each manufacturer in the 

case of manufacturers in an aggregated relationship) will be allowed to certify a 

number of units under the small-volume test group certification procedures in 

accordance with the criteria identified in paragraphs (b)(2)(ii) through (iv) of this 

section.

(ii) If there are no additional manufacturers in an aggregated relationship meeting 

the provisions of paragraph (b)(3) of this section, then the manufacturer may 

certify whole test groups whose total aggregated sales (including heavy-duty

engines) are less than 15,000 units using the small-volume provisions of 

paragraph (c) of this section.

(iii) If there is an aggregated relationship with another manufacturer which 

satisfies the provisions of paragraph (b)(3) of this section, then the following 

provisions shall apply:

(A) If none of the manufacturers own 50 percent or more of another 

manufacturer in the aggregated relationship, then each manufacturer may

certify whole test groups whose total aggregated sales (including heavy-duty

engines) are less than 15,000 units using the small-volume provisions of 

paragraph (c) of this section.

(B) If any of the manufacturers own 50 percent or more of another 

manufacturer in the aggregated relationship, then the limit of 14,999 units 

must be shared among the manufacturers in such a relationship. In total for all 

the manufacturers involved in such a relationship, aggregated sales (including 

heavy-duty engines) of up to 14,999 units may be certified using the smallvolume provisions of paragraph (c) of this section. Only whole test groups 

shall be eligible for small-volume status under paragraph (c) of this section.

(iv) In the case of a joint venture arrangement (50/50 ownership) between two 

manufacturers, each manufacturer retains its eligibility for 14,999 units under the 

small-volume test group certification procedures, but the joint venture must draw 

its maximum 14,999 units from the units allocated to its parent manufacturers. 

Only whole test groups shall be eligible for small-volume status under paragraph 

(c) of this section.
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(3) Sales aggregation for related manufacturers. The projected or actual sales from 

different firms shall be aggregated in the following situations:

(i) Vehicles and/or engines produced by two or more firms, one of which is 10 

percent or greater part owned by another;

(ii) Vehicles and/or engines produced by any two or more firms if a third party

has equity ownership of 10 percent or more in each of the firms;

(iii) Vehicles and/or engines produced by two or more firms having a common 

corporate officer(s) who is (are) responsible for the overall direction of the 

companies;

(iv) Vehicles and/or engines imported or distributed by all firms where the 

vehicles and/or engines are manufactured by the same entity and the importer or 

distributor is an authorized agent of the entity.

(c) Small-volume provisions. Small-volume manufacturers and small-volume test groups 

shall demonstrate compliance with all applicable sections of this subpart, with the 

following exceptions: 

(1) Durability demonstration. Use the provisions of §86.1826 rather than the 

requirements of §§86.1823, 86.1824, and 86.1825.

(2) In-use verification testing. Measure emissions from in-use vehicles as described in 

§86.1845, subject to the following additional provisions:

(i) In-use verification test vehicles may be procured from customers or may be 

owned by, or under the control of the manufacturer, provided that the vehicle has 

accumulated mileage in typical operation on public streets and has received 

typical maintenance.

(ii) In lieu of procuring in-use verification test vehicles that have a minimum 

odometer reading of 50,000 miles, a manufacturer may demonstrate to the 

satisfaction of the Agency that, based on owner survey data, the average mileage 

accumulated after 4 years for a given test group is less than 50,000 miles. The 

Agency may approve procurement of in-use verification test vehicles that have a 

lower minimum odometer reading based on such data.

(iii) The provisions of § 86.1845–04(c)(2) that require one vehicle of each test 

group during high mileage in-use verification testing to have a minimum 

odometer mileage do not apply.

(iv) Manufacturers intending to use the provisions of this paragraph (c) shall 

submit to the Agency a plan detailing how these provisions will be met before 

submitting an application for certification for the subject vehicles.

(d) Operationally independent manufacturers. Manufacturers may submit an application 

to EPA requesting treatment as an operationally independent manufacturer. A 

manufacturer that is granted operationally independent status may qualify for all the 

regulatory provisions of this subpart that apply for small-volume manufacturers on the 

basis of its own vehicle production and/or sales volumes, and would not require 

aggregation with related manufacturers. In this paragraph (d), the term “related 

manufacturer(s)” means manufacturers that would qualify for aggregation under the 

requirements of paragraph (b)(3) of this section.

* * * * *

195. Section 86.1843-01 is amended by revising paragraph (g) to read as follows:
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§ 86.1843-01 General information requirements.

* * * * *

(g) Recordkeeping. (1) This subpart includes various requirements to record data or other 

information. Unless we specify otherwise, store these records in any format and on any

media and keep them readily available for eight years after you send an associated 

application for certification, or eight years after you generate the data if they do not 

support an application for certification. You must promptly send us organized, written 

records in English upon request. We may review them at any time.

(2) Upon written request by the Administrator, a manufacturer shall submit any

information as described in §86.1844–01 within 15 business days. A manufacturer may

request the Administrator to grant an extension. The request must clearly indicate the 

circumstances necessitating the extension.

* * * * *

196. Section 86.1844-01 is amended by revising paragraphs (a), (d)(7), (d)(8), (d)(9), 

(d)(11), and (d)(16)(i) introductory text, removing paragraph (d)(16)(iv), and adding 

paragraph (e)(7) to read as follows:

§ 86.1844-01 Information requirements: Application for certification and submittal 

of information upon request.

(a) All the information listed in this section must be submitted to the Agency according to 

the requirements specified in §86.1843; however, we may ask you to include less 

information than we specify, as long as you keep the specified records. 

* * * * *

(d) * * *

(7) A comprehensive list of all test results, including official certification levels, and the 

applicable intermediate and full useful life emission standards to which the test group is 

to be certified as required in §86.1829. Include the following additional information 

related to testing:

(i) Include a comparison of drive cycle energy and target cycle energy relative to both 

inertia and road load forces as specified in 40 CFR 1066.425 for each drive cycle or 

test phase, as appropriate.

(ii) For gasoline-fueled Tier 3 vehicles, identify the method of accounting for ethanol 

in determining evaporative emissions, as described in §86.1813. 

(iii) Identify any aspects of testing for which the regulations obligate EPA testing to 

conform to your selection of test methods.

(8) A statement that all applicable vehicles will conform to the emission standards for 

which emission data is not being provided, as allowed under §86.1806 or §86.1829. The 

statement shall clearly identify the standards for which emission testing was not 

completed.

(9) Information describing each emission control diagnostic system required by

§86.1806, including all of the following:

(i) A description of the functional operation characteristics of the diagnostic system, 

with additional information demonstrating that the system meets the requirements 

specified in §86.1806. Include all testing and demonstration data submitted to the 

California Air Resources Board for certification.
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(ii) The general method of detecting malfunctions for each emission-related 

powertrain component.

(iii) Any deficiencies, including resolution plans and schedules. 

(iv) A statement that the diagnostic system is adequate for the performance warranty

test described in 40 CFR part 85, subpart W. 

(v) For vehicles certified to meet the leak standard in §86.1813, a description of the 

anticipated test procedure. The description must include, at a minimum, a method for 

accessing the fuel system for measurements and a method for pressurizing the fuel 

system to perform the procedure specified in 40 CFR 1066.985. The recommended 

test method must include at least two separate points for acessing the fuel system, 

with additional access points as appropriate for multiple fuel tanks and multiple 

evaporative or refueling canisters.

* * * * *

(11) A list of all auxiliary emission control devices (AECD) installed on any applicable 

vehicles, including a justification for each AECD, the parameters they sense and control, 

a detailed justification of each AECD that results in a reduction in effectiveness of the 

emission control system, and rationale for why it is not a defeat device as defined under 

§86.1809. The following specific provisions apply for AECDs:

(i) For any AECD uniquely used at high altitudes, EPA may request engineering 

emission data to quantify any emission impact and validity of the AECD. 

(ii) For any AECD uniquely used on multi-fuel vehicles when operated on fuels other 

than gasoline, EPA may request engineering emission data to quantify any emission 

impact and validity of the AECD.

(iii) For Tier 3 vehicles with spark-ignition engines, describe how AECDs are 

designed to comply with the requirements of §86.1811-17(d). Identify which 

components need protection through enrichment strategies; describe the temperature 

limitations for those components; and describe how the enrichment strategy 

corresponds to those temperature limitations. We may also require manufacturers to 

submit this information for certification related to Tier 2 vehicles.

* * * * *

(16) * * *

(i) A statement indicating that the manufacturer has conducted an engineering analysis of 

the complete exhaust system to ensure that the exhaust system has been designed:

* * * * *

(e) * * *

(7) The results of any production vehicle evaluation testing required for OBD systems 

under §86.1806.

* * * * *

§86.1845-01 [Removed]

197. Remove §86.1845-01.

198. Section 86.1845-04 is amended by revising paragraphs (a)(1), (a)(3), (b)(3) 

introductory text, (b)(4), (b)(5), (b)(6), (b)(7), and (c) to read as follows:

§ 86.1845-04 Manufacturer in-use verification testing requirements.

(a) * * *
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(1) Manufacturers of LDV, LDT, MDPV and complete HDV must test, or cause to 

have tested, a specified number of vehicles. Such testing must be conducted in 

accordance with the provisions of this section. 

* * * * *

(3) The following provisions apply regarding the possibility of residual effects from 

varying fuel sulfur levels:

(i) Vehicles certified to Tier 3 standards under §86.1811 must always measure 

emissions over the FTP, then over the HFET (if applicable), then over the US06 

portion of the SFTP. If a Tier 3 vehicle meets all the applicable emission 

standards except the FTP or HFET emission standard for NMOG+NOx, and a

fuel sample from the tested vehicle (representing the as-received condition) has a 

measured fuel sulfur level exceeding 15 ppm when measured as described in 40 

CFR 1065.710, the manufacturer may repeat the FTP and HFET measurements 

and use the new emission values as the official results for that vehicle. For all 

other cases of testing Tier 3 vehicles, measured emission levels from the first test 

will be considered the official results for the test vehicle, regardless of any test 

results from additional test runs. Where repeat testing is allowed, the vehicle may

operate for up to two US06 cycles (with or without measurement) before 

repeating the FTP and HFET measurements. The repeat measurements must 

include both FTP and HFET, even if the vehicle failed only one of those tests, 

unless the HFET is not required for a particular vehicle. Tier 3 vehicles may not 

undergo any other vehicle preconditioning to eliminate fuel sulfur effects on the 

emission control system, unless we approve it in advance.

(ii) Upon a manufacturer's written request, prior to in-use testing, that presents 

information to EPA regarding pre-conditioning procedures designed solely to 

remove the effects of high sulfur in gasoline from vehicles produced through the 

2007 model year, EPA will consider allowing such procedures on a case-by-case 

basis. EPA's decision will apply to manufacturer in-use testing conducted under 

this section and to any in-use testing conducted by EPA. Such procedures are not 

available for complete HDV. For model year 2007 and later Tier 2 vehicles, this 

provision can be used only in American Samoa, Guam, and the Commonwealth of 

the Northern Mariana Islands, and then only if low sulfur gasoline is determined 

by the Administrator to be unavailable in that specific location.

(b) * * *

(3) Number of test vehicles. For each test group, the minimum number of vehicles 

that must be tested is specified in Table S04–06 and Table S04–07 of this paragraph 

(b)(3). After testing the minimum number of vehicles of a specific test group as 

specified in Table S04–06 or S04–07 of this paragraph (b)(3), a manufacturer may

test additional vehicles upon request and approval by the Agency prior to the 

initiation of the additional testing. Any additional testing must be completed within 

the testing completion requirements shown in §86.1845–04(b)(4). The request and 

Agency approval (if any) shall apply to test groups on a case by case basis and apply 

only to testing under this paragraph. Separate approval will be required to test 

additional vehicles under paragraph (c) of this section. In addition to any testing that 

is required under Table S04–06 and Table S04–07, a manufacturer shall test one 

vehicle from each evaporative/refueling family for evaporative/refueling emissions. If 
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a manufacturer believes it is unable to procure the test vehicles necessary to test the 

required number of vehicles in a test group, the manufacturer may request, subject to 

Administrator approval, a decreased sample size for that test group. The request shall 

include a description of the methods the manufacturer has used to procure the 

required number of vehicles. The approval of any such request, and the substitution of 

an alternative sample size requirement for the test group, will be based on a review of 

the procurement efforts made by the manufacturer to determine if all reasonable steps 

have been taken to procure the required test group size. Tables S04–06 and S04–07 

follow:

* * * * *

(4) Completion of testing. Testing of the vehicles in a test group and 

evaporative/refueling family must be completed within 12 months of the end of 

production of that test group (or evaporative/refueling family) for that model year.

(5) Testing. (i) Each test vehicle of a test group shall be tested in accordance with the 

FTP and the US06 portion of the SFTP as described in subpart B of this part, 

when such test vehicle is tested for compliance with applicable exhaust emission 

standards under this subpart. Test vehicles subject to applicable exhaust CO2

emission standards under this subpart shall also be tested in accordance with the 

HFET as described in part 600, subpart B, of this chapter.

(ii) Manufacturers must measure PM emissions over the FTP and US06 driving 

schedules for at least 50 percent of the vehicles tested under paragraph (b)(5)(i) of 

this section.

(iii) Starting with model year 2018 vehicles, manufacturers must demonstrate 

compliance with the Tier 3 leak standard specified in §86.1813, if applicable, as 

described in this paragraph (b)(5)(iii). Manufacturers must evaluate each vehicle 

tested under paragraph (b)(5)(i) of this section, except that leak testing is not 

required for vehicles tested under paragraph (b)(5)(iv) of this section for diurnal 

emissions. In addition, manufacturers must evaluate at least one vehicle from 

each leak family for a given model year. Manufacturers may rely on OBD 

monitoring instead of testing as follows:

(A) A vehicle is considered to pass the leak test if the OBD system completed 

a leak check within the previous 750 miles of driving without showing a leak 

fault code.

(B) Whether or not a vehicle’s OBD system has completed a leak check 

within the previous 750 miles of driving, the manufacturer may operate the 

vehicle as needed to force the OBD system to perform a leak check. If the 

OBD leak check does not show a leak fault, the vehicle is considered to pass 

the leak test.

(C) If the most recent OBD leak check from paragraph (b)(5)(iii)(A) or (B) of 

this section shows a leak-related fault code as specified in §86.1806-17(b), the 

vehicle is presumed to have failed the leak test. Manufacturers may perform 

the leak measurement procedure described in 40 CFR 1066.985 for an official 

result to replace the finding from the OBD leak check.

(D) Manufacturers may not perform repeat OBD checks or leak measurements 

to over-ride a failure under paragraph (b)(5)(iii)(C) of this section.
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(iv) For nongaseous-fueled vehicles, one test vehicle of each 

evaporative/refueling family shall be tested in accordance with the supplemental 

2-diurnal-plus-hot-soak evaporative emission and refueling emission procedures 

described in subpart B of this part, when such test vehicle is tested for compliance 

with applicable evaporative emission and refueling standards under this subpart. 

For gaseous-fueled vehicles, one test vehicle of each evaporative/refueling family

shall be tested in accordance with the 3-diurnal-plus-hot-soak evaporative 

emission and refueling emission procedures described in subpart B of this part, 

when such test vehicle is tested for compliance with applicable evaporative 

emission and refueling standards under this subpart. The test vehicles tested to 

fulfill the evaporative/refueling testing requirement of this paragraph (b)(5)(ii) 

will be counted when determining compliance with the minimum number of 

vehicles as specified in Table S04–06 and Table S04–07 in paragraph (b)(3) of 

this section for testing under paragraph (b)(5)(i) of this section only if the vehicle 

is also tested for exhaust emissions under the requirements of paragraph (b)(5)(i) 

of this section.

(6) Each test vehicle not rejected based on the criteria specified in appendix II to this 

subpart shall be tested in as-received condition. 

(7) A manufacturer may conduct subsequent diagnostic maintenance and/or testing of 

any vehicle. Any such maintenance and/or testing shall be reported to the Agency as 

specified in §86.1847.

(c) High-mileage testing —(1) Test groups. Testing must be conducted for each test 

group.

(2) Vehicle mileage. All test vehicles must have a minimum odometer mileage of 

50,000 miles. At least one vehicle of each test group must have a minimum odometer 

mileage of 105,000 miles or 75 percent of the full useful life mileage, whichever is 

less. See §86.1838–01(c)(2) for small-volume manufacturer mileage requirements.

(3) Number of test vehicles. For each test group, the minimum number of vehicles 

that must be tested is specified in Table S04–06 and Table S04–07 in paragraph (b)(3) 

of this section. After testing the minimum number of vehicles of a specific test group 

as specified in Table S04–06 and Table S04–07 in paragraph (b)(3) of this section, a 

manufacturer may test additional vehicles upon request and approval by the Agency

prior to the initiation of the additional testing. Any additional testing must be 

completed within the testing completion requirements shown in §86.1845–04(c)(4). 

The request and Agency approval (if any) shall apply to test groups on a case by case 

basis and apply only to testing under this paragraph (c). In addition to any testing that 

is required under Table S04–06 and Table S04–07, a manufacturer shall test one 

vehicle from each evaporative/refueling family for evaporative/refueling emissions. If 

a manufacturer believes it is unable to procure the test vehicles necessary to test the 

required number of vehicles in a test group as specified in Table S04–06 or Table 

S04–07, the manufacturer may request, subject to Administrator approval, a 

decreased sample size for that test group. The request shall include a description of 

the methods the manufacturer has used to procure the required number of vehicles. 

The approval of any such request, and the substitution of an alternative sample size 

requirement for the test group, will be based on a review of the procurement efforts 
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made by the manufacturer to determine if all reasonable steps have been taken to 

procure the required test group size.

(4) Initiation and completion of testing. Testing of a test group (or evaporative 

refueling family) must commence within 4 years of the end of production of the test 

group (or evaporative/refueling family) and be completed within 5 years of the end of 

production of the test group (or evaporative/refueling family).

(5) Testing. (i) Each test vehicle shall be tested in accordance with the FTP and the 

US06 portion of the SFTP as described in subpart B of this part when such test 

vehicle is tested for compliance with applicable exhaust emission standards under 

this subpart. Test vehicles subject to applicable exhaust CO2 emission standards 

under this subpart shall also be tested in accordance with the HFET as described 

in 40 CFR part 600, subpart B. One test vehicle from each test group shall be 

tested over the FTP at high altitude. The test vehicle tested at high altitude is not 

required to be one of the same test vehicles tested at low altitude. The test vehicle 

tested at high altitude is counted when determining the compliance with the 

requirements shown in Table S04–06 and Table S04–07 in paragraph (b)(3) of 

this section or the expanded sample size as provided for in this paragraph (c).

(ii) Manufacturers must measure PM emissions over the FTP and US06 driving 

schedules for at least 50 percent of the vehicles tested under paragraph (c)(5)(i) of 

this section.

(iii) Starting with model year 2018 vehicles, manufacturers must evaluate each 

vehicle tested under paragraph (c)(5)(i) of this section to demonstrate compliance 

with the Tier 3 leak standard specified in §86.1813, except that leak testing is not 

required for vehicles tested under paragraph (c)(5)(iv) of this section for diurnal 

emissions. In addition, manufacturers must evaluate at least one vehicle from 

each leak family for a given model year. Manufacturers may rely on OBD 

monitoring instead of testing as described in paragraph (c)(5)(iii) of this section.

(iv) For nongaseous-fueled vehicles, one test vehicle of each 

evaporative/refueling family shall be tested in accordance with the supplemental 

2-diurnal-plus-hot-soak evaporative emission procedures described in subpart B 

of this part, when such test vehicle is tested for compliance with applicable 

evaporative emission and refueling standards under this subpart. For gaseousfueled vehicles, one test vehicle of each evaporative/refueling family shall be 

tested in accordance with the 3-diurnal-plus-hot-soak evaporative emission 

procedures described in subpart B of this part, when such test vehicle is tested for 

compliance with applicable evaporative emission and refueling standards under 

this subpart. The test vehicles tested to fulfill the evaporative/refueling testing 

requirement of this paragraph (b)(5)(ii) will be counted when determining 

compliance with the minimum number of vehicles as specified in Table S04–06 

and table S04–07 in paragraph (b)(3) of this section for testing under paragraph 

(b)(5)(i) of this section only if the vehicle is also tested for exhaust emissions 

under the requirements of paragraph (b)(5)(i) of this section.

(6) Test condition. Each test vehicle not rejected based on the criteria specified in 

appendix II to this subpart shall be tested in as-received condition.
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(7) Diagnostic maintenance. A manufacturer may conduct subsequent diagnostic 

maintenance and/or testing on any vehicle. Any such maintenance and/or testing shall 

be reported to the Agency as specified in §86.1847–01.

* * * * *

(f)(1) A manufacturer must conduct in-use testing on a test group by determining NMOG 

exhaust emissions as described in 40 CFR 1066.635.

(2) For flexible-fueled vehicles certified to NMOG (or NMOG+NOx) standards, the 

manufacturer may ask for EPA approval to demonstrate compliance using an 

equivalent NMOG emission result calculated from a ratio of ethanol NMOG exhaust 

emissions to gasoline NMHC exhaust emissions. Ethanol NMOG exhaust emissions 

are measured values from testing with the ethanol test fuel, expressed as NMOG. 

Gasoline NMHC exhaust emissions are measured values from testing with the 

gasoline test fuel, expressed as NMHC. This ratio must be established during 

certification for each emission-data vehicle for the applicable test group. Use good 

engineering judgment to establish a different ratio for each duty cycle or test interval

as appropriate. Identify the ratio values you develop under this paragraph (f)(1) and 

describe the duty cycle or test interval to which they apply in the Part II application 

for certification. Calculate the equivalent NMOG emission result by multiplying the 

measured gasoline NMHC exhaust emissions for a given duty cycle or test interval by

the appropriate ratio. 

(3) If the manufacturer measures NMOG as described in 40 CFR 1066.635(a), it must 

also measure and report HCHO emissions. As an alternative to measuring the HCHO 

content, if the manufacturer measures NMOG as permitted in 40 CFR 1066.635(c), 

the Administrator may approve, upon submission of supporting data by a 

manufacturer, the use of HCHO to NMHC ratios. To request the use of HCHO to 

NMHC ratios, the manufacturer must establish during certification testing the ratio of 

measured HCHO exhaust emissions to measured NMHC exhaust emissions for each 

emission-`data vehicle for the applicable test group. The results must be submitted to 

the Administrator with the Part II application for certification. Following approval of 

the application for certification, the manufacturer may conduct in-use testing on the 

test group by measuring NMHC exhaust emissions rather than HCHO exhaust 

emissions. The measured NMHC exhaust emissions must be multiplied by the HCHO 

to NMHC ratio submitted in the application for certification for the test group to 

determine the equivalent HCHO exhaust emission values for the test vehicle. The 

equivalent HCHO exhaust emission values must be compared to the HCHO exhaust 

emission standard applicable to the test group.

199. Section 86.1846-01 is revised to read as follows:

§ 86.1846-01 Manufacturer in-use confirmatory testing requirements.

(a) General requirements. (1) Manufacturers must test, or cause testing to be conducted, 

under this section when the emission levels shown by a test group sample from 

testing under §86.1845 exceeds the criteria specified in paragraph (b) of this section. 

The testing required under this section applies separately to each test group and at 

each test point (low and high mileage) that meets the specified criteria. The testing 

requirements apply separately for each model year. These provisions apply to heavy-
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duty vehicles starting with model year 2007. These provisions do not apply to 

emissions of CO2, CH4, and N2O.

(2) [Reserved]

(3) [Reserved]

(4) The provisions of §86.1845-04(a)(3) regarding fuel sulfur effects apply equally to 

testing under this section. 

(b) Criteria for additional testing. (1) A manufacturer shall test a test group or a subset of 

a test group as described in paragraph (j) of this section when the results from testing 

conducted under §86.1845 show mean exhaust emissions for that test group of any 

pollutant(s) (except CO2,CH4, and N2O) to be equal to or greater than 1.30 times the 

applicable in-use standard and a failure rate, among the test group vehicles, for the 

corresponding pollutant(s) of fifty percent or greater.

(i) Additional testing is not required under this paragraph (b)(1) based on

Supplemental FTP testing or evaporative/refueling testing. Testing conducted at 

high altitude under the requirements of §86.1845-04(b) will be included in 

determining if a test group meets the criteria triggering testing required under this 

section.

(ii) The vehicle tested under the requirements of §86.1845–04(c)(2) with a 

minimum odometer miles of 75% of useful life will not be included in 

determining if a test group meets the triggering criteria.

(iii) The SFTP composite emission levels shall include the IUVP FTP emissions, 

the IUVP US06 emissions, and the values from the SC03 Air Conditioning EDV 

certification test (without DFs applied). The calculations shall be made using the 

equations prescribed in §86.164. If more than one set of certification SC03 data 

exists (due to running change testing or other reasons), the manufacturer shall 

choose the SC03 result to use in the calculation from among those data sets using 

good engineering judgment.

(2) If fewer than 50 percent of the vehicles from a leak family pass either the leak test 

or the diurnal test under §86.1845, EPA may require further leak testing under this 

paragraph (b)(2). Testing under this section must include five vehicles from the 

family. If all five of these vehicles fail the test, the manufacturer must test five 

additional vehicles. 

EPA will determine whether to require further leak testing under this section after 

providing the manufacturer an opportunity to discuss the results, including 

consideration of any of the following information, or other items that may be 

relevant: 

(i) Detailed system design, calibration, and operating information, technical 

explanations as to why the individual vehicles tested failed the leak standard.

(ii) Comparison of the subject vehicles to other similar models from the same 

manufacturer. 

(iii) Data or other information on owner complaints, technical service bulletins, 

service campaigns, special policy warranty programs, warranty repair data, state 

I/M data, and data available from other manufacturer-specific programs or 

initiatives.

(iv) Evaporative emission test data on any individual vehicles that did not pass 

leak testing during IUVP. 
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(c) Useful life. Vehicles tested under the provisions of this section must be within the 

useful life specified for the emission standards which were exceeded in the testing under 

§86.1845. Testing should be within the useful life specified, subject to sections 207(c)(5) 

and (c)(6) of the Clean Air Act where applicable.

(d) Number of test vehicles. A manufacturer must test a minimum of ten vehicles of the 

test group or Agency-designated subset. A manufacturer may, at the manufacturer's 

discretion, test more than ten vehicles under this paragraph for a specific test group or 

Agency-designated subset. If a manufacturer chooses to test more than the required ten 

vehicles, all testing must be completed within the time designated in the testing 

completion requirements of paragraph (g) of this section. Any vehicles which are 

eliminated from the sample either prior to or subsequent to testing, or any vehicles for 

which test results are determined to be void, must be replaced in order that the final

sample of vehicles for which test results acceptable to the Agency are available equals a 

minimum of ten vehicles. A manufacturer may cease testing with a sample of five 

vehicles if the results of the first five vehicles tested show mean emissions for each 

pollutant to be less than 75.0 percent of the applicable standard, with no vehicles 

exceeding the applicable standard for any pollutant.

(e) Emission testing. Each test vehicle of a test group or Agency-designated subset shall 

be tested in accordance with the FTP and/or the SFTP (whichever of these tests 

performed under §86.1845 produces emission levels requiring testing under this section) 

as described in subpart B of this part, when such test vehicle is tested for compliance with 

applicable exhaust emission standards under this subpart.

(f) Geographical limitations. (1) Test groups or Agency-designated subsets certified to 

50-state standards: For low altitude testing no more than 50 percent of the test 

vehicles may be procured from California. The test vehicles procured from the 49 

state area must be procured from a location with a heating degree day 30 year annual 

average equal to or greater than 4000.

(2) Test groups or Agency-designated subsets certified to 49 state standards: For lowaltitude testing all vehicles shall be procured from a location with a heating degree 

day 30 year annual average equal to or greater than 4000.

(3) Vehicles procured for high altitude testing may be procured from any area 

provided that the vehicle's primary area of operation was above 4000 feet.

(g) Testing. Testing required under this section must commence within three months of 

completion of the testing under §86.1845 which triggered the confirmatory testing and 

must be completed within seven months of the completion of the testing which triggered 

the confirmatory testing. Any industry review of the results obtained under §86.1845 and 

any additional vehicle procurement and/or testing which takes place under the provisions 

of §86.1845 which the industry believes may affect the triggering of required 

confirmatory testing must take place within the three month period. The data and the 

manufacturers reasoning for reconsideration of the data must be provided to the Agency

within the three month period.

(h) Limit on manufacturer conducted testing. For each manufacturer, the maximum 

number of test group(s) (or Agency-designated subset(s)) of each model year for which 

testing under this section shall be required is limited to 50 percent of the total number of 

test groups of each model year required to be tested by each manufacturer as prescribed 

in §86.1845, rounded to the next highest whole number where appropriate. For each 
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manufacturer with only one test group under §86.1845, such manufacturer shall have a 

maximum potential testing requirement under this section of one test group (or Agencydesignated subset) per model year.

(i) Testing plan. Prior to beginning in-use confirmatory testing the manufacturer must, 

after consultation with the Agency, submit a written plan describing the details of the 

vehicle procurement, maintenance, and testing procedures (not otherwise specified by 

regulation) it intends to use. EPA must approve the test plan before the manufacturer 

may start further testing.

(j) Testing a subset. EPA may designate a subset of the test group based on transmission 

type for testing under this section in lieu of testing the entire test group when the results 

for the entire test group from testing conducted under §86.1845 show mean emissions 

and a failure rate which meet these criteria for additional testing.

200. Section 86.1848-10 is amended by revising paragraph (c)(7) to read as follows:

§ 86.1848-10 Compliance with emission standards for the purpose of certification.

* * * * *

(c) * * *

(7) All certificates of conformity issued are conditional upon compliance with all the 

provisions of §§86.1811 through 86.1816 and §§ 86.1860 through 86.1862 both during 

and after model year production. The manufacturer bears the burden of establishing to the 

satisfaction of the Administrator that the terms and conditions upon which each 

certificate was issued were satisfied. For recall and warranty purposes, vehicles not 

covered by a certificate of conformity will continue to be held to the standards stated or 

referenced in the certificate that otherwise would have applied to the vehicles.

(i) Failure to meet the applicable fleet average standard will be considered to be a failure 

to satisfy the terms and conditions upon which the certificate was issued and the vehicles 

sold in violation of the fleet average standard will not be covered by the certificate.

(ii) Failure to comply fully with the prohibition against selling credits that it has not 

generated or that are not available, as specified in §86.1861, will be considered a failure 

to satisfy the terms and conditions upon which the certificate was issued and the vehicles 

sold in violation of this prohibition will not be covered by the certificate.

(iii) Failure to comply fully with the phase-in requirements of §§86.1811 through 

86.1816 will be considered a failure to satisfy the terms and conditions upon which the 

certificate was issued and the vehicles sold that do not comply with the applicable 

standards, up to the number needed to comply, will not be covered by the certificate.

* * * * *

201. A new §86.1860-17 is added to subpart S to read as follows:

§ 86.1860-17 How to comply with the Tier 3 fleet-average standards.

(a) You must show that you meet the applicable fleet-average NMOG+NOx standards 

from §§ 86.1811 and 86.1816 and the fleet-average evaporative emission standards from 

§86.1813 as described in this section. Note that separate fleet-average calculations are 

required for the FTP and SFTP exhaust emission standards under §86.1811. 

(b) Calculate your fleet-average value for each model year for all vehicle models subject 

to a separate fleet-average standard using the following equation, rounded to the nearest 
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0.001 g/mile for NMOG+NOx emissions and the nearest 0.001 g/test for evaporative 

emissions:

i i

i 1

total

( )

b

N FEL

Fleet average value

N









Where:

i = A counter associated with each separate Tier 3 test group or evaporative family.

b = The number of separate Tier 3 test groups or evaporative families from a given 

averaging set to which you certify your vehicles.

Ni = The actual nationwide sales for the model year for test group or evaporative 

family i. Include allowances for evaporative emissions as described in §86.1813.

FELi = The FEL selected for test group or evaporative family i. Disregard any

separate standards that apply for in-use testing or for testing under high-altitude 

conditions.

Ntotal = The actual nationwide sales for the model year for all your Tier 3 vehicles

from the averaging set, except as described in paragraph (c) of this section. The pool 

of vehicle models included in Ntotal may vary by model year, and it may be different 

for evaporative standards, FTP exhaust standards, and SFTP exhaust standards in a 

given model year. 

(c) Do not include any of the following vehicles to calculate your fleet-average value:

(1) Vehicles that you do not certify to the standards of this part because they are 

permanently exempted under 40 CFR part 85 or part 1068.

(2) Exported vehicles.

(3) Vehicles excluded under § 86.1801.

(4) For model year 2017, do not include vehicle sales in California or the section 177 

states for calculating the fleet average value for evaporative emissions.

(d) Except as specified in paragraph (e) of this section, your calculated fleet-average 

value may not exceed the corresponding fleet-average standard for the model year.

(e) You may generate or use emission credits related to your calculated fleet-average 

value as follows:

(1) You may generate emission credits as described in §86.1861 if your fleet-average 

value is below the corresponding fleet-average standard.

(2) You may use emission credits as described in §86.1861 if your fleet-average value 

is above the corresponding fleet-average standard. Except as specified in paragraph 

(e)(3) of this section, you must use enough credits for each model year to show that 

your adjusted fleet average value does not exceed the fleet-average standard.

(3) The following provisions apply if you do not have enough emission credits to 

demonstrate compliance with a fleet-average standard in a given model year:

(i) You may have a credit deficit for up to three model years within an averaging 

set under §86.1861-17(c). You may not bank emission credits with respect to a 

given emission standard during a model year in which you have a credit deficit in 

the same averaging set. If you fail to meet the fleet-average standard for four 

consecutive model years, the vehicles causing you to exceed the fleet-average 

standard will be considered not covered by the certificate of conformity. You will 

be subject to penalties on an individual-vehicle basis for sale of vehicles not 

covered by a certificate of conformity.
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(ii) You must notify us in writing how you plan to eliminate the credit deficit 

within the specified time frame. If we determine that your plan is unreasonable or 

unrealistic, we may deny an application for certification for a test group or 

evaporative family if its bin standard or FEL would increase your credit deficit. 

We may determine that your plan is unreasonable or unrealistic based on a 

consideration of past and projected use of specific technologies, the historical 

sales mix of your vehicle models, your commitment to limit sales of higheremission vehicles, and expected access to traded credits. We may also consider 

your plan unreasonable if your fleet-average emission level increases relative to 

the first model year of a credit deficit or any later model year. We may require 

that you send us interim reports describing your progress toward resolving your 

credit deficit over the course of a model year. 

(f) If the applicable bin standards and FELs for all your vehicle models are at or below a 

corresponding fleet-average standard for a given model year, and you do not want to 

generate emission credits, you may omit the calculations described in this section.

(g) For purposes of calculating the statute of limitations, the following actions are all 

considered to occur at the expiration of the deadline for offsetting a deficit as specified in 

paragraph (e)(3) of this section:

(1) Failing to meet the requirements of paragraph (e)(3) of this section.

(2) Failing to satisfy the conditions upon which a certificate was issued relative to 

offsetting a deficit.

(3) Selling, offering for sale, introducing or delivering into U.S. commerce, or 

importing vehicles that are found not to be covered by a certificate as a result of 

failing to offset a deficit.

202. A new §86.1861-17 is added to subpart S to read as follows:

§ 86.1861-17 How do the NMOG+NOx and evaporative emission credit programs 

work?

You may use emission credits for purposes of certification to show compliance with the 

applicable fleet-average NMOG+NOx standards from §§ 86.1811 and 86.1816 and the 

fleet-average evaporative emission standards from §86.1813 as described in 40 CFR part 

1037, subpart H, with certain exceptions and clarifications as specified in this section. 

MDPVs are subject to the same provisions of this section that apply to LDT4.

(a) Calculate emission credits as described in this paragraph (a) instead of using the 

provisions of 40 CFR 1037.705. Calculate positive or negative emission credits relative 

to the applicable fleet-average standard. Calculate positive emission credits if your fleetaverage level is below the standard. Calculate negative emission credits if your fleetaverage value is above the standard. Calculate credits separately for each type of 

standard and for each averaging set. Calculate emission credits using the following 

equation, rounded to the nearest whole number:

Emissioncredit V  olume F[ ] leet averagestandard Fleet averagevalue

Where:

Emission credit = The positive or negative credit for each discrete fleet-average 

standard, in units of vehicle-grams per mile for NMOG+NOx and vehicle-grams per 

test for evaporative emissions.
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Volume = Sales volume in a given model year from the collection of test groups or 

evaporative families covered by the fleet-average value, as described in §86.1860.

(b) The following restrictions apply instead of those specified in 40 CFR 1037.740:

(1) Except as specified in paragraph (b)(3) of this section, emission credits may be 

exchanged only within an averaging set, as follows:

(i) HDV represent a separate averaging set with respect to all emission standards.

(ii) LDV and LDT certified to standards based on a useful life of 150,000 miles 

and 15 years together represent a single averaging set with respect to 

NMOG+NOx emission standards. Note that FTP and SFTP credits are not 

interchangeable.

(iii) LDV and LDT1 certified to standards based on a useful life of 120,000 miles 

and 10 years together represent a single averaging set with respect to 

NMOG+NOx emission standards. Note that FTP and SFTP credits are not 

interchangeable.

(iv) The following separate averaging sets apply for evaporative emission 

standards:

(A) LDV and LDT1 together represent a single averaging set.

(B) LDT2 represents a single averaging set.

(C) HLDT represents a single averaging set.

(D) HDV represents a single averaging set.

(2) You may exchange evaporative emission credits across averaging sets as follows 

if you need additional credits to offset a deficit after the final year of maintaining 

deficit credits as allowed under paragraph (c) of this section:

(i) You may exchange LDV/LDT1 and LDT2 emission credits.

(ii) You may exchange HLDT and HDV emission credits.

(3) Except as specified in paragraph (b)(4) of this section, credits expire after five 

years. For example, credits you generate in model year 2018 may be used only

through model year 2023.

(4) For the Tier 3 declining fleet-average FTP and SFTP emission standards for 

NMOG+NOx described in §86.1811-17(b)(8), credits generated in model years 2017 

through 2024 expire after eight years, or after model year 2030, whichever comes 

first; however, these credits may not be traded after five years. This extended credit 

life also applies for small-volume manufacturers generating credits under §86.1811-

17(h)(1) in model years 2022 through 2024. Note that the longer credit life does not 

apply for heavy-duty vehicles, for vehicles certified under the alternate phase-in 

described in §86.1811-17(b)(9), or for vehicles generating early Tier 3 credits under 

§86.1811-17(b)(11) in model year 2017.

(c) The credit-deficit provisions 40 CFR 1037.745 apply to the NMOG+NOx and 

evaporative emission standards for Tier 3 vehicles.

(d) The reporting and recordkeeping provisions of §86.1862 apply instead of those 

specified in 40 CFR 1037.730 and 1037.735.

(e) The provisions of 40 CFR 1037.645 do not apply.

203. Section 86.1862-04 is revised to read as follows:

§ 86.1862-04 Maintenance of records and submittal of information relevant to 

compliance with fleet-average standards.
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(a) Overview. This section describes reporting and recordkeeping requirements for 

vehicles subject to the following standards:

(1) Tier 2 NOx emission standard for LDV and LDT in §86.1811-04.

(2) Tier 3 FTP emission standard for NMOG+NOx for LDV and LDT in §86.1811. 

(3) Tier 3 SFTP emission standard for NMOG+NOx for LDV and LDT (including 

MDPV) in §86.1811. 

(4) Tier 3 evaporative emission standards in §86.1813. 

(5) Tier 3 FTP emission standard for NMOG+NOx for HDV (other than MDPV) in 

§86.1816.

(6) Cold temperature NMHC standards in §86.1811.

(b) Maintenance of records. (1) The manufacturer producing any vehicles subject to a 

fleet-average standard under this subpart must establish and maintain all the 

following information in organized and indexed records for each model year:

(i) Model year.

(ii) Applicable fleet-average standard.

(iii) Calculated fleet-average value.

(iv) All values used in calculating the fleet-average value achieved.

(2) The manufacturer producing any vehicle subject to the provisions in this section 

must keep all the following information for each vehicle:

(i) Model year.

(ii) Applicable fleet-average standard.

(iii) EPA test group or evaporative family, as applicable.

(iv) Assembly plant.

(v) Vehicle identification number.

(vi) The FEL and the fleet-average standard to which the vehicle is certified.

(vii) Information on the point of first sale, including the purchaser, city, and state.

(3) The manufacturer must retain all records required to be maintained under this 

section for a period of eight years from the due date for the annual report. Records 

may be stored in any format and on any media, as long as manufacturers can 

promptly send EPA organized written records in English if we ask for them. 

Manufacturers must keep records readily available as EPA may review them at any 

time.

(4) The Administrator may require the manufacturer to retain additional records or 

submit information not specifically required by this section.

(5) EPA may void ab initio a certificate of conformity for a vehicle certified to 

emission standards as set forth or otherwise referenced in this subpart for which the 

manufacturer fails to retain the records required in this section, to provide such 

information to the Administrator upon request, or to submit the reports required in 

this section in the specified time period.

(c) Reporting. (1) Each manufacturer must submit an annual report. Except as provided in 

paragraph (b)(2) of this section, the annual report must contain, for each applicable 

fleet average standard, the fleet average value achieved, all values required to 

calculate the fleet-average value, the number of credits generated or debits incurred, 

all the values required to calculate the credits or debits, and sufficient information to 

show compliance with all phase-in requirements, if applicable. The annual report 

must also contain the resulting balance of credits or debits.
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(2) When a manufacturer calculates compliance with the fleet-average standard using 

the provisions in §86.1860–04(c)(2) or §86.1860-17(f), the annual report must state 

that the manufacturer has elected to use such provision and must contain the fleetaverage standard as the fleet-average value for that model year.

(3) For each applicable fleet-average standard, the annual report must also include 

documentation on all credit transactions the manufacturer has engaged in since those 

included in the last report. Information for each transaction must include all the 

following information:

(i) Name of credit provider.

(ii) Name of credit recipient.

(iii) Date the transfer occurred.

(iv) Quantity of credits transferred.

(v) Model year in which the credits were earned.

(4) Unless a manufacturer reports the data required by this section in the annual 

production report required under §86.1844–01(e) and subsequent model year 

provisions, a manufacturer must submit an annual report for each model year after 

production ends for all affected vehicles produced by the manufacturer subject to the 

provisions of this subpart and no later than May 1 of the calendar year following the 

given model year. Annual reports must be submitted to: Director, Compliance 

Division, U.S. Environmental Protection Agency, 2000 Traverwood, Ann Arbor, 

Michigan 48105.

(5) Failure by a manufacturer to submit the annual report in the specified time period 

for all vehicles subject to the provisions in this section is a violation of Clean Air Act 

section 203(a)(1) (42 U.S.C 7522(a)(1)) for each subject vehicle produced by that 

manufacturer.

(6) If EPA or the manufacturer determines that a reporting error occurred on an 

annual report previously submitted to EPA, the manufacturer's credit or debit 

calculations will be recalculated. EPA may void erroneous credits, unless transferred, 

and must adjust erroneous debits. In the case of transferred erroneous credits, EPA 

must adjust the selling manufacturer's credit or debit balance to reflect the sale of 

such credits and any resulting generation of debits.

(d) Notice of opportunity for hearing. Any voiding of the certificate under paragraph 

(a)(6) of this section will be made only after EPA has offered the manufacturer concerned 

an opportunity for a hearing conducted in accordance with §86.614 for light-duty

vehicles and light-duty trucks and with 40 CFR part 1068, subpart G, for heavy-duty

vehicles. 

204. Section 86.1863-07 is amended by adding introductory text to read as follows:

§ 86.1863-07 Optional chassis certification for diesel vehicles.

This section does not apply for vehicles certified to the Tier 3 standards in §86.1816-18, 

including those vehicles that certify to the Tier 3 standards before model year 2018.

* * * * *

205. Section 86.1864-10 is amended by revising paragraph (p) to read as follows:

§ 86.1864-10 How to comply with the fleet average cold temperature NMHC 

standards.
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* * * * *

(p) Reporting and recordkeeping. Keep records and submit information for 

demonstrating compliance with the fleet average cold temperature NMHC standard as 

described in §86.1862-04.

206. Section 86.1868-12 is amended by revising paragraphs (f)(1) and (g)(1) to read as 

follows: 

§ 86.1868–12 CO2 credits for improving the efficiency of air conditioning systems.

* * * * *

(f) * * *

(1) The manufacturer shall perform the AC17 test specified in 40 CFR 1066.845 on each 

unique air conditioning system design and vehicle platform combination for which the 

manufacturer intends to accrue air conditioning efficiency credits. The manufacturer must 

test at least one unique air conditioning system within each vehicle platform in a model 

year, unless all unique air conditioning systems within a vehicle platform have been 

previously tested. A unique air conditioning system design is a system with unique or 

substantially different component designs or types and/or system control strategies (e.g., 

fixed displacement vs. variable displacement compressors, orifice tube vs. thermostatic 

expansion valve, single vs. dual evaporator, etc.). In the first year of such testing, the 

tested vehicle configuration shall be the highest production vehicle configuration within 

each platform. In subsequent model years the manufacturer must test other unique air 

conditioning systems within the vehicle platform, proceeding from the highest production 

untested system until all unique air conditioning systems within the platform have been 

tested, or until the vehicle platform experiences a major redesign. Whenever a new 

unique air conditioning system is tested, the highest production configuration using that 

system shall be the vehicle selected for testing. Air conditioning system designs which 

have similar cooling capacity, component types, and control strategies, yet differ in terms 

of compressor pulley ratios or condenser or evaporator surface areas will not be 

considered to be unique system designs. The test results from one unique system design 

may represent all variants of that design. Manufacturers must use good engineering 

judgment to identify the unique air conditioning system designs which will require AC17 

testing in subsequent model years. Results must be reported separately for all four phases 

(two phases with air conditioning off and two phases with air conditioning on) of the test 

to the Environmental Protection Agency, and the results of the calculations required in 40 

CFR 1066.845 must also be reported. In each subsequent model year additional air 

conditioning system designs, if such systems exist, within a vehicle platform that is 

generating air conditioning credits must be tested using the AC17 procedure. When all 

unique air conditioning system designs within a platform have been tested, no additional 

testing is required within that platform, and credits may be carried over to subsequent 

model years until there is a significant change in the platform design, at which point a 

new sequence of testing must be initiated. No more than one vehicle from each creditgenerating platform is required to be tested in each model year.

* * * * *

(g) * * *

(1) For each air conditioning system selected by the manufacturer to generate air 

conditioning efficiency credits, the manufacturer shall perform the AC17 Air 
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Conditioning Efficiency Test Procedure specified in 40 CFR 1066.845, according to the 

requirements of this paragraph (g).

* * * * *

207. Appendix I to Part 86 is amended by revising the appendix heading, paragraph (a) 

before the table, and paragraphs (b) and (c), and removing and reserving paragraph (d) to 

read as follows: 

Appendix I to Part 86—Dynamometer Schedules

(a) EPA light-duty urban dynamometer driving schedule (UDDS). This driving schedule 

is also known as the LA-4 cycle.

(1) The driving schedule in this paragraph (a) applies for light-duty vehicles, lightduty trucks, and heavy-duty vehicles certified under subpart S of this part.

(2) The driving schedule in this paragraph (a) applies for motorcycles with engine 

displacement at or above 170 cc. Calculate the speed-versus-time sequence in 

kilometers per hour by multiplying the listed speed by 1.6 and rounding to the nearest 

0.1 kilometers per hour.

(3) The driving schedule follows:

* * * * *

(b) EPA driving schedule for motorcycles with engine displacement below 170 cc. Use 

the driving schedule specified in paragraph (a)(2) of this appendix, except that the 

schedule specified in this paragraph (b) applies for the portion of the driving schedule 

from 164 to 332 seconds.

Speed Versus Time Sequence

Time 

(sec.)

Speed 

(kph)

164 3.4

165 6.8

166 10.3

167 13.7

168 17.1

169 20.5

170 23.0

171 25.2

172 26.7

173 27.4

174 26.6

175 26.0

176 25.6

177 25.9

178 26.1

179 26.3

180 26.7

181 28.2

182 27.5

183 24.9

184 23.5

185 20.1

186 18.3

187 17.8

188 18.8

189 19.3

190 20.7

191 23.0

192 25.4

193 28.3

194 31.6

195 34.7

196 37.5

197 38.6

198 40.7

199 42.0

200 43.6

201 45.1

202 46.7

203 47.7

204 48.5

205 49.2

206 49.2

207 49.0

208 48.9

209 48.7

210 48.7

211 48.7

212 48.7

213 48.7

214 48.9

215 49.1

216 49.6

217 50.2

218 50.9

219 51.3

220 51.8

221 52.4

222 52.8

223 53.4

224 54.1

225 55.1

226 56.0

227 56.6

228 56.9

229 57.0

230 56.9

231 56.6

232 56.6

233 56.8

234 57.1

235 57.5

236 57.7

237 58.1

238 58.3

239 58.6

240 58.7

241 58.7

242 58.5

243 58.5

244 58.5

245 58.5

246 58.5

247 58.5

248 58.4

249 58.1

250 57.8

251 57.1

252 56.6

253 56.2

254 55.9

255 55.6

256 55.5

257 55.8

258 55.9

259 56.0

260 56.0

261 55.7

262 55.3

263 54.9

264 54.5

265 54.0

266 54.3
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267 53.9

268 53.8

269 53.6

270 53.4

271 53.5

272 53.7

273 54.0

274 54.4

275 54.9

276 55.4

277 55.9

278 56.9

279 57.4

280 57.6

281 58.0

282 58.0

283 57.8

284 57.2

285 56.5

286 55.5

287 54.4

288 53.4

289 53.4

290 53.4

291 52.9

292 51.9

293 51.8

294 51.9

295 51.8

296 51.4

297 51.3

298 51.3

299 51.3

300 50.9

301 50.3

302 49.8

303 48.9

304 47.8

305 46.6

306 45.4

307 44.1

308 43.0

309 41.8

310 39.9

311 38.3

312 36.5

313 35.0

314 33.7

315 32.6

316 31.7

317 31.6

318 31.1

319 30.0

320 28.5

321 25.7

322 22.3

323 20.8

324 19.8

325 19.2

326 17.6

327 16.1

328 12.9

329 11.2

330 8.3

331 4.9

332 1.5

(c) EPA driving schedule for class 3 heavy-duty vehicles. This driving schedule is also known 

as the LA-92 cycle.

Time 

(sec.)

Speed 

(mph)

1 0.0

2 0.0

3 0.0

4 0.0

5 0.0

6 0.0

7 0.0

8 0.0

9 0.0

10 0.0

11 0.0

12 0.0

13 0.0

14 0.0

15 0.0

16 0.0

17 0.0

18 0.0

19 0.0

20 0.0

21 1.2

22 4.2

23 7.3

24 8.8

25 10.8

26 12.3

27 13.1

28 12.3

29 12.3

30 11.5

31 11.5

32 11.1

33 11.1

34 11.1

35 13.1

36 15.0

37 16.9

38 16.9

39 16.1

40 15.7

41 15.4

42 15.0

43 13.8

44 10.8

45 8.4

46 6.1

47 4.2

48 3.5

49 3.5

50 1.5

51 0.0

52 0.0

53 0.0

54 0.0

55 0.0

56 0.0

57 0.0

58 0.0

59 0.0

60 0.0

61 0.0

62 0.0

63 1.2

64 3.5

65 7.7

66 11.1

67 13.8

68 16.5

69 18.4

70 20.4

71 20.7

72 19.6

73 17.3

74 12.3

75 8.1

76 6.1

77 9.6

78 12.7

79 15.7

80 18.0

81 20.4

82 21.9

83 23.4

84 23.8

85 24.6

86 25.0

87 26.1

88 26.1

89 26.9

90 26.9

91 26.9

92 26.5

93 25.7

94 21.9

95 16.5

96 10.0

97 4.6

98 1.5

99 0.4

100 0.0

101 0.0

102 0.0

103 0.0

104 0.0

105 0.0

106 0.0

107 0.0

108 0.4

109 1.2

110 1.9

111 3.8

112 7.7

113 11.5

114 14.6

115 18.0

116 21.5

117 25.0

118 28.4

119 30.7

120 31.9

121 32.3

122 32.3

123 31.9

124 30.3

125 28.0

126 24.2

127 20.0
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128 16.1

129 11.5

130 8.1

131 5.0

132 3.5

133 1.9

134 0.0

135 0.0

136 0.0

137 0.0

138 0.0

139 0.0

140 0.0

141 0.0

142 0.0

143 1.5

144 6.9

145 12.7

146 16.5

147 20.0

148 23.0

149 25.7

150 28.0

151 30.7

152 32.6

153 34.2

154 35.3

155 36.9

156 36.9

157 37.2

158 37.6

159 37.6

160 37.6

161 37.2

162 37.2

163 36.9

164 36.5

165 36.5

166 34.9

167 33.4

168 31.9

169 29.2

170 25.0

171 25.0

172 26.1

173 27.6

174 29.2

175 31.1

176 32.3

177 34.2

178 34.9

179 35.7

180 36.5

181 36.9

182 36.9

183 37.2

184 37.6

185 37.2

186 37.6

187 38.0

188 38.4

189 39.2

190 39.6

191 39.9

192 40.7

193 40.3

194 41.1

195 41.1

196 40.7

197 31.9

198 23.9

199 15.9

200 7.9

201 2.7

202 0.4

203 0.4

204 2.7

205 3.8

206 3.8

207 1.5

208 0.0

209 0.0

210 0.0

211 0.0

212 0.0

213 0.0

214 0.0

215 0.0

216 0.0

217 0.0

218 0.0

219 0.0

220 0.0

221 0.0

222 0.0

223 0.0

224 0.0

225 0.0

226 0.0

227 0.0

228 0.0

229 0.0

230 0.0

231 0.0

232 0.0

233 0.0

234 0.0

235 0.0

236 0.0

237 0.0

238 1.5

239 5.0

240 8.8

241 11.5

242 14.2

243 15.4

244 16.1

245 16.1

246 16.9

247 16.5

248 16.9

249 18.0

250 19.2

251 20.4

252 20.4

253 21.1

254 21.1

255 22.3

256 23.0

257 23.8

258 24.2

259 24.6

260 25.0

261 25.7

262 25.7

263 26.5

264 27.6

265 28.4

266 29.2

267 30.3

268 31.1

269 31.1

270 30.7

271 31.1

272 29.6

273 29.2

274 29.2

275 28.8

276 28.0

277 23.0

278 21.1

279 21.5

280 20.7

281 20.7

282 19.6

283 16.5

284 13.1

285 9.6

286 7.3

287 3.8

288 0.8

289 0.0

290 0.0

291 0.0

292 0.0

293 0.0

294 0.0

295 0.0

296 0.0

297 0.0

298 0.0

299 0.0

300 0.0

301 0.0

302 0.0

303 0.0

304 0.0

305 0.0

306 0.0

307 0.0

308 0.0

309 0.0

310 0.0

311 0.0

312 0.0

313 0.4

314 2.7

315 7.3

316 11.5

317 15.4

318 18.4

319 20.7

320 24.2

321 26.9

322 29.6

323 31.1

324 32.6

325 33.8

326 34.9

327 36.9

328 39.2

329 41.1

330 43.0

331 43.8

332 44.5

333 45.3

334 45.3

335 44.9

336 44.5

337 43.8

338 43.4

339 42.6

340 41.9

341 41.5

342 40.7
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343 40.3

344 41.1

345 41.5

346 42.6

347 43.4

348 44.2

349 44.9

350 45.7

351 46.5

352 46.8

353 47.2

354 48.0

355 47.6

356 48.4

357 48.0

358 47.2

359 46.1

360 45.7

361 44.9

362 44.2

363 43.8

364 44.5

365 44.9

366 45.3

367 46.5

368 48.0

369 48.8

370 49.5

371 49.9

372 49.9

373 49.9

374 49.5

375 49.5

376 48.8

377 48.8

378 48.8

379 48.4

380 48.8

381 49.5

382 50.3

383 50.7

384 51.8

385 52.6

386 53.4

387 54.1

388 55.3

389 55.3

390 56.1

391 56.4

392 56.4

393 56.4

394 57.2

395 56.8

396 57.6

397 57.6

398 57.6

399 58.0

400 58.0

401 58.4

402 58.4

403 58.8

404 59.1

405 58.8

406 58.8

407 58.0

408 58.0

409 57.6

410 57.6

411 57.6

412 57.6

413 57.6

414 59.1

415 59.5

416 59.9

417 60.3

418 60.3

419 61.1

420 60.3

421 59.9

422 59.5

423 59.1

424 59.1

425 59.5

426 59.5

427 59.5

428 59.9

429 60.3

430 60.7

431 60.7

432 61.4

433 61.8

434 61.8

435 61.8

436 61.8

437 61.1

438 60.7

439 60.3

440 60.3

441 60.3

442 59.5

443 58.8

444 59.1

445 58.8

446 58.8

447 58.8

448 58.4

449 58.0

450 58.0

451 58.0

452 58.4

453 59.1

454 59.5

455 59.9

456 59.9

457 60.3

458 61.1

459 61.1

460 61.1

461 61.4

462 61.4

463 61.1

464 60.7

465 59.9

466 59.1

467 59.1

468 59.1

469 59.9

470 59.5

471 59.9

472 58.8

473 58.0

474 57.6

475 56.8

476 56.1

477 55.3

478 54.1

479 52.6

480 49.2

481 46.1

482 43.0

483 37.2

484 29.6

485 21.5

486 16.5

487 15.7

488 18.4

489 21.5

490 25.0

491 27.3

492 29.2

493 30.7

494 31.5

495 31.1

496 31.1

497 30.3

498 30.0

499 30.0

500 29.6

501 30.0

502 28.8

503 28.8

504 28.0

505 28.4

506 28.0

507 28.4

508 28.4

509 28.8

510 28.4

511 28.4

512 28.0

513 26.5

514 24.2

515 22.7

516 20.4

517 17.7

518 15.7

519 13.1

520 10.8

521 8.4

522 7.3

523 5.0

524 3.8

525 3.5

526 1.9

527 0.8

528 0.0

529 0.0

530 0.0

531 0.8

532 1.9

533 3.8

534 6.9

535 9.6

536 11.1

537 11.1

538 10.4

539 8.8

540 9.2

541 10.0

542 10.4

543 10.4

544 5.4

545 1.9

546 0.0

547 0.0

548 0.0

549 0.0

550 0.0

551 0.0

552 0.0

553 0.0

554 0.0

555 0.0

556 0.0

557 0.0
EO 12866 Review Draft

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Page 129 of 378

558 0.0

559 0.0

560 0.0

561 0.0

562 0.0

563 0.0

564 0.0

565 0.0

566 0.0

567 0.0

568 0.0

569 0.0

570 0.0

571 0.0

572 0.4

573 1.5

574 3.5

575 6.1

576 10.4

577 14.2

578 16.9

579 19.2

580 20.0

581 21.5

582 23.4

583 24.6

584 24.2

585 20.0

586 16.9

587 13.4

588 13.4

589 15.7

590 18.4

591 21.1

592 23.4

593 25.3

594 27.6

595 28.8

596 30.3

597 30.7

598 31.5

599 31.1

600 31.1

601 30.3

602 30.3

603 30.3

604 30.7

605 31.1

606 32.3

607 32.6

608 32.6

609 32.6

610 31.1

611 26.9

612 22.3

613 18.0

614 13.8

615 9.6

616 4.6

617 6.1

618 10.0

619 14.2

620 17.3

621 20.0

622 21.5

623 22.3

624 22.3

625 22.3

626 22.3

627 23.0

628 23.0

629 22.7

630 22.3

631 21.9

632 22.7

633 23.8

634 25.0

635 25.3

636 25.7

637 26.5

638 26.9

639 27.3

640 28.0

641 29.2

642 30.0

643 30.0

644 29.6

645 29.6

646 28.8

647 28.4

648 28.0

649 27.3

650 25.7

651 24.6

652 25.0

653 26.5

654 28.0

655 29.6

656 30.7

657 32.3

658 33.0

659 34.2

660 34.6

661 35.3

662 36.1

663 36.1

664 36.9

665 36.9

666 37.6

667 37.6

668 38.4

669 38.0

670 37.6

671 37.6

672 37.2

673 36.9

674 36.1

675 35.7

676 36.1

677 35.7

678 35.7

679 35.7

680 36.1

681 36.1

682 35.7

683 35.7

684 34.9

685 34.6

686 34.2

687 33.8

688 33.4

689 33.0

690 30.3

691 29.2

692 28.4

693 25.0

694 21.1

695 16.9

696 13.4

697 13.1

698 12.3

699 12.7

700 15.7

701 19.2

702 22.3

703 24.6

704 25.7

705 26.5

706 26.5

707 26.9

708 27.3

709 27.3

710 27.6

711 28.4

712 28.8

713 28.8

714 29.2

715 28.8

716 28.8

717 28.0

718 28.0

719 27.6

720 26.5

721 24.6

722 20.7

723 16.5

724 15.0

725 14.2

726 14.2

727 13.8

728 13.8

729 11.9

730 8.4

731 4.2

732 1.2

733 0.0

734 0.0

735 0.0

736 0.0

737 0.0

738 0.0

739 0.0

740 0.0

741 0.0

742 0.0

743 0.0

744 0.0

745 0.0

746 0.0

747 0.0

748 0.0

749 0.0

750 0.0

751 0.0

752 0.0

753 0.0

754 0.0

755 0.0

756 0.0

757 0.0

758 0.0

759 0.0

760 0.0

761 0.0

762 0.0

763 1.5

764 5.4

765 9.2

766 11.5

767 14.6

768 17.3

769 19.2

770 21.1

771 20.7

772 20.7
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773 19.6

774 18.4

775 16.9

776 16.9

777 16.5

778 16.9

779 16.9

780 16.9

781 17.3

782 19.2

783 20.4

784 21.1

785 22.3

786 22.3

787 22.7

788 22.3

789 22.7

790 22.3

791 23.8

792 25.7

793 27.6

794 29.6

795 30.0

796 29.2

797 27.6

798 25.0

799 23.8

800 23.4

801 24.2

802 23.4

803 23.0

804 20.4

805 18.8

806 17.3

807 15.0

808 13.1

809 9.2

810 6.9

811 4.6

812 4.6

813 4.6

814 4.2

815 5.4

816 4.6

817 3.5

818 2.3

819 2.3

820 1.9

821 3.1

822 6.1

823 4.6

824 2.7

825 2.3

826 2.3

827 3.1

828 4.2

829 3.5

830 3.8

831 4.2

832 3.5

833 3.5

834 3.5

835 4.6

836 5.8

837 3.5

838 0.8

839 3.5

840 3.8

841 2.3

842 0.0

843 1.2

844 6.9

845 13.8

846 18.8

847 23.8

848 27.3

849 30.7

850 33.8

851 37.6

852 40.7

853 43.8

854 46.1

855 48.0

856 49.5

857 51.5

858 53.0

859 54.5

860 55.7

861 56.8

862 58.0

863 59.1

864 60.3

865 61.1

866 61.8

867 61.8

868 61.8

869 61.8

870 62.6

871 63.4

872 63.0

873 63.0

874 62.6

875 61.8

876 61.8

877 62.2

878 62.2

879 62.6

880 63.7

881 64.5

882 64.9

883 66.0

884 66.0

885 66.8

886 66.4

887 66.8

888 67.2

889 66.4

890 66.4

891 66.0

892 65.7

893 65.7

894 66.4

895 66.0

896 65.7

897 65.3

898 65.3

899 64.5

900 64.5

901 64.1

902 63.7

903 63.7

904 63.7

905 64.5

906 64.5

907 64.9

908 64.5

909 64.1

910 64.9

911 65.3

912 65.3

913 65.3

914 64.1

915 63.4

916 63.0

917 63.4

918 64.1

919 64.9

920 65.3

921 64.5

922 64.1

923 63.4

924 63.7

925 63.4

926 63.4

927 63.4

928 63.4

929 63.7

930 64.5

931 65.3

932 64.9

933 63.7

934 63.0

935 59.9

936 55.3

937 50.7

938 49.2

939 48.0

940 46.1

941 44.2

942 41.1

943 39.9

944 36.1

945 32.6

946 29.2

947 24.6

948 20.7

949 19.2

950 16.5

951 15.0

952 11.9

953 9.6

954 8.4

955 5.8

956 1.2

957 0.0

958 0.0

959 0.0

960 1.2

961 3.1

962 5.0

963 8.4

964 11.5

965 14.6

966 16.9

967 18.8

968 21.1

969 23.8

970 26.5

971 28.0

972 29.6

973 30.7

974 32.6

975 34.2

976 35.3

977 36.1

978 36.9

979 38.0

980 38.0

981 38.0

982 38.0

983 38.0

984 37.2

985 36.9

986 36.1

987 35.7
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988 34.9

989 34.9

990 33.8

991 31.5

992 28.8

993 25.7

994 24.6

995 23.4

996 22.3

997 21.5

998 20.0

999 20.0

1000 19.2

1001 19.2

1002 18.0

1003 11.9

1004 6.9

1005 2.7

1006 0.8

1007 0.4

1008 0.0

1009 0.0

1010 0.0

1011 0.0

1012 0.0

1013 0.0

1014 0.0

1015 0.0

1016 0.0

1017 0.0

1018 0.0

1019 0.0

1020 0.0

1021 0.0

1022 0.0

1023 0.4

1024 2.7

1025 6.1

1026 9.2

1027 11.5

1028 14.2

1029 16.1

1030 18.0

1031 20.0

1032 21.5

1033 23.0

1034 24.2

1035 25.0

1036 25.7

1037 26.9

1038 27.6

1039 27.6

1040 28.4

1041 29.2

1042 29.2

1043 30.0

1044 29.6

1045 29.6

1046 28.8

1047 28.0

1048 23.8

1049 18.8

1050 11.9

1051 6.1

1052 1.5

1053 1.5

1054 4.2

1055 8.1

1056 10.4

1057 13.1

1058 15.4

1059 18.0

1060 20.4

1061 23.0

1062 25.3

1063 27.3

1064 28.8

1065 30.3

1066 31.1

1067 32.3

1068 31.9

1069 32.3

1070 31.9

1071 31.1

1072 28.8

1073 25.0

1074 22.7

1075 18.8

1076 15.4

1077 13.4

1078 11.9

1079 8.8

1080 5.0

1081 1.9

1082 2.3

1083 2.7

1084 3.5

1085 6.5

1086 10.8

1087 13.8

1088 16.1

1089 18.4

1090 20.4

1091 21.9

1092 21.9

1093 20.7

1094 17.3

1095 13.1

1096 9.6

1097 8.8

1098 10.8

1099 12.7

1100 14.2

1101 14.6

1102 13.1

1103 11.1

1104 11.1

1105 11.1

1106 13.1

1107 15.7

1108 18.4

1109 20.7

1110 23.8

1111 25.7

1112 28.0

1113 30.0

1114 31.1

1115 32.3

1116 34.2

1117 35.7

1118 36.9

1119 38.8

1120 40.3

1121 41.5

1122 42.2

1123 43.0

1124 43.8

1125 43.8

1126 43.4

1127 43.0

1128 42.2

1129 41.9

1130 41.5

1131 41.9

1132 41.9

1133 41.9

1134 42.2

1135 42.6

1136 42.6

1137 42.6

1138 42.6

1139 42.6

1140 42.6

1141 42.6

1142 42.2

1143 43.0

1144 43.4

1145 43.0

1146 42.6

1147 41.9

1148 40.7

1149 36.9

1150 32.6

1151 28.0

1152 23.4

1153 18.4

1154 14.6

1155 12.3

1156 9.2

1157 5.8

1158 1.9

1159 0.4

1160 0.0

1161 0.0

1162 0.0

1163 0.0

1164 0.0

1165 0.4

1166 4.2

1167 9.2

1168 11.9

1169 14.2

1170 15.7

1171 15.0

1172 14.2

1173 13.4

1174 13.8

1175 14.6

1176 14.6

1177 14.2

1178 16.1

1179 15.7

1180 15.7

1181 14.6

1182 13.1

1183 10.0

1184 7.3

1185 3.5

1186 0.8

1187 0.0

1188 0.0

1189 0.0

1190 0.0

1191 0.4

1192 2.7

1193 7.3

1194 11.5

1195 15.4

1196 19.2

1197 21.9

1198 23.8

1199 25.0

1200 26.1

1201 27.3

1202 28.8
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1203 30.0

1204 29.6

1205 29.6

1206 28.8

1207 26.1

1208 22.3

1209 19.2

1210 16.5

1211 12.7

1212 9.6

1213 6.9

1214 4.2

1215 2.3

1216 0.8

1217 0.0

1218 0.0

1219 0.0

1220 0.0

1221 0.0

1222 0.0

1223 0.0

1224 0.0

1225 0.0

1226 0.0

1227 0.0

1228 0.0

1229 0.0

1230 0.0

1231 0.0

1232 0.0

1233 0.0

1234 0.0

1235 0.0

1236 0.0

1237 0.0

1238 0.0

1239 0.0

1240 3.5

1241 10.4

1242 15.4

1243 17.3

1244 17.3

1245 18.4

1246 21.5

1247 24.6

1248 27.3

1249 30.0

1250 31.5

1251 31.9

1252 32.6

1253 33.4

1254 34.9

1255 36.5

1256 37.6

1257 39.2

1258 40.3

1259 40.7

1260 41.1

1261 40.7

1262 40.7

1263 40.7

1264 41.5

1265 42.6

1266 43.0

1267 44.5

1268 45.3

1269 45.3

1270 44.9

1271 43.4

1272 40.3

1273 38.0

1274 36.1

1275 36.5

1276 38.0

1277 39.2

1278 40.7

1279 42.2

1280 43.4

1281 44.9

1282 45.7

1283 46.1

1284 46.8

1285 46.5

1286 46.5

1287 46.5

1288 46.1

1289 46.1

1290 46.1

1291 46.8

1292 47.6

1293 48.0

1294 48.4

1295 48.0

1296 48.0

1297 47.2

1298 46.5

1299 46.8

1300 47.2

1301 48.4

1302 48.4

1303 48.8

1304 48.4

1305 47.6

1306 46.5

1307 44.2

1308 42.2

1309 41.5

1310 41.1

1311 40.7

1312 40.3

1313 39.6

1314 39.2

1315 38.8

1316 38.0

1317 37.6

1318 37.2

1319 36.5

1320 34.6

1321 31.5

1322 29.6

1323 29.2

1324 28.8

1325 28.8

1326 28.0

1327 28.0

1328 28.4

1329 29.6

1330 30.0

1331 30.3

1332 29.2

1333 26.5

1334 25.3

1335 25.0

1336 24.6

1337 24.6

1338 25.3

1339 26.1

1340 27.3

1341 28.4

1342 29.2

1343 29.2

1344 29.6

1345 30.0

1346 31.1

1347 32.6

1348 33.8

1349 34.6

1350 34.9

1351 34.6

1352 34.9

1353 34.6

1354 34.9

1355 34.9

1356 34.9

1357 34.2

1358 33.8

1359 32.6

1360 31.5

1361 30.0

1362 28.8

1363 27.3

1364 23.8

1365 23.0

1366 23.0

1367 22.3

1368 20.4

1369 18.8

1370 17.7

1371 16.1

1372 14.6

1373 12.7

1374 11.1

1375 9.2

1376 8.8

1377 7.3

1378 6.1

1379 5.0

1380 4.2

1381 3.5

1382 2.7

1383 2.3

1384 1.5

1385 1.2

1386 0.0

1387 1.2

1388 4.2

1389 7.3

1390 8.8

1391 10.8

1392 12.3

1393 13.1

1394 12.3

1395 12.3

1396 11.5

1397 11.5

1398 11.1

1399 11.1

1400 11.1

1401 13.1

1402 15.0

1403 16.9

1404 16.9

1405 16.1

1406 15.7

1407 15.4

1408 15.0

1409 13.8

1410 10.8

1411 8.4

1412 6.1

1413 4.2

1414 3.5

1415 3.5

1416 1.5

1417 0.0
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1418 0.0

1419 0.0

1420 0.0

1421 0.0

1422 0.0

1423 0.0

1424 0.0

1425 0.0

1426 0.0

1427 0.0

1428 0.0

1429 0.0

1430 0.0

1431 0.0

1432 0.0

1433 0.0

1434 0.0

1435 0.0

1436 0.0

1437 0.0

1438 0.0

1439 0.0

1440 0.0

1441 0.0

1442 0.0

1443 0.0

1444 0.0

1445 0.0

1446 0.0

1447 0.0

1448 0.0

1449 0.0

1450 0.0

1451 0.0

1452 0.0

1453 0.0

1454 0.0

1455 0.0

1456 1.2

1457 4.2

1458 7.3

1459 8.8

1460 10.8

1461 12.3

1462 13.1

1463 12.3

1464 12.3

1465 11.5

1466 11.5

1467 11.1

1468 11.1

1469 11.1

1470 13.1

1471 15.0

1472 16.9

1473 16.9

1474 16.1

1475 15.7

1476 15.4

1477 15.0

1478 13.8

1479 10.8

1480 8.4

1481 6.1

1482 4.2

1483 3.5

1484 3.5

1485 1.5

1486 0.0

1487 0.0

1488 0.0

1489 0.0

1490 0.0

1491 0.0

1492 0.0

1493 0.0

1494 0.0

1495 0.0

1496 0.0

1497 0.0

1498 1.2

1499 3.5

1500 7.7

1501 11.1

1502 13.8

1503 16.5

1504 18.4

1505 20.4

1506 20.7

1507 19.6

1508 17.3

1509 12.3

1510 8.1

1511 6.1

1512 9.6

1513 12.7

1514 15.7

1515 18.0

1516 20.4

1517 21.9

1518 23.4

1519 23.8

1520 24.6

1521 25.0

1522 26.1

1523 26.1

1524 26.9

1525 26.9

1526 26.9

1527 26.5

1528 25.7

1529 21.9

1530 16.5

1531 10.0

1532 4.6

1533 1.5

1534 0.4

1535 0.0

1536 0.0

1537 0.0

1538 0.0

1539 0.0

1540 0.0

1541 0.0

1542 0.0

1543 0.4

1544 1.2

1545 1.9

1546 3.8

1547 7.7

1548 11.5

1549 14.6

1550 18.0

1551 21.5

1552 25.0

1553 28.4

1554 30.7

1555 31.9

1556 32.3

1557 32.3

1558 31.9

1559 30.3

1560 28.0

1561 24.2

1562 20.0

1563 16.1

1564 11.5

1565 8.1

1566 5.0

1567 3.5

1568 1.9

1569 0.0

1570 0.0

1571 0.0

1572 0.0

1573 0.0

1574 0.0

1575 0.0

1576 0.0

1577 0.0

1578 1.5

1579 6.9

1580 12.7

1581 16.5

1582 20.0

1583 23.0

1584 25.7

1585 28.0

1586 30.7

1587 32.6

1588 34.2

1589 35.3

1590 36.9

1591 36.9

1592 37.2

1593 37.6

1594 37.6

1595 37.6

1596 37.2

1597 37.2

1598 36.9

1599 36.5

1600 36.5

1601 34.9

1602 33.4

1603 31.9

1604 29.2

1605 25.0

1606 25.0

1607 26.1

1608 27.6

1609 29.2

1610 31.1

1611 32.3

1612 34.2

1613 34.9

1614 35.7

1615 36.5

1616 36.9

1617 36.9

1618 37.2

1619 37.6

1620 37.2

1621 37.6

1622 38.0

1623 38.4

1624 39.2

1625 39.6

1626 39.9

1627 40.7

1628 40.3

1629 41.1

1630 41.1

1631 40.7

1632 31.9
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1633 23.9

1634 15.9

1635 7.9

1636 2.7

1637 0.4

1638 0.4

1639 2.7

1640 3.8

1641 3.8

1642 1.5

1643 0.0

1644 0.0

1645 0.0

1646 0.0

1647 0.0

1648 0.0

1649 0.0

1650 0.0

1651 0.0

1652 0.0

1653 0.0

1654 0.0

1655 0.0

1656 0.0

1657 0.0

1658 0.0

1659 0.0

1660 0.0

1661 0.0

1662 0.0

1663 0.0

1664 0.0

1665 0.0

1666 0.0

1667 0.0

1668 0.0

1669 0.0

1670 0.0

1671 0.0

1672 0.0

1673 1.5

1674 5.0

1675 8.8

1676 11.5

1677 14.2

1678 15.4

1679 16.1

1680 16.1

1681 16.9

1682 16.5

1683 16.9

1684 18.0

1685 19.2

1686 20.4

1687 20.4

1688 21.1

1689 21.1

1690 22.3

1691 23.0

1692 23.8

1693 24.2

1694 24.6

1695 25.0

1696 25.7

1697 25.7

1698 26.5

1699 27.6

1700 28.4

1701 29.2

1702 30.3

1703 31.1

1704 31.1

1705 30.7

1706 31.1

1707 29.6

1708 29.2

1709 29.2

1710 28.8

1711 28.0

1712 23.0

1713 21.1

1714 21.5

1715 20.7

1716 20.7

1717 19.6

1718 16.5

1719 13.1

1720 9.6

1721 7.3

1722 3.8

1723 0.8

1724 0.0

1725 0.0

1726 0.0

1727 0.0

1728 0.0

1729 0.0

1730 0.0

1731 0.0

1732 0.0

1733 0.0

1734 0.0

1735 0.0

(d) [Reserved]

* * * * *

Appendix XIII through Appendix XVIII to Part 86—[Removed]

208. Appendix XIII through Appendix XVIII to Part 86 are removed.

PART 600—FUEL ECONOMY AND GREENHOUSE GAS EXHAUST 

EMISSIONS OF MOTOR VEHICLES

209. The authority citation for part 600 continues to read as follows:

Authority: 49 U.S.C. 32901—23919q, Pub. L. 109–58.

Subpart A—[Amended]

210. Section 600.001 is amended by adding paragraph (e) to read as follows:

§600.001 General applicability.

* * * * *

(e) You. The term “you” in this part refers to manufacturers subject to the requirements of 

this part.
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211. Section 600.002 is amended by revising the definitions for “Alcohol” and 

“Alcohol-fueled automobile” and adding a definition for “We (us, our)” in alphabetical 

order to read as follows:

§ 600.002 Definitions.

* * * * *

Alcohol means a mixture containing 85 percent or more by volume methanol, 

denatured ethanol, or other alcohols, in any combination.

Alcohol-fueled automobile means an automobile designed to operate on alcohol, but 

not on gasoline.

* * * * *

We (us, our) means the Administrator of the Environmental Protection Agency and 

any authorized representatives.

* * * * *

212. Section 600.011 is amended by revising paragraphs (b), (c)(2), and (c)(3) to read 

as follows:

§ 600.011 Incorporation by reference.

* * * * *

(b) ASTM International material. The following documents are available from ASTM 

International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA, 19428-

2959, (610) 832-9585, or http://www.astm.org/.

(1) ASTM D975-13a, Standard Specification for Diesel Fuel Oils, approved 

December 1, 2013, IBR approved for § 600.107–08(b). 

(2) ASTM D1298-12b, Standard Test Method for Density, Relative Density, or API

Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method, 

approved June 1, 2012, IBR approved for §§ 600.113–12(f) and (g) and 600.510-

12(g).

(3) ASTM D1945-03 (Reapproved 2010), Standard Test Method for Analysis of 

Natural Gas By Gas Chromatography, approved January 1, 2010, IBR approved for § 

600.113-12(f).

(4) ASTM D3338/D3338M-09, Standard Test Method for Estimation of Net Heat of 

Combustion of Aviation Fuels, approved April 15, 2009, IBR approved for § 

600.113-12(f).

(5) ASTM D3343-05 (Reapproved 2010), Standard Test Method for Estimation of 

Hydrogen Content of Aviation Fuels, approved October 1, 2010, IBR approved for § 

600.113-12(f).

(c) * * *

(2) SAE J1634, Battery Electric Vehicle Energy Consumption and Range Test 

Procedure, revised October 2012, IBR approved for §§ 600.116-12(a) and 600.311-

12(j) and (k).

(3) SAE J1711, Recommended Practice for Measuring the Exhaust Emissions and 

Fuel Economy of Hybrid-Electric Vehicles, Including Plug-In Hybrid Vehicles, 

revised June 2010, IBR approved for §§ 600.114-12(c) and (f), 600.116-12(b) and (c), 

and 600.311-12(c), (j), and (k).

* * * * *
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Subpart B—[Amended]

213. Section 600.111-08 is revised to read as follows:

§ 600.111-08 Test procedures.

This section describes test procedures for the FTP, highway fuel economy test (HFET), 

US06, SC03, and the cold temperature FTP tests. Perform testing according to test 

procedures and other requirements contained in this part 600 and in 40 CFR parts 86 and 

1066, including the provisions of 40 CFR part 86, subparts B, C, and S. Manufacturers 

may certify vehicles based on data collected according to previously published test 

procedures for model years through 2021. In addition, we may approve the use of 

previously published test procedures for later model years as an alternative procedure 

under 40 CFR 1066.10(c). See 40 CFR 86.101 and 86.201 for detailed provisions related 

to this transition. 

(a) FTP testing procedures. Conduct FTP testing as described in 40 CFR 1066.810 

through 1066.820 . You may omit evaporative emission measurements for testing under 

this part 600 unless we specifically require it.

(b) Highway fuel economy testing procedures. Conduct HFET testing as described in 40 

CFR 1066.840.

(c) US06 testing procedures. Conduct US06 testing as described in 40 CFR 1066.830 and 

1066.831.

(d) SC03 testing procedures. Conduct SC03 testing as described in 40 CFR 1066.830 and 

835.

(e) Cold temperature FTP procedures. Conduct cold temperature FTP testing as described 

in 40 CFR part 1066, subpart H.

(f) Testing with alternative fuels. For vehicles designed to operate on an alternative fuel 

in addition to gasoline or diesel fuel, perform FTP and HFET testing as described in 

paragraphs (a) and (b) of this section for each type of fuel on which the vehicle is 

designed to operate. No US06, SC03, or cold temperature FTP testing is required on the 

alternative fuel. 

(g) Testing for vehicles with rechargeable energy storage systems. Test electric vehicles 

and hybrid electric vehicles as described in §600.116.

(h) Special test procedures. We may allow or require you to use procedures other than 

those specified in this section as described in 40 CFR 1066.10(c). For example, special 

test procedures may be used for advanced technology vehicles, including, but not limited 

to fuel cell vehicles, hybrid electric vehicles using hydraulic energy storage, and vehicles 

equipped with hydrogen internal combustion engines. Additionally, we may conduct fuel 

economy and carbon-related exhaust emission testing using the special test procedures 

approved for a specific vehicle.

214. Section 600.113-08 is redesignated as § 600.113, and newly redesignated § 

600.113 is revised to read as follows:

§600.113 Interim provisions.

The following provisions apply instead of other provisions specified in this part through 

model year 2019:

(a) Except as specified in paragraph (e) of this section, manufacturers must demonstrate 

compliance with greenhouse gas emission standards and determine fuel economy values 
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using gasoline test fuel as specified in 40 CFR 86.113-04(a), regardless of any testing 

with Tier 3 test fuel under paragraph (b) of this section.

(b) Manufacturers may demonstrate that vehicles comply with Tier 3 emission standards 

as specified in 40 CFR part 86, subpart S, during fuel economy measurements using the 

gasoline test fuel specified in 40 CFR 86.113-04(a), as long as this test fuel is used for all 

the duty cycles specified in 40 CFR part 86, subpart S. If a vehicle fails to meet a Tier 3 

emission standard using the gasoline test fuel specified in 40 CFR 86.113-04(a), the 

manufacturer must retest the vehicle using the Tier 3 test fuel specified in 40 CFR 

1065.710(b) to demonstrate compliance with all applicable emission standards over that 

test cycle. 

(c) If a manufacturer demonstrates compliance with emission standards for criteria 

pollutants over all five test cycles using the Tier 3 test fuel specified in 40 CFR 

1065.710(b), the manufacturer may use the derived five-cycle calculations to demonstrate 

compliance with greenhouse gas emission standards and determine fuel economy values. 

This also applies for fuel economy labeling, as long as the test group meets the criteria 

described in §600.115. Vehicles tested over the FTP and HFET cycles with the test fuel 

specified in 40 CFR 86.113-04(a) under this paragraph (b) must meet the Tier 3 emission 

standards over those test cycles. 

(d) Manufacturers may perform testing with either gasoline test fuel specified in 40 CFR 

86.113-04(a) or in 40 CFR 1065.710(b) to evaluate whether their vehicles meet the 

criteria for derived 5-cycle testing under 40 CFR §600.115; however, all five tests must 

use test fuel meeting the same specifications. 

(e) For IUVP testing under §86.1845, manufacturers may demonstrate compliance with 

greenhouse gas emission standards using a test fuel meeting specifications for 

demonstrating compliance with emission standards for criteria pollutants.

§ 600.114-08 —[Removed]

215. Remove § 600.114-08.

216. Section 600.116-12 is amended as follows:

a. By revising the section heading.

b. By revising paragraph (a)(5).

c. By redesignating paragraphs (b) and (c) as paragraphs (c) and (d), respectively.

d. By adding a new paragraph (b).

e. By revising the redesignated paragraphs (c) introductory text, (c)(1) introductory text, 

(c)(2) introductory text.

f. By revising paragraph (c)(5).

g. By adding paragraph (c)(9).

§ 600.116-12 Special procedures related to electric vehicles and hybrid electric 

vehicles.

(a) * * *

(5) We may approve alternate measurement procedures with respect to electric vehicles if 

they are necessary or appropriate for meeting the objectives of this part. For example, we 

may approve the use of an earlier version of SAE J1634 for carryover vehicles, or if you 

show that it is equivalent for your vehicle.

* * * * *
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(b) Determine performance values for hybrid electric vehicles that have no plug-in 

capability as specified in §§ 600.210 and 600.311 using the procedures for chargesustaining operation from SAE J1711 (incorporated by reference in § 600.011). We may

approve alternate measurement procedures with respect to these vehicles if that is 

necessary or appropriate for meeting the objectives of this part. For example, we may

approve alternate Net Energy Change tolerances for charge-sustaining operation as 

described in paragraph (c)(5) of this section.

(c) Determine performance values for hybrid electric vehicles that have plug-in capability

as specified in §§ 600.210 and 600.311 using the procedures of SAE J1711 (incorporated 

by reference in § 600.011), with the following clarifications and modifications:

(1) To determine fuel economy and CREE values to demonstrate compliance with CAFE 

and GHG standards, calculate composite values representing combined operation during 

charge-depleting and charge-sustaining operation using the following utility factors 

except as specified in this paragraph (c):

* * * * *

(2) To determine fuel economy and CO2 emission values for labeling purposes, calculate 

composite values representing combined operation during charge-depleting and chargesustaining operation using the following utility factors except as specified in this 

paragraph (c):

* * * * *

(5) The End-of-Test criterion is based on a 1 percent Net Energy Change as specified in 

Section 3.8 of SAE J1711. We may approve alternate Net Energy Change tolerances as 

specified in Section 3.9.1 or Appendix C of SAE J1711 if the 1 percent threshold is 

insufficient or inappropriate for marking the end of charge-depleting operation. For 

charge-sustaining tests, we may approve the use of alternate Net Energy Change 

tolerances as specified in Appendix C of SAE J1711 to correct final fuel economy values, 

CO2 emissions, and carbon-related exhaust emissions. For charge-sustaining tests, do not 

use alternate Net Energy Change tolerances to correct emissions of criteria pollutants. 

Additionally, if we approve an alternate End-of-Test criterion or Net Energy Change 

tolerances for a specific vehicle, we may use the alternate criterion or tolerances for any 

testing we conduct on that vehicle.

* * * * *

(9) The utility factors described in this paragraph (c) are derived from equations in SAE 

J2841. You may alternatively calculate utility factors directly from the corresponding 

equations in SAE J2841.

* * * * *

Subpart C—[Amended]

§§ 600.206-08, 600.207-08, 600.208 -08, 600.209-08, and 600.210-08 —[Removed]

217. Remove §§ 600.206-08, 600.207-08, 600.208-08, 600.209-08, and 600.210-08.

Subpart D—[Amended]

§§ 600.302-08 and 600.311-08 —[Removed]

218. Remove 600.302-08 and 600.311-08.

219. Section 600.311-12 is amended by revising paragraph (g) to read as follows:
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§ 600.311-12 Determination of values for fuel economy labels.

* * * * *

(g) Smog rating. Establish a rating for exhaust emissions other than CO2 based on the 

applicable emission standards for the appropriate model year as shown in Tables 1 

through 3 of this section. For Independent Commercial Importers that import vehicles not 

subject to Tier 2 or Tier 3 emission standards, the vehicle's smog rating is 1. Similarly, if 

a manufacturer certifies vehicles to emission standards that are less stringent than all the 

identified standards for any reason, the vehicle’s smog rating is 1. If EPA or California 

emission standards change in the future, we may revise the emission levels corresponding 

to each rating for future model years as appropriate to reflect the changed standards. If 

this occurs, we would publish the revised ratings as described in §600.302–12(k), 

allowing sufficient lead time to make the changes; we would also expect to initiate a 

rulemaking to update the smog rating in the regulation.

Table 1 of §600.311–12—Criteria for Establishing 

Smog Rating for Model Year 2025 and Later

Rating U.S. EPA Tier 3 Emission 

Standard

California Air Resources Board 

LEV III Emission Standard

1 Bin 160 LEV 160

2 Bin 125 ULEV125

4 Bin 70 ULEV70

5 Bin 50 ULEV50

6 Bin 30 SULEV30

7 Bin 20 SULEV20

10 Bin 0 ZEV

Table 2 of §600.311–12—Criteria for Establishing 

Smog Rating for Model Years 2018 -2024

Rating U.S. EPA Tier 3 

Emission Standard

U.S EPA Tier 2 

Emission Standard

California Air Resources Board 

LEV III Emission Standard

1 Bin 160 Bin 5 through Bin 8 LEV 160

3 Bin 125 Bin 4 ULEV125

5 Bin 70 Bin 3 ULEV70

6 Bin 50 — ULEV50

7 Bin 30 Bin 2 SULEV30

8 Bin 20 — SULEV20

10 Bin 0 Bin 1 ZEV
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Table 3 of §600.311–12—Criteria for Establishing 

Smog Rating through Model Year 2017

Rating U.S. EPA Tier 2 

Emission Standard

California Air Resources 

Board LEV II 

Emission Standard

California Air Resources 

Board LEV III 

Emission Standard

1 — ULEV & LEV II large 

trucks

2 Bin 8 SULEV II large trucks

3 Bin 7 —

4 Bin 6 LEV II, option 1

5 Bin 5 LEV II LEV160

6 Bin 4 ULEV II ULEV125

7 Bin 3 — ULEV70, ULEV50

8 Bin 2 SULEV II SULEV30

9 — PZEV SULEV20, PZEV

10 Bin 1 ZEV ZEV

* * * * *

Subpart F—[Amended]

§§ 600.507-08, 600.509-08, 600.510-08, and 600.512-08 —[Removed]

220. Remove §§ 600.507-08, 600.509-08, 600.510-08, and 600.512-08.

Appendix IV and Appendix V to Part 600—[Removed and reserved]

221. Remove and reserve Appendix IV and Appendix V to Part 600.

PART 1036—CONTROL OF EMISSIONS FROM NEW AND IN-USE HEAVYDUTY HIGHWAY ENGINES

222. The authority citation for part 1036 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart B—[Amended]

223. Section 1036.115 is amended by adding paragraph (b) to read as follows:

§ 1036.115 Other requirements.

* * * * *

(b) You must design and produce your engines to comply with evaporative emission 

standards as follows:

(1) For complete heavy-duty vehicles you produce, you must certify the vehicles to 

emission standards as specified in 40 CFR 1037.103.

(2) For incomplete heavy-duty vehicles, and for engines used in vehicles you do not 

produce, you do not need to certify your engines to evaporative emission standards or 

otherwise meet those standards. However, vehicle manufacturers certifying their 

vehicles with your engines may depend on you to produce your engines according to 

their specifications. Also, your engines must meet applicable exhaust emission 

standards in the installed configuration.

PART 1037—CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR 

VEHICLES 
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224. The authority citation for part 1037 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart B – [Amended]

225. Section 1037.101 is amended by revising paragraph (b)(4) and adding paragraph 

(c)(3) to read as follows:

§ 1037.101 Overview of emission standards for heavy-duty vehicles.

* * * * *

(b) * * *

(4) Fuel evaporative emissions. These requirements are described in 40 CFR part 86 and 

§1037.103.

(c) * * *

(3) For evaporative and refueling emissions, vehicles are regulated based on the type of 

fuel they use. Vehicles fueled with volatile liquid fuels or gaseous fuels are subject to 

evaporative emission standards. Vehicles up to a certain size that are fueled with 

gasoline, diesel fuel, ethanol, methanol, or LPG are subject to refueling emission 

standards. 

226. A new §1037.103 is added to read as follows:

§ 1037.103 Evaporative emission standards. 

(a) Applicability. Evaporative emission standards apply to heavy-duty vehicles as 

follows: 

(1) Complete and incomplete heavy-duty vehicles at or below 14,000 pounds GVWR 

must meet evaporative and refueling emission standards as specified in 40 CFR part 

86, subpart S, instead of the requirements specified in this section. 

(2) Heavy-duty vehicles above 14,000 pounds GVWR that run on volatile liquid fuel 

(such as gasoline or ethanol) or gaseous fuel (such as natural gas or LPG) must meet 

evaporative and refueling emission standards as specified in this section. 

(b) Emission standards. The evaporative and refueling emission standards and 

measurement procedures specified in 40 CFR 86.1813 apply for vehicles above 14,000 

pounds GVWR, except as described in this section. The evaporative emission standards 

phase in over model years 2018 through 2022, with provisions allowing for voluntary

compliance with the standards as early as model year 2015. Count vehicles subject to 

standards under this section the same as heavy-duty vehicles at or below 14,000 pounds 

GVWR to comply with the phase-in requirements specified in 40 CFR 86.1813. These 

vehicles may generate and use emission credits as described in 40 CFR part 86, subpart 

S, but only for vehicles that are tested for certification instead of relying on the provisions 

of paragraph (c) of this section. The following provisions apply instead of what is 

specified in 40 CFR 86.1813:

(1) The refueling standards in 40 CFR 86.1813(b) apply to complete vehicles starting 

in model year 2022; they are optional for incomplete vehicles.

(2) The leak standard in 40 CFR 86.1813(a)(4) does not apply.

(3) The FEL cap relative to the diurnal plus hot soak standard for low-altitude testing 

is 1.9 grams per test.

(4) The diurnal plus hot soak standard for high-altitude testing is 2.3 grams per test.
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(5) Testing does not require measurement of exhaust emissions. Disregard references 

in subpart B of this part to procedures, equipment specifications, and recordkeeping 

related to measuring exhaust emissions. All references to the exhaust test under 40 

CFR part 86, subpart B, are considered the “dynamometer run” as part of the 

evaporative testing sequence under this subpart.

(6) Vehicles not yet subject to the Tier 3 standards in 40 CFR 86.1813 must meet 

evaporative emission standards as specified in §§86.008-10(b) and 86.007-11(b)(3) 

and (4).

(c) Compliance demonstration. You may provide a statement in the application for 

certification that vehicles above 14,000 pounds GVWR comply with evaporative and 

refueling emission standards instead of submitting test data if you include an engineering 

analysis describing how vehicles include design parameters, equipment, operating 

controls, or other elements of design that adequately demonstrate that vehicles comply

with the standards. We would expect emission control components and systems to 

exhibit a comparable degree of control relative to vehicles that comply based on testing. 

For example, vehicles that comply under this paragraph (c) should rely on comparable 

material specifications to limit fuel permeation, and components should be sized and 

calibrated to correspond with the appropriate fuel capacities, fuel flow rates, purge 

strategies, and other vehicle operating characteristics. You may alternatively show that 

design parameters are comparable to those for vehicles at or below 14,000 pounds 

GVWR certified under 40 CFR part 86, subpart S.

(d) CNG refueling requirement. Compressed natural gas vehicles must meet the 

requirements for fueling connection devices as specified in 40 CFR 86.1813-17(f)(1). 

Vehicles meeting these requirements are deemed to comply with evaporative and 

refueling emission standards.

(e) Incomplete vehicles. If you sell incomplete vehicles, you must identify the maximum 

fuel tank capacity for which you designed the vehicle’s evaporative emission control 

system. 

(f) Useful life. Your vehicles must meet the evaporative emission standards of this 

section throughout their useful life, expressed in service miles or calendar years, 

whichever comes first. The useful life values for the standards of this section are those 

that apply for criteria pollutants under 40 CFR part 86.

(g) Auxiliary engines and separate fuel systems. The provisions of this paragraph (g) 

apply for vehicles with auxiliary engines. This includes any engines installed in the final 

vehicle configuration that contribute no motive power through the vehicle’s transmission. 

(1) Auxiliary engines and associated fuel-system components must be installed when 

testing complete vehicles. If the auxiliary engine draws fuel from a separate fuel 

tank, you must fill the extra fuel tank before the start of diurnal testing as described 

for the vehicle’s main fuel tank. Use good engineering judgment to ensure that any 

nonmetal portions of the fuel system related to the auxiliary engine have reached 

stabilized levels of permeation emissions. The auxiliary engine must not operate 

during the running loss test or any other portion of testing under this section.

(2) For testing with incomplete vehicles, you may omit installation of auxiliary 

engines and associated fuel-system components as long as those components installed 

in the final configuration are certified to meet the applicable emission standards for 

Small SI equipment described in 40 CFR 1054.112 or for Large SI engines in 40 CFR 
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1048.105. For any fuel-system components that you do not install, your installation 

instructions must describe this certification requirement.

227. Section 1037.104 is amended by adding paragraph (h)(2) to read as follows:

§ 1037.104 Exhaust emission standards for CO2, CH4, and N2O for heavy-duty 

vehicles at or below 14,000 pounds GVWR.

* * * * *

(h) * * *

(2) The evaporative and refueling emission standards in §1037.103.

* * * * *

Subpart C—[Amended]

228. Section 1037.230 is amended by adding paragraph (e) to read as follows:

§ 1037.230 Vehicle families, sub-families, and configurations.

* * * * *

(e) Divide your vehicles that are subject to evaporative emission standards into groups of 

vehicles with similar physical features expected to affect evaporative emissions. Group 

vehicles in the same evaporative emission family if they are the same in all the following 

aspects, unless we approve a better way of grouping vehicles into families that have 

similar emission control characteristics:

(1) Method of vapor storage, including the number of vapor storage devices, the 

working material, and the total working capacity of vapor storage (as determined 

under 40 CFR 86.132-96(h)(1)(iv)). You may consider the working capacity to be 

the same if the values differ by 20 grams or less.

(2) Method of purging stored vapors.

(3) Material for liquid and vapor fuel lines.

* * * * *

229. A new §1037.243 is added to subpart C to read as follows:

§1037.243 Demonstrating compliance with evaporative emission standards.

(a) For purposes of certification, your vehicle family is considered in compliance with the 

evaporative emission standards in subpart B of this part if you prepare an engineering 

analysis showing that your vehicles in the family will comply with applicable standards 

throughout the useful life, and there are no test results from an emission-data vehicle 

representing the family that exceed an emission standard.

(b) Your evaporative emission family is deemed not to comply if your engineering 

analysis is not adequate to show that all the vehicles in the family will comply with 

applicable emission standards throughout the useful life, or if a test result from an 

emission-data vehicle representing the family exceeds an emission standard.

(c) To compare emission levels with emission standards, apply deterioration factors to the 

measured emission levels. Establish an additive deterioration factor based on an 

engineering analysis that takes into account the expected aging from in-use vehicles. 

(d) Apply the deterioration factor to the official emission result, as described in paragraph 

(c) of this section, then round the adjusted figure to the same number of decimal places as 

the emission standard. Compare the rounded emission levels to the emission standard for 

each emission-data vehicle. 
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(e) Your analysis to demonstrate compliance with emission standards must take into 

account your design strategy for vehicles that require testing. Specifically, vehicles 

above 14,000 pounds GVWR are presumed to need the same technologies that are 

required for heavy-duty vehicles at or below 14,000 pounds GVWR. Similarly, your 

analysis to establish a deterioration factor must take into account your testing to establish 

deterioration factors for smaller vehicles.

Subpart F—[Amended]

230. Section 1037.501 is amended by adding paragraph (a) to read as follows:

§ 1037.501 General testing and modeling provisions.

* * * * *

(a) Use the equipment and procedures specified in §1037.530 to determine whether 

vehicles meet the diurnal, running loss, and hot soak emission standards specified in 

§ 1037.103. 

* * * * *

PART 1039—CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD 

COMPRESSION-IGNITION ENGINES

231. The authority citation for part 1039 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart F—[Amended]

232. Section 1039.505 is revised to read as follows:

§1039.505 How do I test engines using steady-state duty cycles, including rampedmodal testing?

This section describes how to test engines under steady-state conditions. In some cases, 

we allow you to choose the appropriate steady-state duty cycle for an engine; you may

also choose between discrete-mode and ramped-modal testing. In all cases, you must use 

the duty cycle you select in your application for certification for all testing you perform 

for that engine family. If we test your engines to confirm that they meet emission 

standards, we will use the duty cycle you select for your own testing. If you submit 

certification test data using more than one duty cycle, any of the selected duty cycles may

be used for any subsequent testing. We may also perform other testing as allowed by the 

Clean Air Act.

(a) You may perform steady-state testing with either discrete-mode or ramped-modal 

cycles as described in 40 CFR part 1065.

(b) Measure emissions by testing the engine on a dynamometer with one of the following 

duty cycles to determine whether it meets the steady-state emission standards in 

§1039.101(b):

(1) Use the 5-mode duty cycle or the corresponding ramped-modal cycle described in 

paragraph (a) of Appendix II of this part for constant-speed engines. Note that these 

cycles do not apply to all engines used in constant-speed applications, as described in 

§1039.801.

(2) Use the 6-mode duty cycle or the corresponding ramped-modal cycle described in 

paragraph (b) of Appendix II of this part for variable-speed engines below 19 kW. 
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You may instead use the 8-mode duty cycle or the corresponding ramped-modal cycle 

described in appendix IV of this part if some engines from your engine family will be 

used in applications that do not involve governing to maintain engine operation 

around rated speed.

(3) Use the 8-mode duty cycle or the corresponding ramped-modal cycle described in 

paragraph (c) of Appendix II of this part for variable-speed engines at or above 19 

kW.

(c) For constant-speed engines whose design prevents full-load operation for extended 

periods, you may ask for approval under 40 CFR 1065.10(c) to replace full-load

operation with the maximum load for which the engine is designed to operate for 

extended periods.

(d) To allow non-motoring dynamometers on cycles with idle, you may omit additional 

points from the duty-cycle regression as follows:

(1) For variable-speed engines with low-speed governors, you may omit speed, 

torque, and power points from the duty-cycle regression statistics if the following are 

met:

(i) The engine operator demand is at its minimum.

(ii) The dynamometer demand is at its minimum.

(iii) It is an idle point fnref = 0 % (idle) and Tref = 0 % (idle).

(iv) Tref < T ≤ 5 % · Tmaxmapped.

(2) For variable-speed engines without low-speed governors, you may omit torque 

and power points from the duty-cycle regression statistics if the following are met:

(i) The dynamometer demand is at its minimum.

(ii) It is an idle point fnref = 0 % (idle) and Tref = 0 % (idle).

(iii) fnref − (2 % · fntest) < fn < fnref + (2 % · fntest).

(iv) Tref < T ≤ 5 % · Tmaxmapped.

§1039.510—[Amended]

233. Section 1039.510 is amended by removing paragraph (c).

Part 1042— Control of Emissions from New and In-use Marine Compressionignition Engines and Vessels

234. The authority citation for part 1042 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart F—[Amended]

235. Section 1042.505 is revised to read as follows:

§1042.505 Testing engines using discrete-mode or ramped-modal duty cycles.

This section describes how to test engines under steady-state conditions. In some cases, 

we allow you to choose the appropriate steady-state duty cycle for an engine; you may

also choose between discrete-mode and ramped-modal testing. In all cases, you must use 

the duty cycle you select in your application for certification for all testing you perform 

for that engine family. If we test your engines to confirm that they meet emission 

standards, we will use the duty cycles you select for your own testing. If you submit 

certification test data using more than one duty cycle, any of the selected duty cycles may
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be used for any subsequent testing. We may also perform other testing as allowed by the 

Clean Air Act.

(a) You may perform steady-state testing with either discrete-mode or ramped-modal 

cycles as described in 40 CFR part 1065.

(b) Measure emissions by testing the engine on a dynamometer with one of the following 

duty cycles (as specified) to determine whether it meets the emission standards in 

§§1042.101 or 1042.104:

(1) General cycle. Use the 4-mode duty cycle or the corresponding ramped-modal 

cycle described in paragraph (a) of Appendix II of this part for commercial 

propulsion marine engines that are used with (or intended to be used with) fixed-pitch 

propellers, propeller-law auxiliary engines, and any other engines for which the other 

duty cycles of this section do not apply. Use this duty cycle also for commercial 

variable-speed propulsion marine engines that are used with (or intended to be used 

with) controllable-pitch propellers or with electrically coupled propellers, unless these 

engines are not intended for sustained operation (e.g., for at least 30 minutes) at all 

four modes when installed in the vessel.

(2) Recreational marine engines. Except as specified in paragraph (b)(3) of this 

section, use the 5-mode duty cycle or the corresponding ramped-modal cycle 

described in paragraph (b) of Appendix II of this part for recreational marine engines 

with maximum engine power at or above 37 kW.

(3) Controllable-pitch and electrically coupled propellers. Use the 4-mode duty cycle 

or the corresponding ramped-modal cycle described in paragraph (c) of Appendix II 

of this part for constant-speed propulsion marine engines that are used with (or 

intended to be used with) controllable-pitch propellers or with electrically coupled 

propellers. Use this duty cycle also for variable-speed propulsion marine engines that 

are used with (or intended to be used with) controllable-pitch propellers or with 

electrically coupled propellers if the duty cycles in paragraph (b)(1) and (b)(2) of this 

section do not apply.

(4) Constant-speed auxiliary engines. Use the 5-mode duty cycle or the corresponding 

ramped-modal cycle described in 40 CFR part 1039, Appendix II, paragraph (a) for 

constant-speed auxiliary engines.

(5) Variable-speed auxiliary engines. (i) Use the duty cycle specified in paragraph 

(b)(1) of this section for propeller-law auxiliary engines.

(ii) Use the 6-mode duty cycle or the corresponding ramped-modal cycle 

described in 40 CFR part 1039, Appendix II, paragraph (b) for variable-speed 

auxiliary engines with maximum engine power below 19 kW that are not 

propeller-law engines.

(iii) Use the 8-mode duty cycle or the corresponding ramped-modal cycle 

described in 40 CFR part 1039, Appendix III, paragraph (c) for variable-speed 

auxiliary engines with maximum engine power at or above 19 kW that are not 

propeller-law engines.

(c) For constant-speed engines whose design prevents full-load operation for extended 

periods, you may ask for approval under 40 CFR 1065.10(c) to replace full-load 

operation with the maximum load for which the engine is designed to operate for 

extended periods.
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Part 1048— Control of Emissions from New, Large Nonroad Spark-ignition 

Engines

236. The authority citation for part 1048 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart F—[Amended]

237. Section 1048.505 is amended by revising the introductory text and paragraphs 

(a) and (c) and removing paragraphs (d) through (g) to read as follows:

§1048.505 How do I test engines using steady-state duty cycles, including rampedmodal testing?

This section describes how to test engines under steady-state conditions. In some cases, 

we allow you to choose the appropriate steady-state duty cycle for an engine; you may

also choose between discrete-mode and ramped-modal testing. In all cases, you must use 

the duty cycle you select in your application for certification for all testing you perform 

for that engine family. If we test your engines to confirm that they meet emission 

standards, we will use the duty cycles you select for your own testing. If you submit 

certification test data using more than one duty cycle, any of the selected duty cycles may

be used for any subsequent testing. We may also perform other testing as allowed by the 

Clean Air Act.

(a) You may perform steady-state testing with either discrete-mode or ramped-modal 

cycles described in 40 CFR part 1065.

* * * * *

(c) For full-load operating modes, operate the engine at wide-open throttle.

Part 1054— Control of Emissions from New, Small Nonroad Spark-ignition Engines 

and Equipment

238. The authority citation for part 1054 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart F—[Amended]

239. Section 1054.505 is amended by revising paragraph (a) and removing paragraph 

(e) to read as follows:

§1054.505 How do I test engines?

(a) This section describes how to test engines under steady-state conditions. For handheld 

engines you must perform tests with discrete-mode sampling. For nonhandheld engines 

we allow you to perform tests with either discrete-mode or ramped-modal testing 

methods, as described in 40 CFR part 1065. You must use the same modal testing method 

for certification and all other testing you perform for an engine family. If we test your 

engines to confirm that they meet emission standards, we will use the modal testing 

method you select for your own testing. If you submit certification test data collected 

with both discrete-mode and ramped-modal testing (either in your original application or 

in an amendment to your application), either method may be used for subsequent testing. 

We may also perform other testing as allowed by the Clean Air Act. Conduct duty-cycle 

testing as follows:

(1) For discrete-mode testing, sample emissions separately for each mode, then 

calculate an average emission level for the whole cycle using the weighting factors 
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specified for each mode. Control engine speed as specified in this section. Use one of 

the following methods for confirming torque values for nonhandheld engines:

(i) Calculate torque-related cycle statistics and compare with the established 

criteria as specified in 40 CFR 1065.514 to confirm that the test is valid.

(ii) Evaluate each mode separately to validate the duty cycle. All torque feedback 

values recorded during non-idle sampling periods must be within ±2 percent of 

the reference value or within ±0.27 N·m of the reference value, whichever is 

greater. Also, the mean torque value during non-idle sampling periods must be 

within ±1 percent of the reference value or ±0.12 N·m of the reference value, 

whichever is greater. Control torque during idle as specified in paragraph (c) of 

this section.

(2) Unless we specify otherwise, you may simulate the governor for ramped-modal 

testing consistent with good engineering judgment.

* * * * *

PART 1065—ENGINE-TESTING PROCEDURES

240. The authority citation for part 1065 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart A—[Amended]

241. Section 1065.1 is amended by revising paragraph (h) to read as follows:

§1065.1 Applicability.

* * * * *

(h) This part describes procedures and specifications for measuring an engine’s exhaust 

emissions. While the measurements are geared toward engine-based measurements (in 

units of g/kW·hr), many of these provisions apply equally to vehicle-based measurements 

(in units of g/mile or g/kilometer). 40 CFR part 1066 describes the analogous procedures 

for vehicle-based emission measurements, and in many cases states that specific 

provisions of this part 1065 also apply for those vehicle-based measurements. Where 

material from this part 1065 applies for vehicle-based measurements under 40 CFR part 

1066, it is sometimes necessary to include parenthetical statements in this part 1065 to 

properly cite secondary references that are different for vehicle-based testing. See 40 

CFR part 1066 and the standard-setting part for additional information.

242. Section 1065.2 is amended by revising paragraphs (d) and (e) to read as follows:

§1065.2 Submitting information to EPA under this part.

* * * * *

(d) We may require an authorized representative of your company to approve and sign 

the submission, and to certify that all the information submitted is accurate and complete. 

This includes everyone who submits information, including manufacturers and others.

(e) See 40 CFR 1068.10 for provisions related to confidential information. Note however 

that under 40 CFR 2.301, emission data are generally not eligible for confidential 

treatment.

* * * * *
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243. Section 1065.10 is amended by revising paragraphs (a) and (c)(7) introductory

text and adding a paragraph heading to paragraph (d) to read as follows:

§1065.10 Other procedures.

(a) Your testing. The procedures in this part apply for all testing you do to show 

compliance with emission standards, with certain exceptions noted in this section. In 

some other sections in this part, we allow you to use other procedures (such as less 

precise or less accurate procedures) if they do not affect your ability to show that your 

engines comply with the applicable emission standards. This generally requires emission 

levels to be far enough below the applicable emission standards so that any errors caused 

by greater imprecision or inaccuracy do not affect your ability to state unconditionally

that the engines meet all applicable emission standards.

* * * * *

(c) * * *

(7) You may request to use alternate procedures that are equivalent to the specified

procedures, or procedures that are more accurate or more precise than the specified

procedures. We may perform tests with your engines using either the approved alternate 

procedures or the specified procedures. The following provisions apply to requests for 

alternate procedures:

* * * * *

(d) Advance approval. If we require you to request approval to use other procedures 

under paragraph (c) of this section, you may not use them until we approve your request.

244. Section 1065.12 is amended by revising paragraphs (a), (d) introductory text, and 

(e) introductory text to read as follows:

§1065.12 Approval of alternate procedures.

(a) To get approval for an alternate procedure under §1065.10(c), send the Designated 

Compliance Officer an initial written request describing the alternate procedure and why 

you believe it is equivalent to the specified procedure. Anyone may request alternate 

procedure approval. This means that an individual engine manufacturer may request to 

use an alternate procedure. This also means that an instrument manufacturer may request 

to have an instrument, equipment, or procedure approved as an alternate procedure to 

those specified in this part. We may approve your request based on this information 

alone, whether or not it includes all the information specified in this section. Where we 

determine that your original submission does not include enough information for us to 

determine that the alternate procedure is equivalent to the specified procedure, we may

ask you to submit supplemental information showing that your alternate procedure is 

consistently and reliably at least as accurate and repeatable as the specified procedure.

* * * * *

(d) If we do not approve your proposed alternate procedure based on the information in 

your initial request, we may ask you to send additional information to fully evaluate your 

request. While we consider the information specified in this paragraph (d) and the 

statistical criteria of paragraph (e) of this section to be sufficient to demonstrate 

equivalence, it may not be necessary to include all the information or meet the specified 

statistical criteria. For example, systems that do not meet the statistical criteria in 

paragraph (e) of this section because they have a small bias toward high emission results 
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could be approved since they would not adversely affect your ability to demonstrate 

compliance with applicable standards.

* * * * *

(e) Absent any other directions from us, use a t-test and an F-test calculated according to 

§1065.602 to evaluate whether your proposed alternate procedure is equivalent to the 

specified procedure. We may give you specific directions regarding methods for 

statistical analysis, or we may approve other methods that you propose. Such alternate 

methods may be more or less stringent than those specified in this paragraph (e). In 

determining the appropriate statistical criteria, we will consider the repeatability of 

measurements made with the reference procedure. For example, less stringent statistical 

criteria may be appropriate for measuring emission levels being so low that they

adversely affect the repeatability of reference measurements. We recommend that you 

consult a statistician if you are unfamiliar with these statistical tests. Perform the tests as 

follows:

* * * * *

245. Section 1065.15 is amended by revising paragraphs (a), (b), and (c)(2)(ii) to read 

as follows:

§1065.15 Overview of procedures for laboratory and field testing.

* * * * *

(a) In the standard-setting part, we set brake-specific emission standards in g/(kW·hr) (or 

g/(hp·hr)), for the following constituents:

(1) Total oxides of nitrogen, NOx.

(2) Hydrocarbons, HC, which may be expressed in the following ways:

(i) Total hydrocarbons, THC.

(ii) Nonmethane hydrocarbons, NMHC, which results from subtracting methane, CH4,

from THC.

(iii) Total hydrocarbon-equivalent, THCE, which results from adjusting THC 

mathematically to be equivalent on a carbon-mass basis.

(iv) Nonmethane hydrocarbon-equivalent, NMHCE, which results from adjusting NMHC 

mathematically to be equivalent on a carbon-mass basis.

(3) Particulate matter, PM.

(4) Carbon monoxide, CO.

(5) Carbon dioxide, CO2.

(6) Methane, CH4.

(7) Nitrous oxide, N2O.

(b) Note that some engines are not subject to standards for all the emission constituents 

identified in paragraph (a) of this section. Note also that the standard-setting part may

include standards for pollutants not listed in paragraph (a) of this section.

(c) * * *

(2) * * *

(ii) Batch sampling. In batch sampling, continuously extract and store a sample of raw or 

dilute exhaust for later measurement. Extract a sample proportional to the raw or dilute 

exhaust flow rate. You may extract and store a proportional sample of exhaust in an 

appropriate container, such as a bag, and then measure NOx, HC, CO, CO2, CH4, N2O, 

and CH2O concentrations in the container after the test interval. You may deposit PM 
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from proportionally extracted exhaust onto an appropriate substrate, such as a filter. In 

this case, divide the PM by the amount of filtered exhaust to calculate the PM 

concentration. Multiply batch sampled concentrations by the total (raw or dilute) flow 

from which it was extracted during the test interval. This product is the total mass of the 

emitted constituent.

* * * * *

246. Section 1065.20 is amended by revising paragraphs (a)(3), (b) introductory text, 

(c), (f)(1) and (g) to read as follows:

§1065.20 Units of measure and overview of calculations.

(a) * * *

(3) We generally designate temperatures in units of degrees Celsius (°C) unless a

calculation requires an absolute temperature. In that case, we designate temperatures in 

units of Kelvin (K). For conversion purposes throughout this part, 0 °C equals 273.15 K. 

Unless specified otherwise, always use absolute temperature values for multiplying or 

dividing by temperature.

(b) Concentrations. This part does not rely on amounts expressed in parts per million. 

Rather, we express such amounts in the following SI units:

* * * * *

(c) Absolute pressure. Measure absolute pressure directly or calculate it as the sum of 

atmospheric pressure plus a differential pressure that is referenced to atmospheric 

pressure. Always use absolute pressure values for multiplying or dividing by pressure.

* * * * *

(f) * * *

(1) Whenever we specify a range by a single value and corresponding limit values above 

and below that value (such as X ±Y), target the associated control point to that single 

value (X). Examples of this type of range include “±10 % of maximum pressure”, or 

“(30 ±10) kPa”. In these examples, you would target the maximum pressure or 30 kPa, 

respectively.

* * * * *

(g) Scaling of specifications with respect to an applicable standard. Because this part 

1065 is applicable to a wide range of engines and emission standards, some of the 

specifications in this part are scaled with respect to an engine’s applicable standard or 

maximum power. This ensures that the specification will be adequate to determine 

compliance, but not overly burdensome by requiring unnecessarily high-precision 

equipment. Many of these specifications are given with respect to a “flow-weighted 

mean” that is expected at the standard or during testing. Flow-weighted mean is the 

mean of a quantity after it is weighted proportional to a corresponding flow rate. For 

example, if a gas concentration is measured continuously from the raw exhaust of an 

engine, its flow-weighted mean concentration is the sum of the products (dry-to-wet 

corrected, if applicable) of each recorded concentration times its respective exhaust flow 

rate, divided by the sum of the recorded flow rates. As another example, the bag 

concentration from a CVS system is the same as the flow-weighted mean concentration, 

because the CVS system itself flow-weights the bag concentration. Refer to §1065.602 

for information needed to estimate and calculate flow-weighted means. Wherever a 

specification is scaled to a value based upon an applicable standard, interpret the standard 
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to be the family emission limit if the engine is certified under an emission credit program 

in the standard-setting part.

247. Section 1065.25 is revised to read as follows:

§1065.25 Recordkeeping.

(a) The procedures in this part include various requirements to record data or other 

information. Refer to the standard-setting part and §1065.695 regarding specific 

recordkeeping requirements.

(b) You must promptly send us organized, written records in English if we ask for them. 

We may review them at any time.

(c) We may waive specific reporting or recordkeeping requirements we determine to be 

unnecessary for the purposes of this part and the standard-setting part. Note that while 

we will generally keep the records required by this part, we are not obligated to keep 

records we determine to be unnecessary for us to keep. For example, while we require 

you to keep records for invalid tests so that we may verify that your invalidation was 

appropriate, it is not necessary for us to keep records for our own invalid tests. 

Subpart B—[Amended]

248. Section 1065.130 is amended by revising paragraphs (a) and (c)(6) to read as 

follows:

§1065.130 Engine exhaust.

(a) General. Use the exhaust system installed with the engine or one that represents a 

typical in-use configuration. This includes any applicable aftertreatment devices. We 

refer to exhaust piping as an exhaust stack; this is equivalent to a tailpipe for vehicle 

configurations.

* * * * *

(c) * * *

(6) We recommend that you connect multiple exhaust stacks from a single engine into 

one stack upstream of any emission sampling. For raw or dilute partial-flow emission

sampling, to ensure mixing of the multiple exhaust streams before emission sampling, we 

recommend a minimum Reynolds number, Re#, of 4000 for the combined exhaust stream, 

where Re#is based on the inside diameter of the combined flow at the first sampling 

point. You may configure the exhaust system with turbulence generators, such as orifice 

plates or fins, to achieve good mixing; inclusion of turbulence generators may be required 

for Re#less than 4000 to ensure good mixing. Re#is defined in §1065.640. For dilute 

full-flow (CVS) emission sampling, you may configure the exhaust system without 

regard to mixing in the laboratory section of the raw exhaust. For example you may size 

the laboratory section to reduce its pressure drop even if the Re#in the laboratory section 

of the raw exhaust is less than 4000.

* * * * *

249. Section 1065.140 is revised to read as follows:

§1065.140 Dilution for gaseous and PM constituents.

(a) General. You may dilute exhaust with ambient air, purified air, or nitrogen. 

References in this part to “dilution air” may include any of these. For gaseous emission 
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measurement, the dilution air must be at least 15 °C. Note that the composition of the 

dilution air affects some gaseous emission measurement instruments’ response to 

emissions. We recommend diluting exhaust at a location as close as possible to the 

location where ambient air dilution would occur in use. Dilution may occur in a single 

stage or in multiple stages. For dilution in multiple stages, the first stage is considered 

primary dilution and later stages are considered secondary dilution.

(b) Dilution-air conditions and background concentrations. Before dilution air is mixed 

with exhaust, you may precondition it by increasing or decreasing its temperature or 

humidity. You may also remove constituents to reduce their background concentrations. 

The following provisions apply to removing constituents or accounting for background 

concentrations:

(1) You may measure constituent concentrations in the dilution air and compensate for 

background effects on test results. See §1065.650 for calculations that compensate for 

background concentrations (40 CFR 1066.610 for vehicle testing).

(2) Measure these background concentrations the same way you measure diluted exhaust 

constituents, or measure them in a way that does not affect your ability to demonstrate 

compliance with the applicable standards. For example, you may use the following 

simplifications for background sampling:

(i) You may disregard any proportional sampling requirements.

(ii) You may use unheated gaseous sampling systems.

(iii) You may use unheated PM sampling systems.

(iv) You may use continuous sampling if you use batch sampling for diluted emissions.

(v) You may use batch sampling if you use continuous sampling for diluted emissions.

(3) For removing background PM, we recommend that you filter all dilution air, 

including primary full-flow dilution air, with high-efficiency particulate air (HEPA) 

filters that have an initial minimum collection efficiency specification of 99.97 % (see 

§1065.1001 for procedures related to HEPA-filtration efficiencies). Ensure that HEPA 

filters are installed properly so that background PM does not leak past the HEPA filters. 

If you choose to correct for background PM without using HEPA filtration, demonstrate 

that the background PM in the dilution air contributes less than 50 % to the net PM 

collected on the sample filter. You may correct net PM without restriction if you use 

HEPA filtration.

(c) Full-flow dilution; constant-volume sampling (CVS). You may dilute the full flow of 

raw exhaust in a dilution tunnel that maintains a nominally constant volume flow rate, 

molar flow rate or mass flow rate of diluted exhaust, as follows:

(1) Construction. Use a tunnel with inside surfaces of 300 series stainless steel. 

Electrically ground the entire dilution tunnel. We recommend a thin-walled and insulated 

dilution tunnel to minimize temperature differences between the wall and the exhaust 

gases. You may not use any flexible tubing in the dilution tunnel upstream of the PM 

sample probe. You may use nonconductive flexible tubing downstream of the PM 

sample probe and upstream of the CVS flow meter; use good engineering judgment to 

select a tubing material that is not prone to leaks, and configure the tubing to ensure 

smooth flow at the CVS flow meter. 

(2) Pressure control. Maintain static pressure at the location where raw exhaust is 

introduced into the tunnel within ±1.2 kPa of atmospheric pressure. You may use a 

booster blower to control this pressure. If you test using more careful pressure control 
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and you show by engineering analysis or by test data that you require this level of control 

to demonstrate compliance at the applicable standards, we will maintain the same level of 

static pressure control when we test.

(3) Mixing. Introduce raw exhaust into the tunnel by directing it downstream along the 

centerline of the tunnel. If you dilute directly from the exhaust stack, the end of the 

exhaust stack is considered to be the start of the dilution tunnel. You may introduce a 

fraction of dilution air radially from the tunnel’s inner surface to minimize exhaust 

interaction with the tunnel walls. You may configure the system with turbulence 

generators such as orifice plates or fins to achieve good mixing. We recommend a 

minimum Reynolds number, Re#, of 4000 for the diluted exhaust stream, where Re#is 

based on the inside diameter of the dilution tunnel. Re#is defined in §1065.640.

(4) Flow measurement preconditioning. You may condition the diluted exhaust before 

measuring its flow rate, as long as this conditioning takes place downstream of any

heated HC or PM sample probes, as follows:

(i) You may use flow straighteners, pulsation dampeners, or both of these.

(ii) You may use a filter.

(iii) You may use a heat exchanger to control the temperature upstream of any flow 

meter, but you must take steps to prevent aqueous condensation as described in paragraph 

(c)(6) of this section.

(5) Flow measurement. Section 1065.240 describes measurement instruments for diluted 

exhaust flow.

(6) Aqueous condensation. This paragraph (c)(6) describes how you must address 

aqueous condensation in the CVS. As described below, you may meet these 

requirements by preventing or limiting aqueous condensation in the CVS from the 

exhaust inlet to the last emission sample probe. See that paragraph for provisions related 

to the CVS between the last emission sample probe and the CVS flow meter. You may

heat and/or insulate the dilution tunnel walls, as well as the bulk stream tubing 

downstream of the tunnel to prevent or limit aqueous condensation. Where we allow 

aqueous condensation to occur, use good engineering judgment to ensure that the 

condensation does not affect your ability to demonstrate that your engines comply with 

the applicable standards (see §1065.10(a)).

(i) Preventing aqueous condensation. To prevent condensation, you must keep the 

temperature of internal surfaces, excluding any sample probes, above the dew point of the 

dilute exhaust passing through the CVS tunnel. Use good engineering judgment to 

monitor temperatures in the CVS. For the purposes of this paragraph (c)(6), assume that 

aqueous condensation is pure water condensate only, even though the definition of 

“aqueous condensation” in §1065.1001 includes condensation of any constituents that 

contain water. No specific verification check is required under this paragraph (c)(6)(i), 

but we may ask you to show how you comply with this requirement. You may use 

engineering analysis, CVS tunnel design, alarm systems, measurements of wall 

temperatures, and calculation of water dew point to demonstrate compliance with this 

requirement. For optional CVS heat exchangers, you may use the lowest water 

temperature at the inlet(s) and outlet(s) to determine the minimum internal surface 

temperature. 
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(ii) Limiting aqueous condensation. This paragraph (c)(6)(ii) specifies limits of 

allowable condensation and requires you to verify that the amount of condensation that 

occurs during each test interval does not exceed the specified limits.

(A) Use chemical balance equations in §1065.655 to calculate the mole fraction of water 

in the dilute exhaust continuously during testing. Alternatively, you may continuously

measure the mole fraction of water in the dilute exhaust prior to any condensation during 

testing. Use good engineering judgment to select, calibrate and verify water 

analyzers/detectors. The linearity verification requirements of §1065.307 do not apply to 

water analyzers/detectors used to correct for the water content in exhaust samples.

(B) Use good engineering judgment to select and monitor locations on the CVS tunnel 

walls prior to the last emission sample probe. If you are also verifying limited 

condensation from the last emission sample probe to the CVS flow meter, use good 

engineering judgment to select and monitor locations on the CVS tunnel walls, optional 

CVS heat exchanger, and CVS flow meter. For optional CVS heat exchangers, you may 

use the lowest water temperature at the inlet(s) and outlet(s) to determine the minimum 

internal surface temperature. Identify the minimum surface temperature on a continuous 

basis. 

(C) Identify the maximum potential mole fraction of dilute exhaust lost on a continuous 

basis during the entire test interval. This value must be less than or equal to 0.02. 

Calculate on a continuous basis the mole fraction of water that would be in equilibrium 

with liquid water at the measured minimum surface temperature. Subtract this mole 

fraction from the mole fraction of water that would be in the exhaust without 

condensation (either measured or from the chemical balance), and set any negative values 

to zero. This difference is the potential mole fraction of the dilute exhaust that would be 

lost due to water condensation on a continuous basis.

(D) Integrate the product of the molar flow rate of the dilute exhaust and the potential 

mole fraction of dilute exhaust lost, and divide by the totalized dilute exhaust molar flow 

over the test interval. This is the potential mole fraction of the dilute exhaust that would 

be lost due to water condensation over the entire test interval. Note that this assumes no 

re-evaporation. This value must be less than or equal to 0.005.

(7) Flow compensation. Maintain nominally constant molar, volumetric or mass flow of 

diluted exhaust. You may maintain nominally constant flow by either maintaining the 

temperature and pressure at the flow meter or by directly controlling the flow of diluted 

exhaust. You may also directly control the flow of proportional samplers to maintain 

proportional sampling. For an individual test, verify proportional sampling as described 

in §1065.545.

(d) Partial-flow dilution (PFD). You may dilute a partial flow of raw or previously

diluted exhaust before measuring emissions. Section 1065.240 describes PFD-related 

flow measurement instruments. PFD may consist of constant or varying dilution ratios as 

described in paragraphs (d)(2) and (3) of this section. An example of a constant dilution 

ratio PFD is a “secondary dilution PM” measurement system.

(1) Applicability. (i) You may use PFD to extract a proportional raw exhaust sample for 

any batch or continuous PM emission sampling over any transient duty cycle, any steadystate duty cycle, or any ramped-modal cycle.
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(ii) You may use PFD to extract a proportional raw exhaust sample for any batch or 

continuous gaseous emission sampling over any transient duty cycle, any steady-state 

duty cycle, or any ramped-modal cycle.

(iii) You may use PFD to extract a proportional raw exhaust sample for any batch or 

continuous field-testing.

(iv)You may use PFD to extract a proportional diluted exhaust sample from a CVS for 

any batch or continuous emission sampling.

(v) You may use PFD to extract a constant raw or diluted exhaust sample for any

continuous emission sampling.

(vi) You may use PFD to extract a constant raw or diluted exhaust sample for any steadystate emission sampling.

(2) Constant dilution-ratio PFD. Do one of the following for constant dilution-ratio PFD:

(i) Dilute an already proportional flow. For example, you may do this as a way of 

performing secondary dilution from a CVS tunnel to achieve overall dilution ratio for PM 

sampling.

(ii) Continuously measure constituent concentrations. For example, you might dilute to 

precondition a sample of raw exhaust to control its temperature, humidity, or constituent

concentrations upstream of continuous analyzers. In this case, you must take into 

account the dilution ratio before multiplying the continuous concentration by the sampled 

exhaust flow rate. 

(iii) Extract a proportional sample from a separate constant dilution ratio PFD system. 

For example, you might use a variable-flow pump to proportionally fill a gaseous storage 

medium such as a bag from a PFD system. In this case, the proportional sampling must 

meet the same specifications as varying dilution ratio PFD in paragraph (d)(3) of this 

section.

(iv) For each mode of a discrete-mode test (such as a locomotive notch setting or a 

specific setting for speed and torque), use a constant dilution ratio for any PM sampling. 

You must change the overall PM sampling system dilution ratio between modes so that 

the dilution ratio on the mode with the highest exhaust flow rate meets §1065.140(e)(2) 

and the dilution ratios on all other modes is higher than this (minimum) dilution ratio by

the ratio of the maximum exhaust flow rate to the exhaust flow rate of the corresponding 

other mode. This is the same dilution ratio requirement for RMC or field transient 

testing. You must account for this change in dilution ratio in your emission calculations.

(3) Varying dilution-ratio PFD. All the following provisions apply for varying dilutionratio PFD:

(i) Use a control system with sensors and actuators that can maintain proportional 

sampling over intervals as short as 200 ms (i.e., 5 Hz control).

(ii) For control input, you may use any sensor output from one or more measurements; 

for example, intake-air flow, fuel flow, exhaust flow, engine speed, and intake manifold 

temperature and pressure.

(iii) Account for any emission transit time in the PFD system, as necessary.

(iv) You may use preprogrammed data if they have been determined for the specific test 

site, duty cycle, and test engine from which you dilute emissions.

(v) We recommend that you run practice cycles to meet the verification criteria in 

§1065.545. Note that you must verify every emission test by meeting the verification
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criteria with the data from that specific test. Data from previously verified practice cycles 

or other tests may not be used to verify a different emission test.

(vi) You may not use a PFD system that requires preparatory tuning or calibration with a 

CVS or with the emission results from a CVS. Rather, you must be able to independently 

calibrate the PFD.

(e) Dilution air temperature, dilution ratio, residence time, and temperature control of PM 

samples. Dilute PM samples at least once upstream of transfer lines. You may dilute PM 

samples upstream of a transfer line using full-flow dilution, or partial-flow dilution 

immediately downstream of a PM probe. In the case of partial-flow dilution, you may

have up to 26 cm of insulated length between the end of the probe and the dilution stage, 

but we recommend that the length be as short as practical. The intent of these 

specifications is to minimize heat transfer to or from the emission sample before the final 

stage of dilution, other than the heat you may need to add to prevent aqueous 

condensation. This is accomplished by initially cooling the sample through dilution. 

Configure dilution systems as follows:

(1) Set the dilution air temperature to (25 ±5) °C. Use good engineering judgment to 

select a location to measure this temperature that is as close as practical upstream of the 

point where dilution air mixes with raw exhaust. 

(2) For any PM dilution system (i.e., CVS or PFD), add dilution air to the raw exhaust 

such that the minimum overall ratio of diluted exhaust to raw exhaust is within the range 

of (5:1 to 7:1) and is at least 2:1 for any primary dilution stage. Base this minimum value 

on the maximum engine exhaust flow rate for a given test interval. Either measure the 

maximum exhaust flow during a practice run of the test interval or estimate it based on 

good engineering judgment (for example, you might rely on manufacturer-published 

literature).

(3) Configure any PM dilution system to have an overall residence time of (1.0 to 5.5) s, 

as measured from the location of initial dilution air introduction to the location where PM 

is collected on the sample media. Also configure the system to have a residence time of 

at least 0.50 s, as measured from the location of final dilution air introduction to the 

location where PM is collected on the sample media. When determining residence times 

within sampling system volumes, use an assumed flow temperature of 25 °C and pressure 

of 101.325 kPa.

(4) Control sample temperature to a (47 ±5) °C tolerance, as measured anywhere within 

20 cm upstream or downstream of the PM storage media (such as a filter). Measure this 

temperature with a bare-wire junction thermocouple with wires that are (0.500 ±0.025) 

mm diameter, or with another suitable instrument that has equivalent performance.

250. Section 1065.145 is amended by revising paragraphs (a), (c)(1), (c)(2)(ii), 

(d)(1)(ii), (e)(2)(ii), and (e)(3)(ii) to read as follows:

§1065.145 Gaseous and PM probes, transfer lines, and sampling system 

components.

(a) Continuous and batch sampling. Determine the total mass of each constituent with 

continuous or batch sampling. Both types of sampling systems have probes, transfer 

lines, and other sampling system components that are described in this section.

* * * * *

(c) * * *
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(1) Probe design and construction. Use sample probes with inside surfaces of 300 series 

stainless steel or, for raw exhaust sampling, use any nonreactive material capable of 

withstanding raw exhaust temperatures. Locate sample probes where constituents are 

mixed to their mean sample concentration. Take into account the mixing of any 

crankcase emissions that may be routed into the raw exhaust. Locate each probe to 

minimize interference with the flow to other probes. We recommend that all probes 

remain free from influences of boundary layers, wakes, and eddies—especially near the 

outlet of a raw-exhaust stack where unintended dilution might occur. Make sure that 

purging or back-flushing of a probe does not influence another probe during testing. You 

may use a single probe to extract a sample of more than one constituent as long as the 

probe meets all the specifications for each constituent.

(2) * * *

(ii) For probes that extract hydrocarbons for THC or NMHC analysis from the diluted 

exhaust of compression-ignition engines, two-stroke spark-ignition engines, or fourstroke spark-ignition engines at or below 19 kW, we recommend heating the probe to 

minimize hydrocarbon contamination consistent with good engineering judgment. If you 

routinely fail the contamination check in the 1065.520 pretest check, we recommend 

heating the probe section to approximately 190 °C to minimize contamination.

* * * * *

(d) * * *

(1) * * *

(ii) For THC transfer lines for testing compression-ignition engines, two-stroke sparkignition engines, or four-stroke spark-ignition engines at or below 19 kW, maintain a wall 

temperature tolerance throughout the entire line of (191 ±11) C. If you sample from raw 

exhaust, you may connect an unheated, insulated transfer line directly to a probe. Design 

the length and insulation of the transfer line to cool the highest expected raw exhaust 

temperature to no lower than 191 C, as measured at the transfer line’s outlet. For dilute 

sampling, you may use a transition zone between the probe and transfer line of up to 92 

cm to allow your wall temperature to transition to (191 ±11) °C.

* * * * *

(e) * * *

(2) * * *

(ii) Thermal chiller. You may use a thermal chiller upstream of some gas analyzers and 

storage media. You may not use a thermal chiller upstream of a THC measurement 

system for compression-ignition engines, two-stroke spark-ignition engines, or fourstroke spark-ignition engines at or below 19 kW. If you use a thermal chiller upstream of 

an NO2-to-NO converter or in a sampling system without an NO2-to-NO converter, the 

chiller must meet the NO2 loss-performance check specified in §1065.376. Monitor the 

dewpoint, Tdew, and absolute pressure, ptotal, downstream of a thermal chiller. You may

use continuously recorded values of Tdew and ptotal in the amount of water calculations 

specified in §1065.645. If it is valid to assume the degree of saturation in the thermal 

chiller, you may calculate Tdew based on the known chiller performance and continuous 

monitoring of chiller temperature, Tchiller. If it is valid to assume a constant temperature 

offset between Tchiller and Tdew, due to a known and fixed amount of sample reheat 

between the chiller outlet and the temperature measurement location, you may factor in 

this assumed temperature offset value into emission calculations. If we ask for it, you 
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must show by engineering analysis or by data the validity of any assumptions allowed by

this paragraph (e)(2)(ii). For our testing we may use average temperature and pressure 

values over the test interval or a nominal pressure value that we estimate as the dryer’s 

average pressure expected during testing as constant values in the calculations specified 

in §1065.645. For your testing you may use the maximum temperature and minimum 

pressure values observed during a test interval or duty cycle or the high alarm 

temperature setpoint and the low alarm pressure setpoint as constant values in the amount

of water calculations specified in §1065.645. For your testing you may also use a 

nominal ptotal, which you may estimate as the dryer’s lowest absolute pressure expected 

during testing.

(3) * * *

(ii) For testing compression-ignition engines, two-stroke spark-ignition engines, or fourstroke spark-ignition engines at or below 19 kW, if you use a THC sample pump 

upstream of a THC analyzer or storage medium, its inner surfaces must be heated to a 

tolerance of (191 ±11) C.

* * * * *

251. Section 1065.170 is amended by revising paragraphs (a)(1), (b) including Table 1, 

(c)(1)(i) and Figure 1 to read as follows:

§1065.170 Batch sampling for gaseous and PM constituents.

* * * * *

(a) * * *

(1) Verify proportional sampling after an emission test as described in §1065.545. Use 

good engineering judgment to select storage media that will not significantly change 

measured emission levels (either up or down). For example, do not use sample bags for 

storing emissions if the bags are permeable with respect to emissions or if they off gas 

emissions to the extent that it affects your ability to demonstrate compliance with the 

applicable gaseous emission standards. As another example, do not use PM filters that 

irreversibly absorb or adsorb gases to the extent that it affects your ability to demonstrate 

compliance with the applicable PM emission standard.

* * * * *

(b) Gaseous sample storage media. Store gas volumes in sufficiently clean containers 

that minimally off-gas or allow permeation of gases. Use good engineering judgment to 

determine acceptable thresholds of storage media cleanliness and permeation. To clean a 

container, you may repeatedly purge and evacuate a container and you may heat it. Use a 

flexible container (such as a bag) within a temperature-controlled environment, or use a 

temperature controlled rigid container that is initially evacuated or has a volume that can 

be displaced, such as a piston and cylinder arrangement. Use containers meeting the 

specifications in the Table1 of this section, noting that you may request to use other 

container materials under §1065.10. Sample temperatures must stay within the following 

ranges for each container material: 
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(1) Up to 40 °C for TedlarTM and KynarTM.

(2) (191 ±11) °C for TeflonTM and 300 series stainless steel used with measuring THC or 

NMHC from compression-ignition engines, two-stroke spark-ignition engines, and fourstroke spark-ignition engines at or below 19 kW. For all other engines and pollutants, 

these materials may be used for sample temperatures up to 202 °C.

TABLE 1 OF §1065.170– CONTAINER MATERIALS FOR GASEOUS BATCH SAMPLING

Emissions

Engine type

Compression-ignition

Two-stroke spark-ignition

Four-stroke spark-ignition at or below

19 kW

All other engines

CO, CO2, O2,

CH4, C2H6, C3H8,

NO, NO2, N2O

TedlarTM, KynarTM, TeflonTM, or 300 

series stainless steel

TedlarTM, KynarTM, TeflonTM, or 

300 series stainless steel

THC, NMHC TeflonTM or

300 series stainless steel

TedlarTM, KynarTM, TeflonTM, or 

300 series stainless steel

(c) * * *

(1) * * *

(i) If you expect that a filter’s total surface concentration of PM will exceed 400 μg, 

assuming a 38 mm diameter filter stain area, for a given test interval, you may use filter 

media with a minimum initial collection efficiency of 98 %; otherwise you must use a 

filter media with a minimum initial collection efficiency of 99.7 %. Collection efficiency

must be measured as described in ASTM D2986 (incorporated by reference in 

§1065.1010), though you may rely on the sample-media manufacturer’s measurements 

reflected in their product ratings to show that you meet this requirement.

* * * * *
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0

0

.10-0.80 

BETWEEN 

IN ADDITION TO 

TYPICAL RANGES GIVEN FOR 

PERFORATION  AND 

PERFORATION PATTERNS, WE 

RECOMMEND THE FOLLOWING:
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Subpart C—[Amended]

252. Section 1065.201 is amended by revising paragraphs (b), (d), (e), and (h) to read 

as follows:

§1065.201 Overview and general provisions.

* * * * *

(b) Instrument types. You may use any of the specified instruments as described in this 

subpart to perform emission tests. If you want to use one of these instruments in a way 

that is not specified in this subpart, or if you want to use a different instrument, you must 

first get us to approve your alternate procedure under §1065.10. Where we specify more 

than one instrument for a particular measurement, we may identify which instrument 

serves as the reference for comparing with an alternate procedure. You may generally 

use instruments with compensation algorithms that are functions of other gaseous 

measurements and the known or assumed fuel properties for the test fuel. The target 

value for any compensation algorithm is 0 % (that is, no bias high and no bias low), 

regardless of the uncompensated signal’s bias.

* * * * *

(d) Redundant systems. For all measurement instruments described in this subpart, you 

may use data from multiple instruments to calculate test results for a single test. If you 

use redundant systems, use good engineering judgment to use multiple measured values 

in calculations or to disregard individual measurements. Note that you must keep your 

results from all measurements. This requirement applies whether or not you actually use 

the measurements in your calculations.

(e) Range. You may use an instrument’s response above 100 % of its operating range if 

this does not affect your ability to show that your engines comply with the applicable 

emission standards. Note that we require additional testing and reporting if an analyzer 

responds above 100 % of its range. Auto-ranging analyzers do not require additional 

testing or reporting.

* * * * *

(h) Recommended practices. This subpart identifies a variety of recommended but not 

required practices for proper measurements. We believe in most cases it is necessary to 

follow these recommended practices for accurate and repeatable measurements. 

However, we do not specifically require you to follow these recommended practices to 

perform a valid test, as long as you meet the required calibrations and verifications of 

measurement systems specified in subpart D of this part. Similarly, we are not required 

to follow all recommended practices, as long as we meet the required calibrations and 

verifications. Our decision to follow or not follow a given recommendation when we 

perform a test does not depend on whether you followed it during your testing.

253. Section 1065.202 is revised to read as follows:

§1065.202 Data updating, recording, and control.

Your test system must be able to update data, record data and control systems related to 

operator demand, the dynamometer, sampling equipment, and measurement instruments. 

Use data acquisition and control systems that can record at the specified minimum 

frequencies, as follows:
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TABLE 1 OF §1065.202–DATA RECORDING AND CONTROL MINIMUM FREQUENCIES

Applicable 

Test Protocol 

Section

Measured Values

Minimum 

Command and 

Control 

Frequencya

Minimum 

Recording 

Frequencyb,c

§1065.510 Speed and torque during an engine step-map 1 Hz 1 mean value 

per step

§1065.510 Speed and torque during an engine sweep-map 5 Hz 1 Hz means

§1065.514

§1065.530

Transient duty cycle reference and feedback speeds 

and torques 5 Hz 1 Hz means

§1065.514

§1065.530

Steady-state and ramped-modal duty cycle reference 

and feedback speeds and torques 1 Hz 1 Hz

§1065.520

§1065.530

§1065.550

Continuous concentrations of raw or dilute analyzers — 1 Hz

§1065.520

§1065.530

§1065.550

Batch concentrations of raw or dilute analyzers —

1 mean value 

per test interval

§1065.530

§1065.545

Diluted exhaust flow rate from a CVS with a heat 

exchanger upstream of the flow measurement — 1 Hz

§1065.530

§1065.545

Diluted exhaust flow rate from a CVS without a heat 

exchanger upstream of the flow measurement 5 Hz 1 Hz means

§1065.530

§1065.545 Intake-air or raw-exhaust flow rate — 1 Hz means

§1065.530

§1065.545

Dilution air flow if actively controlled (for example, 

a partial-flow PM sampling system)d 5 Hz 1 Hz means

§1065.530

§1065.545 Sample flow from a CVS that has a heat exchanger 1 Hz 1 Hz

§1065.530

§1065.545

Sample flow from a CVS that does not have a heat 

exchanger 5 Hz 1 Hz means

a The specifications for minimum command and control frequency do not apply for CFVs that are not using 

active control .

b

1 Hz means are data reported from the instrument at a higher frequency, but recorded as a series of 1 s

mean values at a rate of 1 Hz.

c

For CFVs in a CVS, the minimum recording frequency is 1 Hz. The minimum recording frequency does 

not apply for CFVs used to control sampling from a CVS utilizing CFVs.

dDilution air flow specifications do not apply for CVS dilution air.

254. Section 1065.205 is revised to read as follows:

§1065.205 Performance specifications for measurement instruments.

Your test system as a whole must meet all the calibrations, verifications, and testvalidation criteria specified outside this section for laboratory testing or field testing, as 

applicable. We recommend that your instruments meet the specifications in Table 1 of 

this section for all ranges you use for testing. We also recommend that you keep any 

documentation you receive from instrument manufacturers showing that your instruments 

meet the specifications in Table 1 of this section.
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TABLE 1 OF §1065.205–RECOMMENDED PERFORMANCE SPECIFICATIONS FOR MEASUREMENT INSTRUMENTS

Measurement Instrument

Measure

d 

quantity 

symbol

Complete System

Rise time (t10-90) and 

Fall time (t90-10)

a

Recording

update frequency Accuracyb Repeatabilityb Noiseb

Engine speed transducer fn 1 s 1 Hz means 2 % of pt. or

0.5 % of max.

1 % of pt. or

0.25 % of max. 0.05 % of max

Engine torque transducer T 1 s 1 Hz means 2 % of pt. or

1 % of max.

1 % of pt. or

0.5 % of max 0.05 % of max.

Electrical work (active-power meter) W 1 s 1 Hz means 2 % of pt. or

0.5 % of max.

1 % of pt. or

0.25 % of max. 0.05 % of max

General pressure transducer (not a part 

of another instrument) p 5 s 1 Hz 2 % of pt. or1 % of max.

1 % of pt. or

0.5 % of max. 0.1 % of max

Atmospheric pressure meter for PMstabilization and balance environments patmos 50 s 5 times per hour 50 Pa 25 Pa 5 Pa

General purpose atmospheric pressure 

meter patmos 50 s 5 times per hour 250 Pa 100Pa 50 Pa

Temperature sensor for PMstabilization and balance environments T 50 s 0.1 Hz 0.25 K 0.1 K 0.1 K

Other temperature sensor (not a part of 

another instrument) T 10 s 0.5 Hz 0.4 % of pt. K or0.2 % of max. K

0.2 % of pt. K or

0.1 % of max. K 0.1 % of max

Dewpoint sensor for intake air, PMstabilization and balance environments Tdew 50 s 0.1 Hz 0.25 K 0.1 K 0.02 K

Other dewpoint sensor Tdew 50 s 0.1 Hz 1 K 0.5 K 0.1 K

Fuel flow meterc

(Fuel totalizer) m

5 s

(—)

1 Hz

(—)

2 % of pt. or

1.5 % of max.

1 % of pt. or

0.75 % of max. 0.5 % of max.

Total diluted exhaust meter (CVS) c

(With heat exchanger before meter) n

1 s

(5 s)

1 Hz means

(1 Hz)

2 % of pt. or

1.5 % of max.

1 % of pt. or

0.75 % of max. 1 % of max.

Dilution air, inlet air, exhaust, and 

sample flow metersc n 1 s 1 Hz means of 5 Hz samples

2.5 % of pt. or

1.5 % of max.

1.25 % of pt. or

0.75 % of max. 1 % of max.

Continuous gas analyzer x 5 s 1 Hz 2 % of pt. or

2 % of meas.

1 % of pt. or

1 % of meas. 1 % of max.

Batch gas analyzer x — —

2 % of pt. or

2 % of meas.

1 % of pt. or

1 % of meas. 1 % of max.

Gravimetric PM balance mPM — — See §1065.790 0.5 g —

Inertial PM balance mPM 5 s 1 Hz 2 % of pt. or

2 % of meas.

1 % of pt. or

1 % of meas. 0.2 % of max.

The performance specifications identified in the table apply separately for rise time and fall time.

Accuracy, repeatability, and noise are all determined with the same collected data, as described in §1065.305, and based on absolute values. “pt.” refers to the overall flow-weighted 

mean value expected at the standard; “max.” refers to the peak value expected at the standard over any test interval, not the maximum of the instrument’s range; “meas” refers to the actual 

weighted mean measured over any test interval.

The procedure for accuracy, repeatability and noise measurement described in §1065.305 may be modified for flow meters to allow noise to be measured at the lowest calibrated value 

instead of zero flow rate.
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255. Section 1065.210 is amended by revising paragraph (c) to read as follows:

§1065.210 Work input and output sensors.

* * * * *

(c) Electrical work. Use a watt-hour meter output to calculate total work according to 

§1065.650. Use a watt-hour meter that outputs active power. Watt-hour meters typically 

combine a Wheatstone bridge voltmeter and a Hall-effect clamp-on ammeter into a single 

microprocessor-based instrument that analyzes and outputs several parameters, such as 

alternating or direct current voltage, current, power factor, apparent power, reactive 

power, and active power.

* * * * *

256. Section 1065.225 is amended by revising paragraph (a) to read as follows:

§1065.225 Intake-air flow meter.

(a) Application. You may use an intake-air flow meter in combination with a chemical 

balance of fuel, inlet air, and exhaust to calculate raw exhaust flow as described in 

§1065.655(e) and (f), as follows:

(1) Use the actual value of calculated raw exhaust in the following cases:

(i) For multiplying raw exhaust flow rate with continuously sampled concentrations.

(ii) For multiplying total raw exhaust flow with batch-sampled concentrations.

(iii) For verifying minimum dilution ratio for PM batch sampling as described in 

§1065.546.

(iv) For calculating the dilution air flow for background correction as described in 

§1065.667.

(2) In the following cases, you may use an intake-air flow meter signal that does not give 

the actual value of raw exhaust, as long as it is linearly proportional to the exhaust flow 

rate’s actual calculated value:

(i) For feedback control of a proportional sampling system, such as a partial-flow dilution 

system.

(ii) For multiplying with continuously sampled gas concentrations, if the same signal is 

used in a chemical-balance calculation to determine work from brake-specific fuel 

consumption and fuel consumed.

* * * * *

257. Section 1065.230 is amended by revising paragraph (d) to read as follows:

§1065.230 Raw exhaust flow meter.

* * * * *

(d) Exhaust cooling. You may cool raw exhaust upstream of a raw-exhaust flow meter, 

as long as you observe all the following provisions: 

(1) Do not sample PM downstream of the cooling.

(2) If cooling causes exhaust temperatures above 202 °C to decrease to below 180 °C, do 

not sample NMHC downstream of the cooling for compression-ignition engines, twostroke spark-ignition engines, or four-stroke spark-ignition engines at or below 19 kW.

(3) The cooling must not cause aqueous condensation.

258. Section 1065.240 is amended by revising paragraph (d) to read as follows:

§1065.240 Dilution air and diluted exhaust flow meters.
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* * * * *

(d) Exhaust cooling. You may cool diluted exhaust upstream of a dilute-exhaust flow 

meter, as long as you observe all the following provisions: 

(1) Do not sample PM downstream of the cooling.

(2) If cooling causes exhaust temperatures above 202 °C to decrease to below 180 °C, do 

not sample NMHC downstream of the cooling for compression-ignition engines, twostroke spark-ignition engines, or four-stroke spark-ignition engines at or below 19 kW.

(3) The cooling must not cause aqueous condensation as described in §1065.140(c)(6).

259. Section 1065.250 is amended by revising paragraph (b) to read as follows:

§1065.250 Nondispersive infrared analyzer.

* * * * *

(b) Component requirements. We recommend that you use an NDIR analyzer that meets 

the specifications in Table 1 of §1065.205. Note that your NDIR-based system must 

meet the calibration and verifications in §§1065.350 and 1065.355 and it must also meet 

the linearity verification in §1065.307.

260. Section 1065.260 is amended by revising paragraphs (b), (c), and (e) to read as 

follows:

§1065.260 Flame-ionization detector.

* * * * *

(b) Component requirements. We recommend that you use a FID analyzer that meets the 

specifications in Table 1 of §1065.205. Note that your FID-based system for measuring 

THC, THCE, or CH4 must meet all the verifications for hydrocarbon measurement in 

subpart D of this part, and it must also meet the linearity verification in §1065.307.

(c) Heated FID analyzers. For measuring THC or THCE from compression-ignition 

engines, two-stroke spark-ignition engines, and four-stroke spark-ignition engines at or 

below 19 kW, you must use heated FID analyzers that maintain all surfaces that are 

exposed to emissions at a temperature of (191 ±11) °C.

* * * * *

(e) NMHC and NMOG. For demonstrating compliance with NMHC standards, you may 

either measure THC and CH4 and determine NMHC as described in §1065.660(b)(2) or 

(3), or you may measure THC and determine NMHC mass as described in 

§1065.660(b)(1). See 40 CFR 1066.635 for methods to demonstrate compliance with 

NMOG standards for vehicle testing.

* * * * *

261. Section 1065.267 is amended by revising paragraph (b) to read as follows:

§1065.267 Gas chromatograph with a flame ionization detector.

* * * * *

(b) Component requirements. We recommend that you use a GC-FID that meets the 

specifications in Table 1 of §1065.205 and that the measurement be done according to 

SAE J1151 (incorporated by reference in §1065.1010). The GC-FID must meet the 

linearity verification in §1065.307.
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262. A new § 1065.269 is added to subpart C under the center header “Hydrocarbon 

Measurements” to read as follows:

§1065.269 Photoacoustic analyzer for ethanol and methanol.

(a) Application. You may use a photoacoustic analyzer to measure ethanol and/or 

methanol concentrations in diluted exhaust for batch sampling.

(b) Component requirements. We recommend that you use a photoacoustic analyzer that 

meets the specifications in Table 1 of §1065.205. Note that your photoacoustic system 

must meet the verification in §1065.369 and it must also meet the linearity verification in 

§1065.307. Use an optical wheel configuration that gives analytical priority to 

measurement of the least stable components in the sample. Select a sample integration 

time of at least 5 seconds. Take into account sample chamber and sample line volumes 

when determining flush times for your instrument.

263. Section 1065.270 is amended by revising paragraph (b) to read as follows:

§1065.270 Chemiluminescent detector.

* * * * *

(b) Component requirements. We recommend that you use a CLD that meets the 

specifications in Table 1 of §1065.205. Note that your CLD-based system must meet the 

quench verification in §1065.370 and it must also meet the linearity verification in 

§1065.307. You may use a heated or unheated CLD, and you may use a CLD that 

operates at atmospheric pressure or under a vacuum.

* * * * *

264. Section 1065.272 is amended by revising paragraph (b) to read as follows:

§1065.272 Nondispersive ultraviolet analyzer.

* * * * *

(b) Component requirements. We recommend that you use an NDUV analyzer that 

meets the specifications in Table 1 of §1065.205. Note that your NDUV-based system 

must meet the verifications in §1065.372 and it must also meet the linearity verification 

in §1065.307.

* * * * *

265. Section 1065.275 is amended by revising paragraph (b) to read as follows:

§1065.275 N2O measurement devices.

* * * * *

(b) Instrument types. You may use any of the following analyzers to measure N2O:

(1) Nondispersive infrared (NDIR) analyzer.

(2) Fourier transform infrared (FTIR) analyzer. Use appropriate analytical procedures for 

interpretation of infrared spectra. For example, EPA Test Method 320 is considered a 

valid method for spectral interpretation (see 

http://www.epa.gov/ttn/emc/methods/method320.html).

(3) Laser infrared analyzer. Examples of laser infrared analyzers are pulsed-mode highresolution narrow band mid-infrared analyzers, and modulated continuous wave highresolution narrow band mid-infrared analyzers.

(4) Photoacoustic analyzer. Use an optical wheel configuration that gives analytical 

priority to measurement of the least stable components in the sample. Select a sample 
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integration time of at least 5 seconds. Take into account sample chamber and sample line 

volumes when determining flush times for your instrument.

(5) Gas chromatograph analyzer. You may use a gas chromatograph with an electroncapture detector (GC-ECD) to measure N2O concentrations of diluted exhaust for batch 

sampling.

(i)You may use a packed or porous layer open tubular (PLOT) column phase of suitable 

polarity and length to achieve adequate resolution of the N2O peak for analysis. 

Examples of acceptable columns are a PLOT column consisting of bonded polystyrenedivinylbenzene or a Porapack Q packed column. Take the column temperature profile 

and carrier gas selection into consideration when setting up your method to achieve 

adequate N2O peak resolution.

(ii) Use good engineering judgment to zero your instrument and correct for drift. You do 

not need to follow the specific procedures in §§1065.530 and 1065.550(b) that would 

otherwise apply. For example, you may perform a span gas measurement before and 

after sample analysis without zeroing and use the average area counts of the pre-span and 

post-span measurements to generate a response factor (area counts/span gas 

concentration), which you then multiply by the area counts from your sample to generate 

the sample concentration.

* * * * *

266. Section 1065.280 is amended by revising paragraph (b) to read as follows:

§1065.280 Paramagnetic and magnetopneumatic O2 detection analyzers.

* * * * *

(b) Component requirements. We recommend that you use a PMD or MPD analyzer that

meets the specifications in Table 1 of §1065.205. Note that it must meet the linearity 

verification in §1065.307.

267. Section 1065.284 is amended by revising paragraph (b) to read as follows:

§1065.284 Zirconia (ZrO2) analyzer.

* * * * *

(b) Component requirements. We recommend that you use a ZrO2 analyzer that meets 

the specifications in Table 1 of §1065.205. Note that your ZrO2-based system must meet 

the linearity verification in §1065.307.

268. Section 1065.295 is amended by revising paragraph (b) to read as follows:

§1065.295 PM inertial balance for field-testing analysis.

* * * * *

(b) Component requirements. We recommend that you use a balance that meets the 

specifications in Table 1 of §1065.205. Note that your balance-based system must meet 

the linearity verification in §1065.307. If the balance uses an internal calibration process 

for routine spanning and linearity verifications, the process must be NIST-traceable.

* * * * *

Subpart D—[Amended]

269. Section 1065.303 is revised to read as follows:
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§1065.303 Summary of required calibration and verifications.

The following table summarizes the required and recommended calibrations and 

verifications described in this subpart and indicates when these have to be performed:

TABLE 1 OF §1065.303–SUMMARY OF REQUIRED CALIBRATION AND VERIFICATIONS

Type of calibration or verification Minimum frequency1

§1065.305: Accuracy, repeatability and noise

Accuracy: Not required, but recommended for initial installation.

Repeatability: Not required, but recommended for initial 

installation.

Noise: Not required, but recommended for initial installation.

§1065.307: Linearity verification

Speed: Upon initial installation, within 370 days before testing 

and after major maintenance.

Torque: Upon initial installation, within 370 days before testing 

and after major maintenance.

Electrical power, current, and voltage: Upon initial installation, 

within 370 days before testing and after major maintenance.2

Fuel flow rate: Upon initial installation, within 370 days before 

testing, and after major maintenance.

Intake-air, dilution air, diluted exhaust, and batch sampler flow 

rates: Upon initial installation, within 370 days before testing and 

after major maintenance, unless flow is verified by propane check 

or by carbon or oxygen balance.

Raw exhaust flow rate: Upon initial installation, within 185 days 

before testing and after major maintenance, unless flow is verified 

by propane check or by carbon or oxygen balance.

Gas dividers: Upon initial installation, within 370 days before 

testing, and after major maintenance.

Gas analyzers (unless otherwise noted): Upon initial installation, 

within 35 days before testing and after major maintenance.

FTIR and photoacoustic analyzers: Upon initial installation, 

within 370 days before testing and after major maintenance.

GC-ECD: Upon initial installation and after major maintenance.

PM balance: Upon initial installation, within 370 days before 

testing and after major maintenance.

Pressure, temperature, and dewpoint: Upon initial installation, 

within 370 days before testing and after major maintenance.

§1065.308: Continuous gas analyzer system 

response and updating-recording verification—

for gas analyzers not continuously compensated 

for other gas species

Upon initial installation or after system modification that would 

affect response.

§1065.309: Continuous gas analyzer systemresponse and updating-recording verification—

for gas analyzers continuously compensated for 

other gas species

Upon initial installation or after system modification that would 

affect response.

§1065.310: Torque Upon initial installation and after major maintenance.

§1065.315: Pressure, temperature, dewpoint Upon initial installation and after major maintenance.

§1065.320: Fuel flow Upon initial installation and after major maintenance.

§1065.325: Intake flow Upon initial installation and after major maintenance.

§1065.330: Exhaust flow Upon initial installation and after major maintenance.

§1065.340: Diluted exhaust flow (CVS) Upon initial installation and after major maintenance.

§1065.341: CVS and batch sampler verification3 Upon initial installation, within 35 days before testing, and after 

major maintenance.

§1065.342 Sample dryer verification

For thermal chillers: upon installation and after major 

maintenance.

For osmotic membranes; upon installation, within 35 days of 

testing, and after major maintenance.
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§1065.345: Vacuum leak

For laboratory testing: upon initial installation of the sampling 

system, within 8 hours before the start of the first test interval of 

each duty-cycle sequence, and after maintenance such as pre-filter 

changes.

For field testing: after each installation of the sampling system on 

the vehicle, prior to the start of the field test, and after 

maintenance such as pre-filter changes.

§1065.350: CO2 NDIR H2O interference Upon initial installation and after major maintenance.

§1065.355: CO NDIR CO2 and H2O interference Upon initial installation and after major maintenance.

§1065.360: FID calibration

THC FID optimization, and THC FID 

verification

Calibrate all FID analyzers: upon initial installation and after 

major maintenance.

Optimize and determine CH4response for THC FID analyzers:

upon initial installation and after major maintenance.

Verify CH4response for THC FID analyzers: upon initial 

installation, within 185 days before testing, and after major 

maintenance.

§1065.362: Raw exhaust FID O2interference

For all FID analyzers: upon initial installation, and after major 

maintenance.

For THC FID analyzers: upon initial installation, after major 

maintenance, and after FID optimization according to §1065.360.

§1065.365: Nonmethane cutter penetration Upon initial installation, within 185 days before testing, and after 

major maintenance.

§1065.369: H2O, CO, and CO2interference 

verification for ethanol photoacoustic analyzers Upon initial installation and after major maintenance.

§1065.370: CLD CO2 and H2O quench Upon initial installation and after major maintenance.

§1065.372: NDUV HC and H2O interference Upon initial installation and after major maintenance.

§1065.375: N2O analyzer interference Upon initial installation and after major maintenance.

§1065.376: Chiller NO2 penetration Upon initial installation and after major maintenance.

§1065.378: NO2-to-NO converter conversion Upon initial installation, within 35 days before testing, and after 

major maintenance.

§1065.390: PM balance and weighing

Independent verification: upon initial installation, within 370 days 

before testing, and after major maintenance.

Zero, span, and reference sample verifications: within 12 hours of 

weighing, and after major maintenance.

§1065.395: Inertial PM balance and weighing

Independent verification: upon initial installation, within 370 days 

before testing, and after major maintenance.

Other verifications: upon initial installation and after major 

maintenance.

1

Perform calibrations and verifications more frequently than we specify, according to measurement system 

manufacturer instructions and good engineering judgment.

2

Perform linearity verification either for electrical power or for current and voltage.

3The CVS verification described in §1065.341 is not required for systems that agree within ±2 % based on a chemical 

balance of carbon or oxygen of the intake air, fuel, and diluted exhaust.

270. Section 1065.305 is amended by revising paragraph (d)(10)(i) to read as follows:

§1065.305 Verifications for accuracy, repeatability, and noise.

* * * * *

(d) * * *

(10) * * *

(i) Your measurement systems meet all the other required calibration, verification, and 

validation specifications that apply as specified in the regulations.

* * * * *

271. Section 1065.307 is revised to read as follows:

§1065.307 Linearity verification.
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(a) Scope and frequency. Perform linearity verification on each measurement system 

listed in Table 1 of this section at least as frequently as indicated in Table 1 of §1065.303, 

consistent with measurement system manufacturer’s recommendations and good 

engineering judgment. The intent of linearity verification is to determine that a 

measurement system responds accurately and proportionally over the measurement range 

of interest. Linearity verification generally consists of introducing a series of at least 10 

reference values to a measurement system. The measurement system quantifies each 

reference value. The measured values are then collectively compared to the reference 

values by using a least-squares linear regression and the linearity criteria specified in 

Table 1 of this section.

(b) Performance requirements. If a measurement system does not meet the applicable 

linearity criteria referenced in Table 1 of this section, correct the deficiency by recalibrating, servicing, or replacing components as needed. Repeat the linearity

verification after correcting the deficiency to ensure that the measurement system meets 

the linearity criteria. Before you may use a measurement system that does not meet 

linearity criteria, you must demonstrate to us that the deficiency does not adversely affect 

your ability to demonstrate compliance with the applicable standards.

(c) Procedure. Use the following linearity verification protocol, or use good engineering 

judgment to develop a different protocol that satisfies the intent of this section, as 

described in paragraph (a) of this section:

(1) In this paragraph (c), the letter “y” denotes a generic measured quantity, the 

superscript over-bar denotes an arithmetic mean (such as y ), and the subscript “ref” 

denotes the known or reference quantity being measured.

(2) Use good engineering judgment to operate a measurement system at normal operating 

conditions. This may include any specified adjustment or periodic calibration of the 

measurement system.

(3) If applicable, zero the instrument as you would before an emission test by introducing 

a zero signal. Depending on the instrument, this may be a zero-concentration gas, a 

reference signal, a set of reference thermodynamic conditions, or some combination of 

these. For gas analyzers, use a zero gas that meets the specifications of §1065.750 and 

introduce it directly at the analyzer port.

(4) If applicable, span the instrument as you would before an emission test by introducing 

a span signal. Depending on the instrument, this may be a span-concentration gas, a 

reference signal, a set of reference thermodynamic conditions, or some combination of 

these. For gas analyzers, use a span gas that meets the specifications of §1065.750 and 

introduce it directly at the analyzer port.

(5) If applicable, after spanning the instrument, check zero with the same signal you used 

in paragraph (c)(3) of this section. Based on the zero reading, use good engineering 

judgment to determine whether or not to rezero and or re-span the instrument before 

continuing.

(6) For all measured quantities, use the instrument manufacturer’s recommendations and 

good engineering judgment to select reference values, yrefi, that cover a range of values 

that you expect would prevent extrapolation beyond these values during emission testing. 

We recommend selecting a zero reference signal as one of the reference values for the 

linearity verification. For pressure, temperature, dewpoint, power, current, voltage, 

photoacoustic analyzers, and GC-ECD linearity verifications, we recommend at least 
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three reference values. For all other linearity verifications select at least ten reference 

values.

(7) Use the instrument manufacturer’s recommendations and good engineering judgment 

to select the order in which you will introduce the series of reference values. For 

example, you may select the reference values randomly to avoid correlation with 

previous measurements and to avoid hysteresis; you may select reference values in 

ascending or descending order to avoid long settling times of reference signals; or you 

may select values to ascend and then descend to incorporate the effects of any instrument 

hysteresis into the linearity verification.

(8) Generate reference quantities as described in paragraph (d) of this section. For gas 

analyzers, use gas concentrations known to be within the specifications of §1065.750 and 

introduce them directly at the analyzer port.

(9) Introduce a reference signal to the measurement instrument.

(10) Allow time for the instrument to stabilize while it measures the value at the 

reference condition. Stabilization time may include time to purge an instrument and time 

to account for its response.

(11) At a recording frequency of at least f Hz, specified in Table 1 of §1065.205, measure 

the value at the reference condition for 30 seconds (you may select a longer sampling 

period if the recording update frequency is less than 0.5 Hz) and record the arithmetic 

mean of the recorded values, i

y . Refer to §1065.602 for an example of calculating an 

arithmetic mean.

(12) Repeat the steps in paragraphs (c)(9) though (11) of this section until measurements 

are complete at each of the reference conditions.

(13) Use the arithmetic means, i

y , and reference values, yrefi , to calculate least-squares 

linear regression parameters and statistical values to compare to the minimum 

performance criteria specified in Table 1 of this section. Use the calculations described 

in §1065.602. Using good engineering judgment, you may weight the results of 

individual data pairs (i.e. (yrefi, i

y )), in the linear regression calculations.

(d) Reference signals. This paragraph (d) describes recommended methods for 

generating reference values for the linearity-verification protocol in paragraph (c) of this 

section. Use reference values that simulate actual values, or introduce an actual value 

and measure it with a reference-measurement system. In the latter case, the reference 

value is the value reported by the reference-measurement system. Reference values and 

reference-measurement systems must be NIST-traceable. We recommend using 

calibration reference quantities that are NIST-traceable within 0.5 % uncertainty, if not 

specified elsewhere in this part 1065. Use the following recommended methods to 

generate reference values or use good engineering judgment to select a different 

reference:

(1) Speed. Run the engine or dynamometer at a series of steady-state speeds and use a 

strobe, photo tachometer, or laser tachometer to record reference speeds.

(2) Torque. Use a series of calibration weights and a calibration lever arm to simulate 

engine torque. You may instead use the engine or dynamometer itself to generate a 

nominal torque that is measured by a reference load cell or proving ring in series with the 

torque-measurement system. In this case, use the reference load cell measurement as the 
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reference value. Refer to §1065.310 for a torque-calibration procedure similar to the 

linearity verification in this section.

(3) Electrical power, current, and voltage. You must perform linearity verification for 

either electrical power meters, or for current and voltage meters. Perform linearity 

verifications using a reference meter and controlled sources of current and voltage. We 

recommend using a complete calibration system that is suitable for the electrical power 

distribution industry.

(4) Fuel rate. Operate the engine at a series of constant fuel-flow rates or re-circulate fuel 

back to a tank through the fuel flow meter at different flow rates. Use a gravimetric 

reference measurement (such as a scale, balance, or mass comparator) at the inlet to the 

fuel-measurement system. Use a stopwatch or timer to measure the time intervals over 

which reference masses of fuel are introduced to the fuel measurement system. The 

reference fuel mass divided by the time interval is the reference fuel flow rate.

(5) Flow rates—inlet air, dilution air, diluted exhaust, raw exhaust, or sample flow. Use a 

reference flow meter with a blower or pump to simulate flow rates. Use a restrictor, 

diverter valve, a variable-speed blower or a variable-speed pump to control the range of 

flow rates. Use the reference meter’s response as the reference values.

(i) Reference flow meters. Because the flow range requirements for these various flows 

are large, we allow a variety of reference meters. For example, for diluted exhaust flow 

for a full-flow dilution system, we recommend a reference subsonic venturi flow meter 

with a restrictor valve and a blower to simulate flow rates. For inlet air, dilution air, 

diluted exhaust for partial-flow dilution, raw exhaust, or sample flow, we allow reference 

meters such as critical flow orifices, critical flow venturis, laminar flow elements, master 

mass flow standards, or Roots meters. Make sure the reference meter is calibrated and its 

calibration is NIST-traceable. If you use the difference of two flow measurements to 

determine a net flow rate, you may use one of the measurements as a reference for the 

other.

(ii) Reference flow values. Because the reference flow is not absolutely constant, sample 

and record values of refi n for 30 seconds and use the arithmetic mean of the values, ref n , 

as the reference value. Refer to §1065.602 for an example of calculating arithmetic 

mean.

(6) Gas division. Use one of the two reference signals:

(i) At the outlet of the gas-division system, connect a gas analyzer that meets the linearity 

verification described in this section and has not been linearized with the gas divider 

being verified. For example, verify the linearity of an analyzer using a series of reference 

analytical gases directly from compressed gas cylinders that meet the specifications of 

§1065.750. We recommend using a FID analyzer or a PMD or MPD O2 analyzer 

because of their inherent linearity. Operate this analyzer consistent with how you would 

operate it during an emission test. Connect a span gas to the gas-divider inlet. Use the 

gas-division system to divide the span gas with purified air or nitrogen. Select gas 

divisions that you typically use. Use a selected gas division as the measured value. Use 

the analyzer response divided by the span gas concentration as the reference gas-division 

value. Because the instrument response is not absolutely constant, sample and record 

values of xrefi for 30 seconds and use the arithmetic mean of the values, ref x , as the 

reference value. Refer to §1065.602 for an example of calculating arithmetic mean.
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(ii) Using good engineering judgment and the gas divider manufacturer’s

recommendations, use one or more reference flow meters to measure the flow rates of the 

gas divider and verify the gas-division value.

(7) Continuous constituent concentration. For reference values, use a series of gas 

cylinders of known gas concentration or use a gas-division system that is known to be 

linear with a span gas. Gas cylinders, gas-division systems, and span gases that you use 

for reference values must meet the specifications of §1065.750.

(8) Temperature. You may perform the linearity verification for temperature 

measurement systems with thermocouples, RTDs, and thermistors by removing the 

sensor from the system and using a simulator in its place. Use a NIST-traceable 

simulator that is independently calibrated and, as appropriate, cold-junctioncompensated. The simulator uncertainty scaled to absolute temperature must be less than 

0.5 % of Tmax. If you use this option, you must use sensors that the supplier states are 

accurate to better than 0.5 % of Tmax compared with their standard calibration curve.

(9) Mass. For linearity verification for gravimetric PM balances, use external calibration 

weights that meet the requirements in §1065.790.

(e) Measurement systems that require linearity verification. Table 1 of this section 

indicates measurement systems that require linearity verification, subject to the following 

provisions:

(1) Perform linearity verification more frequently based on the instrument manufacturer’s 

recommendation or good engineering judgment.

(2) The expression “xmin” refers to the reference value used during linearity verification 

that is closest to zero. This is the value used to calculate the first tolerance in Table 1 of 

this section using the intercept, a0. Note that this value may be zero, positive, or negative 

depending on the reference values. For example, if the reference values chosen to 

validate a pressure transducer vary from -10 to -1 kPa, xmin is -1 kPa. If the reference 

values used to validate a temperature device vary from 290 to 390 K, xmin is 290 K.

(3) The expression “max” generally refers to the absolute value of the reference value 

used during linearity verification that is furthest from zero. This is the value used to scale 

the first and third tolerances in Table 1 of this section using a0 and SEE. For example, if 

the reference values chosen to validate a pressure transducer vary from -10 to -1 kPa, 

then pmax is +10 kPa. If the reference values used to validate a temperature device vary

from 290 to 390 K, then Tmax is 390 K. For gas dividers where “max” is expressed as, 

xmax/xspan; xmax is the maximum gas concentration used during the verification, xspan is the 

undivided, undiluted, span gas concentration, and the resulting ratio is the maximum 

divider point reference value used during the verification (typically 1). The following are 

special cases where “max” refers to a different value:

(i) For linearity verification with a PM balance, mmax refers to the typical mass of a PM 

filter.

(ii) For linearity verification of torque on the engine’s primary output shaft, Tmax refers to 

the manufacturer’s specified engine torque peak value of the lowest torque engine to be 

tested.

(4) The specified ranges are inclusive. For example, a specified range of 0.98-1.02 for a1

means 0.98a11.02.

(5) Linearity verification is optional for systems that pass the flow-rate verification for 

diluted exhaust as described in §1065.341 (the propane check) or for systems that agree 
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within ±2 % based on a chemical balance of carbon or oxygen of the intake air, fuel, and 

exhaust.

(6) You must meet the a1 criteria for these quantities only if the absolute value of the 

quantity is required, as opposed to a signal that is only linearly proportional to the actual 

value.

(7) Linearity verification is required for the following temperature measurements:

(i) The following temperature measurements always require linearity verification:

(A) Air intake.

(B) Aftertreatment bed(s), for engines tested with aftertreatment devices subject to coldstart testing.

(C) Dilution air for gaseous and PM sampling, including CVS, double-dilution, and 

partial-flow systems.

(D) PM sample.

(E) Chiller sample, for gaseous sampling systems that use thermal chillers to dry samples

and use chiller temperature to calculate the dewpoint at the outlet of the chiller. For your 

testing, if you choose to use a high alarm temperature setpoint for the chiller temperature 

as a constant value in determining the amount of water removed from the emission 

sample, you may use good engineering judgment to verify the accuracy of the high alarm 

temperature setpoint instead of linearity verification on the chiller temperature. To verify

that the alarm trip point value is no less than 2.0 °C below the reference value at the trip 

point, we recommend that you input a reference simulated temperature signal below the 

alarm trip point and increase this signal until the high alarm trips.

(ii) Linearity verification is required for the following temperature measurements if these 

temperature measurements are specified by the engine manufacturer:

(A) Fuel inlet.

(B) Air outlet to the test cell’s charge air cooler air outlet, for engines tested with a 

laboratory heat exchanger that simulates an installed charge air cooler.

(C) Coolant inlet to the test cell’s charge air cooler, for engines tested with a laboratory 

heat exchanger that simulates an installed charge air cooler.

(D) Oil in the sump/pan.

(E) Coolant before the thermostat, for liquid-cooled engines.

(8) Linearity verification is required for the following pressure measurements:

(i) The following pressure measurements always require linearity verification:

(A) Air intake restriction.

(B) Exhaust back pressure as required in §1065.130(h).

(C) Barometer.

(D) CVS inlet gage pressure where the raw exhaust enters the tunnel.

(E) Sample dryer, for gaseous sampling systems that use either osmotic-membrane or 

thermal chillers to dry samples. For your testing, if you choose to use a low alarm 

pressure setpoint for the sample dryer pressure as a constant value in determining the 

amount of water removed from the emission sample, you may use good engineering 

judgment to verify the accuracy of the low alarm pressure setpoint instead of linearity 

verification on the sample dryer pressure. To verify that the trip point value is no more 

than 4.0 kPa above the reference value at the trip point, we recommend that you input a 

reference pressure signal above the alarm trip point and decrease this signal until the low 

alarm trips.
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(ii) Linearity verification is required for the following pressure measurements if these 

pressure measurements are specified by the engine manufacturer:

(A) The test cell’s charge air cooler and interconnecting pipe pressure drop, for turbocharged engines tested with a laboratory heat exchanger that simulates an installed charge 

air cooler.

(B) Fuel outlet.

TABLE 1 OF §1065.307–MEASUREMENT SYSTEMS THAT REQUIRE LINEARITY 

VERIFICATION

Measurement system Quantity Linearity criteria

| xmin(a1-1)+a0| a1 SEE r

2

Speed fn ≤ 0.05 % ∙ fnmax 0.98-1.02 ≤ 2 % ∙ nmax f ≥ 0.990

Torque T ≤ 1 % ∙ Tmax 0.98-1.02 ≤ 2 % ∙ Tmax ≥ 0.990

Electrical power P ≤ 1 % ∙ Pmax 0.98-1.02 ≤ 2 % ∙ Pmax ≥ 0.990

Current I ≤ 1 % ∙ max

I 0.98-1.02 ≤ 2 % ∙ maxI ≥ 0.990

Voltage U ≤ 1 % ∙ Umax 0.98-1.02 ≤ 2 % ∙ Umax ≥ 0.990

Fuel flow rate m ≤ 1 % ∙ mmax

 0.98-1.02 ≤ 2 % ∙ mmax ≥ 0.990

Intake-air

flow rate1 n ≤ 1 % ∙ max n 0.98-1.02 ≤ 2 % ∙ max n ≥ 0.990

Dilution air

flow rate1 n ≤ 1 % ∙ max n 0.98-1.02 ≤ 2 % ∙ max n ≥ 0.990

Diluted exhaust

flow rate1 n ≤ 1 % ∙ max n 0.98-1.02 ≤ 2 % ∙ max n ≥ 0.990

Raw exhaust

flow rate1 n ≤ 1 % ∙ max n 0.98-1.02 ≤ 2 % ∙ max n ≥ 0.990

Batch sampler

flow rates1 n ≤ 1 % ∙ max n 0.98-1.02 ≤ 2 % ∙ max n ≥ 0.990

Gas dividers x/xspan ≤ 0.5 % ∙ xmax/xspan 0.98-1.02 ≤ 2 % ∙ xmax/xspan ≥ 0.990

Gas analyzers for 

laboratory testing x ≤ 0.5 % ∙ max x 0.99-1.01 ≤ 1 % ∙ max x ≥ 0.998

Gas analyzers for 

field testing x ≤ 1 % ∙ max x 0.99-1.01 ≤ 1 % ∙ max x ≥ 0.998

PM balance m ≤ 1 % ∙ mmax 0.99-1.01 ≤ 1 % ∙ mmax ≥ 0.998

Pressures p ≤ 1 % ∙ max

p 0.99-1.01 ≤ 1 % ∙ maxp ≥ 0.998

Dewpoint for intake 

air, PM-stabilization 

and balance 

environments

Tdew ≤ 0.5 % ∙ Tdewmax 0.99-1.01 ≤ 0.5 % ∙Tdewmax ≥ 0.998

Other dewpoint 

measurements Tdew ≤ 1 % ∙ Tdewmax 0.99-1.01 ≤ 1 % ∙ Tdewmax ≥ 0.998

Analog-to-digital 

conversion of 

temperature signals

T ≤ 1 % ∙ Tmax 0.99-1.01 ≤ 1 % ∙ Tmax ≥ 0.998

1

For flow meters that determine volumetric flow rate, Vstd , you may substitute Vstd for n as the quantity and 

substitute Vstdmax for max n .

272. Section 1065.308 is amended by revising paragraph (d)(2) and adding paragraph 

(g) to read as follows:

§1065.308 Continuous gas analyzer system-response and updating-recording 

verification—for gas analyzers not continuously compensated for other gas species.

* * * * *
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(d) * * *

(2) Equipment setup. We recommend using minimal lengths of gas transfer lines 

between all connections and fast-acting three-way valves (2 inlets, 1 outlet) to control the 

flow of zero and blended span gases to the sample system’s probe inlet or a tee near the 

outlet of the probe. If you inject the gas at a tee near the outlet of the probe, you may

correct the transformation time, t50, for an estimate of the transport time from the probe 

inlet to the tee. Normally the gas flow rate is higher than the sample flow rate and the 

excess is overflowed out the inlet of the probe. If the gas flow rate is lower than the 

sample flow rate, the gas concentrations must be adjusted to account for the dilution from 

ambient air drawn into the probe. We recommend you use the final, stabilized analyzer 

reading as the final gas concentration. Select span gases for the species being measured. 

You may use binary or multi-gas span gases. You may use a gas blending or mixing 

device to blend span gases. A gas blending or mixing device is recommended when 

blending span gases diluted in N2 with span gases diluted in air. You may use a multi-gas 

span gas, such as NO-CO-CO2-C3H8-CH4, to verify multiple analyzers at the same time. 

If you use standard binary span gases, you must run separate response tests for each 

analyzer. In designing your experimental setup, avoid pressure pulsations due to 

stopping the flow through the gas-blending device. The change in gas concentration must 

be at least 20 % of the analyzer’s range.

* * * * *

(g) Optional procedure. Instead of using a three-way valve to switch between zero and 

span gases, you may use a fast-acting two-way valve to switch sampling between ambient 

air and span gas at the probe inlet. For this alternate procedure, the following provisions 

apply:

(1) If your probe is sampling from a continuously flowing gas stream (e.g., a CVS 

tunnel), you may adjust the span gas flow rate to be different than the sample flow rate.

(2) If your probe is sampling from a gas stream that is not continuously flowing (e.g., a 

raw exhaust stack), you must adjust the span gas flow rate to be less than the sample flow 

rate so ambient air is always being drawn into the probe inlet. This avoids errors 

associated with overflowing span gas out of the probe inlet and drawing it back in when 

sampling ambient air.

(3) When sampling ambient air or ambient air mixed with span gas, all the analyzer 

readings must be stable within ±0.5 % of the target gas concentration step size. If any 

analyzer reading is outside the specified range, you must resolve the problem and verify

that all the analyzer readings meet this specification.

(4) For oxygen analyzers, you may use purified N2 as the zero gas and ambient air (plus 

purified N2 if needed) as the reference gas. Perform the verification with seven repeat 

measurements that each consist of stabilizing with purified N2, switching to ambient air

and observing the analyzer’s rise and stabilized reading, followed by switching back to 

purified N2 and observing the analyzer’s fall and stabilized reading.

273. Section 1065.309 is amended by revising paragraphs (a) and (d)(2) and adding 

paragraphs (g) and (h) to read as follows:

§1065.309 Continuous gas analyzer system-response and updating-recording 

verification—for gas analyzers continuously compensated for other gas species.
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(a) Scope and frequency. This section describes a verification procedure for system 

response and updating-recording frequency for continuous gas analyzers that output a 

single gas species mole fraction (i.e., concentration) based on a continuous combination 

of multiple gas species measured with multiple detectors (i.e., gas analyzers continuously

compensated for other gas species). See §1065.308 for verification procedures that apply 

to continuous gas analyzers that are not continuously compensated for other gas species 

or that use only one detector for gaseous species. Perform this verification to determine 

the system response of the continuous gas analyzer and its sampling system. This 

verification is required for continuous gas analyzers used for transient or ramped-modal 

testing. You need not perform this verification for batch gas analyzers or for continuous 

gas analyzers that are used only for discrete-mode testing. For this check we consider 

water vapor a gaseous constituent. This verification does not apply to any processing of 

individual analyzer signals that are time-aligned to their t50 times and were verified 

according to §1065.308. For example, this verification does not apply to correction for 

water removed from the sample done in post-processing according to §1065.659 (40 CFR 

1066.620 for vehicle testing) and it does not apply to NMHC determination from THC 

and CH4 according to §1065.660. Perform this verification after initial installation (i.e., 

test cell commissioning) and after any modifications to the system that would change the 

system response.

* * * * *

(d) * * *

(2) Equipment setup. We recommend using minimal lengths of gas transfer lines 

between all connections and fast-acting three-way valves (2 inlets, 1 outlet) to control the 

flow of zero and blended span gases to the sample system’s probe inlet or a tee near the 

outlet of the probe. If you inject the gas at a tee near the outlet of the probe, you may

correct the transformation time, t50, for an estimate of the transport time from the probe 

inlet to the tee. Normally the gas flow rate is higher than the sample flow rate and the 

excess is overflowed out the inlet of the probe. If the gas flow rate is lower than the 

sample flow rate, the gas concentrations must be adjusted to account for the dilution from 

ambient air drawn into the probe. We recommend you use the final, stabilized analyzer 

reading as the final gas concentration. Select span gases for the species being 

continuously combined, other than H2O. Select concentrations of compensating species 

that will yield concentrations of these species at the analyzer inlet that covers the range of 

concentrations expected during testing. You may use binary or multi-gas span gases. 

You may use a gas blending or mixing device to blend span gases. A gas blending or 

mixing device is recommended when blending span gases diluted in N2 with span gases 

diluted in air. You may use a multi-gas span gas, such as NO-CO-CO2-C3H8-CH4, to 

verify multiple analyzers at the same time. In designing your experimental setup, avoid 

pressure pulsations due to stopping the flow through the gas blending device. The 

change in gas concentration must be at least 20 % of the analyzer’s range. If H2O 

correction is applicable, then span gases must be humidified before entering the analyzer; 

however, you may not humidify NO2 span gas by passing it through a sealed 

humidification vessel that contains water. You must humidify NO2 span gas with another 

moist gas stream. We recommend humidifying your NO-CO-CO2-C3H8-CH4, balance N2

blended gas by flowing the gas mixture through a sealed vessel that humidifies the gas by

bubbling it through distilled water and then mixing the gas with dry NO2 gas, balance 
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purified air. If your system does not use a sample dryer to remove water from the sample 

gas, you must humidify your span gas to the highest sample H2O content that you 

estimate during emission sampling. If your system uses a sample dryer during testing, it 

must pass the sample dryer verification check in §1065.342, and you must humidify your 

span gas to an H2O content greater than or equal to the level determined in 

§1065.145(e)(2). If you are humidifying span gases without NO2, use good engineering 

judgment to ensure that the wall temperatures in the transfer lines, fittings, and valves 

from the humidifying system to the probe are above the dewpoint required for the target 

H2O content. If you are humidifying span gases with NO2, use good engineering 

judgment to ensure that there is no condensation in the transfer lines, fittings, or valves 

from the point where humidified gas is mixed with NO2 span gas to the probe. We 

recommend that you design your setup so that the wall temperatures in the transfer lines, 

fittings, and valves from the humidifying system to the probe are at least 5 oC above the 

local sample gas dewpoint. Operate the measurement and sample handling system as you 

do for emission testing. Make no modifications to the sample handling system to reduce 

the risk of condensation. Flow humidified gas through the sampling system before this 

check to allow stabilization of the measurement system’s sampling handling system to 

occur, as it would for an emission test.

* * * * *

(g) Optional procedure. Follow the optional procedures in §1065.308(g), noting that you 

may use compensating gases mixed with ambient air for oxygen analyzers.

(h) Analyzers with H2O compensation sampling downstream of a sample dryer. You 

may omit humidifying the span gas as described in this paragraph (h). If an analyzer 

compensates only for H2O, you may apply the requirements of §1065.308 instead of the 

requirements of this section. You may omit humidifying the span gas if you meet the 

following conditions:

(1) The analyzer is located downstream of a sample dryer.

(2) The maximum value for H2O mole fraction downstream of the dryer must be less than 

or equal to 0.010. Verify this during each sample dryer verification according to 

§1065.342.

274. Section 1065.310 is revised to read as follows:

§1065.310 Torque calibration.

(a) Scope and frequency. Calibrate all torque-measurement systems including 

dynamometer torque measurement transducers and systems upon initial installation and 

after major maintenance. Use good engineering judgment to repeat the calibration. 

Follow the torque transducer manufacturer’s instructions for linearizing your torque 

sensor’s output. We recommend that you calibrate the torque-measurement system with 

a reference force and a lever arm.

(b) Recommended procedure to quantify lever-arm length. Quantify the lever-arm 

length, NIST-traceable within 0.5 % uncertainty. The lever arm’s length must be 

measured from the centerline of the dynamometer to the point at which the reference 

force is measured. The lever arm must be perpendicular to gravity (i.e., horizontal), and 

it must be perpendicular to the dynamometer’s rotational axis. Balance the lever arm’s 

torque or quantify its net hanging torque, NIST-traceable within 1 % uncertainty, and 

account for it as part of the reference torque.
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(c) Recommended procedure to quantify reference force. We recommend dead-weight 

calibration, but you may use either of the following procedures to quantify the reference 

force, NIST-traceable within 0.5 % uncertainty.

(1) Dead-weight calibration. This technique applies a known force by hanging known 

weights at a known distance along a lever arm. Make sure the weights’ lever arm is 

perpendicular to gravity (i.e., horizontal) and perpendicular to the dynamometer’s 

rotational axis. Apply at least six calibration-weight combinations for each applicable 

torque-measuring range, spacing the weight quantities about equally over the range. 

Oscillate or rotate the dynamometer during calibration to reduce frictional static 

hysteresis. Determine each weight’s reference force by multiplying its NIST-traceable 

mass by the local acceleration of Earth’s gravity, as described in §1065.630. Calculate 

the reference torque as the weights’ reference force multiplied by the lever arm reference 

length.

(2) Strain gage, load transducer, or proving ring calibration. This technique applies force 

either by hanging weights on a lever arm (these weights and their lever arm length are not 

used as part of the reference torque determination) or by operating the dynamometer at 

different torques. Apply at least six force combinations for each applicable torquemeasuring range, spacing the force quantities about equally over the range. Oscillate or 

rotate the dynamometer during calibration to reduce frictional static hysteresis. In this 

case, the reference torque is determined by multiplying the force output from the 

reference meter (such as a strain gage, load transducer, or proving ring) by its effective 

lever-arm length, which you measure from the point where the force measurement is 

made to the dynamometer’s rotational axis. Make sure you measure this length 

perpendicular to the reference meter’s measurement axis and perpendicular to the 

dynamometer’s rotational axis.

275. Section 1065.315 is amended by revising paragraph (a)(2) to read as follows:

§1065.315 Pressure, temperature, and dewpoint calibration.

(a) * * *

(2) Temperature. We recommend digital dry-block or stirred-liquid temperature 

calibrators, with data logging capabilities to minimize transcription errors. We 

recommend using calibration reference quantities that are NIST-traceable within 0.5 % 

uncertainty. You may perform linearity verification for temperature measurement 

systems with thermocouples, RTDs, and thermistors by removing the sensor from the 

system and using a simulator in its place. Use a NIST-traceable simulator that is 

independently calibrated and, as appropriate, cold-junction compensated. The simulator 

uncertainty scaled to absolute temperature must be less than 0.5 % of Tmax. If you use 

this option, you must use sensors that the supplier states are accurate to better than 0.5 % 

of Tmax compared with their standard calibration curve.

* * * * *

276. Section 1065.341 is amended by revising the section heading and paragraphs (a)

introductory text, (d) introductory text, and (f)(3) to read as follows:

§1065.341 CVS, PFD, and batch sampler verification (propane check).

(a) A propane check serves as a CVS verification to determine if there is a discrepancy in 

measured values of diluted exhaust flow. You may use the same procedure to verify
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PFDs and batch samplers. For purposes of PFD and batch sampler verification, read the 

term CVS to mean PFD or batch sampler as appropriate. A propane check also serves as 

a batch-sampler verification to determine if there is a discrepancy in a batch sampling 

system that extracts a sample from a CVS, as described in paragraph (g) of this section. 

Using good engineering judgment and safe practices, this check may be performed using 

a gas other than propane, such as CO2 or CO. A failed propane check might indicate one 

or more problems that may require corrective action, as follows:

* * * * *

(d) If you performed the vacuum-side leak verification of the HC sampling system as 

described in paragraph (c)(8) of this section, you may use the HC contamination 

procedure in §1065.520(f) to verify HC contamination. Otherwise, zero, span, and verify

contamination of the HC sampling system, as follows:

* * * * *

(f) * * *

(3) Calculate total C3H8 mass based on your CVS and HC data as described in §1065.650 

(40 CFR 1066.605 for vehicle testing) and §1065.660, using the molar mass of C3H8, 

MC3H8, instead the effective molar mass of HC, MHC.

* * * * *

277. Section 1065.350 is amended by revising paragraphs (d) and (e)(1) to read as 

follows:

§1065.350 H2O interference verification for CO2 NDIR analyzers.

* * * * *

(d) Procedure. Perform the interference verification as follows:

(1) Start, operate, zero, and span the CO2 NDIR analyzer as you would before an 

emission test. If the sample is passed through a dryer during emission testing, you may 

run this verification test with the dryer if it meets the requirements of §1065.342. 

Operate the dryer at the same conditions as you will for an emission test. You may also 

run this verification test without the sample dryer.

(2) Create a humidified test gas by bubbling zero gas that meets the specifications in 

§1065.750 through distilled H2O in a sealed vessel. If the sample is not passed through a 

dryer during emission testing, control the vessel temperature to generate an H2O level at 

least as high as the maximum expected during emission testing. If the sample is passed 

through a dryer during emission testing, control the vessel temperature to generate an 

H2O level at least as high as the level determined in §1065.145(e)(2) for that dryer.

(3) Introduce the humidified test gas into the sample system. You may introduce it

downstream of any sample dryer, if one is used during testing.

(4) If the sample is not passed through a dryer during this verification test, measure the 

H2O mole fraction, xH2O, of the humidified test gas, as close as possible to the inlet of the 

analyzer. For example, measure dewpoint, Tdew, and absolute pressure, ptotal, to calculate 

xH2O. Verify that the H2O content meets the requirement in paragraph (d)(2) of this 

section. If the sample is passed through a dryer during this verification test, you must 

verify that the H2O content of the humidified test gas downstream of the vessel meets the 

requirement in paragraph (d)(2) of this section based on either direct measurement of the 

H2O content (e.g., dewpoint and pressure) or an estimate based on the vessel pressure and 

temperature. Use good engineering judgment to estimate the H2O content. For example, 
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you may use previous direct measurements of H2O content to verify the vessel’s level of 

saturation.

(5) If a sample dryer is not used in this verification test, use good engineering judgment 

to prevent condensation in the transfer lines, fittings, or valves from the point where xH2O

is measured to the analyzer. We recommend that you design your system so the wall 

temperatures in the transfer lines, fittings, and valves from the point where xH2O is 

measured to the analyzer are at least 5 oC above the local sample gas dewpoint.

(6) Allow time for the analyzer response to stabilize. Stabilization time may include time 

to purge the transfer line and to account for analyzer response.

(7) While the analyzer measures the sample’s concentration, record 30 seconds of 

sampled data. Calculate the arithmetic mean of this data. The analyzer meets the 

interference verification if this value is within (0.0 ±0.4) mmol/mol.

(e) * * *

(1) You may omit this verification if you can show by engineering analysis that for your 

CO2 sampling system and your emission-calculation procedures, the H2O interference for 

your CO2 NDIR analyzer always affects your brake-specific emission results within 0.5 

% of each of the applicable standards. This specification also applies for vehicle testing, 

except that it relates to emission results in g/mile or g/kilometer.

* * * * *

278. Section 1065.355 is amended by revising paragraphs (d)(2) and (d)(4) to read as 

follows:

§1065.355 H2O and CO2 interference verification for CO NDIR analyzers.

* * * * *

(d) * * *

(2) Create a humidified CO2 test gas by bubbling a CO2 span gas that meets the 

specifications in §1065.750 through distilled H2O in a sealed vessel. If the sample is not 

passed through a dryer during emission testing, control the vessel temperature to generate 

an H2O level at least as high as the maximum expected during emission testing. If the 

sample is passed through a dryer during emission testing, control the vessel temperature 

to generate an H2O level at least as high as the level determined in §1065.145(e)(2) for 

that dryer. Use a CO2 span gas concentration at least as high as the maximum expected 

during testing.

* * * * *

(4) If the sample is not passed through a dryer during this verification test, measure the 

H2O mole fraction, xH2O, of the humidified CO2 test gas as close as possible to the inlet of 

the analyzer. For example, measure dewpoint, Tdew, and absolute pressure, ptotal, to 

calculate xH2O. Verify that the H2O content meets the requirement in paragraph (d)(2) of 

this section. If the sample is passed through a dryer during this verification test, you must 

verify that the H2O content of the humidified test gas downstream of the vessel meets the 

requirement in paragraph (d)(2) of this section based on either direct measurement of the 

H2O content (e.g., dewpoint and pressure) or an estimate based on the vessel pressure and 

temperature. Use good engineering judgment to estimate the H2O content. For example, 

you may use previous direct measurements of H2O content to verify the vessel’s level of 

saturation.

* * * * *
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279. Section 1065.360 is amended by revising paragraphs (a)(3), (b), (d), and (e) to 

read as follows:

§1065.360 FID optimization and verification.

(a) * * *

(3) Verify the CH4 response within 185 days before testing as described in paragraph (e) 

of this section.

(b) Calibration. Use good engineering judgment to develop a calibration procedure, such 

as one based on the FID-analyzer manufacturer’s instructions and recommended 

frequency for calibrating the FID. Alternately, you may remove system components for 

off-site calibration. For a FID that measures THC, calibrate using C3H8 calibration gases 

that meet the specifications of §1065.750. For a FID that measures CH4, calibrate using 

CH4 calibration gases that meet the specifications of §1065.750. We recommend FID 

analyzer zero and span gases that contain approximately the flow-weighted mean 

concentration of O2 expected during testing. If you use a FID to measure CH4

downstream of a nonmethane cutter, you may calibrate that FID using CH4 calibration 

gases with the cutter. Regardless of the calibration gas composition, calibrate on a 

carbon number basis of one (C1). For example, if you use a C3H8 span gas of 

concentration 200 mol/mol, span the FID to respond with a value of 600 mol/mol. As 

another example, if you use a CH4 span gas with a concentration of 200 mol/mol, span 

the FID to respond with a value of 200 mol/mol.

* * * * *

(d) THC FID CH4 response factor determination. This procedure is only for FID 

analyzers that measure THC. Since FID analyzers generally have a different response to 

CH4 versus C3H8, determine each THC-FID analyzer’s CH4 response factor, RFCH4[THCFID], after FID optimization. Use the most recent RFCH4[THC-FID] measured according to 

this section in the calculations for HC determination described in §1065.660 to 

compensate for CH4 response. Determine RFCH4[THC-FID] as follows, noting that you do 

not determine RFCH4[THC-FID] for FIDs that are calibrated and spanned using CH4 with a 

nonmethane cutter:

(1) Select a C3H8 span gas concentration that you use to span your analyzers before 

emission testing. Use only span gases that meet the specifications of §1065.750. Record 

the C3H8 concentration of the gas.

(2) Select a CH4 span gas concentration that you use to span your analyzers before 

emission testing. Use only span gases that meet the specifications of §1065.750. Record 

the CH4 concentration of the gas.

(3) Start and operate the FID analyzer according to the manufacturer’s instructions.

(4) Confirm that the FID analyzer has been calibrated using C3H8. Calibrate on a carbon 

number basis of one (C1). For example, if you use a C3H8 span gas of concentration 200 

mol/mol, span the FID to respond with a value of 600 mol/mol.

(5) Zero the FID with a zero gas that you use for emission testing.

(6) Span the FID with the C3H8 span gas that you selected under paragraph (d)(1) of this 

section.

(7) Introduce at the sample port of the FID analyzer, the CH4 span gas that you selected 

under paragraph (d)(2) of this section.
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(8) Allow time for the analyzer response to stabilize. Stabilization time may include time 

to purge the analyzer and to account for its response.

(9) While the analyzer measures the CH4 concentration, record 30 seconds of sampled 

data. Calculate the arithmetic mean of these values.

(10) For analyzers with multiple ranges, you need to perform the procedure in this 

paragraph (d) only on a single range. 

(11) Divide the mean measured concentration by the recorded span concentration of the 

CH4 calibration gas. The result is the FID analyzer’s response factor for CH4, RFCH4[THCFID].

(e) THC FID CH4 response verification. This procedure is only for FID analyzers that 

measure THC. Verify RFCH4[THC-FID] as follows:

(1) Perform a CH4 response factor determination as described in paragraph (d) of this 

section. If the resulting value of RFCH4[THC-FID] is within 5 % of its most recent 

previously determined value, the THC FID passes the CH4 response verification. For 

example, if the most recent previous value for RFCH4[THC-FID] was 1.05 and it increased by

0.05 to become 1.10 or it decreased by 0.05 to become 1.00, either case would be 

acceptable because 4.8 % is less than 5 %.

(2) If RFCH4[THC-FID] is not within the tolerance specified in paragraph (e)(1) of this 

section, use good engineering judgment to verify that the flow rates and/or pressures of 

FID fuel, burner air, and sample are at their most recent previously recorded values, as 

determined in paragraph (c) of this section. You may adjust these flow rates as 

necessary. Then determine the RFCH4[THC-FID] as described in paragraph (d) of this section 

and verify that it is within the tolerance specified in this paragraph (e).

(3) If RFCH4[THC-FID] is not within the tolerance specified in this paragraph (e), re-optimize 

the FID response as described in paragraph (c) of this section.

(4) Determine a new RFCH4[THC-FID] as described in paragraph (d) of this section. Use this 

new value of RFCH4[THC-FID] in the calculations for HC determination, as described in 

§1065.660.

(5) For analyzers with multiple ranges, you need to perform the procedure in this 

paragraph (e) only on a single range.

280. Section 1065.362 is amended by adding paragraph (d )(15) to read as follows:

§1065.362 Non-stoichiometric raw exhaust FID O2 interference verification.

* * * * *

(d) * *

(15) For analyzers with multiple ranges, you need to perform the procedure in this 

paragraph (d) only on a single range. 

281. Section 1065.365 is amended by revising paragraphs (a), (b), (d)(1), (e)(1), (f) 

introductory text, and (f)(1) to read as follows:

§1065.365 Nonmethane cutter penetration fractions.

(a) Scope and frequency. If you use a FID analyzer and a nonmethane cutter (NMC) to 

measure methane (CH4), determine the nonmethane cutter’s penetration fractions of CH4, 

PFCH4, and ethane, PFC2H6. As detailed in this section, these penetration fractions may be 

determined as a combination of NMC penetration fractions and FID analyzer response 

factors, depending on your particular NMC and FID analyzer configuration. Perform this 
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verification after installing the nonmethane cutter. Repeat this verification within 185 

days of testing to verify that the catalytic activity of the cutter has not deteriorated. Note 

that because nonmethane cutters can deteriorate rapidly and without warning if they are 

operated outside of certain ranges of gas concentrations and outside of certain 

temperature ranges, good engineering judgment may dictate that you determine a 

nonmethane cutter’s penetration fractions more frequently.

(b) Measurement principles. A nonmethane cutter is a heated catalyst that removes 

nonmethane hydrocarbons from an exhaust sample stream before the FID analyzer 

measures the remaining hydrocarbon concentration. An ideal nonmethane cutter would 

have a CH4 penetration fraction, PFCH4, of 1.000, and the penetration fraction for all other 

nonmethane hydrocarbons would be 0.000, as represented by PFC2H6. The emission 

calculations in §1065.660 use the measured values from this verification to account for 

less than ideal NMC performance.

* * * * *

(d) * * *

(1) Select CH4 and C2H6 analytical gas mixtures and ensure that both mixtures meet the 

specifications of §1065.750. Select a CH4 concentration that you would use for spanning 

the FID during emission testing and select a C2H6 concentration that is typical of the peak 

NMHC concentration expected at the hydrocarbon standard or equal to the THC 

analyzer’s span value. For CH4 analyzers with multiple ranges, perform this procedure 

on the highest range used for emission testing.

* * * * *

(e) * * *

(1) Select CH4 and C2H6 analytical gas mixtures and ensure that both mixtures meet the 

specifications of §1065.750. Select a CH4 concentration that you would use for spanning 

the FID during emission testing and select a C2H6 concentration that is typical of the peak 

NMHC concentration expected at the hydrocarbon standard and the C2H6 concentration 

typical of the peak total hydrocarbon (THC) concentration expected at the hydrocarbon 

standard or equal to the THC analyzer’s span value. For CH4 analyzers with multiple 

ranges, perform this procedure on the highest range used for emission testing.

* * * * *

(f) Procedure for a FID calibrated with CH4, bypassing the NMC. If you use a FID with 

an NMC that is calibrated with CH4, by bypassing the NMC, determine its combined 

ethane (C2H6) response factor and penetration fraction, RFPFC2H6[NMC-FID] , as well as its 

CH4 penetration fraction, PFCH4[NMC-FID], as follows:

(1) Select CH4 and C2H6 analytical gas mixtures and ensure that both mixtures meet the 

specifications of §1065.750. Select a CH4 concentration that you would use for spanning 

the FID during emission testing and select a C2H6 concentration that is typical of the peak 

NMHC concentration expected at the hydrocarbon standard or equal to the THC 

analyzer’s span value. For CH4 analyzers with multiple ranges, perform this procedure 

on the highest range used for emission testing.

* * * * *

282. A new § 1065.369 is added to subpart D under the center header “Hydrocarbon 

Measurements” to read as follows:
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§1065.369 H2O, CO, and CO2 interference verification for photoacoustic alcohol 

analyzers.

(a) Scope and frequency. If you measure ethanol or methanol using a photoacoustic

analyzer, verify the amount of H2O, CO, and CO2 interference after initial analyzer 

installation and after major maintenance.

(b) Measurement principles. H2O, CO, and CO2 can positively interfere with a 

photoacoustic analyzer by causing a response similar to ethanol or methanol. If the 

photoacoustic analyzer uses compensation algorithms that utilize measurements of other 

gases to meet this interference verification, simultaneously conduct these other 

measurements to test the compensation algorithms during the analyzer interference 

verification.

(c) System requirements. Photoacoustic analyzers must have combined interference that 

is within (0.0 ± 0.5) μmol/mol. We strongly recommend a lower interference that is 

within (0.0 ± 0.25) μmol/mol.

(d) Procedure. Perform the interference verification by following the procedure in 

§1065.375(d), comparing the results to paragraph (c) of this section.

283. Section 1065.370 is amended by revising paragraphs (d)(9) and (e)(5) to read as 

follows:

§1065.370 CLD CO2 and H2O quench verification.

* * * * *

(d) * * *

(9) While flowing NO and CO2 through the gas divider, stabilize the output of the gas 

divider. Determine the CO2 concentration from the gas divider output, applying gas 

property correction as necessary to ensure accurate gas division, or measure it using an 

NDIR. Record this concentration, xCO2act, and use it in the quench verification 

calculations in §1065.675. Alternatively, you may use a simple gas blending device and 

use an NDIR to determine this CO2 concentration. If you use an NDIR, it must meet the 

requirements of this part for laboratory testing and you must span it with the CO2 span 

gas from paragraph (d)(4) of this section.

* * * * *

(e) * * *

(5) Humidify the NO span gas by bubbling it through distilled H2O in a sealed vessel. If 

the humidified NO span gas sample does not pass through a sample dryer for this 

verification test, control the vessel temperature to generate an H2O level approximately

equal to the maximum mole fraction of H2O expected during emission testing. If the 

humidified NO span gas sample does not pass through a sample dryer, the quench 

verification calculations in §1065.675 scale the measured H2O quench to the highest 

mole fraction of H2O expected during emission testing. If the humidified NO span gas 

sample passes through a dryer for this verification test, control the vessel temperature to 

generate an H2O level at least as high as the level determined in §1065.145(e)(2). For 

this case, the quench verification calculations in §1065.675 do not scale the measured 

H2O quench.

* * * * *

284. Section 1065.375 is amended by revising paragraph (d) to read as follows:
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§1065.375 Interference verification for N2O analyzers.

* * * * *

(d) Procedure. Perform the interference verification as follows:

(1) Start, operate, zero, and span the N2O analyzer as you would before an emission test. 

If the sample is passed through a dryer during emission testing, you may run this 

verification test with the dryer if it meets the requirements of §1065.342. Operate the 

dryer at the same conditions as you will for an emission test. You may also run this 

verification test without the sample dryer.

(2) Create a humidified test gas by bubbling a multi component span gas that incorporates 

the target interference species and meets the specifications in §1065.750 through distilled 

H2O in a sealed vessel. If the sample is not passed through a dryer during emission 

testing, control the vessel temperature to generate an H2O level at least as high as the 

maximum expected during emission testing. If the sample is passed through a dryer 

during emission testing, control the vessel temperature to generate an H2O level at least 

as high as the level determined in §1065.145(e)(2) for that dryer. Use interference span 

gas concentrations that are at least as high as the maximum expected during testing.

(3) Introduce the humidified interference test gas into the sample system. You may

introduce it downstream of any sample dryer, if one is used during testing. 

(4) If the sample is not passed through a dryer during this verification test, measure the 

H2O mole fraction, xH2O, of the humidified interference test gas as close as possible to the 

inlet of the analyzer. For example, measure dewpoint, Tdew, and absolute pressure, ptotal, 

to calculate xH2O. Verify that the H2O content meets the requirement in paragraph (d)(2) 

of this section. If the sample is passed through a dryer during this verification test, you 

must verify that the H2O content of the humidified test gas downstream of the vessel 

meets the requirement in paragraph (d)(2) of this section based on either direct 

measurement of the H2O content (e.g., dewpoint and pressure) or an estimate based on 

the vessel pressure and temperature. Use good engineering judgment to estimate the H2O

content. For example, you may use previous direct measurements of H2O content to 

verify the vessel’s level of saturation.

(5) If a sample dryer is not used in this verification test, use good engineering judgment 

to prevent condensation in the transfer lines, fittings, or valves from the point where xH2O

is measured to the analyzer. We recommend that you design your system so that the wall 

temperatures in the transfer lines, fittings, and valves from the point where xH2O is 

measured to the analyzer are at least 5 oC above the local sample gas dewpoint.

(6) Allow time for the analyzer response to stabilize. Stabilization time may include time 

to purge the transfer line and to account for analyzer response.

(7) While the analyzer measures the sample’s concentration, record its output for 30 

seconds. Calculate the arithmetic mean of this data. When performed with all the gases 

simultaneously, this is the combined interference.

(8) The analyzer meets the interference verification if the result of paragraph (d)(7) of 

this section meets the tolerance in paragraph (c) of this section.

(9) You may also run interference procedures separately for individual interference gases. 

If the interference gas levels used are higher than the maximum levels expected during 

testing, you may scale down each observed interference value (the arithmetic mean of 30 

second data described in paragraph (d)(7) of this section) by multiplying the observed 

interference by the ratio of the maximum expected concentration value to the actual value 
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used during this procedure. You may run separate interference concentrations of H2O 

(down to 0.025 mol/mol H2O content) that are lower than the maximum levels expected 

during testing, but you must scale up the observed H2O interference by multiplying the 

observed interference by the ratio of the maximum expected H2O concentration value to 

the actual value used during this procedure. The sum of the scaled interference values 

must meet the tolerance for combined interference as specified in paragraph (c) of this 

section.

285. Section 1065.376 is amended by revising paragraphs (b), (d)(2)(vi), and 

(d)(2)(viii) to read as follows:

§1065.376 Chiller NO2 penetration.

* * * * *

(b) Measurement principles. A chiller removes H2O, which can otherwise interfere with 

a NOx measurement. However, liquid H2O remaining in an improperly designed chiller 

can remove NO2 from the sample. If a chiller is used without an NO2-to-NO converter 

upstream, it could remove NO2 from the sample prior NOx measurement.

* * * * *

(d) * * *

(2) * * *

(vi) Next saturate the sampling system by overflowing a dewpoint generator’s output, set 

at a dewpoint of 50 C, to the gas sampling system’s probe or overflow fitting. Sample 

the dewpoint generator’s output through the sampling system and chiller for at least 10 

minutes until the chiller is expected to be removing a constant rate of H2O.

* * * * *

(viii) Correct xNOxmeas to xNOxdry based upon the residual H2O vapor that passed through 

the chiller at the chiller’s outlet temperature and pressure.

* * * * *

Subpart E—[Amended]

286. Section 1065.405 is revised to read as follows:

§1065.405 Test engine preparation and maintenance.

This part 1065 describes how to test engines for a variety of purposes, including 

certification testing, production-line testing, and in-use testing. Depending on which type 

of testing is being conducted, different preparation and maintenance requirements apply

for the test engine. 

(a) If you are testing an emission-data engine for certification, make sure it is built to 

represent production engines, consistent with paragraph (f) of this section. This includes 

governors that you normally install on production engines. Production engines should 

also be tested with their installed governors. If your engine is equipped with multiple 

user-selectable governor types and if the governor does not manipulate the emission

control system (i.e., the governor only modulates an "operator demand" signal such as 

commanded fuel rate, torque, or power), choose the governor type that allows the test cell 

to most accurately follow the duty cycle. If the governor manipulates the emission

control system, treat it as an adjustable parameter. See paragraph (b) of this section for 

guidance on setting adjustable parameters. If you do not install governors on production 
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engines, simulate a governor that is representative of a governor that others will install on 

your production engines. In certain circumstances, you may incorporate test cell 

components to simulate an in-use configuration, consistent with good engineering 

judgment. For example, §§1065.122 and 1065.125 allow the use of test cell components 

to represent engine cooling and intake air systems. The provisions in §1065.110(e) also 

apply to emission-data engines for certification.

(b) We may set adjustable parameters to any value in the valid range, and you are

responsible for controlling emissions over the full valid range. For each adjustable 

parameter, if the standard-setting part has no unique requirements and if we have not 

specified a value, use good engineering judgment to select the most common setting. If 

information on the most common setting is not available, select the setting representing

the engine’s original shipped configuration. If information on the most common and 

original settings is not available, set the adjustable parameter in the middle of the valid 

range.

(c) Testing generally occurs only after the test engine has undergone a stabilization step 

(or in-use operation). If the engine has not already been stabilized, run the test engine, 

with all emission control systems operating, long enough to stabilize emission levels. 

Note that you must generally use the same stabilization procedures for emission-data 

engines for which you apply the same deterioration factors so low-hour emission-data 

engines are consistent with the low-hour engine used to develop the deterioration factor.

(1) Unless otherwise specified in the standard-setting part, you may consider emission 

levels stable without measurement after 50 h of operation. If the engine needs less 

operation to stabilize emission levels, record your reasons and the methods for doing this, 

and give us these records if we ask for them. If the engine will be tested for certification 

as a low-hour engine, see the standard-setting part for limits on testing engines to 

establish low-hour emission levels.

(2) You may stabilize emissions from a catalytic exhaust aftertreatment device by 

operating it on a different engine, consistent with good engineering judgment. Note that 

good engineering judgment requires that you consider both the purpose of the test and 

how your stabilization method will affect the development and application of 

deterioration factors. For example, this method of stabilization is generally not 

appropriate for production engines. We may also allow you to stabilize emissions from a 

catalytic exhaust aftertreatment device by operating it on an engine-exhaust simulator.

(d) Record any maintenance, modifications, parts changes, diagnostic or emissions 

testing and document the need for each event. You must provide this information if we 

request it.

(e) For accumulating operating hours on your test engines, select engine operation that 

represents normal in-use operation for the engine family.

(f) If your engine will be used in a vehicle equipped with a canister for storing 

evaporative hydrocarbons for eventual combustion in the engine and the test sequence 

involves a cold-start or hot-start duty cycle, attach a canister to the engine before running 

an emission test. You may omit using an evaporative canister for any hot-stabilized duty

cycles. You may request to omit using an evaporative canister during testing if you can 

show that it would not affect your ability to show compliance with the applicable 

emission standards. You may operate the engine without an installed canister for service 
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accumulation. Prior to an emission test, use the following steps to precondition a canister 

and attach it to your engine:

(1) Use a canister and plumbing arrangement that represents the in-use configuration of 

the largest capacity canister in all expected applications.

(2) Precondition the canister as described in 40 CFR 86.132-96(j).

(3) Connect the canister’s purge port to the engine.

(4) Plug the canister port that is normally connected to the fuel tank.

(g) This paragraph (g) defines the components that are considered to be part of the engine 

for laboratory testing. See §1065.110 for provisions related to system boundaries with 

respect to work inputs and outputs. 

(1) This paragraph (g)(1) describes certain criteria for considering a component to be part 

of the test engine. The criteria are intended to apply broadly, such that a component 

would generally be considered part of the engine in cases of uncertainty. Except as 

specified in paragraph (g)(2) of this section, an engine-related component meeting both 

the following criteria is considered to be part of the test engine for purposes of testing and 

for stabilizing emission levels, preconditioning, and measuring emission levels:

(i) The component directly affects the functioning of the engine, is related to controlling

emissions, or transmits engine power. This would include engine cooling systems, 

engine controls, and transmissions.

(ii) The component is covered by the applicable certificate of conformity. For example, 

this criterion would typically exclude radiators not described in an application for 

certification.

(2) This paragraph (g)(2) applies for engine-related components that meet the criteria of 

paragraph (g)(1) of this section, but that are part of the laboratory setup or are used for 

other engines. Such components are considered to be part of the test engine for 

preconditioning, but not for engine stabilization. For example, if you test your engines 

using the same laboratory exhaust tubing for all tests, there would be no restrictions on 

the number of test hours that could be accumulated with the tubing, but it would need to 

be preconditioned separately for each engine.

287. Section 1065.410 is amended by revising paragraph (c) to read as follows:

§1065.410 Maintenance limits for stabilized test engines.

* * * * *

(c) If you inspect an engine, keep a record of the inspection and update your application 

to document any changes that result. You may use any kind of equipment, instrument, or 

tool to identify bad engine components or perform maintenance if it is available at

dealerships and other service outlets.

* * * * *

Subpart F—[Amended]

288. Section 1065.501 is revised to read as follows:

§1065.501 Overview.

(a) Use the procedures detailed in this subpart to measure engine emissions over a 

specified duty cycle. Refer to subpart J of this part for field test procedures that describe 

how to measure emissions during in-use engine operation. This section describes how to:
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(1) Map your engine, if applicable, by recording specified speed and torque data, as 

measured from the engine’s primary output shaft.

(2) Transform normalized duty cycles into reference duty cycles for your engine by using 

an engine map.

(3) Prepare your engine, equipment, and measurement instruments for an emission test.

(4) Perform pre-test procedures to verify proper operation of certain equipment and 

analyzers.

(5) Record pre-test data.

(6) Start or restart the engine and sampling systems.

(7) Sample emissions throughout the duty cycle.

(8) Record post-test data.

(9) Perform post-test procedures to verify proper operation of certain equipment and 

analyzers.

(10) Weigh PM samples.

(b) Unless we specify otherwise, you may control the regeneration timing of infrequently 

regenerated aftertreatment devices such as diesel particulate filters using good 

engineering judgment. You may control the regeneration timing using a sequence of 

engine operating conditions or you may initiate regeneration with an external 

regeneration switch or other command. This provision also allows you to ensure that a 

regeneration event does not occur during an emission test.

(c) An emission test generally consists of measuring emissions and other parameters 

while an engine follows one or more duty cycles that are specified in the standard-setting 

part. There are two general types of duty cycles:

(1) Transient cycles. Transient duty cycles are typically specified in the standard-setting 

part as a second-by-second sequence of speed commands and normalized torque (or 

power) commands. Operate an engine over a transient cycle such that the speed and 

torque of the engine’s primary output shaft follows the target values. Proportionally

sample emissions and other parameters and use the calculations in subpart G of this part 

to calculate emissions. Start a transient test according to the standard-setting part, as 

follows:

(i) A cold-start transient cycle where you start to measure emissions just before starting 

an engine that has not been warmed up.

(ii) A hot-start transient cycle where you start to measure emissions just before starting a 

warmed-up engine.

(iii) A hot running transient cycle where you start to measure emissions after an engine is 

started, warmed up, and running.

(2) Steady-state cycles. Steady-state duty cycles are typically specified in the standardsetting part as a list of discrete operating points (modes or notches), where each operating 

point has one value of a normalized speed command and one value of a normalized 

torque (or power) command. Ramped-modal cycles for steady-state testing also list test 

times for each mode and transition times between modes where speed and torque are 

linearly ramped between modes, even for cycles with % power. Start a steady-state cycle 

as a hot running test, where you start to measure emissions after an engine is started, 

warmed up and running. Run a steady-state duty cycle as a discrete-mode cycle or a 

ramped-modal cycle, as follows:
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(i) Discrete-mode cycles. Before emission sampling, stabilize an engine at the first 

discrete mode of the duty cycle specified in the standard-setting part. Sample emissions 

and other parameters for that mode in the same manner as a transient cycle, with the 

exception that reference speed and torque values are constant. Record data for that mode, 

transition to the next mode, and then stabilize the engine at the next mode. Continue to 

sample each mode discretely as a separate test interval and calculate composite brakespecific emission results according to §1065.650(g)(2).

(A) Use good engineering judgment to determine the time required to stabilize the 

engine. You may make this determination before starting the test based on prior 

experience, or you may make this determination in real time based an automated stability

criteria. If needed, you may continue to operate the engine after reaching stability to get 

laboratory equipment ready for sampling.

(B) Collect PM on separate PM sample media for each mode.

(C) The minimum sample time is 60 seconds. We recommend that you sample both 

gaseous and PM emissions over the same test interval. If you sample gaseous and PM 

emissions over different test intervals, there must be no change in engine operation 

between the two test intervals. These two test intervals may completely or partially 

overlap, they may run consecutively, or they may be separated in time.

(ii) Ramped-modal cycles. Perform ramped-modal cycles similar to the way you would 

perform transient cycles, except that ramped-modal cycles involve mostly steady-state 

engine operation. Generate a ramped-modal duty cycle as a sequence of second-bysecond (1 Hz) reference speed and torque points. Run the ramped-modal duty cycle in 

the same manner as a transient cycle and use the 1 Hz reference speed and torque values 

to validate the cycle, even for cycles with % power. Proportionally sample emissions and 

other parameters during the cycle and use the calculations in subpart G of this part to 

calculate emissions. 

(d) Other subparts in this part identify how to select and prepare an engine for testing 

(subpart E), how to perform the required engine service accumulation (subpart E), and 

how to calculate emission results (subpart G).

(e) Subpart J of this part describes how to perform field testing.

289. Section 1065.510 is amended by revising paragraph (d)(5)(ii) to read as follows:

§1065.510 Engine mapping.

* * * * *

(d) * * *

(5) * * *

(ii) For any constant-speed engine, you may perform an engine map with a continuous 

torque sweep by continuing to record the mean feedback speed and torque at 1 Hz or 

more frequently. Use the dynamometer to increase torque. Increase the reference torque 

at a constant rate from no-load to the endpoint torque as defined in paragraph (d)(5)(i) of 

this section. You may continue mapping at higher torque setpoints. Unless the standardsetting part specifies otherwise, target a torque sweep rate equal to the manufacturerdeclared test torque (or a torque derived from your published power level if the declared 

test torque is not known) divided by 180 seconds. Stop recording after you complete the 

sweep. Verify that the average torque sweep rate over the entire map is within ±7 % of 

the target torque sweep rate. Use linear interpolation to determine intermediate values 
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from this series of mean feedback speed and torque values. Use this series of mean 

feedback speeds and torques to generate the power map as described in paragraph (e) of 

this section.

* * * * *

290. Section 1065.512 is amended by revising paragraph (b)(5) to read as follows:

§1065.512 Duty cycle generation.

* * * * *

(b) * * *

(5) Ramped-modal cycles. For ramped-modal cycles, generate reference speed and 

torque values at 1 Hz and use this sequence of points to run the cycle and validate it in 

the same manner as with a transient cycle. During the transition between modes, linearly 

ramp the denormalized reference speed and torque values between modes to generate 

reference points at 1 Hz. Do not linearly ramp the normalized reference torque values 

between modes and then denormalize them. Do not linearly ramp normalized or 

denormalized reference power points. These cases will produce nonlinear torque ramps 

in the denormalized reference torques. If the speed and torque ramp runs through a point 

above the engine’s torque curve, continue to command the reference torques and allow 

the operator demand to go to maximum. Note that you may omit power and either torque 

or speed points from the cycle-validation criteria under these conditions as specified in 

§1065.514.

* * * * *

291. A new § 1065.516 is added to subpart F to read as follows:

§1065.516 Sample system decontamination and preconditioning.

This section describes how to manage the impact of sampling system contamination on 

emission measurements. Use good engineering judgement to determine if you should 

decontaminate and precondition your sampling system. Contamination occurs when a 

regulated pollutant accumulates in the sample system in a high enough concentration to 

cause release during emission tests. Hydrocarbons and PM are generally the only

regulated pollutants that contaminate sample systems. Note that although this section 

focuses on avoiding excessive contamination of sampling systems, you must also use 

good engineering judgment to avoid loss of sample to a sampling system that is too clean.

The goal of decontamination is not to perfectly clean the sampling system, but rather to 

achieve equilibrium between the sampling system and the exhaust so emission 

components are neither lost to nor entrained from the sampling system.

(a) You may perform contamination checks as follows to determine if decontamination is 

needed:

(1) For dilute exhaust sampling systems, measure hydrocarbon and PM emissions by

sampling with the CVS dilution air turned on, without an engine connected to it.

(2) For raw analyzers and systems that collect PM samples from raw exhaust, measure 

hydrocarbon and PM emissions by sampling purified air or nitrogen.

(3) When calculating zero emission levels, apply all applicable corrections, including 

initial THC contamination and diluted (CVS) exhaust background corrections.

(4) Sampling systems are considered contaminated if either of the following conditions

applies:
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(i) The hydrocarbon emission level exceeds 2 % of the flow-weighted mean 

concentration expected at the HC standard.

(ii) The PM emission level exceeds 5 % of the level expected at the standard and exceeds 

20 μg on a 47 mm PTFE membrane filter.

(b) To precondition or decontaminate sampling systems, use the following recommended 

procedure or select a different procedure using good engineering judgment:

(1) Start the engine and use good engineering judgment to operate it at a condition that 

generates high exhaust temperatures at the sample probe inlet.

(2) Operate any dilution systems at their expected flow rates. Prevent aqueous 

condensation in the dilution systems.

(3) Operate any PM sampling systems at their expected flow rates.

(4) Sample PM for at least 10 min using any sample media. You may change sample 

media at any time during this process and you may discard them without weighing them.

(5) You may purge any gaseous sampling systems that do not require decontamination 

during this procedure.

(6) You may conduct calibrations or verifications on any idle equipment or analyzers 

during this procedure.

(c) If your sampling system is still contaminated following the procedures specified in 

paragraph (b) of this section, you may use more aggressive procedures to decontaminate 

the sampling system, as long as the decontamination does not cause the sampling system 

to be cleaner than an equilibrium condition such that artificially low emission 

measurements may result.

292. A new § 1065.518 is added to subpart F to read as follows:

§1065.518 Engine preconditioning.

(a) This section applies for engines where measured emissions are affected by prior 

operation, such as with a diesel engine that relies on urea-based selective catalytic 

reduction. Note that §1065.520(e) allows you to run practice duty cycles before the 

emission test; this section recommends how to do this for the purpose of preconditioning 

the engine. Follow the standard-setting part if it specifies a different engine 

preconditioning procedure.

(b) The intent of engine preconditioning is to manage the representativeness of emissions 

and emission controls over the duty cycle and to reduce bias.

(c) This paragraph (c) specifies the engine preconditioning procedures for different types 

of duty cycles. You must identify the amount of preconditioning before starting to 

precondition. You must run the predefined amount of preconditioning. You may

measure emissions during preconditioning. You may not abort an emission test sequence 

based on emissions measured during preconditioning. For confirmatory testing, you may

ask us to run more preconditioning cycles than we specify in this paragraph (c); we will

agree to this only if you show that additional preconditioning cycles are required to meet 

the intent of paragraph (b) of this section, for example, due to the effect of DPF 

regeneration on NH3 storage in the SCR catalyst. Perform preconditioning as follows, 

noting that the specific cycles for preconditioning are the same ones that apply for 

emission testing:

(1) Cold-start transient cycle. Precondition the engine by running at least one hot-start

transient cycle. We will precondition your engine by running two hot-start transient 
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cycles. Immediately after completing each preconditioning cycle, shut down the engine 

and complete the engine-off soak period. Immediately after completing the last 

preconditioning cycle, shut down the engine and begin the cold soak as described in 

§1065.530(a)(1).

(2) Hot-start transient cycle. Precondition the engine by running at least one hot-start 

transient cycle. We will precondition your engine by running two hot-start transient 

cycles. Immediately after completing each preconditioning cycle, shut down the engine, 

then start the next cycle (including the emission test) as soon as practical. For any repeat 

cycles, start the next cycle within 60 seconds after completing the last preconditioning 

cycle (this is optional for manufacturer testing).

(3) Hot-running transient cycle. Precondition the engine by running at least one hotrunning transient cycle. We will precondition your engine by running two hot-running 

transient cycles. Do not shut down the engine between cycles. Immediately after 

completing each preconditioning cycle, start the next cycle (including the emission test)

as soon as practical. For any repeat cycles, start the next cycle within 60 seconds after 

completing the last preconditioning cycle (this is optional for manufacturer testing). See 

§1065.530(a)(1)(iii) for additional instructions if the cycle begins and ends under 

different operating conditions.

(4) Discrete-mode cycle for steady-state testing. Precondition the engine at the same 

operating condition as the next test mode, unless the standard-setting part specifies 

otherwise. We will precondition your engine by running it for at least five minutes 

before sampling.

(5) Ramped-modal cycle for steady-state testing. Precondition the engine by running at 

least the second half of the ramped-modal cycle, based on the number of test modes. For 

example, for the five-mode cycle specified in 40 CFR 1039.505(b)(1), the second half of 

the cycle consists of modes three through five. We will precondition your engine by

running one complete ramped-modal cycle. Do not shut down the engine between 

cycles. Immediately after completing each preconditioning cycle, start the next cycle 

(including the emission test) as soon as practical. For any repeat cycles, start the next

cycle within 60 seconds after completing the last preconditioning cycle. See 

§1065.530(a)(1)(iii) for additional instructions if the cycle begins and ends under 

different operating conditions.

(d) You may conduct calibrations or verifications on any idle equipment or analyzers 

during engine preconditioning.

293. Section 1065.520 is revised to read as follows:

§1065.520 Pre-test verification procedures and pre-test data collection.

(a) For tests in which you measure PM emissions, follow the procedures for PM sample 

preconditioning and tare weighing according to §1065.590.

(b) Unless the standard-setting part specifies different tolerances, verify at some point 

before the test that ambient conditions are within the tolerances specified in this 

paragraph (b). For purposes of this paragraph (b), “before the test” means any time from 

a point just prior to engine starting (excluding engine restarts) to the point at which 

emission sampling begins.

(1) Ambient temperature of (20 to 30) °C. See §1065.530(j) for circumstances under 

which ambient temperatures must remain within this range during the test. 
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(2) Atmospheric pressure of (80.000 to 103.325) kPa and within ±5 kPa of the value 

recorded at the time of the last engine map. You are not required to verify atmospheric 

pressure prior to a hot start test interval for testing that also includes a cold start.

(3) Dilution air conditions as specified in §1065.140, except in cases where you preheat 

your CVS before a cold start test. We recommend verifying dilution air conditions just 

prior to the start of each test interval.

(c) You may test engines at any intake-air humidity, and we may test engines at any 

intake-air humidity.

(d) Verify that auxiliary-work inputs and outputs are configured as they were during 

engine mapping, as described in§1065.510(a).

(e) You may perform a final calibration of the speed, torque, and proportional-flow 

control systems, which may include performing practice duty cycles (or portions of duty

cycles). This may be done in conjunction with the preconditioning in §1065.518.

(f) Verify the amount of nonmethane hydrocarbon contamination in the exhaust and 

background HC sampling systems within 8 hours before the start of the first test interval 

of each duty-cycle sequence for laboratory tests. You may verify the contamination of a 

background HC sampling system by reading the last bag fill and purge using zero gas. 

For any NMHC measurement system that involves separately measuring CH4 and 

subtracting it from a THC measurement or for any CH4 measurement system that uses an 

NMC, verify the amount of THC contamination using only the THC analyzer response. 

There is no need to operate any separate CH4 analyzer for this verification; however, you 

may measure and correct for THC contamination in the CH4 sample path for the cases 

where NMHC is determined by subtracting CH4 from THC or, where CH4 is determined, 

using an NMC as configured in §1065.365(d), (e), and (f); and using the calculations in 

§1065.660(b)(2). Perform this verification as follows:

(1) Select the HC analyzer range for measuring the flow-weighted mean concentration 

expected at the HC standard.

(2) Zero the HC analyzer at the analyzer zero or sample port. Note that FID zero and span 

balance gases may be any combination of purified air or purified nitrogen that meets the 

specifications of §1065.750. We recommend FID analyzer zero and span gases that 

contain approximately the flow-weighted mean concentration of O2 expected during 

testing.

(3) Span the HC analyzer using span gas introduced at the analyzer span or sample port. 

Span on a carbon number basis of one (C1). For example, if you use a C3H8 span gas of 

concentration 200 mol/mol, span the FID to respond with a value of 600 mol/mol.

(4) Overflow zero gas at the HC probe inlet or into a tee near the probe outlet.

(5) Measure the THC concentration in the sampling and background systems as follows:

(i) For continuous sampling, record the mean THC concentration as overflow zero gas 

flows.

(ii) For batch sampling, fill the sample medium (e.g., bag) and record its mean THC 

concentration.

(iii) For the background system, record the mean THC concentration of the last fill and 

purge.

(6) Record this value as the initial THC concentration, xTHC[THC-FID]init, and use it to 

correct measured values as described in §1065.660.

(7) You may correct the measured initial THC concentration for drift as follows:
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(i) For batch and continuous HC analyzers, after determining the initial THC 

concentration, flow zero gas to the analyzer zero or sample port. When the analyzer 

reading is stable, record the mean analyzer value.

(ii) Flow span gas to the analyzer span or sample port. When the analyzer reading is 

stable, record the mean analyzer value.

(iii) Use mean analyzer values from paragraphs (f)(2), (f)(3), (f)(7)(i), and (f)(7)(ii) of 

this section to correct the initial THC concentration recorded in paragraph (f)(6) of this 

section for drift, as described in §1065.550.

(8) If any of the xTHC[THC-FID]init values exceed the greatest of the following values, 

determine the source of the contamination and take corrective action, such as purging the 

system during an additional preconditioning cycle or replacing contaminated portions:

(i) 2 % of the flow-weighted mean concentration expected at the HC (THC or NMHC) 

standard.

(ii) 2 % of the flow-weighted mean concentration of HC (THC or NMHC) measured 

during testing.

(iii) 2 mol/mol.

(9) If corrective action does not resolve the deficiency, you may request to use the 

contaminated system as an alternate procedure under §1065.10.

294. Section 1065.526 is revised to read as follows:

§1065.526 Repeating of void modes or test intervals.

(a) Test modes and test intervals can be voided because of instrument malfunction, 

engine stalling, emissions exceeding instrument ranges, and other unexpected deviations 

from the specified procedures. This section specifies circumstances for which a test 

mode or test interval can be repeated without repeating the entire test.

(b) This section is intended to result in replicate test modes and test intervals that are 

identical to what would have occurred if the cause of the voiding had not occurred. It 

does not allow you to repeat test modes or test intervals in any circumstances that would 

be inconsistent with good engineering judgment. For example, the procedures specified 

here for repeating a mode or interval may not apply for certain engines that include 

hybrid energy storage features or emission controls that involve physical or chemical 

storage of pollutants. This section applies for circumstances in which emission 

concentrations exceed the analyzer range only if it is due to operator error or analyzer 

malfunction. It does not apply for circumstances in which the emission concentrations 

exceed the range because they were higher than expected.

(c) If one of the modes of a discrete-mode duty cycle is voided while running the duty 

cycle as provided in this section, you may void the results for that individual mode and 

continue the duty cycle as follows: 

(1) If the engine has stalled or been shut down, restart the engine.

(2) Use good engineering judgment to restart the duty cycle using the appropriate steps in 

§1065.530(b). 

(3) Stabilize the engine by operating it at the mode at which the duty cycle was 

interrupted and continue with the duty cycle as specified in the standard-setting part.

(d) If an individual mode of a discrete-mode duty cycle sequence is voided after running 

the full duty cycle, you may void results for that mode and repeat testing for that mode as 

follows:
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(1) Use good engineering judgment to restart the test sequence using the appropriate steps 

in §1065.530(b).

(2) Stabilize the engine by operating it at that mode.

(3) Sample emissions over an appropriate test interval.

(4) If you sampled gaseous and PM emissions over separate test intervals for a voided 

mode, you must void both test intervals and repeat sampling of both gaseous and PM 

emissions for that mode.

(e) If a transient or ramped-modal cycle test interval is voided as provided in this section, 

you may repeat the test interval as follows:

(1) Use good engineering judgment to restart (as applicable) and precondition the engine 

to the same condition as would apply for normal testing. This may require you to 

complete the voided test interval. For example, you may generally repeat a hot-start test 

of a heavy-duty highway engine after completing the voided hot-start test and allowing 

the engine to soak for 20 minutes.

(2) Complete the remainder of the test according to the provisions in this subpart.

(f) Keep records from the voided test mode or test interval in the same manner as 

required for unvoided tests.

295. Section 1065.530 is amended by revising paragraphs (a), (b), and (c) to read as 

follows:

§1065.530 Emission test sequence.

(a) Time the start of testing as follows:

(1) Perform one of the following if you precondition the engine as described in 

§1065.518:

(i) For cold-start duty cycles, shut down the engine. Unless the standard-setting part 

specifies that you may only perform a natural engine cooldown, you may perform a 

forced engine cooldown. Use good engineering judgment to set up systems to send 

cooling air across the engine, to send cool oil through the engine lubrication system, to 

remove heat from coolant through the engine cooling system, and to remove heat from 

any exhaust aftertreatment systems. In the case of a forced aftertreatment cooldown, 

good engineering judgment would indicate that you not start flowing cooling air until the 

aftertreatment system has cooled below its catalytic activation temperature. For 

platinum-group metal catalysts, this temperature is about 200 °C. Once the aftertreatment

system has naturally cooled below its catalytic activation temperature, good engineering 

judgment would indicate that you use clean air with a temperature of at least 15 °C, and 

direct the air through the aftertreatment system in the normal direction of exhaust flow. 

Do not use any cooling procedure that results in unrepresentative emissions (see 

§1065.10(c)(1)). You may start a cold-start duty cycle when the temperatures of an 

engine’s lubricant, coolant, and aftertreatment systems are all between (20 and 30) °C. 

(ii) For hot-start emission measurements, shut down the engine immediately after 

completing the last preconditioning cycle. For any repeat cycles, start the hot-start 

transient emission test within 60 seconds after completing the last preconditioning cycle

(this is optional for manufacturer testing).

(iii) For testing that involves hot-stabilized emission measurements, such as any steadystate testing with a ramped-modal cycle, start the hot-stabilized emission test within 60 

seconds after completing the last preconditioning cycle (the time between cycles is 
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optional for manufacturer testing). If the hot-stabilized cycle begins and ends with 

different operating conditions, add a linear transition period of 20 seconds between hotstabilized cycles where you linearly ramp the (denormalized) reference speed and torque 

values over the transition period. See §1065.501(c)(2)(i) for discrete-mode cycles.

(2) If you do not precondition the engine as described in §1065.518, perform one of the 

following:

(i) For cold-start duty cycles, prepare the engine according to paragraph (a)(1)(i) of this 

section.

(ii) For hot-start duty cycles, first operate the engine at any speed above peak-torque 

speed and at (65 to 85) % of maximum mapped power until either the engine coolant, 

block, or head absolute temperature is within ±2 % of its mean value for at least 2 min or 

until the engine thermostat controls engine temperature. Shut down the engine. Start the 

duty cycle within 20 min of engine shutdown.

(iii) For testing that involves hot-stabilized emission measurements, bring the engine 

either to warm idle or the first operating point of the duty cycle. Start the test within 10 

min of achieving temperature stability. Determine temperature stability either as the 

point at which the engine coolant, block, or head absolute temperature is within ±2 % of 

its mean value for at least 2 min, or as the point at which the engine thermostat controls 

engine temperature.

(b) Take the following steps before emission sampling begins:

(1) For batch sampling, connect clean storage media, such as evacuated bags or tareweighed filters.

(2) Start all measurement instruments according to the instrument manufacturer’s 

instructions and using good engineering judgment.

(3) Start dilution systems, sample pumps, cooling fans, and the data-collection system.

(4) Pre-heat or pre-cool heat exchangers in the sampling system to within their operating 

temperature tolerances for a test.

(5) Allow heated or cooled components such as sample lines, filters, chillers, and pumps 

to stabilize at their operating temperatures.

(6) Verify that there are no significant vacuum-side leaks according to §1065.345.

(7) Adjust the sample flow rates to desired levels, using bypass flow, if desired. 

(8) Zero or re-zero any electronic integrating devices, before the start of any test interval.

(9) Select gas analyzer ranges. You may automatically or manually switch gas analyzer 

ranges during a test only if switching is performed by changing the span over which the 

digital resolution of the instrument is applied. During a test you may not switch the gains 

of an analyzer’s analog operational amplifier(s).

(10) Zero and span all continuous analyzers using NIST-traceable gases that meet the 

specifications of §1065.750. Span FID analyzers on a carbon number basis of one (1), C1. 

For example, if you use a C3H8 span gas of concentration 200 mol/mol, span the FID to 

respond with a value of 600 mol/mol. Span FID analyzers consistent with the 

determination of their respective response factors, RF, and penetration fractions, PF, 

according to §1065.365.

(11) We recommend that you verify gas analyzer responses after zeroing and spanning by

sampling a calibration gas that has a concentration near one-half of the span gas 

concentration. Based on the results and good engineering judgment, you may decide 

whether or not to re-zero, re-span, or re-calibrate a gas analyzer before starting a test.
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(12) Drain any accumulated condensate from the intake air system before starting a duty

cycle, as described in §1065.125(e)(1). If engine and aftertreatment preconditioning 

cycles are run before the duty cycle, treat the preconditioning cycles and any associated 

soak period as part of the duty cycle for the purpose of opening drains and draining 

condensate. Note that you must close any intake air condensate drains that are not 

representative of those normally open during in-use operation.

(c) Start and run each test interval as described in this paragraph (c). The procedure 

varies depending on whether the test interval is part of a discrete-mode cycle, and 

whether the test interval includes engine starting. Note that the standard-setting part may

apply different requirements for running test intervals. For example, 40 CFR part 1033 

specifies a different way to perform discrete-mode testing.

(1) For steady-state discrete-mode duty cycles, start the duty cycle with the engine 

warmed-up and running as described in §1065.501(c)(2)(i). Run each mode in the 

sequence specified in the standard-setting part. This will require controlling engine 

speed, engine load, or other operator demand settings as specified in the standard-setting 

part. Simultaneously start any electronic integrating devices, continuous data recording, 

and batch sampling. We recommend that you stabilize the engine for at least 5 minutes 

for each mode. Once sampling begins, sample continuously for at least 1 minute. Note 

that longer sample times may be needed for accurately measuring very low emission 

levels.

(2) For transient and steady-state ramped-modal duty cycles that do not include engine 

starting, start the test interval with the engine running as soon as practical after 

completing engine preconditioning. Simultaneously start any electronic integrating 

devices, continuous data recording, batch sampling, and execution of the duty cycle.

(3) If engine starting is part of the test interval, simultaneously start any electronic 

integrating devices, continuous data recording, and batch sampling before attempting to 

start the engine. Initiate the sequence of points in the duty cycle when the engine starts.

(4) For batch sampling systems, you may advance or delay the start and end of sampling 

at the beginning and end of the test interval to improve the accuracy of the batch sample, 

consistent with good engineering judgment.

* * * * *

296. Section 1065.545 is revised to read as follows:

§1065.545 Verification of proportional flow control for batch sampling.

For any proportional batch sample such as a bag or PM filter, demonstrate that 

proportional sampling was maintained using one of the following, noting that you may

omit up to 5 % of the total number of data points as outliers:

(a) For any pair of flow rates, use recorded sample and total flow rates, where total flow 

rate means the raw exhaust flow rate for raw exhaust sampling and the dilute exhaust 

flow rate for CVS sampling, or their 1 Hz means with the statistical calculations in 

§1065.602. Determine the standard error of the estimate, SEE, of the sample flow rate 

versus the total flow rate. For each test interval, demonstrate that SEE was less than or 

equal to 3.5 % of the mean sample flow rate.

(b) For any pair of flow rates, use recorded sample and total flow rates, where total flow 

rate means the raw exhaust flow rate for raw exhaust sampling and the dilute exhaust 

flow rate for CVS sampling, or their 1 Hz means to demonstrate that each flow rate was 
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constant within ±2.5 % of its respective mean or target flow rate. You may use the 

following options instead of recording the respective flow rate of each type of meter:

(1) Critical-flow venturi option. For critical-flow venturis, you may use recorded venturiinlet conditions or their 1 Hz means. Demonstrate that the flow density at the venturi 

inlet was constant within ±2.5 % of the mean or target density over each test interval. 

For a CVS critical-flow venturi, you may demonstrate this by showing that the absolute 

temperature at the venturi inlet was constant within ±4 % of the mean or target absolute 

temperature over each test interval. 

(2) Positive-displacement pump option. You may use recorded pump-inlet conditions or 

their 1 Hz means. Demonstrate that the flow density at the pump inlet was constant 

within ±2.5 % of the mean or target density over each test interval. For a CVS pump, 

you may demonstrate this by showing that the absolute temperature at the pump inlet was 

constant within ±2 % of the mean or target absolute temperature over each test interval.

(c) Using good engineering judgment, demonstrate with an engineering analysis that the 

proportional-flow control system inherently ensures proportional sampling under all 

circumstances expected during testing. For example, you might use CFVs for both 

sample flow and total dilute exhaust (CVS) flow and demonstrate that they always have 

the same inlet pressures and temperatures and that they always operate under critical-flow 

conditions.

297. Section 1065.546 is amended by revising the section heading and the introductory

text to read as follows:

§1065.546 Verification of minimum dilution ratio for PM batch sampling.

Use continuous flows and/or tracer gas concentrations for transient and ramped-modal 

cycles to verify the minimum dilution ratios for PM batch sampling as specified in 

§1065.140(e)(2) over the test interval. You may use mode-average values instead of 

continuous measurements for discrete mode steady-state duty cycles. Determine the 

minimum primary and minimum overall dilution ratios using one of the following 

methods (you may use a different method for each stage of dilution):

* * * * *

298. Section 1065.550 is revised to read as follows:

§1065.550 Gas analyzer range verification and drift verification.

(a) Range verification. If an analyzer operated above 100 % of its range at any time 

during the test, perform the following steps:

(1) For batch sampling, re-analyze the sample using the lowest analyzer range that results 

in a maximum instrument response below 100 %. Report the result from the lowest range 

from which the analyzer operates below 100 % of its range.

(2) For continuous sampling, repeat the entire test using the next higher analyzer range. 

If the analyzer again operates above 100 % of its range, repeat the test using the next 

higher range. Continue to repeat the test until the analyzer always operates at less than 

100 % of its range.

(b) Drift verification. Gas analyzer drift verification is required for all gaseous exhaust 

constituents for which an emission standard applies. It is also required for CO2 even if 

there is no CO2 emission standard. It is not required for other gaseous exhaust 

constituents for which only a reporting requirement applies (such as CH4 and N2O).
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(1) Verify drift using one of the following methods:

(i) For regulated exhaust constituents determined from the mass of a single component, 

perform drift verification based on the regulated constituent. For example, when NOx

mass is determined with a dry sample measured with a CLD and the removed water is 

corrected based on measured CO2, CO, THC, and NOx concentrations, you must verify

the calculated NOx value.

(ii) For regulated exhaust constituents determined from the masses of multiple 

subcomponents, perform the drift verification based on either the regulated constituent or 

all the mass subcomponents. For example, when NOx is measured with separate NO and 

NO2 analyzers, you must verify either the NOx value or both the NO and NO2 values.

(iii) For regulated exhaust constituents determined from the concentrations of multiple 

gaseous emission subcomponents prior to performing mass calculations, perform drift 

verification on the regulated constituent. You may not verify the concentration 

subcomponents (e.g., THC and CH4 for NMHC) separately. For example, for NMHC 

measurements, perform drift verification on NMHC; do not verify THC and CH4

separately.

(2) Drift verification requires two sets of emission calculations. For each set of 

calculations, include all the constituents in the drift verification. Calculate one set using 

the data before drift correction and calculate the other set after correcting all the data for 

drift according to §1065.672. Note that for purposes of drift verification, you must leave 

unaltered any negative emission results over a given test interval (i.e., do not set them to 

zero). These unaltered results are used when verifying either test interval results or 

composite brake-specific emissions over the entire duty cycle for drift. For each 

constituent to be verified, both sets of calculations must include the following:

(i) Calculated mass (or mass rate) emission values over each test interval.

(ii) If you are verifying each test interval based on brake-specific values, calculate brakespecific emission values over each test interval.

(iii) If you are verifying over the entire duty cycle, calculate composite brake-specific 

emission values.

(3) The duty cycle is verified for drift if you satisfy the following criteria:

(i) For each regulated gaseous exhaust constituent, you must satisfy one of the following:

(A) For each test interval of the duty cycle, the difference between the uncorrected and 

the corrected brake-specific emission values of the regulated constituent must be within 

±4 % of the uncorrected value or the applicable emissions standard, whichever is greater. 

Alternatively, the difference between the uncorrected and the corrected emission mass (or 

mass rate) values of the regulated constituent must be within 4 % of the uncorrected 

value or the composite work (or power) multiplied by the applicable emissions standard, 

whichever is greater. For purposes of verifying each test interval, you may use either the 

reference or actual composite work (or power).

(B) For each test interval of the duty cycle and for each mass subcomponent of the 

regulated constituent, the difference between the uncorrected and the corrected brakespecific emission values must be within ±4 % of the uncorrected value. Alternatively, the 

difference between the uncorrected and the corrected emissions mass (or mass rate) 

values must be within ±4 % of the uncorrected value.
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(C) For the entire duty cycle, the difference between the uncorrected and the corrected 

composite brake-specific emission values of the regulated constituent must be within ±4 

% of the uncorrected value or applicable emission standard, whichever is greater.

(D) For the entire duty cycle and for each subcomponent of the regulated constituent, the 

difference between the uncorrected and the corrected composite brake-specific emission 

values must be within ±4 % of the uncorrected value.

(ii) Where no emission standard applies for CO2, you must satisfy one of the following:

(A) For each test interval of the duty cycle, the difference between the uncorrected and 

the corrected brake-specific CO2 values must be within ±4 % of the uncorrected value; or 

the difference between the uncorrected and the corrected CO2 mass (or mass rate) values 

must be within ±4 % of the uncorrected value.

(B) For the entire duty cycle, the difference between the uncorrected and the corrected 

composite brake-specific CO2 values must be within ±4 % of the uncorrected value.

(4) If the test is not verified for drift as described in paragraph (b)(1) of this section, you 

may consider the test results for the duty cycle to be valid only if, using good engineering 

judgment, the observed drift does not affect your ability to demonstrate compliance with 

the applicable emission standards. For example, if the drift-corrected value is less than 

the standard by at least two times the absolute difference between the uncorrected and 

corrected values, you may consider the data to be verified for demonstrating compliance 

with the applicable standard.

Subpart G—[Amended]

[Note to Editor: The equations and other mathematical expressions in this subpart 

depend on careful use of italics. In general, variable expressions are italicized and 

subscripts are not. Please take steps to avoid changing the font from the original 

Word file. This has been a problem in some published rules.]

299. Section 1065.601 is amended by revising paragraph (b) to read as follows:

§1065.601 Overview.

* * * * *

(b) You may use data from multiple systems to calculate test results for a single emission 

test, consistent with good engineering judgment. You may also make multiple 

measurements from a single batch sample, such as multiple weighings of a PM filter or 

multiple readings from a bag sample. Although you may use an average of multiple 

measurements from a single test, you may not use test results from multiple emission 

tests to report emissions.

(1) We allow weighted means where appropriate.

(2) You may discard statistical outliers, but you must report all results.

(3) For emission measurements related to durability testing, we may allow you to exclude 

certain test points other than statistical outliers relative to compliance with emission 

standards, consistent with good engineering judgment and normal measurement 

variability; however, you must include these results when calculating the deterioration 

factor. This would allow you to use durability data from an engine that has an 

intermediate test result above the standard that cannot be discarded as a statistical outlier, 

as long as good engineering judgment indicates that the test result does not represent the 
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engine’s actual emission level. Note that good engineering judgment would preclude you 

from excluding endpoints. Also, if normal measurement variability causes emission 

results below zero, include the negative result in calculating the deterioration factor to 

avoid an upward bias. These provisions related to durability testing are intended to 

address very stringent standards where measurement variability is large relative to the 

emission standard.

* * * * *

300. Section 1065.602 is amended by revising paragraphs (f), (j), (k), and (l)(1)(ii) to 

read as follows:

§1065.602 Statistics.

* * * * *

(f) t-test. Determine if your data passes a t-test by using the following equations and 

tables:

(1) For an unpaired t-test, calculate the t statistic and its number of degrees of freedom,

, as follows:

ref

2 2

ref y

ref

y y

t

N N

 







Eq. 1065.602-5

2

2 2

ref y

ref

2 2 2

2

y

ref

ref

ref 1 1

N N

v

N N

N N

 

 

    

 



              

 

Eq. 1065.602-6

Example:

ref y = 1205.3

y = 1123.8

ref = 9.399

y = 10.583

Nref = 11

N = 7

2 2

1205.3 1123.8

9.399 10.583

11 7

t







t = 16.63

ref = 9.399

y = 10.583
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Nref = 11

N = 7

2

2 2

2 2 2 2

9.399 10.583

11 7

9.399 10.583

11 7

11 1 7 1

v

    

 



            

 

v = 11.76

(2) For a paired t-test, calculate the t statistic and its number of degrees of freedom, , as 

follows, noting that the i

 are the errors (e.g., differences) between each pair of yrefi and 

yi:

ε

N

t









Eq. 1065.602-7

Example:

 = –0.12580

N = 16

ε = 0.04837

0.12580 16

0.04837

t

 



t = 10.403

v = N – 1

Example:

N = 16

v = 16 – 1 

v = 15

(3) Use Table 1 of this section to compare t to the tcrit values tabulated versus the number 

of degrees of freedom. If t is less than tcrit, then t passes the t-test. The Microsoft Excel 

software has a TINV function that returns results equivalent results and may be used in 

place of Table 1, which follows:
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TABLE 1 OF §1065.602–

CRITICAL t VALUES VERSUS NUMBER OF DEGREES OF FREEDOM, 

1



Confidence

90% 95%

1 6.314 12.706

2 2.920 4.303

3 2.353 3.182

4 2.132 2.776

5 2.015 2.571

6 1.943 2.447

7 1.895 2.365

8 1.860 2.306

9 1.833 2.262

10 1.812 2.228

11 1.796 2.201

12 1.782 2.179

13 1.771 2.160

14 1.761 2.145

15 1.753 2.131

16 1.746 2.120

18 1.734 2.101

20 1.725 2.086

22 1.717 2.074

24 1.711 2.064

26 1.706 2.056

28 1.701 2.048

30 1.697 2.042

35 1.690 2.030

40 1.684 2.021

50 1.676 2.009

70 1.667 1.994

100 1.660 1.984

1000+ 1.645 1.960

1 Use linear interpolation to 

establish values not shown here.

* * * * *

(j) Standard estimate of error. Calculate a standard estimate of error, SEE, as follows:

2

i 0y 1y refi

i 1

y

( )

2

N

y a a y

SEE

N



    

 







Eq. 1065.602-11

Example:
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N = 6000

y1 = 2045.8

a0y = –16.8083 

a1y = 1.0110

yref1= 2045.0

 

2 2

6000 ref 6000

y

2045.8 ( 16.8083) (1.0110 2045.0) ... ( 16.8083) (1.0110 )

6000 2

y y

SEE

          

 





SEEy = 5.348

(k) Coefficient of determination. Calculate a coefficient of determination, 

2

y

r , as 

follows:

 

2

i 0y 1y refi

2 i 1

y

2

i

i 1

( )

1

N

N

y a a y

r

y y





    

 

 







Eq. 1065.602-12

Example:

N = 6000

y1 = 2045.8

a0y = –16.8083 

a1y = 1.0110

yref1 = 2045.0

y = 1480.5

 

 

2 2

2 6000 ref6000

y 2 2

6000

2045.8 ( 16.8083) (1.0110 2045.0) ... ( 16.8083) (1.0110 )

1

2045.8 1480.5 ... 1480.5

y y

r

y

          

 

 

      

2

y

r = 0.9859

(l) * * *

(1) * * *

(ii) Based on your engine design, estimate maximum power, Pmax, the design speed at 

maximum power, fnmax, the design maximum intake manifold boost pressure, pinmax, and 

temperature, Tinmax. Also, estimate a mean fraction of power that is lost due to friction 

and pumping, Pfrict . Use this information along with the engine displacement volume, 

Vdisp, an approximate volumetric efficiency, V, and the number of engine strokes per 

power stroke (two-stroke or four-stroke), Nstroke, to estimate the maximum raw exhaust 

molar flow rate, exhmax n . 

* * * * *

301. Section 1065.610 is amended by revising paragraphs (a) introductory text, (a)(1), 

(c)(3), and (d)(3)(ii) to read as follows:
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§1065.610 Duty cycle generation.

* * * * *

(a) Maximum test speed, fntest. This section generally applies to duty cycles for variablespeed engines. For constant-speed engines subject to duty cycles that specify normalized 

speed commands, use the no-load governed speed as the measured fntest. This is the 

highest engine speed where an engine outputs zero torque. For variable-speed engines, 

determine fntest as follows:

(1) Develop a measured value for fntest as follows:

(i) Determine maximum power, Pmax, from the engine map generated according to 

§1065.510 and calculate the value for power equal to 98 % of Pmax. 

(ii) Determine the lowest and highest engine speeds corresponding to 98 % of Pmax, using 

linear interpolation as appropriate.

(iii) Determine the engine speed corresponding to maximum power, fnPmax, by calculating 

the average of the two speed values from paragraph (a)(1)(ii) of this section. 

(iv) Transform the map into a normalized power-versus-speed map by dividing power 

terms by Pmax and dividing speed terms by fnPmax. Use the following equation to calculate 

a quantity representing the sum of squares from the normalized map:

2 2 Sum nnormi normi of squares   f P

Eq. 1065.610-1

Where: 

i = an indexing variable that represents one recorded value of an engine map.

fnnormi = an engine speed normalized by dividing it by fnPmax.

Pnormi = an engine power normalized by dividing it by Pmax.

(v) Determine the maximum value for the sum of the squares from the map and multiply

that value by 0.98. 

(vi) Determine the lowest and highest engine speeds corresponding to the value 

calculated in paragraph (a)(1)(v) of this section, using linear interpolation as appropriate. 

Calculate fntest as the average of these two speed values.

(viii) The following example illustrates a calculation of fntest:

(fn1 = 2360, P1 = 223.1, fnnorm1 = 1.002, Pnorm1 = 0.967)

(fn2 = 2364, P2 = 227.7, fnnorm2 = 1.004, Pnorm2 = 0.986)

(fn3 = 2369, P3 = 230.0, fnnorm3 = 1.006, Pnorm3 = 0.994)

(fn4 = 2374, P4 = 220.8, fnnorm4 = 1.008, Pnorm4 = 0.951)

   

ntest

0.98 230.0 223.1 0.98 230.0 230.0 2360 2364 2360 2369 2374 2369

227.7 223.1 220.8 230.0

2

2363 2371 2367r min

2

f

         

                    





 

Sum of squares = (1.0022+ 0.9672) = 1.94

Sum of squares = (1.0042+ 0.9862) = 1.98

Sum of squares = (1.0062+ 0.9942) = 2.00

Sum of squares = (1.008

2

+ 0.9512) = 1.92
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   

npmax

0.98 2.0 1.94 0.98 2.0 2.0 2360 2364 2360 2369 2374 2369

1.98 1.94 1.92 2.0

2

2363 2371 2367 r min

2

f

         

      

             





 

* * * * *

(c) * * *

(3) Intermediate speed. Based on the map, determine maximum torque, Tmax, and the 

corresponding speed, fnTmax, calculated as the average of the lowest and highest speeds at 

which torque is equal to 98 % of Tmax. Use linear interpolation between points to 

determine the speeds where torque is equal to 98% of Tmax. Identify your reference 

intermediate speed as one of the following values:

(i) fnTmax if it is between (60 and 75) % of maximum test speed.

(ii) 60 % of maximum test speed if fnTmax is less than 60 % of maximum test speed.

(iii) 75 % of maximum test speed if fnTmax is greater than 75 % of maximum test speed.

(d) * * *

(3) * * *

(ii) If the cycle begins with a set of contiguous idle points (zero-percent speed, and zeropercent torque), leave the reference torques set to zero for this initial contiguous idle 

segment. This is to represent free idle operation with the transmission in neutral or park 

at the start of the transient duty cycle, after the engine is started. If the initial idle 

segment is longer than 24 seconds, change the reference torques for the remaining idle 

points in the initial contiguous idle segment to CITT (i.e., change idle points 

corresponding to 25 seconds to the end of the initial idle segment to CITT). This is to 

represent shifting the transmission to drive.

* * * * *

302. Section 1065.630 is revised to read as follows:

§1065.630 Local acceleration of gravity.

(a) The acceleration of Earth’s gravity, ag, varies depending on the test location. 

Determine ag at your location by entering latitude, longitude, and elevation data into the 

U.S. National Oceanographic and Atmospheric Administration’s surface gravity

prediction Web site at http://www.ngs.noaa.gov/cgi-bin/grav_pdx.prl. 

(b) If the Web site specified in paragraph (a) of this section is unavailable, you may

calculate ag for your latitude as follows:

ag = 9.7803267715 ∙ [1 + 5.2790414 ∙ 10-3∙sin2() + 2.32718 ∙ 10-5∙sin4()

+ 1.262 ∙ 10-7∙sin6() + 7 ∙ 10-10∙sin8()]

Eq. 1065.630-1

Where:

 = Degrees north or south latitude.

Example:

 = 45 °

ag = 9.7803267715 ∙ (1 + 5.2790414 ∙ 10-3∙sin2(45) + 2.32718 ∙ 10-5∙sin4(45)

+ 1.262 ∙ 10-7∙sin6(45) + 7 ∙ 10-10∙sin8(45) 
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ag = 9.8061992026 m/s2

303. Section 1065.640 is revised to read as follows:

§1065.640 Flow meter calibration calculations.

This section describes the calculations for calibrating various flow meters. After you 

calibrate a flow meter using these calculations, use the calculations described in 

§1065.642 to calculate flow during an emission test. Paragraph (a) of this section first 

describes how to convert reference flow meter outputs for use in the calibration 

equations, which are presented on a molar basis. The remaining paragraphs describe the 

calibration calculations that are specific to certain types of flow meters.

(a) Reference meter conversions. The calibration equations in this section use molar flow 

rate, ref n , as a reference quantity. If your reference meter outputs a flow rate in a 

different quantity, such as standard volume rate, Vstdref



, actual volume rate, Vactref



, or mass 

rate, mref  , convert your reference meter output to a molar flow rate using the following 

equations, noting that while values for volume rate, mass rate, pressure, temperature, and 

molar mass may change during an emission test, you should ensure that they are as 

constant as practical for each individual set point during a flow meter calibration:

stdref std actref act ref

ref

std act mix

V p V p m

n

T R T R M

 



 

  



Eq. 1065.640-1

Where:

ref n = reference molar flow rate.

Vstdref

 = reference volume flow rate, corrected to a standard pressure and a standard 

temperature.

Vactref

 = reference volume flow rate at the actual pressure and temperature of the flow rate.

mref  = reference mass flow.

pstd = standard pressure.

pact = actual pressure of the flow rate.

Tstd = standard temperature.

Tact = actual temperature of the flow rate.

R = molar gas constant.

Mmix = molar mass of the flow rate.

Example 1:

Vstdref

 = 1000.00 ft3

/min = 0.471948 m3/s

pstd = 29.9213 in Hg @ 32 °F = 101.325 kPa = 101325 Pa = 101325 kg/(m∙s2)

Tstd = 68.0 °F = 293.15 K

R = 8.314472 J/(mol∙K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

ref

0.471948 101325

293.15 8.314472

n









ref n = 19.619 mol/s
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Example 2: 

mref  = 17.2683 kg/min = 287.805 g/s

Mmix = 28.7805 g/mol

ref

287.805

28.7805

n 

ref n = 10.0000 mol/s

(b) PDP calibration calculations. For each restrictor position, calculate the following 

values from the mean values determined in §1065.340, as follows:

(1) PDP volume pumped per revolution, Vrev (m3/r):

ref in

rev

in nPDP

n R T

V

p f

 







Eq. 1065.640-2 

Example:

ref n = 25.096 mol/s

R = 8.314472 J/(mol∙K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

Tin = 299.5 K

in p = 98.290 kPa = 98290 Pa = 98290 kg/(m∙s2

)

nPDP f = 1205.1 r/min = 20.085 r/s

25.096 8.314472 299.5

98290 20.085

Vrev

 





Vrev = 0.03166 m3/r

(2) PDP slip correction factor, Ks (s/r):

out in

s

nPDP out

1 p p K

f p



 

Eq. 1065.640-3

Example:

nPDP f = 1205.1 r/min = 20.085 r/s

out p = 100.103 kPa

in p = 98.290 kPa

s

1 100.103 98.290

20.085 100.103

K



 

Ks = 0.006700 s/r

(3) Perform a least-squares regression of PDP volume pumped per revolution, Vrev, versus 

PDP slip correction factor, Ks, by calculating slope, a1, and intercept, a0, as described in 

§1065.602.

(4) Repeat the procedure in paragraphs (b)(1) through (3) of this section for every speed 

that you run your PDP.

(5) The following example illustrates these calculations:
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TABLE 1 OF §1065.640–

EXAMPLE OF PDP CALIBRATION DATA

nPDP f

(revolution/s)

a1 

(m3/s)

a0 

(m3/revolution)

12.6 0.841 0.056

16.5 0.831 -0.013

20.9 0.809 0.028

23.4 .788 -0.061

(6) For each speed at which you operate the PDP, use the corresponding slope, a1, and 

intercept, a0, to calculate flow rate during emission testing as described in §1065.642.

(c) Venturi governing equations and permissible assumptions. This section describes the 

governing equations and permissible assumptions for calibrating a venturi and calculating 

flow using a venturi. Because a subsonic venturi (SSV) and a critical-flow venturi (CFV) 

both operate similarly, their governing equations are nearly the same, except for the 

equation describing their pressure ratio, r (i.e., rSSV versus rCFV). These governing 

equations assume one-dimensional isentropic inviscid compressible flow of an ideal gas. 

In paragraph (c)(4) of this section, we describe other assumptions that you may make, 

depending upon how you conduct your emission tests. If we do not allow you to assume 

that the measured flow is an ideal gas, the governing equations include a first-order 

correction for the behavior of a real gas; namely, the compressibility factor, Z. If good 

engineering judgment dictates using a value other than Z=1, you may either use an 

appropriate equation of state to determine values of Z as a function of measured pressures 

and temperatures, or you may develop your own calibration equations based on good 

engineering judgment. Note that the equation for the flow coefficient, Cf, is based on the 

ideal gas assumption that the isentropic exponent, , is equal to the ratio of specific heats, 

Cp/Cv. If good engineering judgment dictates using a real gas isentropic exponent, you 

may either use an appropriate equation of state to determine values of  as a function of 

measured pressures and temperatures, or you may develop your own calibration 

equations based on good engineering judgment. Calculate molar flow rate, , as 

follows:

t in

d f

mix in

A p n C C

Z M R T



  

  



Eq. 1065.640-4

Where:

Cd = discharge coefficient, as determined in paragraph (c)(1) of this section.

Cf = flow coefficient, as determined in paragraph (c)(2) of this section.

At = venturi throat cross-sectional area.

pin = venturi inlet absolute static pressure.

Z = compressibility factor.

Mmix = molar mass of gas mixture.

R = molar gas constant.

Tin = venturi inlet absolute temperature.
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(1) Using the data collected in §1065.340, calculate Cd using the following equation:

mix in

d ref

f t in

Z M R T

C n

C A p

  

 

 



Eq. 1065.640-5

Where: 

ref n = a reference molar flow rate.

(2) Determine Cf using one of the following methods:

(i) For CFV flow meters only, determine CfCFV from the following table based on your 

values for  and , using linear interpolation to find intermediate values:

TABLE 2 OF §1065.640–

CfCFV VERSUS  AND  FOR CFV FLOW METERS

CfCFV



exh =

1.385

dexh =

air=

1.399

0.000 0.6822 0.6846

0.400 0.6857 0.6881

0.500 0.6910 0.6934

0.550 0.6953 0.6977

0.600 0.7011 0.7036

0.625 0.7047 0.7072

0.650 0.7089 0.7114

0.675 0.7137 0.7163

0.700 0.7193 0.7219

0.720 0.7245 0.7271

0.740 0.7303 0.7329

0.760 0.7368 0.7395

0.770 0.7404 0.7431

0.780 0.7442 0.7470

0.790 0.7483 0.7511

0.800 0.7527 0.7555

0.810 0.7573 0.7602

0.820 0.7624 0.7652

0.830 0.7677 0.7707

0.840 0.7735 0.7765

0.850 0.7798 0.7828

(ii) For any CFV or SSV flow meter, you may use the following equation to calculate Cf :
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 

   

1

2

1

2

f

4

2 1

1

r

C

r









 





 

  

 



  

 

Eq. 1065.640-6

Where:

 = isentropic exponent. For an ideal gas, this is the ratio of specific heats of the gas 

mixture, Cp/Cv.

r = pressure ratio, as determined in paragraph (c)(3) of this section.

 = ratio of venturi throat to inlet diameters.

(3) Calculate r as follows:

(i) For SSV systems only, calculate rSSV using the following equation:

SSV

SSV

in

1

p

r

p



 

Eq. 1065.640-7

Where:

ΔpSSV = Differential static pressure; venturi inlet minus venturi throat.

(ii) For CFV systems only, calculate rCFV iteratively using the following equation:

1 2

4

CFV CFV

1 1

2 2

r r



 

 





   

       

Eq. 1065.640-8

(4)You may make any of the following simplifying assumptions of the governing 

equations, or you may use good engineering judgment to develop more appropriate 

values for your testing:

(i) For emission testing over the full ranges of raw exhaust, diluted exhaust and dilution 

air, you may assume that the gas mixture behaves as an ideal gas: Z=1.

(ii) For the full range of raw exhaust you may assume a constant ratio of specific heats of 

=1.385.

(iii) For the full range of diluted exhaust and air (e.g., calibration air or dilution air), you 

may assume a constant ratio of specific heats of =1.399.

(iv) For the full range of diluted exhaust and air, you may assume the molar mass of the 

mixture is a function only of the amount of water in the dilution air or calibration air, 

xH2O, determined as described in §1065.645, as follows:

Mmix = Mair ∙ (1 – xH2O) + MH2O ∙ xH2O

Eq. 1065.640-9

Example:

Mair = 28.96559 g/mol

xH2O = 0.0169 mol/mol

MH2O = 18.01528 g/mol

Mmix = 28.96559 ∙ (1– 0.0169) + 18.01528 ∙ 0.0169

Mmix = 28.7805 g/mol 

(v) For the full range of diluted exhaust and air, you may assume a constant molar mass 

of the mixture, Mmix, for all calibration and all testing as long as your assumed molar 

mass differs no more than ±1 % from the estimated minimum and maximum molar mass 
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during calibration and testing. You may assume this, using good engineering judgment, 

if you sufficiently control the amount of water in calibration air and in dilution air or if 

you remove sufficient water from both calibration air and dilution air. The following 

table gives examples of permissible ranges of dilution air dewpoint versus calibration air 

dewpoint:

TABLE 3 OF §1065.640–

EXAMPLES OF DILUTION AIR AND CALIBRATION AIR 

DEWPOINTS AT WHICH YOU MAY ASSUME A CONSTANT Mmix

If calibration 

Tdew (C) is...

assume the following 

constant Mmix (g/mol)...

for the following ranges of Tdew

(C) during emission testsa

dry 28.96559 dry to 18

0 28.89263 dry to 21

5 28.86148 dry to 22

10 28.81911 dry to 24

15 28.76224 dry to 26

20 28.68685 -8 to 28

25 28.58806 12 to 31

30 28.46005 23 to 34

aRange valid for all calibration and emission testing over the atmospheric 

pressure range (80.000 to 103.325) kPa.

(5) The following example illustrates the use of the governing equations to calculate the 

discharge coefficient, Cd of an SSV flow meter at one reference flow meter value. Note 

that calculating Cd for a CFV flow meter would be similar, except that Cf would be 

determined from Table 2 of this section or calculated iteratively using values of  and  

as described in paragraph (c)(2) of this section.

Example:

ref n = 57.625 mol/s

Z = 1

Mmix = 28.7805 g/mol = 0.0287805 kg/mol

R = 8.314472 J/(mol∙K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

Tin = 298.15 K

At = 0.01824 m2

pin = 99.132 kPa = 99132.0 Pa = 99132 kg/(m∙s2)

 = 1.399

 = 0.8

Δp = 2.312 kPa

SSV

2.312 1 0.977

99.132

r   

 

   

1.399 1

1.399

2

1.399

1

2

f

4

2 1.399 0.977 1

1.399 1 0.8 0.977

C





    

  

  

 
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Cf = 0.274

d

1 0.0287805 8.314472 298.15 57.625

0.274 0.01824 99132.0

C

  

 

 

Cd = 0.982

(d) SSV calibration. Perform the following steps to calibrate an SSV flow meter:

(1) Calculate the Reynolds number, Re#, for each reference molar flow rate, ref n , using 

the throat diameter of the venturi, dt. Because the dynamic viscosity, μ, is needed to 

compute Re#, you may use your own fluid viscosity model to determine μ for your 

calibration gas (usually air), using good engineering judgment. Alternatively, you may

use the Sutherland three-coefficient viscosity model to approximate μ, as shown in the 

following sample calculation for Re#:

# mix ref

t

4 M n Re =

  d

 

 



Eq. 1065.640-10

Where, using the Sutherland three-coefficient viscosity model:

3

2

in 0

0

0 in

T T S

T T S

 

    

           

Eq. 1065.640-11

Where:

μ0 = Sutherland reference viscosity.

T0 = Sutherland reference temperature.

S = Sutherland constant.

TABLE 4 OF §1065.640–

SUTHERLAND THREE-COEFFICIENT VISCOSITY MODEL PARAMETERS

Gasa μ0 T0 S

Temp range 

within ±2 % 

errorb

Pressure 

limitb

kg/(m∙s) K K K kPa

Air 1.716∙10-5273 111 170 to 1900 ≤ 1800

CO2 1.370∙10-5273 222 190 to 1700 ≤ 3600

H2O 1.12∙10-5350 1064 360 to 1500 ≤ 10000 

O2 1.919∙10-5273 139 190 to 2000 ≤ 2500

N2 1.663∙10-5273 107 100 to 1500 ≤ 1600

aUse tabulated parameters only for the pure gases, as listed. Do not combine 

parameters in calculations to calculate viscosities of gas mixtures.

bThe model results are valid only for ambient conditions in the specified 

ranges.

Example:

μ0 = 1.716∙10-5kg/(m∙s)

T0 = 273 K
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S = 111 K

3

2

5 298.15 273 111 1.716 10

273 298.15 111



     

            

μ = 1.838∙10-5kg/(m∙s)

Mmix = 28.7805 g/mol

ref n = 57.625 mol/s

dt = 152.4 mm = 0.1524 m

Tin = 298.15 K

#

5

4 28.7805 57.625

3.14159 0.1524 1.838 10

Re = 

 

  

Re#= 7.538∙108

(2) Create an equation for Cd as a function of Re#, using paired values of the two 

quantities. The equation may involve any mathematical expression, including a 

polynomial or a power series. The following equation is an example of a commonly used 

mathematical expression for relating Cd and Re#:

6

d 0 1 #

10 C a a

Re

  

Eq. 1065.640-12

(3) Perform a least-squares regression analysis to determine the best-fit coefficients for

the equation and calculate the equation’s regression statistic, SEE, according to 

§1065.602.

(4) If the equation meets the criterion of SEE ≤ 0.5 %, you may use the equation to 

determine Cd for emission tests, as described in §1065.642.

(5) If the equation does not meet the specified statistical criterion, you may use good 

engineering judgment to omit calibration data points; however you must use at least 

seven calibration data points to demonstrate that you meet the statistical criterion. This 

will usually involve narrowing the range of flow rates for a better curve fit.

(6) Take corrective action if the equation does not meet the specified statistical criterion

even after omitting calibration data points. For example, select another mathematical 

expression for the Cd versus Re#equation, check for leaks, or repeat the calibration 

process. If you must repeat the process, we recommend applying tighter tolerances to 

measurements and allowing more time for flows to stabilize.

(7) Once you have an equation that meets the specified statistical criterion, you may use 

the equation only for the corresponding range of Re#.

(e) CFV calibration. Some CFV flow meters consist of a single venturi and some consist 

of multiple venturis, where different combinations of venturis are used to meter different 

flow rates. For CFV flow meters that consist of multiple venturis, either calibrate each 

venturi independently to determine a separate discharge coefficient, Cd, for each venturi, 

or calibrate each combination of venturis as one venturi. In the case where you calibrate 

a combination of venturis, use the sum of the active venturi throat areas as At, the square 

root of the sum of the squares of the active venturi throat diameters as dt, and the ratio of 

the venturi throat to inlet diameters as the ratio of the square root of the sum of the active 
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venturi throat diameters (dt) to the diameter of the common entrance to all the venturis 

(D). To determine the Cd for a single venturi or a single combination of venturis, perform 

the following steps:

(1) Use the data collected at each calibration set point to calculate an individual Cd for 

each point using Eq. 1065.640-4.

(2) Calculate the mean and standard deviation of all the Cd values according to Eqs. 

1065.602-1 and 1065.602-2.

(3) If the standard deviation of all the Cd values is less than or equal to 0.3 % of the mean 

Cd, use the mean Cd in Eq. 1065.642-4, and use the CFV only up to the highest r

measured during calibration using the following equation:

CFV

in

1

p

r

p



 

Eq. 1065.640-13

Where:

pCFV = Differential static pressure; venturi inlet minus venturi outlet.

(4) If the standard deviation of all the Cd values exceeds 0.3 % of the mean Cd, omit the 

Cd value corresponding to the data point collected at the highest r measured during 

calibration.

(5) If the number of remaining data points is less than seven, take corrective action by

checking your calibration data or repeating the calibration process. If you repeat the 

calibration process, we recommend checking for leaks, applying tighter tolerances to 

measurements and allowing more time for flows to stabilize.

(6) If the number of remaining Cd values is seven or greater, recalculate the mean and 

standard deviation of the remaining Cd values.

(7) If the standard deviation of the remaining Cd values is less than or equal to 0.3 % of 

the mean of the remaining Cd, use that mean Cd in Eq. 1065.642-4, and use the CFV 

values only up to the highest r associated with the remaining Cd.

(8) If the standard deviation of the remaining Cd still exceeds 0.3 % of the mean of the 

remaining Cd values, repeat the steps in paragraph (e)(4) through (8) of this section.

304. Section 1065.642 is revised to read as follows:

§1065.642 SSV, CFV, and PDP molar flow rate calculations.

This section describes the equations for calculating molar flow rates from various flow 

meters. After you calibrate a flow meter according to §1065.640, use the calculations 

described in this section to calculate flow during an emission test. 

(a) PDP molar flow rate. Based upon the speed at which you operate the PDP for a test 

interval, select the corresponding slope, a1, and intercept, a0, as calculated in §1065.640, 

to calculate molar flow rate, n as follows:

in rev

nPDP

in

p V n f

R T



 





Eq. 1065.642-1

Where:

1 out in

rev 0

nPDP out

a p p V a

f p



  
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Eq. 1065.642-2

Example:

a1 = 0.8405 (m3/s)

fnPDP = 12.58 r/s

pout = 99.950 kPa

pin = 98.575 kPa = 98575 Pa = 98575 kg/(m∙s2)

a0 = 0.056 (m3/r)

R = 8.314472 J/(mol∙K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

Tin = 323.5 K

rev

0.8405 99.950 98.575 0.056

12.58 99.950

V



  

Vrev = 0.06383 m3/r

98575 0.06383 12.58

8.314472 323.5

n



 





n = 29.428 mol/s

(b) SSV molar flow rate. Based on the Cd versus Re#equation you determined according 

to §1065.640, calculate SSV molar flow rate, n during an emission test as follows: 

t in

d f

mix in

A p n C C

Z M R T



  

  



Eq. 1065.642-3

Example: 

At = 0.01824 m2

pin = 99.132 kPa = 99132 Pa = 99132 kg/(m∙s2)

Z = 1

Mmix = 28.7805 g/mol = 0.0287805 kg/mol

R = 8.314472 J/(mol·K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

Tin = 298.15 K

Re#= 7.232·105

 = 1.399

 = 0.8

p = 2.312 kPa

Using Eq. 1065.640-7,

rssv = 0.997

Using Eq. 1065.640-6,

Cf = 0.274

Using Eq. 1065.640-5,

Cd = 0.990

0.01824 99132 0.990 0.274

1 0.0287805 8.314472 298.15

n



  

  


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n = 58.173 mol/s

(c) CFV molar flow rate. Some CFV flow meters consist of a single venturi and some 

consist of multiple venturis, where different combinations of venturis are used to meter 

different flow rates. If you use multiple venturis and you calibrated each venturi 

independently to determine a separate discharge coefficient, Cd (or calibration coefficient,

Kv), for each venturi, calculate the individual molar flow rates through each venturi and 

sum all their flow rates to determine n . If you use multiple venturis and you calibrated 

each combination of venturis, calculate n using the sum of the active venturi throat areas 

as At, the square root of the sum of the squares of the active venturi throat diameters as dt, 

and the ratio of the venturi throat to inlet diameters as the ratio of the square root of the 

sum of the active venturi throat diameters (dt) to the diameter of the common entrance to 

all the venturis (D).

(1) To calculate the molar flow rate through one venturi or one combination of venturis, 

use its respective mean Cd and other constants you determined according to §1065.640 

and calculate its molar flow rate n during an emission test, as follows:

t in

d f

mix in

A p n C C

Z M R T



  

  



Eq. 1065.642-4

Example: 

Cd = 0.985

Cf = 0.7219

At = 0.00456 m2

pin = 98.836 kPa = 98836 Pa = 98836 kg/(m∙s2)

Z = 1

Mmix = 28.7805 g/mol = 0.0287805 kg/mol

R = 8.314472 J/(mol·K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

Tin = 378.15 K

0.00456 98836 0.985 0.7219

1 0.0287805 8.314472 378.15

n



  

  



n = 33.690 mol/s

(2) To calculate the molar flow rate through one venturi or a combination of venturis, you 

may use its respective mean, Kv, and other constants you determined according to 

§1065.640 and calculate its molar flow rate n during an emission test. Note that if you

follow the permissible ranges of dilution air dewpoint versus calibration air dewpoint in 

Table 3 of §1065.640, you may set Mmix-cal and Mmix equal to 1. Calculate n as follows:

mix-cal in std

in std mix

K p vp M

n

T M T R



  





Eq. 1065.642-5

Where:

stdref in-cal

in-cal

v

V T

K

p





Eq. 1065.642-6
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Vstdref = volume flow rate of the standard at reference conditions of 293.15 K and 101.325 

kPa.

Tin-cal = venturi inlet temperature during calibration.

Pin-cal = venturi inlet pressure during calibration.

Mmix-cal = molar mass of gas mixture used during calibration.

Mmix = molar mass of gas mixture during the emission test calculated using Equation 

1065.640-9.

Example: 

Vstdref = 0.4895 m3

Tin-cal = 302.52 K

Pin-cal = 99.654 kPa = 99654 Pa = 99654 kg/(m∙s2)

pin = 98.836 kPa = 98836 Pa = 98836 kg/(m∙s2)

pstd = 101.325 kPa = 101325 Pa = 101325 kg/(m∙s2)

Mmix-cal = 28.9656 g/mol = 0.0289656 kg/mol

Mmix = 28.7805 g/mol = 0.0287805 kg/mol

Tin = 353.15 K

Tstd = 293.15 K

R = 8.314472 J/(mol·K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

0.4895 302.52 4 0.5 0.000074954 m s K kg

99654

Kv



   

0.000074954 98936 101325 0.0289656

353.15 293.15 8.314472 0.0287805

n



  





n = 16.457 mol/s

305. Section 1065.644 is revised to read as follows:

§1065.644 Vacuum-decay leak rate.

This section describes how to calculate the leak rate of a vacuum-decay leak verification, 

which is described in §1065.345(e). Use the following equation to calculate the leak rate, 

leak n , and compare it to the criterion specified in §1065.345(e):

 

2 1

vac 2 1

leak

2 1

p p

V T T

n

R t t

    

 

 





Eq. 1065.644-1

Where:

Vvac = geometric volume of the vacuum-side of the sampling system.

R = molar gas constant.

p2 = vacuum-side absolute pressure at time t2.

T2 = vacuum-side absolute temperature at time t2.

p1 = vacuum-side absolute pressure at time t1.

T1 = vacuum-side absolute temperature at time t1.

t2 = time at completion of vacuum-decay leak verification test.

t1 = time at start of vacuum-decay leak verification test.
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Example:

Vvac = 2.0000 L = 0.00200 m3

R = 8.314472 J/(mol·K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

p2 = 50.600 kPa = 50600 Pa = 50600 kg/(m∙s2)

T2 = 293.15 K

p1 = 25.300 kPa = 25300 Pa = 25300 kg/(m∙s2)

T1 = 293.15 K

t2 = 10:57:35 AM

t1 = 10:56:25 AM

 

leak

50600 25300

0.0002 293.15 293.15

8.314472 10:57 :35 10:56:25

n

    

 

 





leak

0.00200 86.304

8.314472 70

n  

leak n  0.00030 mol/s

306. Section 1065.645 is amended by revising the introductory text and paragraph (a) 

and adding paragraph (d) to read as follows:

§1065.645 Amount of water in an ideal gas.

This section describes how to determine the amount of water in an ideal gas, which you 

need for various performance verifications and emission calculations. Use the equation 

for the vapor pressure of water in paragraph (a) of this section or another appropriate 

equation and, depending on whether you measure dewpoint or relative humidity, perform 

one of the calculations in paragraph (b) or (c) of this section. Paragraph (d) of this 

section provides an equation for determining dewpoint from relative humidity and dry

bulb temperature measurements. The equations for the vapor pressure of water as 

presented in this section are derived from equations in “Saturation Pressure of Water on 

the New Kelvin Temperature Scale” (Goff, J.A., Transactions American Society of 

Heating and Air-Conditioning Engineers, Vol. 63, No. 1607, pages 347 – 354). Note that 

the equations were originally published to derive vapor pressure in units of atmospheres 

and have been modified to derive results in units of kPa by converting the last term in 

each equation.

(a) Vapor pressure of water. Calculate the vapor pressure of water for a given saturation 

temperature condition, Tsat, as follows, or use good engineering judgment to use a 

different relationship of the vapor pressure of water to a given saturation temperature 

condition:

(1) For humidity measurements made at ambient temperatures from (0 to 100) °C, or for 

humidity measurements made over super-cooled water at ambient temperatures from (–

50 to 0) °C, use the following equation:
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sat

sat

8.2969 1

sat 4 273.16

10 H2O 10

sat

273.16 4.76955 1

3

273.16 log ( ) 10.79574 1 5.02800 log 1.50475 10 1 10

273.16

0.42873 10 10 1 0.2138602

T

T

T

p

T

 

    

  

 

   

  

     

                     

 

      

 

Eq. 1065.645-1

Where:

pH2O = vapor pressure of water at saturation temperature condition, kPa.

Tsat = saturation temperature of water at measured conditions, K.

Example:

Tsat = 9.5 °C = 282.65 K

282.65 8.2969 1

4 273.16

10 H2O 10

273.16 4.76955 1

3 282.65

273.16 282.65 log ( ) 10.79574 1 5.02800 log 1.50475 10 1 10

282.65 273.16

0.42873 10 10 1 0.2138602

p

 

   

  

 

   

  

     

                   

 

      

 

log10(pH2O) = 0.074297

pH2O = 100.074297 = 1.186581 kPa

(2) For humidity measurements over ice at ambient temperatures from (–100 to 0) °C, use 

the following equation:

10 H2O 10

sat sat

sat

273.16 273.16 log ( ) 9.096853 1 3.566506 log

0.876812 1 0.2138602

273.16

p

T T

T

   

             

 

       

Eq. 1065.645-2

Example:

Tice = –15.4 °C = 257.75 K

10 H2O 10

273.16 273.16 log ( ) 9.096853 1 3.566506 log

257.75 257.75

257.75 0.876812 1 0.2138602

273.16

p

   

             

 

       

log10(pH20) = –0.798207

pH2O = 10–0.79821 = 0.159145 kPa
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* * * * *

(d) Dewpoint determination from relative humidity and dry bulb temperature. This 

paragraph (d) describes how to calculate dewpoint temperature from relative humidity, 

RH %. This is based on “ITS-90 Formulations for Vapor Pressure, Frostpoint 

Temperature, Dewpoint Temperature, and Enhancement Factors in the Range –100 to 

+100 °C” (Hardy, B., The Proceedings of the Third International Symposium on 

Humidity & Moisture, Teddington, London, England, April 1998). Calculate pH20sat as 

described in paragraph (a) of this section based on setting Tsat equal to Tamb. Calculate 

pH20scaled by multiplying pH20sat by RH %. Calculate the dewpoint, Tdew, from pH20 using 

the following equation:

     

     

2 3 2 1 1 6

H2O H2O H2O

dew 2 3 1 3 5

H2O H2O H2O

2.0798233 10 2.0156028 10 ln 4.6778925 10 ln 9.2288067 10 ln

1 1.3319669 10 ln 5.6577518 10 ln 7.5172865 10 ln

p p p

T

p p p

 

  

         



        

Eq. 1065.645-5

Where: 

ln(pH2O) = the natural log of pH2Oscaled, which is the water vapor pressure scaled to the

relative humidity at the location of the relative humidity measurement, Tsat = Tamb.

Example:

RH % = 39.61 %

Tsat = Tamb = 20.00 °C = 293.15K

Using Eq. 1065.645-1,

pH2Osat = 2.3371 kPa

pH2Oscaled = (39.61 %) = 0.925717 kPa = 925.717 Pa

     

     

2 1 1 6 2 3

dew 1 3 2 3 5

2.0798233 10 2.0156028 10 ln 925.717 4.6778925 10 ln 925.717 9.2288067 10 ln 925.717

1 1.3319669 10 ln 925.717 5.6577518 10 ln 925.717 7.5172865 10 ln 925.717

T

 

  

         



        

Tdew = 279.00 K = 5.85 °C

307. Section 1065.650 is amended by revising paragraphs (c)(1)(i), (c)(1)(ii), and (f)(4)

to read as follows:

§1065.650 Emission calculations.

* * * * *

(c) * * *

(1) * * *

(i) Correct all gaseous emission analyzer concentration readings, including continuous 

readings, sample bag readings, and dilution air background readings, for drift as 

described in §1065.672. Note that you must omit this step where brake-specific 

emissions are calculated without the drift correction for performing the drift validation 

according to §1065.550(b). When applying the initial THC and CH4 contamination 

readings according to §1065.520(f), use the same values for both sets of calculations. 

You may also use as-measured values in the initial set of calculations and corrected 

values in the drift-corrected set of calculations as described in §1065.520(g)(7).

(ii) Correct all THC and CH4 concentrations for initial contamination as described in 

§1065.660(a), including continuous readings, sample bags readings, and dilution air 
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background readings.

* * * * *

(f) * * *

(4) Example. The following example shows how to calculate mass of emissions using 

proportional values:

N = 3000

frecord = 5 Hz

efuel = 285 g/(kW∙hr)

wfuel = 0.869 g/g

Mc = 12.0107 g/mol

1

n

 = 3.922 mol/s = 14119.2 mol/hr

xCcombdry1 = 91.634 mmol/mol = 0.091634 mol/mol

xH2Oexh1 = 27.21 mmol/mol = 0.02721 mol/mol

Using Eq. 1065.650-5,

t = 0.2 s

2 Ccombdry2 3000 Ccombdry3000

H2Oexh2 H2Oexh3000

3.922 0.091634 12.0107 ... 0.2

1 0.02721 1 1

285 0.869

n x n x

x x

W

    

     

    





   



W = 5.09 (kW∙hr)

* * * * *

308. Section 1065.655 is amended by revising paragraphs (c) introductory text, (c)(3), 

(d), (e), and (f)(2) to read as follows:

§1065.655 Chemical balances of fuel, intake air, and exhaust.

* * * * *

(c) Chemical balance procedure. The calculations for a chemical balance involve a 

system of equations that require iteration. We recommend using a computer to solve this 

system of equations. You must guess the initial values of up to three quantities: the 

amount of water in the measured flow, xH2Oexh, fraction of dilution air in diluted exhaust, 

xdil/exh, and the amount of products on a C1 basis per dry mole of dry measured flow, 

xCcombdry. You may use time-weighted mean values of combustion air humidity and 

dilution air humidity in the chemical balance; as long as your combustion air and dilution 

air humidities remain within tolerances of ±0.0025 mol/mol of their respective mean 

values over the test interval. For each emission concentration, x, and amount of water, 

xH2Oexh, you must determine their completely dry concentrations, xdry and xH2Oexhdry. You 

must also use your fuel’s atomic hydrogen-to-carbon ratio, , oxygen-to-carbon ratio, 

sulfur-to-carbon ratio, , and nitrogen-to-carbon ratio, . You may calculate , , , 

and  based on measured fuel composition as described in paragraph (d)(1) or (d)(2) of 

this section, or you may use default values for a given fuel as described in paragraph 

(d)(3) of this section. Use the following steps to complete a chemical balance:

* * * * *

(3) Use the following symbols and subscripts in the equations for this paragraph (c):

xdil/exh = amount of dilution gas or excess air per mole of exhaust.

xH2Oexh = amount of H2O in exhaust per mole of exhaust.
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xCcombdry = amount of carbon from fuel in the exhaust per mole of dry exhaust.

xH2dry = amount of H2 in exhaust per amount of dry exhaust.

KH2Ogas = water-gas reaction equilibrium coefficient. You may use 3.5 or calculate your 

own value using good engineering judgment.

xH2Oexhdry = amount of H2O in exhaust per dry mole of dry exhaust.

xprod/intdry = amount of dry stoichiometric products per dry mole of intake air.

xdil/exhdry = amount of dilution gas and/or excess air per mole of dry exhaust.

xint/exhdry = amount of intake air required to produce actual combustion products per mole 

of dry (raw or diluted) exhaust.

xraw/exhdry = amount of undiluted exhaust, without excess air, per mole of dry (raw or 

diluted) exhaust.

xO2int = amount of intake air O2 per mole of intake air.

xCO2intdry = amount of intake air CO2 per mole of dry intake air. You may use xCO2intdry = 

375 μmol/mol, but we recommend measuring the actual concentration in the intake air.

xH2Ointdry = amount of intake air H2O per mole of dry intake air.

xCO2int = amount of intake air CO2 per mole of intake air.

xCO2dil = amount of dilution gas CO2 per mole of dilution gas.

xCO2dildry = amount of dilution gas CO2 per mole of dry dilution gas. If you use air as 

diluent, you may use xCO2dildry = 375 μmol/mol, but we recommend measuring the actual 

concentration in the intake air.

xH2Odildry = amount of dilution gas H2O per mole of dry dilution gas.

xH2Odil = amount of dilution gas H2O per mole of dilution gas.

x[emission]meas = amount of measured emission in the sample at the respective gas analyzer.

x[emission]dry = amount of emission per dry mole of dry sample.

xH2O[emission]meas = amount of H2O in sample at emission-detection location. Measure or 

estimate these values according to §1065.145(e)(2).

xH2Oint = amount of H2O in the intake air, based on a humidity measurement of intake air.

 = atomic hydrogen-to-carbon ratio of the mixture of fuel(s) being combusted, weighted 

by molar consumption.

 = atomic oxygen-to-carbon ratio of the mixture of fuel(s) being combusted, weighted 

by molar consumption.

 = atomic sulfur-to-carbon ratio of the mixture of fuel(s) being combusted, weighted by 

molar consumption.

 = atomic nitrogen-to-carbon ratio of the mixture of fuel(s) being combusted, weighted 

by molar consumption.

* * * * *

(d) Carbon mass fraction and fuel composition. Determine carbon mass fraction of fuel, 

wc, and fuel composition represented by α, β, γ, and δ using one of the following 

methods:

(1) You may calculate wc as described in this paragraph (d)(1) based on measured fuel 

properties. To do so, you must determine values for  and  in all cases, but you may set 

 and  to zero if the default value listed in Table 1 of this section is zero. Calculate wc

using the following equation:

C

c

C H O S N

1

1

M

w

M M   M M   M





        
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Eq. 1065.655-19

Where:

[Note to Editor: The following expression for wc is a lower-case omega in the 

Federal Register. It should be an italicized lower-case w.]

wc = carbon mass fraction of fuel.

MC = molar mass of carbon.

 = atomic hydrogen-to-carbon ratio of the mixture of fuel(s) being combusted, weighted 

by molar consumption.

MH = molar mass of hydrogen.

 = atomic oxygen-to-carbon ratio of the mixture of fuel(s) being combusted, weighted 

by molar consumption.

MO = molar mass of oxygen.

 = atomic sulfur-to-carbon ratio of the mixture of fuel(s) being combusted, weighted by 

molar consumption.

MS = molar mass of sulfur.

 = atomic nitrogen-to-carbon ratio of the mixture of fuel(s) being combusted, weighted 

by molar consumption.

MN = molar mass of nitrogen.

Example:

 = 1.8

 = 0.05

 = 0.0003

= 0.0001

MC = 12.0107

MH = 1.00794

MO = 15.9994

MS = 32.065

MN = 14.0067

c

1 12.0107

1 12.0107 1.8 1.00794 0.05 15.9994 0.0003 32.065 0.0001 14.0067

w





        

wc = 0.8206

(2) Determine a fuel’s elemental mass fractions and values for α, β, γ, and δ as follows: 

(i) For gaseous fuels, use the default values for α, β, γ, and δ in Table 1 of this section or 

use good engineering judgment to determine those values based on measurement. 

(ii) Determine mass fractions of liquid fuels as follows:

(A) You may determine the carbon and hydrogen mass fractions according to ASTM 

D5291 (incorporated by reference in §1065.1010). When using ASTM D5291 to 

determine carbon and hydrogen mass fractions of gasoline (with or without blended 

ethanol), use good engineering judgment to adapt the method as appropriate.

(B) Determine oxygen mass fraction of gasoline (with or without blended ethanol) 

according to ASTM D5599 (incorporated by reference in §1065.1010). For all other 

liquid fuels, determine the oxygen mass fraction using good engineering judgment.
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(C) Determine the nitrogen mass fraction according to ASTM D4629 or ASTM D5762

(incorporated by reference in §1065.1010) for all liquid fuels. Select the correct method

based on the expected nitrogen content.

(D) Determine the sulfur mass fraction according to subpart H of this part.

(iii) For liquid fuels, use the default values for α, β, γ, and δ in Table 1 of this section, or 

you may determine the value for any of these parameters based on measurement. 

Calculate these values using the following equations:

H C

C H

w M

w M









 

Eq. 1065.655-20

O C

C O

w M

w M









Eq. 1065.655-21

S C

C S

w M

w M









Eq. 1065.655-22

N C

C N

w M

w M









Eq. 1065.655-23

Where:

wC = carbon mass fraction of fuel.

wH = hydrogen mass fraction of fuel.

wO = oxygen mass fraction of fuel.

wS = sulfur mass fraction of fuel.

wN = nitrogen mass fraction of fuel.

Example:

wC = 0.8206

wH = 0.1239

wO = 0.0547

wS = 0.00066

wN = 0.000095

MC = 12.0107

MH = 1.00794

MO = 15.9994

MS = 32.065

MN = 14.0067

0.1239 12.0107

0.8206 1.00794









0.0547 12.0107

0.8206 15.9994









0.00066 12.0107

0.8206 32.065








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0.000095 12.0107

0.8206 14.0067









 = 1.8

 = 0.05

 = 0.0003

= 0.0001

TABLE 1 OF §1065.655–DEFAULT VALUES OF , , , , AND wc, FOR VARIOUS FUELS

Fuel

Atomic hydrogen,

oxygen, sulfur, and 

nitrogen-to-carbon ratios

CHαOβSN

Carbon mass 

fraction, wc

g/g

Gasoline CH1.85O0S0N0 0.866

E10 Gasoline CH1.92O0.03S0N0 0.833

E15 Gasoline CH1.95O0.05S0N0 0.817

E85 Gasoline CH2.73O0.38S0N0 0.576

#1 Diesel CH1.93O0S0N0 0.861

#2 Diesel CH1.80O0S0N0 0.869

Liquefied petroleum gas CH2.64O0S0N0 0.819

Natural gas CH3.78 O0.016S0N0 0.747

E100 Ethanol CH3O0.5S0N0 0.521

M100 Methanol CH4O1S0N0 0.375

Residual fuel blends Must be determined by measured fuel properties as 

described in paragraph (d)(1) of this section.

(e) Calculated raw exhaust molar flow rate from measured intake air molar flow rate or 

fuel mass flow rate. You may calculate the raw exhaust molar flow rate from which you 

sampled emissions, exh n , based on the measured intake air molar flow rate, int n , or the 

measured fuel mass flow rate, mfuel  , and the values calculated using the chemical balance 

in paragraph (c) of this section. The chemical balance must be based on raw exhaust gas 

concentrations. Solve for the chemical balance in paragraph (c) of this section at the 

same frequency that you update and record int n or mfuel  . For laboratory tests, calculating 

raw exhaust molar flow rate using measured fuel mass flow rate is valid only for steadystate testing. See §1065.915(d)(5)(iv) for application to field testing.

(1) Crankcase flow rate. If engines are not subject to crankcase controls under the 

standard-setting part, you may calculate raw exhaust flow based on int n or mfuel  using one 

of the following:

(i) You may measure flow rate through the crankcase vent and subtract it from the 

calculated exhaust flow.

(ii) You may estimate flow rate through the crankcase vent by engineering analysis as 

long as the uncertainty in your calculation does not adversely affect your ability to show 

that your engines comply with applicable emission standards.

(iii) You may assume your crankcase vent flow rate is zero.
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(2) Intake air molar flow rate calculation. Calculate exh n based on int n using the following 

equation:

 

 

int

exh

int/exhdry raw/exhdry

H2Oexhdry

1

1

n

n

x x

x



  

  



 





Eq. 1065.655-24

Where:

exh n = raw exhaust molar flow rate from which you measured emissions.

int n = intake air molar flow rate including humidity in intake air.

Example:

int n = 3.780 mol/s

xint/exhdry = 0.69021 mol/mol

xraw/exhdry = 1.10764 mol/mol

xH20exhdry = 107.64 mmol/mol = 0.10764 mol/mol

 

 

exh

3.780

0.69021 1.10764

1

1 0.10764

n 

  

  

  



exh n = 6.066 mol/s

(3) Fuel mass flow rate calculation. This calculation may be used only for steady-state 

laboratory testing. See §1065.915(d)(5)(iv) for application to field testing. Calculate 

exh n based on mfuel  using the following equation:

fuel c H  2Oexhdry 

exh

c Ccombdry

m w 1 x

n

M x

  









Eq. 1065.655-25

Where:

exh n = raw exhaust molar flow rate from which you measured emissions.

mfuel  = fuel mass flow rate.

Example:

mfuel  = 7.559 g/s

wc = 0.869 g/g

MC = 12.0107 g/mol

xCcombdry = 99.87 mmol/mol = 0.09987 mol/mol

xH20exhdry = 107.64 mmol/mol = 0.10764 mol/mol

 

exh

7.559 0.869 1 0.10764

12.0107 0.09987

n

  







exh n = 6.066 mol/s
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(f) * * *

(2) Dilute exhaust and intake air molar flow rate calculation. Calculate exh n as follows:

exh  raw/exhdry int/exhdry   H2Oexh  dexh int n x     x x  1   n n

Eq. 1065.655-26

Example:

int n  7.930 mol/s

raw/exhdry x  0.1544 mol/mol

0.1451mol/mol xint/exhdry 

H2Oexh x   32.46 mmol/mol 0.03246 mol/mol

dexh n  49.02 mol/s

n

exh   0.1544 0.1451  1 0.03246  49.02 7.930   0.4411 7.930 8  .371 mol/s

309. Section 1065.659 is amended by revising paragraphs (a) and (d) to read as 

follows:

§1065.659 Removed water correction.

(a) If you remove water upstream of a concentration measurement, x, correct for the 

removed water. Perform this correction based on the amount of water at the 

concentration measurement, xH2O[emission]meas, and at the flow meter, xH2Oexh, whose flow is 

used to determine the mass emission rate or total mass over a test interval. For 

continuous analyzers downstream of a sample dryer for transient and ramped-modal 

cycles, you must apply this correction on a continuous basis over the test interval, even if 

you use one of the options in §1065.145(e)(2) that results in a constant value for 

xH2O[emission]meas because xH2Oexh varies over the test interval. For batch analyzers, 

determine the flow-weighted average based on the continuous xH2Oexh values determined 

as described in paragraph (c) of this section. For batch analyzers, you may determine the 

flow-weighted average xH2Oexh based on a single value of xH2Oexh determined as described 

in paragraphs (c)(2) and (3) of this section, using flow-weighted average or batch 

concentration inputs.

* * * * *

(d) Perform a removed water correction to the concentration measurement using the 

following equation:

H2Oexh

[emission]meas

H2O[emission]meas

1

1

x

x x

x

  

  

  

Eq. 1065.659-1

Example:

xCOmeas = 29.0 μmol/mol

xH2OCOmeas = 8.601 mmol/mol = 0.008601 mol/mol

xH2Oexh = 34.04 mmol/mol = 0.03404 mol/mol

CO

1 0.03404 29.0

1 0.008601

x

  

     
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xCO = 28.3 μmol/mol

310. Section 1065.665 is revised to read as follows:

§1065.665 THCE and NMHCE determination.

(a) If you measured an oxygenated hydrocarbon's mass concentration, first calculate its 

molar concentration in the exhaust sample stream from which the sample was taken (raw 

or diluted exhaust), and convert this into a C1-equivalent molar concentration. Add these 

C1-equivalent molar concentrations to the molar concentration of non-oxygenated total

hydrocarbon (NOTHC). The result is the molar concentration of total hydrocarbon 

equivalent (THCE). Calculate THCE concentration using the following equations, noting 

that Eq. 1065.665-3 is required only if you need to convert your oxygenated hydrocarbon

(OHC) concentration from mass to moles:

THCE NOTHC  OHCi OHCi-init

1

N

i

x x x x



  

Eq. 1065.665-1

NOTHC THC[THC-FID]cor  OHCi OHCi-init  OHCi[THC-FID] 

1

N

i

x x x x RF



   

Eq. 1065.665-2

dexhOHCi

OHCi dexhOHCi

OHCi

dexh dexh

dexh

m

M n

x

m n

M

 

Eq. 1065.665-3

Where:

xTHCE = The sum of the C1-equivalent concentrations of non-oxygenated hydrocarbons, 

alcohols, and aldehydes.

xNOTHC = The sum of the C1-equivalent concentrations of NOTHC.

xOHCi = The C1-equivalent concentration of oxygenated species i in diluted exhaust, not 

corrected for initial contamination.

xOHCi-init = The C1-equivalent concentration of the initial system contamination (optional) 

of oxygenated species i, dry-to-wet corrected. 

xTHC[THC-FID]cor = The C1-equivalent response to NOTHC and all OHC in diluted exhaust, 

HC contamination and dry-to-wet corrected, as measured by the THC-FID.

RFOHCi[THC-FID] = The response factor of the FID to species i relative to propane on a C1-

equivalent basis.

C

#

= the mean number of carbon atoms in the particular compound.

Mdexh = The molar mass of diluted exhaust as determine in §1065.340.

mdexhOHCi = The mass of oxygenated species i in dilute exhaust.

MOHCi = The C1-equivalent molecular weight of oxygenated species i.

mdexh = The mass of diluted exhaust

ndexhOHCi = The number of moles of oxygenated species i in total diluted exhaust flow.

ndexh = The total diluted exhaust flow.

(b) If we require you to determine nonmethane hydrocarbon equivalent (NMHCE), use 

the following equation:

xNMHCE = xTHCE – RFCH4[THC-FID]  xCH4
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Eq. 1065.665-4

Where:

xNMHCE = The sum of the C1-equivalent concentrations of nonoxygenated nonmethane 

hydrocarbon (NONMHC), alcohols, and aldehydes.

RFCH4[THC-FID] = response factor of THC-FID to CH4.

xCH4 = concentration of CH4, HC contamination (optional) and dry-to-wet corrected, as 

measured by the gas chromatograph FID.

(c) The following example shows how to determine NMHCE emissions based on ethanol 

(C2H5OH), methanol (CH3OH), acetaldehyde (C2H4O), and formaldehyde (CH2O) as C1-

equivalent molar concentrations:

xTHC[THC-FID]cor = 145.6 μmol/mol

xCH4 = 18.9 μmol/mol

xC2H5OH = 100.8 μmol/mol

xCH3OH = 1.1 μmol/mol

xC2H4O = 19.1 μmol/mol

xCH2O = 1.3 μmol/mol

RFCH4[THC-FID] = 1.07

RFC2H5OH[THC-FID] = 0.76

RFCH3OH[THC-FID] = 0.74

RFH2H4O[THC-FID] = 0.50

RFCH2O[THC-FID] = 0.0

xNMHCE = xTHC[THC-FID]cor – (xC2H5OH  RFC2H5OH[THC-FID] + xCH3OH  RFCH3OH[THC-FID] + 

xC2H4O  RFC2H4O[THC-FID] + xCH2O  RFCH2O[THC-FID] + xC2H5OH + xCH3OH + xC2H4O + xCH2O –

(RFCH4[THC-FID]  xCH4)

xNMHCE = 145.6 – (100.8 ∙ 0.76 + 1.1  0.74 + 19.1  0.50 + 1.3  0+ 100.8 + 1.1 + 19.1 + 

1.3 – (1.07  18.9)

xNMHCE = 160.71 μmol/mol

311. Section 1065.690 is amended by revising paragraph (e) to read as follows:

§1065.690 Buoyancy correction for PM sample media.

* * * * *

(e) Correction calculation. Correct the PM sample media for buoyancy using the 

following equations:

air

weight

cor uncor

air

media

1

1

m m









 

  

  

 



   

Eq. 1065.690-1

Where:

mcor = PM mass corrected for buoyancy.

muncor = PM mass uncorrected for buoyancy.

air = density of air in balance environment.
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weight = density of calibration weight used to span balance.

media = density of PM sample media, such as a filter.

abs mix

air

amb

p M

R T









Eq. 1065.690-2

Where:

pabs = absolute pressure in balance environment.

Mmix = molar mass of air in balance environment.

R = molar gas constant.

Tamb = absolute ambient temperature of balance environment.

Example:

pabs = 99.980 kPa

Tsat = Tdew = 9.5 °C

Using Eq. 1065.645-1,

pH20 = 1.1866 kPa

Using Eq. 1065.645-3,

xH2O = 0.011868 mol/mol

Using Eq. 1065.640-9,

Mmix = 28.83563 g/mol

R = 8.314472 J/(mol·K)

Tamb = 20 °C

air

99.980 28.83563

8.314472 293.15









air = 1.18282 kg/m3

muncorr = 100.0000 mg

weight = 8000 kg/m3

media = 920 kg/m3

cor

1.18282 1

8000 100.0000 1.18282 1

920

m

 

  

  

  

 

mcor = 100.1139 mg

312. Section 1065.695 is amended by revising paragraph (c)(4)(i) and adding 

paragraph (c)(6)(x) to read as follows:

§1065.695 Data requirements.

* * * * *

(c) * * *

(4) * * *

(i) Linearity verification.

* * * * *

(6) * * *

(x) Number and type of preconditioning cycles.

* * * * *
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Subpart H—[Amended]

313. Section 1065.701 is amended by revising paragraphs (a), (d), and (f) to read as 

follows:

§1065.701 General requirements for test fuels.

(a) General. For all emission measurements, use test fuels that meet the specifications in 

this subpart, unless the standard-setting part directs otherwise. Section 1065.10(c)(1) 

does not apply with respect to test fuels. Note that the standard-setting parts generally 

require that you design your emission controls to function properly when using 

commercially available fuels, even if they differ from the test fuel. Where we specify

multiple grades of a certain fuel type (such as diesel fuel with different sulfur 

concentrations), see the standard-setting part to determine which grade to use.

* * * * *

(d) Fuel specifications. Specifications in this section apply as follows:

(1) Measure and calculate values as described in the appropriate reference procedure. 

Record and report final values expressed to at least the same number of decimal places as 

the applicable limit value. The right-most digit for each limit value is significant unless 

specified otherwise. For example, for a specified distillation temperature of 60 °C, 

determine the test fuel’s value to at least the nearest whole number. 

(2) The fuel parameters specified in this subpart depend on measurement procedures that 

are incorporated by reference. For any of these procedures, you may instead rely upon 

the procedures identified in 40 CFR part 80 for measuring the same parameter. For 

example, we may identify different reference procedures for measuring gasoline 

parameters in 40 CFR 80.46.

* * * * *

(f) Service accumulation and field testing fuels. If we do not specify a serviceaccumulation or field-testing fuel in the standard-setting part, use an appropriate 

commercially available fuel such as those meeting minimum specifications from the 

following table:

TABLE 1 OF §1065.701–EXAMPLES OF SERVICE-ACCUMULATION AND FIELD-TESTING 

FUELS

Fuel category Subcategory Reference procedure1

Diesel

Light distillate and light blends with 

residual ASTM D975

Middle distillate ASTM D6985

Biodiesel (B100) ASTM D6751

Intermediate and residual fuel All See §1065.705

Gasoline

Automotive gasoline ASTM D4814

Automotive gasoline with ethanol 

concentration up to 10 volume %. ASTM D4814

Alcohol Ethanol (E51-83) ASTM D5798

Methanol (M70-M85) ASTM D5797

Aviation fuel

Aviation gasoline ASTM D910

Gas turbine ASTM D1655

Jet B wide cut ASTM D6615

Gas turbine fuel General ASTM D2880

1ASTM specifications are incorporated by reference in §1065.1010.
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314. Section 1065.703 is amended by revising paragraph (b) to include Table 1 to read 

as follows:

§1065.703 Distillate diesel fuel.

* * * * *

(b) There are three grades of #2 diesel fuel specified for use as a test fuel. See the 

standard-setting part to determine which grade to use. If the standard-setting part does 

not specify which grade to use, use good engineering judgment to select the grade that 

represents the fuel on which the engines will operate in use. The three grades are 

specified in the following table:

TABLE 1 OF §1065.703–TEST FUEL SPECIFICATIONS FOR DISTILLATE DIESEL FUEL

Property Unit Ultra Low

Sulfur

Low

Sulfur

High

Sulfur

Reference

Procedure1

Cetane Number — 40 - 50 40 - 50 40 - 50 ASTM D613

Distillation range:

Initial boiling point

10 pct. point 

50 pct. point

90 pct. point 

Endpoint

°C

171 - 204

204 - 238

243 - 282

293 - 332

321 - 366

171 - 204

204 - 238

243 - 282

293 - 332

321 - 366

171 - 204

204 - 238

243 - 282

293 - 332

321 - 366

ASTM D86

Gravity °API 32 - 37 32 - 37 32 - 37 ASTM D4052

Total sulfur, ultra low sulfur mg/kg 7 – 15 See 40 CFR 80.580

Total sulfur, low and high sulfur mg/kg 300 - 500 800 - 2500 ASTM D2622or 

alternates as allowed 

under 40 CFR 80.580

Aromatics, min. (Remainder shall be 

paraffins, naphthenes, and olefins)

g/kg 100 100 100 ASTM D5186

Flashpoint, min. °C 54 54 54 ASTM D93

Kinematic Viscosity cSt 2.0 - 3.2 2.0 - 3.2 2.0 - 3.2 ASTM D445

1ASTM procedures are incorporated by reference in §1065.1010. See §1065.701(d) for other allowed procedures.

* * * * *

315. Section 1065.705 is revised to read as follows:

§1065.705 Residual and intermediate residual fuel.

This section describes the specifications for fuels meeting the definition of residual fuel 

in 40 CFR 80.2, including fuels marketed as intermediate fuel. Residual fuels for service 

accumulation and any testing must meet the following specifications:

(a) The fuel must be a commercially available fuel that is representative of the fuel that 

will be used by the engine in actual use.

(b) The fuel must be free of used lubricating oil. Demonstrate this by showing that the 

fuel meets at least one of the following specifications.

(1) Zinc is at or below 15 mg per kg of fuel based on the procedures specified in IP470, 

IP501, or ISO 8217 (incorporated by reference in §1065.1010).

(2) Phosphorus is at or below 15 mg per kg of fuel based on the procedures specified in 

IP500, IP501, or ISO 8217 (incorporated by reference in §1065.1010).

(3) Calcium is at or below 30 mg per kg of fuel based on the procedures specified in 

IP470, IP501, or ISO 8217 (incorporated by reference in §1065.1010).

(c) The fuel must meet the specifications for one of the categories in the following table:
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TABLE 1 OF §1065.705–SERVICE ACCUMULATION AND TEST FUEL SPECIFICATIONS FOR RESIDUAL FUEL

Property Unit

Category ISO-F- Reference Procedure 1

RMA

30

RMB

30

RMD

80

RME

180

RMF

180

RMG

380

RMH

380

RMK

380

RMH

700

RMK

700

Density at 15 °C, max. kg/m3960.0 975.0 980.0 991.0 991.0 1010.0 991.0 1010.0 ISO 3675 or ISO 12185 (see 

also ISO 8217)

Kinematic viscosity at 

50 °C, max. cSt 30.0 80.0 180.0 380.0 700.0 ISO 3104

Flash point, min. °C 60 60 60 60 60 ISO 2719 (see also ISO 8217)

Pour point (upper)

Winter quality, max.

Summer quality, max.

°C 0

6

24

24

30

30

30

30

30

30

30

30 ISO 3016

Carbon residue, max. (kg/kg) % 10 14 15 20 18 22 22 ISO 10370

Ash, max. (kg/kg) % 0.10 0.10 0.10 0.15 0.15 0.15 ISO 6245

Water, max. (m3/m3) % 0.5 0.5 0.5 0.5 0.5 ISO 3733

Sulfur, max. (kg/kg) % 3.50 4.00 4.50 4.50 4.50 ISO 8754 or ISO 14596 (see 

also ISO 8217)

Vanadium, max. mg/kg 150 350 200 500 300 600 600 ISO 14597 or IP 501 or IP 470 

(see also ISO 8217)

Total sediment 

potential, max. (kg/kg) % 0.10 0.10 0.10 0.10 0.10 ISO 10307-2 (see also ISO 8217)

Aluminium plus 

silicon, max. mg/kg 80 80 80 80 80 ISO 10478 or IP 501 or IP 470 (see also ISO 8217:2012)

1

ISO procedures are incorporated by reference in §1065.1010. See §1065.701(d) for other allowed procedures.
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316. Section 1065.710 is revised to read as follows:

§1065.710 Gasoline.

(a) This section specifies test fuel properties for gasoline with ethanol (low-level blend 

only) and for gasoline without ethanol. Note that the “fuel type” for the fuels specified in 

paragraphs (b) and (c) of this section is considered to be gasoline. In contrast, fuels with 

higher ethanol concentrations, such as fuel containing 82 percent ethanol, are considered 

to be ethanol fuels rather than gasoline. We specify some test fuel parameters that apply

uniquely for low-temperature testing and for testing at altitudes above 1,219 m. For all 

other testing, use the test fuel parameters specified for general testing. Unless the 

standard-setting part specifies otherwise, use the fuel specified in paragraph (c) of this 

section for general testing. 

(b) The following specifications apply for a blended gasoline test fuel that has nominally

10 % ethanol (commonly called E10 test fuel):

(1) Prepare the blended test fuel from typical refinery gasoline blending components. 

You may not use pure compounds, except as follows:

(i) You may use neat ethanol as a blendstock.

(ii) You may adjust the test fuel’s vapor pressure by adding butane.

(iii) You may adjust the test fuel’s benzene content by adding benzene.

(iv) You may adjust the test fuel’s sulfur content by adding sulfur compounds that are 

representative of those found with in-use fuels.

(2) Table 1 of this section identifies limit values consistent with the units in the reference 

procedure for each fuel property. These values are generally specified in international 

units. Values presented in parentheses are for information only. Table 1 follows:
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TABLE 1 OF §1065.710–TEST FUEL SPECIFICATIONS FOR A LOW-LEVEL ETHANOL-GASOLINE BLEND

Property Unit

SPECIFICATION

Reference Procedure1

General 

Testing

LowTemperature 

Testing

High Altitude 

Testing

Antiknock Index (R+M)/2 - 87.0 - 88.42 87.0 

Minimum ASTM D2699 and D2700

Sensitivity (R-M) - 7.5 Minimum ASTM D2699 and D2700

Dry Vapor Pressure Equivalent

(DVPE)

3,4 kPa (psi) 60.0-63.4 

(8.7-9.2)

77.2-81.4

(11.2-11.8)

52.4-55.2 

(7.6-8.0) ASTM D5191

Distillation 4

10% evaporated °C (°F) 49-60(120-140)

43-54 

(110-130)

49-60

(120-140)

ASTM D86

50% evaporated °C (°F) 88-99 (190-210)

90% evaporated °C (°F) 157-168 (315-335)

Evaporated final boiling point °C (°F) 193-216 (380-420)

Residue milliliter 2.0 Maximum

Total Aromatic Hydrocarbons volume % 21.0-25.0

ASTM D5769

C6 Aromatics (benzene) volume % 0.5-0.7

C7 Aromatics (toluene) volume % 5.2-6.4

C8 Aromatics volume % 5.2-6.4

C9 Aromatics volume % 5.2-6.4

C10+ Aromatics volume % 4.4-5.6

Olefins5 mass % 4.0-10.0 ASTM D6550

Ethanol blended volume % 9.6-10.0 See paragraph (b)(3) of this section.

Ethanol confirmatory6volume % 9.4-10.2 ASTM D4815 or D5599

Total Content of Oxygenates 

Other than Ethanol 6 volume % 0.1 Maximum ASTM D4815 or D5599

Sulfur mg/kg 8.0-11.0 ASTM D2622, D5453 or D7039

Lead g/liter 0.0026 Maximum ASTM D3237

Phosphorus g/liter 0.0013 Maximum ASTM D3231

Copper Corrosion - No. 1 Maximum ASTM D130

Solvent-Washed Gum Content mg/100 

milliliter 3.0 Maximum ASTM D381

Oxidation Stability minute 1000 Minimum ASTM D525

1ASTM procedures are incorporated by reference in §1065.1010. See §1065.701(d) for other allowed procedures.

2Octane specifications apply only for testing related to exhaust emissions. For engines or vehicles that require the use of premium fuel, as 

described in paragraph (d) of this section, the adjusted specification for antiknock index is a minimum value of 91.0; no maximum value 

applies. All other specifications apply for this high-octane fuel.

3Calculate dry vapor pressure equivalent, DVPE, based on the measured total vapor pressure, pT, using the following equation: DVPE (kPa) = 

0.956∙pT - 2.39 or DVPE (psi) = 0.956∙pT – 0.347. DVPE is intended to be equivalent to Reid Vapor Pressure using a different test method.

4

Parenthetical values are shown for informational purposes only. 

5The reference procedure prescribes measurement of olefin concentration in mass %. Multiply this result by 0.857 and round to the first 

decimal place to determine the olefin concentration in volume %. 

6ASTM D5599 prescribes concentration measurements for ethanol and other oxygenates in mass %. Convert results to volume % as 

specified in Section 14.3 of ASTM D4815.
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(3) The ethanol-blended specification in Table 1 of this section is based on the volume % 

ethanol content of the fuel as determined during blending by the fuel supplier and as 

stated by the supplier at the time of fuel delivery. Use good engineering judgment to 

determine the volume % of ethanol based on the volume of each blendstock. We 

recommend using a flow-based or gravimetric procedure that has an accuracy and 

repeatability of ± 0.1 %.

(c) The specifications of this paragraph (c) apply for testing with neat gasoline. This is 

sometimes called indolene or E0 test fuel. Gasoline for testing must have octane values 

that represent commercially available fuels for the appropriate application. Test fuel 

specifications apply as follows:

TABLE 2 OF §1065.710–TEST FUEL SPECIFICATIONS FOR NEAT (E0) GASOLINE

Property Unit

SPECIFICATION Reference 

Procedure1 General Testing Low-Temperature 

Testing

Distillation Range:

Evaporated initial boiling point

10% evaporated

50% evaporated

90% evaporated

Evaporated final boiling point

°C 24 - 352

49 - 57

93 - 110

149 - 163

Maximum, 213

24 - 36

37 - 48

82 – 101

158 - 174

Maximum, 212

ASTM D86

Hydrocarbon composition:

Olefins

Aromatics

Saturates

volume % Maximum, 0.10

Maximum, 0.35

Remainder

Maximum, 0.175

Maximum, 0.304

Remainder

ASTM D1319

Lead g/liter Maximum, 0.013 Maximum, 0.013 ASTM D3237

Phosphorous g/liter Maximum, 0.0013 Maximum, 0.005 ASTM D3231

Total sulfur mg/kg Maximum, 80 Maximum, 80 ASTM D2622

Dry vapor pressure equivalent3kPa 60.0 - 63.4

2,4 77.2 - 81.4 ASTM D5191

1ASTM procedures are incorporated by reference in §1065.1010. See §1065.701(d) for other allowed 

procedures.

2

For testing at altitudes above 1219 m, the specified initial boiling point range is (23.9 to 40.6) °C and the 

specified volatility range is (52.0 to 55.2) kPa.

3Calculate dry vapor pressure equivalent, DVPE, based on the measured total vapor pressure, pT, in kPa using the 

following equation: DVPE (kPa) = 0.956∙pT - 2.39 or DVPE (psi) = 0.956∙pT – 0.347. DVPE is intended to be 

equivalent to Reid Vapor Pressure using a different test method.

4

For testing unrelated to evaporative emissions, the specified range is (55.2 to 63.4) kPa.

(d) Use the high-octane gasoline specified in paragraph (b) of this section only for 

engines or vehicles for which the manufacturer conditions the warranty on the use of 

premium gasoline.

317. Section 1065.715 is amended by revising paragraph (a) to read as follows:

§1065.715 Natural gas.
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(a) Except as specified in paragraph (b) of this section, natural gas for testing must meet 

the specifications in the following table:

TABLE 1 OF §1065.715–TEST FUEL SPECIFICATIONS FOR NATURAL GAS

Property Value1

Methane, CH4 Minimum, 0.87 mol/mol

Ethane, C2H6 Maximum, 0.055 mol/mol

Propane, C3H8 Maximum, 0.012 mol/mol

Butane, C4H10 Maximum, 0.0035 mol/mol

Pentane, C5H12 Maximum, 0.0013 mol/mol

C6 and higher Maximum, 0.001 mol/mol

Oxygen Maximum, 0.001 mol/mol

Inert gases (sum of CO2 and N2) Maximum, 0.051 mol/mol

1 Demonstrate compliance with fuel specifications based on the reference procedures in 

ASTM D1945 (incorporated by reference in §1065.1010), or on other measurement 

procedures using good engineering judgment. See §1065.701(d) for other allowed 

procedures.

* * * * *

318. Section 1065.720 is amended by revising paragraph (a) to read as follows:

§1065.720 Liquefied petroleum gas.

(a) Except as specified in paragraph (b) of this section, liquefied petroleum gas for testing 

must meet the specifications in the following table:

TABLE 1 OF §1065.720–TEST FUEL SPECIFICATIONS FOR LIQUEFIED PETROLEUM GAS

Property Value Reference Procedure1

Propane, C3H8 Minimum, 0.85 m3/m3 ASTM D2163

Vapor pressure at 38 °C Maximum, 1400 kPa ASTM D1267or D25982

Volatility residue (evaporated temperature, 35 °C) Maximum, -38 °C ASTM D1837

Butanes Maximum, 0.05 m3/m3 ASTM D2163

Butenes Maximum, 0.02 m3/m3 ASTM D2163

Pentenes and heavier Maximum, 0.005 m3/m3 ASTM D2163

Propene Maximum, 0.1 m3/m3 ASTM D2163

Residual matter (residue on evap. of 100) ml oil stain 

observ.)

Maximum, 0.05 ml pass3 ASTM D2158

Corrosion, copper strip Maximum, No. 1 ASTM D1838

Sulfur Maximum, 80 mg/kg ASTM D2784

Moisture content pass ASTM D2713

1ASTM procedures are incorporated by reference in §1065.1010. See §1065.701(d) for other allowed procedures.

2

If these two test methods yield different results, use the results from ASTM D1267.

3The test fuel must not yield a persistent oil ring when you add 0.3 ml of solvent residue mixture to a filter paper in 0.1 

ml increments and examine it in daylight after two minutes.

* * * * *

319. A new § 1065.725 is added to subpart H to read as follows:

§1065.725 High-level ethanol-gasoline blends.

For testing vehicles capable of operating on a high-level ethanol-gasoline blend, create a

test fuel as follows:

(a) Add ethanol to an E10 fuel meeting the specifications described in §1065.710 until 

the ethanol content of the blended fuel is between 80 and 83 volume %. 

(b) You may alternatively add ethanol to a gasoline base fuel with no ethanol if you can 

demonstrate that such a base fuel blended with the proper amount of ethanol would meet 
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all the specifications for E10 test fuel described in §1065.710, other than the ethanol 

content.

(c) The ethanol used for blending must be either denatured ethanol meeting the 

specifications in 40 CFR 80.1610, or fuel-grade ethanol with no denaturant. Account for 

the volume of any denaturant when calculating volumetric percentages.

(d) The blended test fuel must have a dry vapor pressure equivalent between 41.5 and 

45.1 kPa (6.0 and 6.5 psi) when measured using the procedure specified in §1065.710. 

You may add commercial grade butane as needed to meet this specification.

320. Section 1065.750 is amended by revising the introductory text and paragraph (a) 

to read as follows:

§1065.750 Analytical Gases.

Analytical gases must meet the accuracy and purity specifications of this section, unless 

you can show that other specifications would not affect your ability to show that you 

comply with all applicable emission standards.

(a) Subparts C, D, F, and J of this part refer to the following gas specifications:

(1) Use purified gases to zero measurement instruments and to blend with calibration 

gases. Use gases with contamination no higher than the highest of the following values 

in the gas cylinder or at the outlet of a zero-gas generator:

(i) 2 % contamination, measured relative to the flow-weighted mean concentration 

expected at the standard. For example, if you would expect a flow-weighted CO 

concentration of 100.0 mol/mol, then you would be allowed to use a zero gas with CO 

contamination less than or equal to 2.000 mol/mol.

(ii) Contamination as specified in the following table:

TABLE 1 OF §1065.750–GENERAL SPECIFICATIONS FOR PURIFIED GASES1

Constituent Purified Air Purified N2

THC (C1-equivalent) ≤ 0.05 mol/mol ≤ 0.05 mol/mol

CO ≤ 1 mol/mol ≤ 1 mol/mol

CO2 ≤ 10 mol/mol ≤ 10 mol/mol

O2 0.205 to 0.215 mol/mol ≤ 2 mol/mol

NOx ≤ 0.02 mol/mol ≤ 0.02 mol/mol

N2O

2

≤ 0.02 mol/mol ≤ 0.02 mol/mol

1We do not require these levels of purity to be NIST-traceable.

2The N2O limit applies only if the standard-setting part requires you to report N2O or certify to an N2O 

standard.

(2) Use the following gases with a FID analyzer:

(i) FID fuel. Use FID fuel with a stated H2 concentration of (0.39 to 0.41) mol/mol, 

balance He or N2, and a stated total hydrocarbon concentration of 0.05 mol/mol or less. 

For GC-FIDs that measure methane (CH4) using a FID fuel that is balance N2, perform 

the CH4 measurement as described in SAE J1151 (incorporated by reference in 

§1065.1010).

(ii) FID burner air. Use FID burner air that meets the specifications of purified air in 

paragraph (a)(1) of this section. For field testing, you may use ambient air.

(iii) FID zero gas. Zero flame-ionization detectors with purified gas that meets the 

specifications in paragraph (a)(1) of this section, except that the purified gas O2
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concentration may be any value. Note that FID zero balance gases may be any

combination of purified air and purified nitrogen. We recommend FID analyzer zero 

gases that contain approximately the expected flow-weighted mean concentration of O2

in the exhaust sample during testing.

(iv) FID propane span gas. Span and calibrate THC FID with span concentrations of 

propane, C3H8. Calibrate on a carbon number basis of one (C1). For example, if you use 

a C3H8 span gas of concentration 200 mol/mol, span a FID to respond with a value of 

600 mol/mol. Note that FID span balance gases may be any combination of purified air 

and purified nitrogen. We recommend FID analyzer span gases that contain 

approximately the flow-weighted mean concentration of O2 expected during testing. If 

the expected O2 concentration in the exhaust sample is zero, we recommend using a 

balance gas of purified nitrogen.

(v) FID CH4 span gas. If you always span and calibrate a CH4 FID with a nonmethane 

cutter, then span and calibrate the FID with span concentrations of CH4. Calibrate on a 

carbon number basis of one (C1). For example, if you use a CH4 span gas of 

concentration 200 mol/mol, span a FID to respond with a value of 200 mol/mol. Note 

that FID span balance gases may be any combination of purified air and purified 

nitrogen. We recommend FID analyzer span gases that contain approximately the 

expected flow-weighted mean concentration of O2 in the exhaust sample during testing. 

If the expected O2 concentration in the exhaust sample is zero, we recommend using a 

balance gas of purified nitrogen.

(3) Use the following gas mixtures, with gases traceable within ±1 % of the NISTaccepted value or other gas standards we approve:

(i) CH4, balance purified air and/or N2 (as applicable).

(ii) C2H6, balance purified air and/or N2 (as applicable).

(iii) C3H8, balance purified air and/or N2 (as applicable).

(iv) CO, balance purified N2.

(v) CO2, balance purified N2.

(vi) NO, balance purified N2.

(vii)) NO2, balance purified air.

(viii) O2, balance purified N2.

(ix) C3H8, CO, CO2, NO, balance purified N2.

(x) C3H8, CH4, CO, CO2, NO, balance purified N2.

(xi) N2O, balance purified air and/or N2 (as applicable).

(4) You may use gases for species other than those listed in paragraph (a)(3) of this 

section (such as methanol in air, which you may use to determine response factors), as 

long as they are traceable to within ±3 % of the NIST-accepted value or other similar 

standards we approve, and meet the stability requirements of paragraph (b) of this 

section.

(5) You may generate your own calibration gases using a precision blending device, such 

as a gas divider, to dilute gases with purified N2 or purified air. If your gas divider meets

the specifications in §1065.248, and the gases being blended meet the requirements of 

paragraphs (a)(1) and (3) of this section, the resulting blends are considered to meet the 

requirements of this paragraph (a).

* * * * *
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Subpart I—[Amended]

321. Section 1065.805 is amended by revising paragraphs (d) and (f) to read as 

follows:

§1065.805 Sampling system.

* * * * *

(d) You may bubble a sample of the exhaust through water to collect alcohols for later 

analysis. You may also use a photoacoustic analyzer to quantify ethanol and methanol in 

an exhaust sample as described in §1065.269.

* * * * *

(f) You may sample alcohols or carbonyls using "California Non-Methane Organic Gas 

Test Procedures" (incorporated by reference in §1065.1010). If you use this method, 

follow its calculations to determine the mass of the alcohol/carbonyl in the exhaust 

sample, but follow subpart G of this part for all other calculations (40 CFR part 1066, 

subpart G, for vehicle testing).

* * * * *

322. Section 1065.845 is revised to read as follows:

§1065.845 Response factor determination. 

Since FID analyzers generally have an incomplete response to alcohols and carbonyls, 

determine each FID analyzer’s alcohol/carbonyl response factor (RFOHCi[THC-FID]) after 

FID optimization to subtract those responses from the FID reading. Use the most 

recently determined alcohol/carbonyl response factors to compensate for 

alcohol/carbonyl response. You are not required to determine the response factor for a 

compound unless you will subtract its response to compensate for a response.

(a) You may generate response factors as described in paragraph (b) of this section, or 

you may use the following default response factors, consistent with good engineering 

judgment:

TABLE 1 OF §1065.845–DEFAULT VALUES FOR THC FID

RESPONSE FACTOR RELATIVE TO PROPANE ON A C1-EQUIVALENT BASIS

Compound Response factor (RF)

acetaldehyde 0.50

ethanol 0.75

formaldehyde 0.00

methanol 0.63

propanol 0.85

(b) Determine the alcohol/carbonyl response factors as follows:

(1) Select a C3H8 span gas that meets the specifications of §1065.750. Note that FID 

zero and span balance gases may be any combination of purified air or purified nitrogen 

that meets the specifications of §1065.750. We recommend FID analyzer zero and span 

gases that contain approximately the flow-weighted mean concentration of O2 expected 

during testing. Record the C3H8 concentration of the gas.
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(2) Select or prepare an alcohol/carbonyl calibration gas that meets the specifications of 

§1065.750 and has a concentration typical of the peak concentration expected at the 

hydrocarbon standard. Record the calibration concentration of the gas.

(3) Start and operate the FID analyzer according to the manufacturer’s instructions.

(4) Confirm that the FID analyzer has been calibrated using C3H8. Calibrate on a carbon 

number basis of one (C1). For example, if you use a C3H8 span gas of concentration 200 

mol/mol, span the FID to respond with a value of 600 mol/mol.

(5) Zero the FID. Note that FID zero and span balance gases may be any combination of 

purified air or purified nitrogen that meets the specifications of §1065.750. We 

recommend FID analyzer zero and span gases that contain approximately the flowweighted mean concentration of O2 expected during testing.

(6) Span the FID with the C3H8 span gas that you selected under paragraph (a)(1) of this 

section.

(7) Introduce at the inlet of the FID analyzer the alcohol/carbonyl calibration gas that you 

selected under paragraph (a)(2) of this section.

(8) Allow time for the analyzer response to stabilize. Stabilization time may include time 

to purge the analyzer and to account for its response.

(9) While the analyzer measures the alcohol/carbonyl concentration, record 30 seconds of 

sampled data. Calculate the arithmetic mean of these values.

(10) Divide the mean measured concentration by the recorded span concentration of the 

alcohol/carbonyl calibration gas on a C1-equivalent basis. The result is the FID 

analyzer’s response factor for alcohol/carbonyl, RFOHCi[THC-FID] on a C1-equivalent basis.

(c) Alcohol/carbonyl calibration gases must remain within ±2 % of the labeled 

concentration. You must demonstrate the stability based on a quarterly measurement 

procedure with a precision of ±2 % percent or another method that we approve. Your 

measurement procedure may incorporate multiple measurements. If the true 

concentration of the gas changes deviates by more than ±2 %, but less than ±10 %, the 

gas may be relabeled with the new concentration.

323. Section 1065.850 is revised to read as follows:

§1065.850 Calculations.

Use the calculations specified in §1065.665 to determine THCE or NMHCE and the 

calculations specified in 40 CFR 1066.635 to determine NMOG.

Subpart J—[Amended]

324. Section 1065.905 is amended by revising paragraphs (a) and (d)(2)(i)(A) to read 

as follows:

§1065.905 General provisions.

(a) General. Unless the standard-setting part specifies deviations from the provisions of 

this subpart, field testing and laboratory testing with PEMS must conform to the 

provisions of this subpart. Use good engineering judgment when testing with PEMS to 

ensure proper function of the instruments under test conditions. For example, this may

require additional maintenance or calibration for field testing or may require verification 

after moving the PEMS unit.

(d) * * *
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(2) * * *

(i) * * *

(A) Use good engineering judgment to control dilution air temperature. If you choose to 

directly and actively control dilution air temperature, set the temperature to 25 °C.

325. Section 1065.915 is amended by revising paragraph (a) to read as follows:

§1065.915 PEMS instruments.

(a) Instrument specifications. We recommend that you use PEMS that meet the 

specifications of subpart C of this part. For unrestricted use of PEMS in a laboratory or 

similar environment, use a PEMS that meets the same specifications as each lab 

instrument it replaces. For field testing or for testing with PEMS in a laboratory or 

similar environment, under the provisions of §1065.905(b), the specifications in the 

following table apply instead of the specifications in Table 1 of §1065.205.
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TABLE 1 OF §1065.915–RECOMMENDED MINIMUM PEMS MEASUREMENT INSTRUMENT PERFORMANCE

Measurement Measured 

quantity symbol

Rise time, t10-90, 

and

Fall time, t90-10

Recording update 

frequency Accuracy1 Repeatability1 Noise1

Engine speed transducer fn 1 s 1 Hz means 5 % of pt. or

1 % of max.

2 % of pt. or

1 % of max. 0.5 % of max

Engine torque estimator, BSFC

(This is a signal from an engine’s ECM) T or BSFC 1 s 1 Hz means 8 % of pt. or5 % of max.

2 % of pt. or

1 % of max. 1 % of max.

General pressure transducer

(not a part of another instrument) p 5 s 1 Hz 5 % of pt. or5 % of max.

2 % of pt. or

0.5 % of max. 1 % of max

Atmospheric pressure meter patmos 50 s 0.1 Hz 250 Pa 200 Pa 100 Pa

General temperature sensor

(not a part of another instrument) T 5 s 1 Hz 1 % of pt. K or5 K

0.5 % of pt. K or

2 K

0.5 % of max

0.5 K

General dewpoint sensor Tdew 50 s 0.1 Hz 3 K 1 K 1 K

Exhaust flow meter n 1 s 1 Hz means 5 % of pt. or

3 % of max. 2 % of pt. 2 % of max.

Dilution air, inlet air, exhaust, and sample 

flow meters n 1 s 1 Hz means 2.5 % of pt. or1.5 % of max.

1.25 % of pt. or

0.75 % of max. 1 % of max.

Continuous gas analyzer x 5 s 1 Hz 4 % of pt. or

4 % of meas.

2 % of pt. or

2 % of meas. 1 % of max.

Gravimetric PM balance mPM — — See §1065.790 0.5 g —

Inertial PM balance mPM — —

4 % of pt. or

4 % of meas.

2 % of pt. or

2 % of meas. 1 % of max

1Accuracy, repeatability, and noise are all determined with the same collected data, as described in §1065.305, and based on absolute values. “pt.” refers to the overall 

flow-weighted mean value expected at the standard; “max.” refers to the peak value expected at the standard over any test interval, not the maximum of the instrument’s 

range; “meas” refers to the actual flow-weighted mean measured over any test interval.
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* * * * *

326. Section 1065.920 is amended by revising paragraphs (a), (b) introductory text, 

and (b)(7) introductory text to read as follows:

§1065.920 PEMS Calibrations and verifications.

(a) Subsystem calibrations and verifications. Use all the applicable calibrations and 

verifications in subpart D of this part, including the linearity verifications in §1065.307, 

to calibrate and verify PEMS. Note that a PEMS does not have to meet the systemresponse and updating-recording verifications of §1065.308 and §1065.309 if it meets the 

overall verification described in paragraph (b) of this section or if it measures PM using 

any method other than that described in §1065.170(c)(1). This section does not apply to 

ECM signals. Note that because the regulations of this part require you to use good 

engineering judgment, it may be necessary to perform additional verifications and 

analysis. It may also be necessary to limit the range of conditions under which the PEMS 

can be used or to include specific additional maintenance to ensure that it functions 

properly under the test conditions. As provided in 40 CFR 1068.5, we will deem your 

system to not meet the requirements of this section if we determine that you did not use 

good engineering judgment to verify the measurement equipment. We may also deem 

your system to meet these requirements only under certain test conditions. If we ask for 

it, you must send us a summary of your verifications. We may also ask you to provide 

additional information or analysis to support your conclusions.

(b) Overall verification. This paragraph (b) specifies methods and criteria for verifying 

the overall performance of systems not fully compliant with requirements that apply for 

laboratory testing. Maintain records to show that the particular make, model, and 

configuration of your PEMS meets this verification. You may rely on data and other 

information from the PEMS manufacturer. However, we recommend that you generate 

your own records to show that your specific PEMS meets this verification. If you 

upgrade or change the configuration of your PEMS, your record must show that your new 

configuration meets this verification. The verification required by this section consists of 

operating an engine over a duty cycle in the laboratory and statistically comparing data 

generated and recorded by the PEMS with data simultaneously generated and recorded by

laboratory equipment as follows:

* * * * *

(7) The PEMS passes the verification of this paragraph (b) if any one of the following are 

true for each constituent:

* * * * *

Subpart K—[Amended]

327. Section 1065.1001 is amended as follows:

a. By removing the definition for “C1 equivalent (or basis)”.

b. By adding a definition for “C1-equivalent (or basis)”.

c. By removing the definition for “Engine”.

d. By revising the definitions for “HEPA filter”, “Hydrocarbon (HC)”, “Oxygenated 

fuels”, and “Precision”.

e. By adding a definition for “Purified air”.
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§1065.1001 Definitions.

* * * * *

C1-equivalent (or basis) means a convention of expressing HC concentrations 

based on the total number of carbon atoms present, such that the C1 equivalent of a molar 

HC concentration equals the molar concentration multiplied by the mean number of 

carbon atoms in each HC molecule. For example, the C1 equivalent of 10 mol/mol of 

propane (C3H8) is 30 mol/mol. C1 equivalent molar values may be denoted as “ppmC” 

in the standard-setting part. Molar mass may also be expressed on a C1 basis. Note that 

calculating HC masses from molar concentrations and molar masses is only valid where 

they are each expressed on the same carbon basis.

* * * * *

HEPA filter means high-efficiency particulate air filters that are rated to achieve a 

minimum initial particle-removal efficiency of 99.97 % using ASTM F1471 

(incorporated by reference in §1065.1010).

* * * * *

Hydrocarbon (HC) means THC, THCE, NMHC, NMOG, or NMHCE, as 

applicable. Hydrocarbon generally means the hydrocarbon group on which the emission 

standards are based for each type of fuel and engine.

* * * * *

Oxygenated fuels means fuels composed of at least 25 % oxygen-containing 

compounds, such as ethanol or methanol. Testing engines that use oxygenated fuels 

generally requires the use of the sampling methods in subpart I of this part. However, 

you should read the standard-setting part and subpart I of this part to determine 

appropriate sampling methods.

* * * * *

Precision means two times the standard deviation of a set of measured values of a 

single zero or reference quantity. See also the related definitions of noise and 

repeatability in this section.

* * * * *

Purified air means air meeting the specifications for purified air in §1065.750. Purified 

air may be produced by purifying ambient air. The purification may occur at the test site 

or at another location (such as at a gas supplier’s facility). Alternatively, purified air may 

be synthetically generated, using good engineering judgment, from purified oxygen and 

nitrogen. The addition of other elements normally present in purified ambient air (such 

as Ar) is not required.

* * * * *

328. Section 1065.1005 is revised to read as follows:

§1065.1005 Symbols, abbreviations, acronyms, and units of measure.

The procedures in this part generally follow the International System of Units (SI), as 

detailed in NIST Special Publication 811, which we incorporate by reference in 

§1065.1010. See §1065.20 for specific provisions related to these conventions. This 

section summarizes the way we use symbols, units of measure, and other abbreviations.

(a) Symbols for quantities. This part uses the following symbols and units of measure for 

various quantities:

Symbol Quantity Unit Unit symbol Units in terms of SI 

base units
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 atomic hydrogen-to-carbon ratio mole per mole mol/mol 1

A area square meter m

2 m2

a0intercept of least squares regression

a1 slope of least squares regression

ag acceleration of Earth’s gravity meter per square second m/s2 m/s2

 ratio of diameters meter per meter m/m 1

 atomic oxygen-to-carbon ratio mole per mole mol/mol 1

C# number of carbon atoms in a molecule

Cd discharge coefficient

Cfflow coefficient

δ atomic nitrogen-to-carbon ratio mole per mole mol/mol 1

d Diameter meter m m

DR dilution ratio mole per mole mol/mol 1



error between a quantity and its 

reference

e

brake-specific emission or fuel 

consumption gram per kilowatt hour g/(kW∙hr) g∙3.6-1

∙106∙m-2∙kg∙s2

F F-test statistic

f frequency hertz Hz s

-1

fn angular speed (shaft) revolutions per minute r/min 2∙π∙60-1∙m·m-1·s-1

 ratio of specific heats

(joule per kilogram 

kelvin) per (joule per 

kilogram kelvin) 

(J/(kg∙K))/(J/(kg∙K)) 1

 atomic sulfur-to-carbon ratio mole per mole mol/mol 1

K correction factor 1

Kv calibration coefficient m

4

∙s∙K0.5/kg m

4

∙s∙K0.5∙kg-1

l length meter m m

 viscosity, dynamic pascal second Pa∙s m

-1

∙kg∙s-1

M molar mass1gram per mole g/mol 10-3∙kg∙mol-1

m mass kilogram kg kg

m mass rate kilogram per second kg/s kg∙s-1

 viscosity, kinematic meter squared per 

second m

2

/s m

2

∙s-1

N total number in series

n amount of substance mole mol mol

n amount of substance rate mole per second mol/s mol∙s-1

P power kilowatt kW 103∙m2∙kg∙s-3

PF penetration fraction

p pressure pascal Pa m

-1

∙kg∙s-2

 mass density kilogram per cubic 

meter kg/m3

kg∙m-3

p differential static pressure pascal Pa m

-1

∙kg∙s-2

r ratio of pressures pascal per pascal Pa/Pa 1

r

2

coefficient of determination

Ra average surface roughness micrometer m 10-6 m

Re# Reynolds number

RF response factor

RH relative humidity

 non-biased standard deviation

S Sutherland constant kelvin K K

SEE standard estimate of error

T absolute temperature kelvin K K

T Celsius temperature degree Celsius °C K-273.15

T torque (moment of force) newton meter N∙m m

2

∙kg∙s-2

 plane angle degrees ° rad

t time second s s

t time interval, period, 1/frequency second s s
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V volume cubic meter m

3 m3

V volume rate cubic meter per second m

3

/s m

3

∙s-1

W work kilowatt hour kW∙hr 3.6∙10-6∙m2∙kg∙s-2

wc carbon mass fraction gram per gram g/g 1

x amount of substance mole fraction2 mole per mole mol/mol 1

x flow-weighted mean concentration mole per mole mol/mol 1

y generic variable

Z compressibility factor

1

See paragraph (f)(2) of this section for the values to use for molar masses. Note that in the cases of NOx and HC, the 

regulations specify effective molar masses based on assumed speciation rather than actual speciation. 

2 Note that mole fractions for THC, THCE, NMHC, NMHCE, and NOTHC are expressed on a C1 equivalent basis. 

(b) Symbols for chemical species. This part uses the following symbols for chemical 

species and exhaust constituents:

Symbol Species

Ar argon

C carbon

CH2O formaldehyde

CH3OH methanol

CH4 methane

C2H4O acetaldehyde

C2H5OH ethanol

C2H6 ethane

C3H7OH propanol

C3H8 propane

C4H10 butane

C5H12 pentane

CO carbon monoxide

CO2 carbon dioxide

H atomic hydrogen

H2 molecular hydrogen

H2O water

H2SO4 sulfuric acid

HC hydrocarbon

He helium

85Kr krypton 85

N2 molecular nitrogen

NH3 ammonia

NMHC nonmethane hydrocarbon

NMHCE nonmethane hydrocarbon equivalent

NO nitric oxide

NO2 nitrogen dioxide

NOx oxides of nitrogen

N2O nitrous oxide

NMOG nonmethane organic gases

NONMHC non-oxygenated nonmethane hydrocarbon

NOTHC non-oxygenated total hydrocarbon

O2 molecular oxygen

OHC oxygenated hydrocarbon

210Po polonium 210

PM particulate matter

S sulfur

SVOC semi-volatile organic compound

THC total hydrocarbon

THCE total hydrocarbon equivalent

ZrO2 zirconium dioxide
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(c) Prefixes. This part uses the following prefixes to define a quantity:

Symbol Quantity Value

 micro 10-6

m milli 10-3

c centi 10-2

k kilo 103

M mega 106

(d) Superscripts. This part uses the following superscripts to define a quantity:

Superscript Quantity

overbar (such as y ) arithmetic mean

overdot (such as y)

quantity per unit time

(e) Subscripts. This part uses the following subscripts to define a quantity:

Subscript Quantity

abs absolute quantity

act actual condition

air air, dry

amb ambient

atmos atmospheric

bkgnd background

cal calibration quantity

CFV critical flow venturi

comb combined

composite composite value

cor corrected quantity

dil dilution air

dew dewpoint

dexh diluted exhaust

dry dry condition

dutycycle duty cycle

exh raw exhaust

exp expected quantity

fn feedback speed

frict friction

fuel fuel consumption

hi,idle condition at high-idle

i an individual of a series

idle condition at idle

in quantity in

init initial quantity, typically before an emission test

int intake air

j an individual of a series

mapped conditions over which an engine can operate

max

the maximum (i.e., peak) value expected at the standard over a 

test interval; not the maximum of an instrument range

meas measured quantity

media PM sample media

mix mixture of diluted exhaust and air

norm normalized

out quantity out

P power

part partial quantity

PDP positive-displacement pump

post after the test interval

pre before the test interval
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prod stoichiometric product

record record rate

ref reference quantity

rev revolution

sat saturated condition

s slip

span span quantity

SSV subsonic venturi

std standard condition

stroke engine strokes per power stroke

T torque

test test quantity

test,alt alternate test quantity

uncor uncorrected quantity

vac vacuum side of the sampling system

weight calibration weight

zero zero quantity

(f) Constants. (1) This part uses the following constants for the composition of dry air:

Symbol Quantity mol/mol 

xArair amount of argon in dry air 0.00934

xCO2air amount of carbon dioxide in dry air 0.000375

xN2air amount of nitrogen in dry air 0.78084

xO2air amount of oxygen in dry air 0.209445

(2) This part uses the following molar masses or effective molar masses of chemical 

species:

Symbol Quantity g/mol

(10-3·kg·mol-1)

Mair molar mass of dry air128.96559

MAr molar mass of argon 39.948

MC molar mass of carbon 12.0107

MCH3OH molar mass of methanol 32.04186

MC2H5OH molar mass of ethanol 46.06844

MC2H4O molar mass of acetaldehyde 44.05256

MC3H8 molar mass of propane 44.09562

MC3H7OH molar mass of propanol 60.09502

MCO molar mass of carbon monoxide 28.0101

MCH4 molar mass of methane 16.0425

MCO2 molar mass of carbon dioxide 44.0095

MH molar mass of atomic hydrogen 1.00794

MH2 molar mass of molecular hydrogen 2.01588

MH2O molar mass of water 18.01528

MCH2O molar mass of formaldehyde 30.02598

MHe molar mass of helium 4.002602

MN molar mass of atomic nitrogen 14.0067

MN2 molar mass of molecular nitrogen 28.0134

MNH3 molar mass of ammonia 17.03052

MNMHC effective C1 molar mass of nonmethane hydrocarbon213.875389

MNMHCE

effective C1 molar mass of nonmethane hydrocarbon 

equivalent2 13.875389

MNOx effective molar mass of oxides of nitrogen346.0055

MN2O molar mass of nitrous oxide 44.0128

MO molar mass of atomic oxygen 15.9994

MO2 molar mass of molecular oxygen 31.9988

MS molar mass of sulfur 32.065

MTHC effective C1 molar mass of total hydrocarbon213.875389
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MTHCE effective C1 molar mass of total hydrocarbon equivalent213.875389

1

See paragraph (f)(1) of this section for the composition of dry air.

2The effective molar masses of THC, THCE, NMHC, and NMHCE are defined on a C1 basis and 

are based on an atomic hydrogen-to-carbon ratio, , of 1.85 (with β, γ, and δ equal to zero).

3The effective molar mass of NOx

is defined by the molar mass of nitrogen dioxide, NO2.

(3) This part uses the following molar gas constant for ideal gases:

Symbol Quantity J/(mol∙K)

(m2∙kg∙s-2∙mol-1∙K-1)

R molar gas constant 8.314472

(4) This part uses the following ratios of specific heats for dilution air and diluted 

exhaust:

Symbol Quantity [J/(kg∙K)]/[J/(kg∙K)] 

air ratio of specific heats for intake air 

or dilution air

1.399

dil ratio of specific heats for diluted 

exhaust

1.399

exh ratio of specific heats for raw 

exhaust

1.385

(g) Other acronyms and abbreviations. This part uses the following additional 

abbreviations and acronyms: 

ABS acrylonitrile-butadiene-styrene

ASTM American Society for Testing and Materials

BMD bag mini-diluter

BSFC brake-specific fuel consumption

CARB California Air Resources Board

CFR Code of Federal Regulations

CFV critical-flow venturi

CI compression-ignition

CITT Curb Idle Transmission Torque

CLD chemiluminescent detector

CVS constant-volume sampler

DF deterioration factor

ECM electronic control module

EFC electronic flow control

e.g. for example

EGR exhaust gas recirculation

EPA Environmental Protection Agency

FEL Family Emission Limit

FID flame-ionization detector

FTIR Fourier transform infrared

GC gas chromatograph

GC-ECD gas chromatograph with an electron-capture detector

GC-FID gas chromatograph with a flame ionization detector

HEPA high-efficiency particulate air

IBP initial boiling point

IBR incorporated by reference

i.e. in other words

ISO International Organization for Standardization

LPG liquefied petroleum gas

MPD magnetopneumatic detection

NDIR nondispersive infrared

NDUV nondispersive ultraviolet

NIST National Institute for Standards and Technology
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NMC nonmethane cutter

PDP positive-displacement pump

PEMS portable emission measurement system

PFD partial-flow dilution

PLOT porous layer open tubular

PMD paramagnetic detection

PMP Polymethylpentene

pt. a single point at the mean value expected at the standard.

psi pounds per square inch

PTFE polytetrafluoroethylene (commonly known as TeflonTM)

RE rounding error

RESS rechargeable energy storage system

RFPF response factor penetration fraction

RMC ramped-modal cycle

rms root-mean square

RTD resistive temperature detector

SAW surface acoustic wave

SEE standard estimate of error

SSV subsonic venturi

SI spark-ignition

THC-FID total hydrocarbon flame ionization detector

TINV inverse student t-test function in Microsoft Excel

UCL upper confidence limit

UFM ultrasonic flow meter

U.S.C. United States Code

329. Section 1065.1010 is revised to read as follows:

§1065.1010 Incorporation by reference.

(a) Certain material is incorporated by reference into this part with the approval of the 

Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. To enforce 

any edition other than that specified in this section, a document must be published in the 

Federal Register and the material must be available to the public. All approved 

materials are available for inspection at the Air and Radiation Docket and Information 

Center (Air Docket) in the EPA Docket Center (EPA/ DC) at Rm. 3334, EPA West 

Bldg., 1301 Constitution Ave. NW., Washington, DC. The EPA/DC Public Reading 

Room hours of operation are 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding

legal holidays. The telephone number of the EPA/DC Public Reading Room is (202) 

566–1744, and the telephone number for the Air Docket is (202) 566–1742. These 

approved materials are also available for inspection at the National Archives and Records 

Administration (NARA). For information on the availability of this material at NARA,

call (202) 741–6030 or go to http:// www.archives.gov/federal_register/ 

code_of_federal_regulations/ ibr_locations.html. In addition, these materials are 

available from the sources listed below.

(b) ASTM material. The following standards are available from ASTM International, 100

Barr Harbor Dr., P.O. Box C700, West Conshohocken, PA 19428–2959, (877) 909–

ASTM, or http://www.astm.org:

(1) ASTM D86-12, Standard Test Method for Distillation of Petroleum Products at 

Atmospheric Pressure, approved December 1, 2012, IBR approved for §§1065.703(b)

and 1065.710(b) and (c).

(2) ASTM D93-13, Standard Test Methods for Flash Point by Pensky- Martens Closed 

Cup Tester, approved July 15, 2013, IBR approved for §1065.703(b).
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(3) ASTM D130-12, Standard Test Method for Corrosiveness to Copper from Petroleum 

Products by Copper Strip Test, approved November 1, 2012, IBR approved for 

§1065.710(b).

(4) ASTM D381-12, Standard Test Method for Gum Content in Fuels by Jet Evaporation, 

approved April 15, 2012, IBR approved for §1065.710(b).

(5) ASTM D445-12, Standard Test Method for Kinematic Viscosity of Transparent and

Opaque Liquids (and Calculation of Dynamic Viscosity), approved April 15, 2012, IBR 

approved for §1065.703(b).

(6) ASTM D525-12a, Standard Test Method for Oxidation Stability of Gasoline 

(Induction Period Method), approved September 1, 2012, IBR approved for 

§1065.710(b).

(7) ASTM D613-13, Standard Test Method for Cetane Number of Diesel Fuel Oil, 

approved December 1, 2013, IBR approved for §1065.703(b).

(8) ASTM D910-13a, Standard Specification for Aviation Gasolines, approved December 

1, 2013, IBR approved for §1065.701(f).

(9) ASTM D975-13a, Standard Specification for Diesel Fuel Oils, approved December 1, 

2013, IBR approved for §1065.701(f).

(10) ASTM D1267-12, Standard Test Method for Gage Vapor Pressure of Liquefied 

Petroleum (LP) Gases (LP-Gas Method), approved November 1, 2012, IBR approved for 

§1065.720(a).

(11) ASTM D1319-13, Standard Test Method for Hydrocarbon Types in Liquid 

Petroleum Products by Fluorescent Indicator Adsorption, approved May 1, 2013, IBR

approved for §1065.710(c).

(12) ASTM D1655-13a, Standard Specification for Aviation Turbine Fuels, approved 

December 1, 2013, IBR approved for §1065.701(f).

(13) ASTM D1837-11, Standard Test Method for Volatility of Liquefied Petroleum (LP)

Gases, approved October 1, 2011, IBR approved for §1065.720(a).

(14) ASTM D1838-12a, Standard Test Method for Copper Strip Corrosion by Liquefied 

Petroleum (LP) Gases, approved December 1, 2012, IBR approved for §1065.720(a).

(15) ASTM D1945-03 (Reapproved 2010), Standard Test Method for Analysis of Natural 

Gas by Gas Chromatography, approved January 1, 2010, IBR approved for §1065.715(a).

(16) ASTM D2158-11, Standard Test Method for Residues in Liquefied Petroleum (LP) 

Gases, approved January 1, 2011, IBR approved for §1065.720(a).

(17) ASTM D2163-07, Standard Test Method for Analysis of Liquefied Petroleum (LP) 

Gases and Propene Concentrates by Gas Chromatography, approved December 1, 2007, 

IBR approved for §1065.720(a).

(18) ASTM D2598-12, Standard Practice for Calculation of Certain Physical Properties 

of Liquefied Petroleum (LP) Gases from Compositional Analysis, approved November 1, 

2012, IBR approved for §1065.720(a).

(19) ASTM D2622-10, Standard Test Method for Sulfur in Petroleum Products by

Wavelength Dispersive X-ray Fluorescence Spectrometry, approved February 15, 2010, 

IBR approved for §§1065.703(b) and 1065.710(b) and (c).

(20) ASTM D2699-13b, Standard Test Method for Research Octane Number of SparkIgnition Engine Fuel, approved October 1, 2013, IBR approved for §1065.710(b).

(21) ASTM D2700-13b, Standard Test Method for Motor Octane Number of SparkIgnition Engine Fuel, approved October 1, 2013, IBR approved for §1065.710(b).
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(22) ASTM D2713-13, Standard Test Method for Dryness of Propane (Valve Freeze

Method), approved October 1, 2013, IBR approved for §1065.720(a).

(23) ASTM D2784-11, Standard Test Method for Sulfur in Liquefied Petroleum Gases 

(Oxy-Hydrogen Burner or Lamp), approved January 1, 2011, IBR approved for 

§1065.720(a).

(24) ASTM D2880-13b, Standard Specification for Gas Turbine Fuel Oils, approved 

November 15, 2013, IBR approved for §1065.701(f).

(25) ASTM D2986-95a (Reapproved 1999), Standard Practice for Evaluation of Air 

Assay Media by the Monodisperse DOP (Dioctyl Phthalate) Smoke Test, approved 

September 10, 1995, IBR approved for §1065.170(c). This standard was withdrawn in 

2004.

(26) ASTM D3231-13, Standard Test Method for Phosphorus in Gasoline, approved June 

15, 2013, IBR approved for §1065.710(b) and (c).

(27) ASTM D3237-12, Standard Test Method for Lead in Gasoline By Atomic 

Absorption Spectroscopy, approved June 1, 2012, IBR approved for §1065.710(b) and 

(c).

(28) ASTM D4052-11, Standard Test Method for Density, Relative Density, and API 

Gravity of Liquids by Digital Density Meter, approved October 15, 2011, IBR approved 

for §1065.703(b).

(29) ASTM D4629-12, Standard Test Method for Trace Nitrogen in Liquid Petroleum 

Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence 

Detection, approved April 15, 2012, IBR approved for §1065.655(d).

(30) ASTM D4814-13b, Standard Specification for Automotive Spark-Ignition Engine 

Fuel, approved December 1, 2013, IBR approved for §1065.701(f).

(31) ASTM D4815-13, Standard Test Method for Determination of MTBE, ETBE, 

TAME, DIPE, tertiary-Amyl Alcohol and C1 to C4 Alcohols in Gasoline by Gas 

Chromatography, approved October 1, 2013, IBR approved for §1065.710(b).

(32) ASTM D5186-03 (Reapproved 2009), Standard Test Method for Determination of 

the Aromatic Content and Polynuclear Aromatic Content of Diesel Fuels and Aviation 

Turbine Fuels By Supercritical Fluid Chromatography, approved April 15, 2009, IBR 

approved for §1065.703(b).

(33) ASTM D5191-13, Standard Test Method for Vapor Pressure of Petroleum Products 

(Mini Method), approved December 1, 2013, IBR approved for §1065.710(b) and (c).

(34) ASTM D5291-10, Standard Test Method for Instrumental Determination of Carbon, 

Hydrogen, and Nitrogen in Petroleum Products and Lubricants, approved May 1, 2010, 

IBR approved for §1065.655(d).

(35) ASTM D5453-12, Standard Test Method for Determination of Total Sulfur in Light 

Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel, and Engine Oil by

Ultraviolet Fluorescence, approved November 1, 2012, IBR approved for §1065.710(b).

(36) ASTM D5599-00 (Reapproved 2010), Standard Test Method for Determination of 

Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame Ionization 

Detection, approved October 1, 2010, IBR approved for §§1065.655(d) and 1065.710(b).

(37) ASTM D5762-12 Standard Test Method for Nitrogen in Petroleum and Petroleum 

Products by Boat-Inlet Chemiluminescence, approved April 15, 2012, IBR approved for 

§1065.655(d).
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(38) ASTM D5769-10, Standard Test Method for Determination of Benzene, Toluene, 

and Total Aromatics in Finished Gasolines by Gas Chromatography/Mass Spectrometry, 

approved May 1, 2010, IBR approved for §1065.710(b).

(39) ASTM D5797-13, Standard Specification for Fuel Methanol (M70- M85) for 

Automotive Spark-Ignition Engines, approved June 15, 2013, IBR approved for 

§1065.701(f).

(40) ASTM D5798-13a, Standard Specification for Ethanol Fuel Blends for Flexible Fuel 

Automotive Spark-Ignition Engines, approved June 15, 2013, IBR approved for 

§1065.701(f).

(41) ASTM D6550-10, Standard Test Method for Determination of Olefin Content of 

Gasolines by Supercritical-Fluid Chromatography, approved October 1, 2010, IBR 

approved for §1065.710(b).

(42) ASTM D6615-11a, Standard Specification for Jet B Wide-Cut Aviation Turbine 

Fuel, approved October 1, 2011, IBR approved for §1065.701(f).

(43) ASTM D6751-12, Standard Specification for Biodiesel Fuel Blend Stock (B100) for 

Middle Distillate Fuels, approved August 1, 2012, IBR approved for §1065.701(f).

(44) ASTM D6985-04a, Standard Specification for Middle Distillate Fuel Oil—Military

Marine Applications, approved November 1, 2004, IBR approved for §1065.701(f). This 

standard was withdrawn in 2010.

(45) ASTM D7039-13, Standard Test Method for Sulfur in Gasoline, Diesel Fuel, Jet 

Fuel, Kerosine, Biodiesel, Biodiesel Blends, and Gosoline-Ethenol Blends by

Monochromatic Wavelength Dispersive X-ray Fluorescence Spectrometry, approved 

September 15, 2013, IBR approved for §1065.710(b).

(46) ASTM F1471-09, Standard Test Method for Air Cleaning Performance of a HighEfficiency Particulate Air Filter System, approved March 1, 2009, IBR approved for 

§1065.1001.

(c) California Air Resources Board material. The following documents are available

from the California Air Resources Board, Haagen-Smit Laboratory, 9528 Telstar Ave., El 

Monte, CA 91731–2908, (800) 242–4450, or http://www.arb.ca.gov:

(1) California Non-Methane Organic Gas Test Procedures, Amended July 30, 2002, 

Mobile Source Division, California Air Resources Board, IBR approved for 

§1065.805(f).

(2) [Reserved]

(d) Institute of Petroleum material. The following documents are available from the 

Energy Institute, 61 New Cavendish St., London, W1G 7AR, UK, or by calling +44–

(0)20–7467–7100, or at http://www.energyinst.org:

(1) IP 470, 2005, Determination of aluminum, silicon, vanadium, nickel, iron, calcium, 

zinc, and sodium in residual fuels by atomic absorption spectrometry, IBR approved for

§1065.705(b).

(2) IP 500, 2003, Determination of the phosphorus content of residual fuels by ultraviolet spectrometry, IBR approved for §1065.705(b).

(3) IP 501, 2005, Determination of aluminum, silicon, vanadium, nickel, iron, sodium, 

calcium, zinc and phosphorus in residual fuel oil by ashing, fusion and inductively

coupled plasma emission spectrometry, IBR approved for §1065.705(b).
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(e) ISO material. The following standards are available from the International 

Organization for Standardization, 1, ch. de la Voie-Creuse, CP 56, CH–1211 Geneva 20,

Switzerland, 41–22–749–01–11, or http://www.iso.org:

(1) ISO 2719:2002, Determination of flash point—Pensky-Martens closed cup method, 

IBR approved for §1065.705(c).

(2) ISO 3016:1994, Petroleum products—Determination of pour point, IBR approved for 

§1065.705(c).

(3) ISO 3104:1994/Cor 1:1997, Petroleum products—Transparent and opaque liquids—

Determination of kinematic viscosity and calculation of dynamic viscosity, IBR approved 

for §1065.705(c).

(4) ISO 3675:1998, Crude petroleum and liquid petroleum products— Laboratory

determination of density— Hydrometer method, IBR approved for §1065.705(c).

(5) ISO 3733:1999, Petroleum products and bituminous materials— Determination of 

water—Distillation method, IBR approved for §1065.705(c).

(6) ISO 6245:2001, Petroleum products—Determination of ash, IBR approved for 

§1065.705(c).

(7) ISO 8217:2012, Petroleum products—Fuels (class F)—Specifications of marine fuels, 

Fifth edition, revised August 15, 2012, IBR approved for §1065.705(b) and (c).

(8) ISO 8754:2003, Petroleum products—Determination of sulfur content—Energydispersive X-ray Fluorescence spectrometry, IBR approved for §1065.705(c).

(9) ISO 10307–2(E):2009, Petroleum products—Total sediment in residual fuel oils—

Part 2: Determination using standard procedures for ageing, Second Ed., February 1, 

2009, as modified by ISO 10307-2:2009/Cor.1:2010(E), Technical Corrigendum 1, 

published May 15, 2010, IBR approved for §1065.705(c).

(10) ISO 10370:1993/Cor 1:1996, Petroleum products—Determination of carbon 

residue—Micro method, IBR approved for §1065.705(c).

(11) ISO 10478:1994, Petroleum products—Determination of aluminium and silicon in 

fuel oils—Inductively coupled plasma emission and atomic absorption spectroscopy 

methods, IBR approved for §1065.705(c).

(12) ISO 12185:1996/Cor 1:2001, Crude petroleum and petroleum products—

Determination of density—Oscillating U-tube method, IBR approved for §1065.705(c).

(13) ISO 14596:2007, Petroleum products—Determination of sulfur content—

Wavelength-dispersive X-ray fluorescence spectrometry, IBR approved for §1065.705(c).

(14) ISO 14597:1997, Petroleum products—Determination of vanadium and nickel 

content—Wavelength dispersive X-ray fluorescence spectrometry, IBR approved for

§1065.705(c).

(15) ISO 14644–1:1999, Cleanrooms and associated controlled environments, IBR 

approved for §1065.190(b).

(f) NIST material. The following documents are available from National Institute of 

Standards and Technology, 100 Bureau Drive, Stop 1070, Gaithersburg, MD 20899-

1070, (301) 975-6478, or www.nist.gov:

(1) NIST Special Publication 811, 2008 Edition, Guide for the Use of the International 

System of Units (SI), March 2008, IBR approved for §§1065.20(a) and 1065.1005.

(2) NIST Technical Note 1297, 1994 Edition, Guidelines for Evaluating and Expressing 

the Uncertainty of NIST Measurement Results, Barry N. Taylor and Chris E. Kuyatt, IBR 

approved for §1065.1001.
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(g) SAE International material. The following standards are available from SAE

International, 400 Commonwealth Dr., Warrendale, PA 15096–0001, (724) 776–4841, or 

http://www.sae.org:

(1) SAE 770141, 1977, Optimization of Flame Ionization Detector for Determination of 

Hydrocarbon in Diluted Automotive Exhausts, Glenn D. Reschke, IBR approved for 

§1065.360(c).

(2) SAE J1151, Methane Measurement Using Gas Chromatography, stabilized September 

2011, IBR approved for §§ 1065.267(b) and 1065.750(a).

330. A new subpart L consisting of § 1065.1101 through § 1065.1111 is added to part 

1065 to read as follows:

Subpart L—METHODS FOR UNREGULATED AND SPECIAL POLLUTANTS

Sec.

1065.1101 Applicability.

SEMI-VOLATILE ORGANIC COMPOUNDS

1065.1103 General provisions for SVOC measurement.

1065.1105 Sampling system design.

1065.1107 Sample media and sample system preparation; sampler assembly.

1065.1109 Post-test sampler disassembly and sample extraction.

1065.1111 Sample analysis.

Subpart L—METHODS FOR UNREGULATED AND SPECIAL POLLUTANTS

§1065.1101 Applicability.

This subpart specifies procedures that may be used to measure emission constituents that 

are not measured (or not separately measured) by the test procedures in the other subparts 

of this part. These procedures are included to facilitate consistent measurement of 

unregulated pollutants for purposes other than compliance with emission standards. 

Unless otherwise specified in the standard-setting part, use of these procedures is optional 

and does not replace any requirements in the rest of this part. 

SEMI-VOLATILE ORGANIC COMPOUNDS

§1065.1103 General provisions for SVOC measurement.

The provisions of §§1065.1103 through 1065.1111 specify procedures for measuring

semi-volatile organic compounds (SVOC) along with PM. These sections specify how to 

collect a sample of the SVOCs during exhaust emission testing, as well as how to use wet 

chemistry techniques to extract SVOCs from the sample media for analysis. Note that 

the precise method you use will depend on the category of SVOCs being measured. For 

example, the method used to measure polynuclear aromatic hydrocarbons (PAHs) will 

differ slightly from the method used to measure dioxins. Follow standard analytic 

chemistry methods for any aspects of the analysis that are not specified.

(a) Laboratory cleanliness is especially important throughout SVOC testing. Thoroughly 

clean all sampling system components and glassware before testing to avoid sample 

contamination. For the purposes of this subpart, the sampling system is defined as 
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sample pathway from the sample probe inlet to the downstream most point where the 

sample is captured (in this case the condensate trap).

(b) We recommend that media blanks be analyzed for each batch of sample media 

(sorbent, filters, etc.) prepared for testing. Blank sorbent modules (i.e., field blanks) 

should be stored in a sealed environment and should periodically accompany the test 

sampling system throughout the course of a test, including sampling system and sorbent 

module disassembly, sample packaging, and storage. Use good engineering judgment to 

determine the frequency with which you should generate field blanks. The field blank 

sample should be close to the sampler during testing.

(c) We recommend the use of isotope dilution techniques, including the use of 

isotopically labeled surrogate, internal, alternate, and injection standards.

(d) If your target analytes degrade when exposed to ultraviolet radiation, such as 

nitropolynuclear aromatic hydrocarbons (nPAHs), perform these procedures in the dark 

or with ultraviolet filters installed over the lights.

(e) The following definitions and abbreviations apply for SVOC measurements:

(1) Soxhlet extraction means the extraction method invented by Franz von Soxhlet, in 

which the sample is placed in a thimble and rinsed repeatedly with a recycle of the 

extraction solvent.

(2) XAD-2 means a hydrophobic crosslinked polystyrene copolymer resin adsorbent 

known commercially as Amberlite® XAD®-2, or an equivalent adsorbent like XAD-4.

(3) Semi-volatile organic compound (SVOC) means an organic compound that is 

sufficiently volatile to exist in vapor form in engine exhaust, but that readily condenses to 

liquid or solid form under atmospheric conditions. Most SVOCs have at least 14 carbon 

atoms per molecule or they have a boiling point between (240 and 400) °C. SVOCs 

include dioxin, quinone, and nitro-PAH compounds. They may be a natural byproduct of 

combustion or they may be created post-combustion. Note that SVOCs may be included 

in measured values of hydrocarbons and/or PM using the procedures specified in this 

part.

(4) Kuderna-Danish concentrator means laboratory glassware known by this name that 

consists of an air-cooled condenser on top of an extraction bulb.

(5) Dean-Stark trap means laboratory glassware known by this name that uses a reflux 

condenser to collect water from samples extracted under reflux.

(6) PUF means polyurethane foam.

(7) Isotopically labeled means relating to a compound in which either all the hydrogen 

atoms are replaced with the atomic isotope hydrogen-2 (deuterium) or one of the carbon 

atoms at a defined position in the molecule is replaced with the atomic isotope carbon-13.

§1065.1105 Sampling system design.

(a) General. We recommend that you design your SVOC batch sampler to extract sample 

from undiluted emissions to maximize the sampled SVOC quantity. To the extent 

practical, adjust sampling times based on the emission rate of target analytes from the 

engine to obtain analyte concentrations above the detection limit. In some instances you 

may need to run repeat test cycles without replacing the sample media or disassembling

the batch sampler.

(b) Sample probe, transfer lines, and sample media holder design and construction. The 

sampling system should consist of a sample probe, transfer line, PM filter holder, cooling 
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coil, sorbent module, and condensate trap. Construct sample probes, transfer lines, and 

sample media holders that have inside surfaces of nickel, titanium or another nonreactive 

material capable of withstanding raw exhaust gas temperatures. Seal all joints in the hot 

zone of the system with gaskets made of nonreactive material similar to that of the 

sampling system components. You may use teflon gaskets in the cold zone. We 

recommend locating all components as close to probes as practical to shorten sampling 

system length and minimize the surface exposed to engine exhaust.

(c) Sample system configuration. This paragraph (c) specifies the components necessary

to collect SVOC samples, along with our recommended design parameters. Where you 

do not follow our recommendations, use good engineering judgment to design your 

sampling system so it does not result in loss of SVOC during sampling. The sampling 

system should contain the following components in series in the order listed:

(1) Use a sample probe similar to the PM sample probe specified in subpart B of this part. 

(2) Use a PM filter holder similar to the holder specified in subpart B of this part, 

although you will likely need to use a larger size to accommodate the high sample flow 

rates. We recommend using a 110 mm filter for testing spark ignition engines or engines 

that utilize exhaust aftertreatment for PM removal and a 293 mm filter for other engines. 

If you are not analyzing separately for SVOCs in gas and particle phases, you do not have 

to control the temperature of the filter holder. Note that this differs from normal PM 

sampling procedures, which maintain the filter at a much lower temperature to capture a 

significant fraction of exhaust SVOC on the filter. In this method, SVOCs that pass 

through the filter will be collected on the downstream sorbent module. If you are 

collecting SVOCs in gas and particle phases, control your filter face temperature 

according to §1065.140(e)(4). 

(3) Use good engineering judgment to design a cooling coil that will drop the sample 

temperature to approximately 5 °C. Note that downstream of the cooling coil, the sample 

will be a mixture of vapor phase hydrocarbons in CO2, air, and a primarily aqueous liquid 

phase. 

(4) Use a hydrophobic sorbent in a sealed sorbent module. Note that this sorbent module 

is intended to be the final stage for collecting the SVOC sample and should be sized 

accordingly. We recommend sizing the module to hold 40 g of XAD-2 along with PUF

plugs at either end of the module, noting that you may vary the mass of XAD used for 

testing based on the anticipated SVOC emission rate.

(5) Include a condensate trap to separate the aqueous liquid phase from the gas stream. 

We recommend using a peristaltic pump to remove water from the condensate trap over 

the course of the test to prevent build-up of the condensate. Note that for some tests it 

may be appropriate to collect this water for analysis.

(d) Sampler flow control. For testing using the recommended filter and sorbent module 

sizes, we recommend targeting an average sample flow rate of 70 liters per minute to 

maximize SVOC collection. The sampler must be designed to maintain proportional 

sampling throughout the test. Verify proportional sampling after an emission test as 

described in §1065.545.

(e) Water bath. Design the sample system with a water bath in which the cooling coil, 

sorbent module, and condensate trap will be submerged. Use a heat exchanger or ice to 

maintain the bath temperature at (3 to 7) °C.
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§1065.1107 Sample media and sample system preparation; sample system assembly.

This section describes the appropriate types of sample media and the cleaning procedure 

required to prepare the media and wetted sample surfaces for sampling.

(a) Sample media. The sampling system uses two types of sample media in series: the 

first to simultaneously capture the PM and associated particle phase SVOCs, and a 

second to capture SVOCs that remain in the gas phase, as follows:

(1) For capturing PM, we recommend using pure quartz filters with no binder. Select the 

filter diameter to minimize filter change intervals, accounting for the expected PM 

emission rate, sample flow rate, and number of repeat tests. Note that when repeating test 

cycles to increase sample mass, you may replace the filter without replacing the sorbent 

or otherwise disassembling the batch sampler. In those cases, include all filters in the 

extraction.

(2) For capturing gaseous SVOCs, utilize XAD-2 resin contained between two PUF 

plugs.

(b) Sample media and sampler preparation. Prepare pre-cleaned PM filters and precleaned PUF plugs/XAD-2 as needed. Store sample media in containers protected from 

light and ambient air if you do not use them immediately after cleaning.

(1) Pre-clean the filters via Soxhlet extraction with methylene chloride for 24 hours and 

dry over dry nitrogen in a low-temperature vacuum oven.

(2) Pre-clean PUF and XAD-2 with a series of Soxhlet extractions: 8 hours with water, 22 

hours with methanol, 22 hours with methylene chloride, and 22 hours with toluene,

followed by drying with nitrogen.

(3) Clean sampler components, including the probe, filter holder, condenser, sorbent 

module, and condensate collection vessel by rinsing three times with methylene chloride 

and then three times with toluene. Prepare pre-cleaned aluminum foil for capping the 

probe inlet of the sampler after the sampling system has been assembled.

(c) Sorbent spiking. Use good engineering judgment to verify the extent to which your 

extraction methods recover SVOCs absorbed on the sample media. We recommend 

spiking the XAD-2 resin with a surrogate standard before testing with a carbon-13 or 

hydrogen-2 isotopically labeled standard for each of the class of analytes targeted for 

analysis. Perform this spiking as follows: 

(1) Insert the lower PUF plug into the bottom of the sorbent module.

(2) Add half of one portion of XAD-2 resin to the module and spike the XAD-2 in the 

module with the standard.

(3) Wait 1 hour for the solvent from the standard(s) to evaporate, add the remaining 20 g 

of the XAD-2 resin to the module, and then insert a PUF plug in the top of the sorbent 

module.

(4) Cover the inlet and outlet of the sorbent module with pre-cleaned aluminum foil.

(d) Sampling system assembly. After preparing the sample media and the sampler, 

assemble the condensate trap, cooling coil, filter holder with filter, sample probe, and

sorbent module, then lower the assembly into the reservoir. Cover the probe inlet with 

pre-cleaned aluminum foil.

§1065.1109 Post-test sampler disassembly and sample extraction.

This section describes the process for disassembling and rinsing the sampling system and 

extracting and cleaning up the sample.
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(a) Sampling system disassembly. Disassemble the sampling system in a clean 

environment as follows after the test:

(1) Remove the PM filter, PUF plugs, and all the XAD-2 from the sampling system and 

place them into a Soxhlet extraction thimble. Store them at or below 37 °C until analysis.

(2) Rinse sampling system wetted surfaces upstream of the condensate trap with acetone 

followed by toluene (or a comparable solvent system), ensuring that all the solvent 

remaining in liquid phase is collected (note that a fraction of the acetone and toluene will 

likely be lost to evaporation during mixing). Rinse with solvent volumes that are 

sufficient to cover all the surfaces exposed to the sample during testing. We recommend 

three fresh solvent rinses with acetone and two with toluene. We recommend rinse 

volumes of 60 ml per rinse for all sampling system components except the condenser 

coil, of which you should use 200 ml per rinse. Keep the acetone rinsate separate from 

the toluene rinsate to the extent practicable. Rinsate fractions should be stored separately 

in glass bottles that have been pre-rinsed with acetone, hexane, and toluene (or purchase

pre-cleaned bottles). 

(3) Use good engineering judgment to determine if you should analyze the aqueous 

condensate phase for SVOCs. If you determine that analysis is necessary, use toluene to 

perform a liquid-liquid extraction of the SVOCs from the collected aqueous condensate 

using a separatory funnel or an equivalent method. Add the toluene from this aqueous 

extraction to the toluene rinsate fraction described in paragraph (a)(2) of this section.

(4) Reduce rinsate solvent volumes as needed using a Kuderna-Danish concentrator or 

rotary evaporator and retain these rinse solvents for reuse during sample media extraction

for the same test. Be careful to avoid loss of low molecular weight analytes when 

concentrating with rotary evaporation.

(b) Sample extraction. Extract the SVOCs from the sorbent using Soxhlet extraction as 

described in this paragraph (b). Two 16 hour extractions are necessary to accommodate 

the Soxhlet extractions of all SVOCs from a single sample. This reduces the possibility

of losing low molecular weight SVOCs and promotes water removal. We recommend 

performing the first extraction with acetone/hexane and the second using toluene (or an 

equivalent solvent system). You may alternatively use an equivalent method such as an 

automated solvent extractor.

(1) We recommend equipping the Soxhlet extractor with a Dean-Stark trap to facilitate 

removal of residual water from the sampling system rinse. The Soxhlet apparatus must 

be large enough to allow extraction of the PUF, XAD-2, and filter in a single batch. 

Include in the extractor setup a glass thimble with a coarse or extra coarse sintered glass 

bottom. Pre-clean the extractor using proper glass-cleaning procedures. We recommend 

that the Soxhlet apparatus be cleaned with a (4 to 8) hour Soxhlet extraction with 

methylene chloride at a cycling rate of three cycles per hour. Discard the solvent used for 

pre-cleaning (no analysis is necessary).

(2) Load the extractor thimble before placing it in the extractor by first rolling the PM 

filter around the inner circumference of the thimble, with the sampled side facing in. 

Push one PUF plug down into the bottom of the thimble, add approximately half of the 

XAD-2, and then spike the XAD-2 in the thimble with the isotopically labeled extraction 

standards of known mass. Target the center of the XAD-2 bed for delivering the 

extraction standard. We recommend using multiple isotopically labeled extraction 

standards that cover the range of target analytes. This generally means that you should 
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use isotopically labeled standards at least for the lowest and highest molecular weight 

analytes for each category of compounds (such as PAHs and dioxins). These extraction 

standards monitor the efficiency of the extraction and are also used to determine analyte 

concentrations after analysis. Upon completion of spiking, add the remaining XAD-2 to 

the thimble, insert the remaining PUF plug, and place the thimble into the extractor. Note 

that if you are collecting and analyzing for SVOCs in gas and particle phases, perform 

separate extractions for the filter and XAD-2.

(3) For the initial extraction, combine the concentrated acetone rinses (from the sampling 

system in paragraph (a) of this section) with enough hexane to bring the solvent volume 

up to the target level of 700 ml. Assemble the extractor and turn on the heating controls 

and cooling water. Allow the sample to reflux for 16 hours with the rheostat adjusted to 

cycle the extraction at a rate of (3.0 ±0.5) cycles per hour. Drain the water from the 

Dean-Stark trap as it accumulates by opening the stopcock on the trap. Set aside the 

water for analysis or discard it. In most cases, any water present will be removed within 

approximately 2 hours after starting the extraction.

(4) After completing the initial extraction, remove the solvent and concentrate it to (4.0 

±0.5) ml using a Kuderna-Danish concentrator that includes a condenser such as a threeball Snyder column with venting dimples and a graduated collection tube. Using this 

concentrator will minimize evaporative loss of analytes with lower molecular weight.

(i) Rinse the round bottom flask of the extractor with (60 to 100) ml of hexane and add 

the rinsate to this concentrated extract.

(ii) Concentrate the mixture to (4 ±0.5) ml using a Kuderna-Danish concentrator or 

similar apparatus.

(iii) Repeat the steps in paragraphs (b)(4)(i) and (ii) of this section three times, or as 

necessary to remove all the residual solvent from the round bottom flask of the extractor, 

concentrating the final rinsate to (4 ±0.5) ml.

(5) For the second extraction, combine the toluene rinses (from the sampling system in 

paragraph (a) of this section) with any additional toluene needed to bring the solvent 

volume up to the target level of 700 ml. As noted in paragraph (a) of this section, you 

may need to concentrate the rinsate before adding it to the extraction apparatus if the 

rinsate solvent volume is too large. Allow the sample to reflux for 16 hours with the 

rheostat adjusted to cycle the extraction at a rate of (3.0 ±0.5) cycles per hour. Check the 

Dean-Stark trap for water during the first 2 hours of the extraction (though little or no 

water should be present during this stage).

(6) Upon completion of the second extraction, remove the solvent and concentrate it to (4 

±0.5) ml as described in paragraph (b)(4) of this section. Using hexane from paragraph 

(b)(4) of this section as the rinse solvent effectively performs a solvent exchange of 

toluene with hexane.

(7) Combine the concentrated extract from paragraph (b)(4) of this section with the 

concentrated extract from paragraph (b)(6) of this section. Divide the extract into a 

number of fractions based on the number of analyses you need to perform. Perform the 

separate sample clean-up described in paragraph (c) of this section as needed for each 

fraction.

(c) Sample clean-up. This paragraph (c) describes how to perform sample cleaning to 

remove from the sample extract any solids and any SVOCs that will not be analyzed. 

This process, known as “sample clean-up”, reduces the potential for interference or co-
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elution of peaks during analytical analysis. Before performing the sample clean-up, spike 

the extract with an alternate standard that contains a known mass of isotopically labeled 

compounds that are identical to the target analytes (except for the labeling). The category

of the target analyte compounds (such as PAHs or dioxin) will determine the number of 

compounds that make up the standard. For example, PAHs require the use of four

compounds in the alternate standard to cover the four basic ring structures of PAHs (2-

ring, 3-ring, 4-ring, and 5-ring structures). These alternate standards are used to monitor 

the efficiency of the clean-up procedure. Before sample clean-up, concentrate the 

fractionated sample to about 2 ml with a Kuderna-Danish concentrator or rotary

evaporator, and then transfer the extract to an 8 ml test tube with hexane rinse. 

Concentrate it to a volume of about 1 ml using a Kuderna-Danish concentrator. Use good 

engineering judgment to select an appropriate column chromatographic clean-up option

for your target analytes. Note that these clean-up techniques generally remove 

compounds based on their polarity. The following procedures are examples of clean-up 

techniques for PAHs and nPAHs.

(1) PAH clean-up. The following method is appropriate for clean-up of extracts intended 

for analysis of PAHs:

(i) Pack a glass gravity column (250 mm x 10 mm recommended) by inserting a clean 

glass wool plug into the bottom of the column and add 10 g of activated silica gel in

methylene chloride. Tap the column to settle the silica gel and then add a 1 cm layer of 

anhydrous sodium sulfate. Verify the volume of solvent required to completely elute all 

the PAHs and adjust the weight of the silica gel accordingly to account for variations 

among batches of silica gel that may affect the elution volume of the various PAHs.

(ii) Elute the column with 40 ml of hexane. The rate for all elutions should be about 2 

ml/min. You may increase the elution rate by using dry air or nitrogen to maintain the 

headspace slightly above atmospheric pressure. Discard the eluate just before exposing

the sodium sulfate layer to the air or nitrogen and transfer the 1 ml sample extract onto 

the column using two additional 2 ml rinses of hexane. Just before exposing the sodium 

sulfate layer to the air or nitrogen, begin elution of the column with 25 ml of hexane 

followed by 25 ml of 40 volume % methylene chloride in hexane. Collect the entire 

eluate and concentrate it to about 5 ml using the Kuderna-Danish concentrator or a rotary

evaporator. Make sure not to evaporate all the solvent from the extract during the 

concentration process. Transfer the eluate to a small sample vial using a hexane rinse and 

concentrate it to 100 μl using a stream of nitrogen without violently disturbing the 

solvent. Store the extracts in a refrigerator at or below 4 °C, and away from light.

(2) nPAH clean up. The following procedure, adapted from “Determination and 

Comparison of Nitrated-Polycyclic Aromatic Hydrocarbons Measured in Air and Diesel 

Particulate Reference Materials” (Bamford, H.A., et al, Chemosphere, Vol. 50, Issue 5, 

pages 575 – 587), is an appropriate method to clean up extracts intended for analysis of 

nPAHs:

(i) Condition an aminopropyl solid phase extraction (SPE) cartridge by eluting it with 20 

ml of 20 volume % methylene chloride in hexane. Transfer the extract quantitatively to 

the SPE cartridge with at least two methylene chloride rinses. Elute the extract through 

the SPE cartridge by using 40 ml of 20 volume % methylene chloride in hexane to 

minimize potential interference of polar constituents, and then reduce the extract to 0.5 

ml in hexane and subject it to normal-phase liquid chromatography using a pre-prepared 
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9.6 mm x 25 cm semi-preparative Chromegabond®amino/cyano column (5 μm particle 

size) to isolate the nPAH fraction. The mobile phase is 20 volume % methylene chloride

in hexane at a constant flow rate of 5 ml per minute. Back-flash the column with 60 ml 

of methylene chloride and then condition it with 200 ml of 20 volume % methylene 

chloride in hexane before each injection. Collect the effluent and concentrate it to about 

2 ml using the Kuderna-Danish concentrator or a rotary evaporator. Transfer it to a 

minivial using a hexane rinse and concentrate it to 100 μl using a gentle stream of 

nitrogen. Store the extracts at or below 4 °C, and away from light.

(ii) [Reserved]

§1065.1111 Sample analysis.

This subpart does not specify chromatographic or analytical methods to analyze extracts, 

because the appropriateness of such methods is highly dependent on the nature of the 

target analytes. However, we recommend that you spike the extract with an injection 

standard that contains a known mass of an isotopically labeled compound that is identical 

to one of the target analytes (except for labeling). This injection standard allows you to

monitor the efficiency of the analytical process by verifying the volume of sample 

injected for analysis.

331. Part 1066 is revised to read as follows:

Part 1066—VEHICLE-TESTING PROCEDURES

Subpart A—APPLICABILITY AND GENERAL PROVISIONS

1066.1 Applicability.

1066.2 Submitting information to EPA under this part.

1066.5 Overview of this part 1066 and its relationship to the standard-setting part.

1066.10 Other procedures.

1066.15 Overview of test procedures.

1066.20 Units of measure and overview of calculations.

1066.25 Recordkeeping.

Subpart B—EQUIPMENT, MEASUREMENT INSTRUMENTS, FUEL, AND 

ANALYTICAL GAS SPECIFICATIONS

1066.101 Overview.

1066.105 Ambient controls and vehicle cooling fans.

1066.110 Equipment specifications for emission sampling systems.

1066.120 Measurement instruments.

1066.125 Data updating, recording, and control.

1066.130 Measurement instrument calibrations and verifications.

1066.135 Linearity verification.

1066.140 Diluted exhaust flow calibration.

1066.145 Engine fluids, test fuels, analytical gases, and other calibration standards.

1066.150 Analyzer interference and quench verification limit.

Subpart C—DYNAMOMETER SPECIFICATIONS

1066.201 Dynamometer overview.
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1066.210 Dynamometers.

1066.215 Summary of verification procedures for chassis dynamometers.

1066.220 Linearity verification for chassis dynamometer systems.

1066.225 Roll runout and diameter verification procedure.

1066.230 Time verification procedure.

1066.235 Speed verification procedure.

1066.240 Torque transducer verification.

1066.245 Response time verification.

1066.250 Base inertia verification.

1066.255 Parasitic loss verification.

1066.260 Parasitic friction compensation verification.

1066.265 Acceleration and deceleration verification.

1066.270 Unloaded coastdown verification.

1066.275 Daily dynamometer readiness verification.

1066.290 Verification of speed accuracy for the driver’s aid.

Subpart D—COASTDOWN

1066.301 Overview of coastdown procedures.

1066.305 Coastdown procedures for motor vehicles at or below 14,000 pounds GVWR.

1066.310 Coastdown procedures for vehicles above 14,000 pounds GVWR.

1066.315 Dynamometer road-load setting.

Subpart E—PREPARING VEHICLES AND RUNNING AN EXHAUST

EMISSION TEST

1066.401 Overview.

1066.405 Vehicle preparation and preconditioning.

1066.410 Dynamometer test procedure.

1066.415 Vehicle operation.

1066.420 Test preparation.

1066.425 Performing emission tests.

Subpart F—ELECTRIC VEHICLES AND HYBRID ELECTRIC VEHICLES

1066.501 Overview.

Subpart G—CALCULATIONS

1066.601 Overview.

1066.605 Mass-based and molar-based exhaust emission calculations.

1066.610 Dilution air background correction.

1066.615 NOx intake-air humidity correction.

1066.620 Removed water correction.

1066.625 Flow meter calibration calculations.

1066.630 PDP, SSV, and CFV flow rate calculations.

1066.635 NMOG determination.

1066.695 Data requirements.

Subpart H—COLD TEMPERATURE TEST PROCEDURES
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1066.701 Applicability and general provisions.

1066.710 Cold-testing procedures for measuring CO and NMHC emissions and 

determining fuel economy.

Subpart I—EXHAUST EMISSION TEST PROCEDURES FOR MOTOR 

VEHICLES

1066.801 Applicability and general provisions.

1066.805 Road-load power, test weight, and inertia weight class determination.

1066.810 Vehicle preparation.

1066.815 Exhaust emission test procedures for FTP emissions.

1066.816 Vehicle preconditioning for FTP testing.

1066.820 Composite calculations for FTP exhaust emissions.

1066.830 Supplemental Federal Test Procedures; overview.

1066.831 Exhaust emission test procedures for aggressive driving.

1066.835 Exhaust emission test procedure for SC03 emissions.

1066.840 Highway fuel economy test procedure.

1066.845 AC17 Air conditioning efficiency test procedure.

Subpart J—EVAPORATIVE EMISSION TEST PROCEDURES

§1066.901 Applicability and general provisions.

TEST EQUIPMENT AND CALCULATIONS FOR EVAPORATIVE AND REFUELING EMISSIONS

1066.910 SHED enclosure specifications.

1066.915 Enclosures; auxiliary systems and equipment.

1066.920 Enclosure calibrations.

1066.925 Enclosure calculations for evaporative and refueling emissions.

1066.930 Equipment for point-source measurement of running losses.

EVAPORATIVE AND REFUELING EMISSION TEST PROCEDURES FOR MOTOR VEHICLES

1066.950 Fuel temperature profile.

1066.955 Diurnal emission test.

1066.960 Running loss test.

1066.965 Hot soak test.

1066.970 Refueling test for liquid fuels.

1066.971 Vehicle and canister preconditioning for the refueling test.

1066.975 Refueling test for LPG.

1066.980 Fuel dispensing spitback procedure.

1066.985 Fuel storage system leak test procedure.

Subpart K—DEFINITIONS AND OTHER REFERENCE MATERIAL

1066.1001 Definitions.

1066.1005 Symbols, abbreviations, acronyms, and units of measure.

1066.1010 Incorporation by reference.

Authority: 42 U.S.C. 7401-7671q.

Subpart A—APPLICABILITY AND GENERAL PROVISIONS
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§1066.1 Applicability.

(a) This part describes the emission measurement procedures that apply to testing we 

require for the following vehicles:

(1) Model year 2014 and later heavy-duty highway vehicles we regulate under 40 CFR 

part 1037 that are not subject to chassis testing for exhaust emissions under 40 CFR part 

86.

(2) Model year 2022 and later motor vehicles (light-duty and heavy-duty) that are subject 

to chassis testing for exhaust emissions under 40 CFR part 86, other than highway

motorcycles. See 40 CFR part 86 for provisions describing how to implement this part 

1066.

(b) The procedures of this part may apply to other types of vehicles, as described in this 

part and in the standard-setting part.

(c) The testing in this part 1066 is designed for measuring exhaust, evaporative, and 

refueling emissions. Procedures for measuring evaporative and refueling emissions for 

motor vehicles are in some cases integral with exhaust measurement procedures as 

described in §1066.801. Subpart J of this part describes provisions that are unique to 

evaporative and refueling emission measurements. Other subparts in this part are written 

with a primary focus on measurement of exhaust emissions.

(d) The term “you” means anyone performing testing under this part other than EPA. 

(1) This part is addressed primarily to manufacturers of vehicles, but it applies equally to 

anyone who does testing under this part for such manufacturers. 

(2) This part applies to any manufacturer or supplier of test equipment, instruments, 

supplies, or any other goods or services related to the procedures, requirements, 

recommendations, or options in this part. 

(e) Paragraph (a) of this section identifies the parts of the CFR that define emission 

standards and other requirements for particular types of vehicles. In this part, we refer to 

each of these other parts generically as the “standard-setting part.” For example, 40 CFR 

part 1037 is the standard-setting part for heavy-duty highway vehicles and parts 86 and 

600 are the standard-setting parts for light-duty vehicles. For vehicles subject to 40 CFR 

part 86, subpart S, treat subpart I and subpart J of this part as belonging to 40 CFR part 

86. This means that references to the standard-setting part include subpart I and subpart J 

of this part.

(f) Unless we specify otherwise, the terms “procedures” and “test procedures” in this part 

include all aspects of vehicle testing, including the equipment specifications, calibrations, 

calculations, and other protocols and procedural specifications needed to measure 

emissions.

(g) For additional information regarding these test procedures, visit our Web site at 

www.epa.gov, and in particular http://www.epa.gov/nvfel/testing/regulations.htm.

§1066.2 Submitting information to EPA under this part.

(a) You are responsible for statements and information in your applications for 

certification, requests for approved procedures, selective enforcement audits, laboratory

audits, production-line test reports, or any other statements you make to us related to this 

part 1066. If you provide statements or information to someone for submission to EPA, 

you are responsible for these statements and information as if you had submitted them to

EPA yourself.
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(b) In the standard-setting part and in 40 CFR 1068.101, we describe your obligation to 

report truthful and complete information and the consequences of failing to meet this 

obligation. See also 18 U.S.C. 1001 and 42 U.S.C. 7413(c)(2). This obligation applies 

whether you submit this information directly to EPA or through someone else.

(c) We may void any certificates or approvals associated with a submission of 

information if we find that you intentionally submitted false, incomplete, or misleading 

information. For example, if we find that you intentionally submitted incomplete 

information to mislead EPA when requesting approval to use alternate test procedures, 

we may void the certificates for all engine families certified based on emission data 

collected using the alternate procedures. This would also apply if you ignore data from 

incomplete tests or from repeat tests with higher emission results.

(d) We may require an authorized representative of your company to approve and sign 

the submission, and to certify that all the information submitted is accurate and complete. 

This includes everyone who submits information, including manufacturers and others.

(e) See 40 CFR 1068.10 for provisions related to confidential information. Note however 

that under 40 CFR 2.301, emission data are generally not eligible for confidential 

treatment.

(f) Nothing in this part should be interpreted to limit our ability under Clean Air Act 

section 208 (42 U.S.C. 7542) to verify that vehicles conform to the regulations.

§1066.5 Overview of this part 1066 and its relationship to the standard-setting part.

(a) This part specifies procedures that can apply generally to testing various categories of 

vehicles. See the standard-setting part for directions in applying specific provisions in 

this part for a particular type of vehicle. Before using this part’s procedures, read the 

standard-setting part to answer at least the following questions:

(1) What drive schedules must I use for testing?

(2) Should I warm up the test vehicle before measuring emissions, or do I need to 

measure cold-start emissions during a warm-up segment of the duty cycle?

(3) Which exhaust constituents do I need to measure? Measure all exhaust constituents 

that are subject to emission standards, any other exhaust constituents needed for 

calculating emission rates, and any additional exhaust constituents as specified in the 

standard-setting part. See 40 CFR 1065.5 regarding requests to omit measurement of 

N2O and CH4 for vehicles not subject to an N2O or CH4 emission standard.

(4) Do any unique specifications apply for test fuels?

(5) What maintenance steps may I take before or between tests on an emission-data 

vehicle?

(6) Do any unique requirements apply to stabilizing emission levels on a new vehicle?

(7) Do any unique requirements apply to test limits, such as ambient temperatures or 

pressures?

(8) What requirements apply for evaporative and refueling emissions?

(9) Are there any emission standards specified at particular operating conditions or 

ambient conditions?

(10) Do any unique requirements apply for durability testing?

(b) The testing specifications in the standard-setting part may differ from the 

specifications in this part. In cases where it is not possible to comply with both the 

standard-setting part and this part, you must comply with the specifications in the 
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standard-setting part. The standard-setting part may also allow you to deviate from the 

procedures of this part for other reasons.

(c) The following table shows how this part divides testing specifications into subparts:

TABLE 1 OF §1066.5—DESCRIPTION OF PART 1066 SUBPARTS

This subpart Describes these specifications or procedures

Subpart A Applicability and general provisions.

Subpart B Equipment for testing.

Subpart C Dynamometer specifications.

Subpart D Coastdowns for testing.

Subpart E How to prepare your vehicle and run an emission test.

Subpart F How to test electric vehicles and hybrid electric vehicles.

Subpart G Test procedure calculations.

Subpart H Cold temperature testing.

Subpart I Exhaust emission test procedures for motor vehicles.

Subpart J Evaporative and refueling emission test procedures.

Subpart K Definitions and reference material.

§1066.10 Other procedures.

(a) Your testing. The procedures in this part apply for all testing you do to show 

compliance with emission standards, with certain exceptions noted in this section. In 

some other sections in this part, we allow you to use other procedures (such as less 

precise or less accurate procedures) if they do not affect your ability to show that your 

vehicles comply with the applicable emission standards. This generally requires emission 

levels to be far enough below the applicable emission standards so that any errors caused 

by greater imprecision or inaccuracy do not affect your ability to state unconditionally

that the engines meet all applicable emission standards.

(b) Our testing. These procedures generally apply for testing that we do to determine if 

your vehicles comply with applicable emission standards. We may perform other testing 

as allowed by the Act.

(c) Exceptions. We may allow or require you to use procedures other than those 

specified in this part as described in 40 CFR 1065.10(c). All the test procedures noted as 

exceptions to the specified procedures are considered generically as "other procedures." 

Note that the terms "special procedures" and "alternate procedures" have specific 

meanings; "special procedures" are those allowed by 40 CFR 1065.10(c)(2) and 

"alternate procedures" are those allowed by 40 CFR 1065.10(c)(7). If we require you to 

request approval to use other procedures under this paragraph (c), you may not use them 

until we approve your request.

§1066.15 Overview of test procedures.

This section outlines the procedures to test vehicles that are subject to emission standards.

(a) The standard-setting part describes the emission standards that apply. Evaporative 

and refueling emissions are generally in the form of grams total hydrocarbon equivalent 

per test. We set exhaust emission standards in g/mile (or g/km), for the following 

constituents:

(1) Total oxides of nitrogen, NOx.
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(2) Hydrocarbons, HC, which may be expressed in the following ways:

(i) Total hydrocarbons, THC.

(ii) Nonmethane hydrocarbons, NMHC, which results from subtracting methane, CH4, 

from THC.

(iii) Total hydrocarbon-equivalent, THCE, which results from adjusting THC 

mathematically to be equivalent on a carbon-mass basis.

(iv) Nonmethane hydrocarbon-equivalent, NMHCE, which results from adjusting NMHC 

mathematically to be equivalent on a carbon-mass basis.

(v) Nonmethane organic gases, NMOG, which are calculated either from fully or partially

speciated measurement of hydrocarbons including oxygenates, or by adjusting measured 

NMHC values based on fuel oxygenate properties.

(3) Particulate matter, PM.

(4) Carbon monoxide, CO.

(5) Carbon dioxide, CO2.

(6) Methane, CH4.

(7) Nitrous oxide, N2O.

(8) Formaldehyde, CH2O.

(b) Note that some vehicles may not be subject to standards for all the exhaust emission 

constituents identified in paragraph (a) of this section. Note also that the standard-setting 

part may include standards for pollutants not listed in paragraph (a) of this section.

(c) The provisions of this part apply for chassis dynamometer testing where vehicle speed

is controlled to follow a prescribed duty cycle while simulating vehicle driving through 

the dynamometer’s road-load settings. We generally set exhaust emission standards over 

test intervals and/or drive schedules, as follows:

(1) Vehicle operation. Testing involves measuring emissions and miles travelled while 

operating the vehicle on a chassis dynamometer. Refer to the definitions of “duty cycle” 

and “test interval” in §1066.1001. Note that a single drive schedule may have multiple 

test intervals and require weighting of results from multiple test intervals to calculate a 

composite distance-based emission value to compare to the standard.

(2) Constituent determination. Determine the total mass of each exhaust constituent over 

a test interval by selecting from the following methods:

(i) Continuous sampling. In continuous sampling, measure the exhaust constituent’s 

concentration continuously from raw or dilute exhaust. Multiply this concentration by

the continuous (raw or dilute) flow rate at the emission sampling location to determine 

the constituent’s flow rate. Sum the constituent’s flow rate continuously over the test 

interval. This sum is the total mass of the emitted constituent.

(ii) Batch sampling. In batch sampling, continuously extract and store a sample of raw or 

dilute exhaust for later measurement. Extract a sample proportional to the raw or dilute 

exhaust flow rate, as applicable. You may extract and store a proportional sample of 

exhaust in an appropriate container, such as a bag, and then measure NOx, HC, CO, CO2, 

CH4, N2O, and CH2O concentrations in the container after the test interval. You may

deposit PM from proportionally extracted exhaust onto an appropriate substrate, such as a 

filter. In this case, divide the PM by the amount of filtered exhaust to calculate the PM 

concentration. Multiply batch sampled concentrations by the total (raw or dilute) flow 

from which it was extracted during the test interval. This product is the total mass of the 

emitted constituent.
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(iii) Combined sampling. You may use continuous and batch sampling simultaneously

during a test interval, as follows:

(A) You may use continuous sampling for some constituents and batch sampling for 

others.

(B) You may use continuous and batch sampling for a single constituent, with one being 

a redundant measurement, subject to the provisions of 40 CFR 1065.201. 

(d) Refer to subpart G of this part and the standard-setting part for calculations to 

determine g/mile emission rates.

(e) You must use good engineering judgment for all aspects of testing under this part. 

While this part highlights several specific cases where good engineering judgment is 

especially relevant, the requirement to use good engineering judgment is not limited to 

those provisions where we specifically re-state this requirement.

§1066.20 Units of measure and overview of calculations.

(a) System of units. The procedures in this part follow both conventional English units 

and the International System of Units (SI), as detailed in NIST Special Publication 811, 

which we incorporate by reference in §1066.1010. Except where specified, equations 

work with either system of units. Where the equations depend on the use of specific 

units, the regulation identifies the appropriate units.

(b) Units conversion. Use good engineering judgment to convert units between 

measurement systems as needed. For example, if you measure vehicle speed as 

kilometers per hour and we specify a precision requirement in terms of miles per hour, 

convert your measured kilometer per hour value to miles per hour before comparing it to 

our specification. The following conventions are used throughout this document and 

should be used to convert units as applicable:

(1) 1 hp = 33,000 ft∙lbf/min = 550 ft∙lbf/s = 0.7457 kW.

(2) 1 lbf = 32.174 ft∙lbm/s2 = 4.4482 N.

(3) 1 inch = 25.4 mm.

(4) 1 mile = 1609.344 m.

(5) For ideal gases, 1 μmol/mol = 1 ppm.

(6) For ideal gases, 10 mmol/mol = 1 %.

(c) Temperature. We generally designate temperatures in units of degrees Celsius (°C) 

unless a calculation requires an absolute temperature. In that case, we designate 

temperatures in units of Kelvin (K). For conversion purposes throughout this part, 0 °C 

equals 273.15 K. Unless specified otherwise, always use absolute temperature values for 

multiplying or dividing by temperature. 

(d) Absolute pressure. Measure absolute pressure directly or calculate it as the sum of 

atmospheric pressure plus a differential pressure that is referenced to atmospheric 

pressure. Always use absolute pressure values for multiplying or dividing by pressure.

(e) Rounding. The rounding provisions of 40 CFR 1065.20 apply for calculations in this 

part. This generally specifies that you round final values but not intermediate values. 

Use good engineering judgment to record the appropriate number of significant digits for 

all measurements.

(f) Interpretation of ranges. Interpret a range as a tolerance unless we explicitly identify

it as an accuracy, repeatability, linearity, or noise specification. See 40 CFR 1065.1001 

for the definition of tolerance. In this part, we specify two types of ranges:
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(1) Whenever we specify a range by a single value and corresponding limit values above 

and below that value (such as X ±Y), target the associated control point to that single 

value (X). Examples of this type of range include “±10 % of maximum pressure”, or 

“(30 ±10) kPa”. In these examples, you would target the maximum pressure or 30 kPa, 

respectively.

(2) Whenever we specify a range by the interval between two values, you may target any 

associated control point to any value within that range. An example of this type of range 

is “(40 to 50) kPa”.

(g) Scaling of specifications with respect to an applicable standard. Because this part 

1066 applies to a wide range of vehicles and emission standards, some of the 

specifications in this part are scaled with respect to a vehicle’s applicable standard or 

weight. This ensures that the specification will be adequate to determine compliance, but 

not overly burdensome by requiring unnecessarily high-precision equipment. Many of 

these specifications are given with respect to a “flow-weighted mean” that is expected at 

the standard or during testing. Flow-weighted mean is the mean of a quantity after it is 

weighted proportional to a corresponding flow rate. For example, if a gas concentration 

is measured continuously from the raw exhaust of an engine, its flow-weighted mean 

concentration is the sum of the products of each recorded concentration times its 

respective exhaust flow rate, divided by the sum of the recorded flow rates. As another 

example, the bag concentration from a CVS system is the same as the flow-weighted 

mean concentration, because the CVS system itself flow-weights the bag concentration.

§1066.25 Recordkeeping.

(a) The procedures in this part include various requirements to record data or other 

information. Refer to the standard-setting part and §1066.695 regarding specific 

recordkeeping requirements. 

(b) You must promptly send us organized, written records in English if we ask for them. 

We may review them at any time.

(c) We may waive specific reporting or recordkeeping requirements we determine to be 

unnecessary for the purposes of this part and the standard-setting part. Note that while 

we will generally keep the records required by this part, we are not obligated to keep 

records we determine to be unnecessary for us to keep. For example, while we require 

you to keep records for invalid tests so we may verify that your invalidation was 

appropriate, it is not necessary for us to keep records for our own invalid tests.

Subpart B—EQUIPMENT, MEASUREMENT INSTRUMENTS, FUEL, AND 

ANALYTICAL GAS SPECIFICATIONS

§1066.101 Overview.

(a) This subpart addresses equipment related to emission testing, as well as test fuels and 

analytical gases.

(b) The provisions of 40 CFR part 1065 specify engine-based procedures for measuring 

emissions. Except as specified otherwise in this part, the provisions of 40 CFR part 1065 

apply for testing required by this part as follows:
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(1) The provisions of 40 CFR part 1065, subpart B, describe equipment specifications for 

exhaust dilution and sampling systems; these specifications apply for testing under this 

part as described in §1066.110. 

(2) The provisions of 40 CFR part 1065, subpart C, describe specifications for 

measurement instruments; these specifications apply for testing under this part as 

described in §1066.120.

(3) The provisions of 40 CFR part 1065, subpart D, describe specifications for 

measurement instrument calibrations and verifications; these specifications apply for 

testing under this part as described in §1066.130.

(4) The provisions of 40 CFR part 1065, subpart H, describe specifications for fuels, 

engine fluids, and analytical gases; these specifications apply for testing under this part as 

described in §1066.145.

(5) The provisions of 40 CFR part 1065, subpart I, describe specifications for testing with 

oxygenated fuels; these specifications apply for NMOG determination as described in 

§1066.635.

(c) The provisions of this subpart are intended to specify systems that can very accurately 

and precisely measure emissions from motor vehicles such as light-duty vehicles. To the 

extent that this level of accuracy or precision is not necessary for testing highway

motorcycles or nonroad vehicles, we may waive or modify the specifications and 

requirements of this part for testing these other vehicles, consistent with good 

engineering judgment. For example, it may be appropriate to allow the use of a 

hydrokinetic dynamometer that is not able to meet all the performance specifications 

described in this subpart.

§1066.105 Ambient controls and vehicle cooling fans.

(a) Ambient conditions. Dynamometer testing under this part generally requires that you 

maintain the test cell within a specified range of ambient temperature and humidity. Use 

good engineering judgment to maintain relatively uniform temperatures throughout the 

test cell before testing. You are generally not required to maintain uniform temperatures 

throughout the test cell while the vehicle is running due to the heat generated by the 

vehicle. Measured humidity values must represent the conditions to which the vehicle is 

exposed, which includes intake air; other than the intake air, humidity does not affect 

emissions, so humidity need not be uniform throughout the test cell.

(b) General requirements for cooling fans. Use good engineering judgment to select and 

configure fans to cool the test vehicle in a way that meets the specifications of paragraph 

(c) of this section and simulates in-use operation. If you demonstrate that the specified 

fan configuration is impractical for special vehicle designs, such as vehicles with rearmounted engines, or it does not provide adequate cooling to properly represent in-use 

operation, you may ask us to approve increasing fan capacity or using additional fans.

(c) Allowable cooling fans for vehicles at or below 14,000 pounds GVWR. Cooling fan 

specifications for vehicles at or below 14,000 pounds GVWR depend on the test cycle.

Paragraph (c)(1) of this section summarizes the cooling fan specifications for the 

different test cycles; the detailed specifications are described in paragraphs (c)(2) through 

(5) of this section. See §1066.410 for instruction regarding how to use the fans during 

testing.

(1) Cooling fan specifications for different test cycles are summarized as follows:
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(i) For the FTP test cycle, the allowable cooling fan configurations are described in 

paragraphs (c)(2) and (3) of this section.

(ii) For the HFET test cycle, the allowable cooling fan configurations are described in 

paragraphs (c)(2) and (3) of this section.

(iii) For the US06 test cycle, the allowable cooling fan configurations are described in 

paragraphs (c)(2) and (4) of this section.

(iv) For the LA-92 test cycle, the allowable cooling fan configurations are described in 

paragraphs (c)(2) and (4) of this section.

(v) For SC03 and AC17 test cycles, the allowable cooling fan configuration is described 

in paragraph (c)(5) of this section.

(2) You may use a road-speed modulated fan system meeting the specifications of this 

paragraph (c)(2) for anything other than SC03 and AC17 testing. Use a road-speed 

modulated fan that achieves a linear speed of cooling air at the blower outlet that is 

within ±3.0 mph (±1.3 m/s) of the corresponding roll speed when vehicle speeds are 

between 5 and 30 mph, and within ±6.5 mph (±2.9 m/s) of the corresponding roll speed at 

higher vehicle speeds; however you may limit the fan’s maximum linear speed to 70 

mph. We recommend that the cooling fan have a minimum opening of 0.2 m2and a 

minimum width of 0.8 m.

(i) Verify the air flow velocity for fan speeds corresponding to vehicle speeds of 20 and 

40 mph using an instrument that has an accuracy of ±2 % of the measured air flow speed.

(ii) For fans with rectangular outlets, divide the fan outlet into sections as shown in 

Figure 1 of this section. As illustrated by the “+” in the following figure, measure flow 

from the center of each section; do not measure the flow from the center section.

Figure 1 of §1066.105—Rectangular fan outlet grid

(iii) For fans with circular outlets, divide the fan outlet into 8 equal sections as shown in 

Figure 2 of this section. As illustrated by the “+” in the following figure, measure flow 

on the radial centerline of each section, at a radius of two-thirds of the fan’s total radius.
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Figure 2 of §1066.105—Circular fan outlet grid

(iv) Verify that the uniformity of the fan’s axial flow is constant across the discharge area 

within a tolerance of ±4.0 mph of the vehicle’s speed at fan speeds corresponding to 20 

mph, and within ±8.0 mph at fan speeds corresponding to 40 mph. For example, at a 

vehicle speed of 20.2 mph, axial flow at all locations denoted by the “+” across the 

discharge nozzle must be between 16.2 and 24.2 mph. When measuring the axial air flow 

velocity, use good engineering judgment to determine the distance from the nozzle outlet 

at each point of the fan outlet grid. Use these values to calculate a mean air flow velocity

across the discharge area at each speed setting. The instrument used to verify the air 

velocity must have an accuracy of ±2 % of the measured air flow velocity.

(v) Use a multi-axis flow meter or another method to verify that the fan’s air flow 

perpendicular to the axial air flow is less than 15% of the axial air flow, consistent with 

good engineering judgment. Demonstrate this by comparing the perpendicular air flow 

velocity to the mean air flow velocities determined in paragraph (c)(2)(iv) of this section 

at vehicle speeds of 20 and 40 mph.

(3) You may use a fixed-speed fan with a maximum capacity up to 2.50 m3/s for FTP and 

HFET testing. 

(4) You may use a fixed-speed fan with a maximum capacity up to 7.10 m3/s for US06 

and LA-92 testing.

(5) For SC03 and AC17 testing, use a road-speed modulated fan with a minimum

discharge area that is equal to or exceeds the vehicle’s frontal inlet area. We recommend 

using a fan with a discharge area of 1.7 m2.

(i) Air flow volumes must be proportional to vehicle speed. Select a fan size that will 

produce a flow volume of approximately 45 m3/s at 60 mph. If this fan is also the only

source of test cell air circulation or if fan operational mechanics make the 0 mph air flow 

requirement impractical, air flow of 2 mph or less at 0 mph vehicle speed is allowed.

(ii) Verify the uniformity of the fan’s axial flow as described in paragraph (c)(2)(iv) of 

this section, except that you must measure the axial air flow velocity 60 cm from the 

nozzle outlet at each point of the discharge area grid.

(iii) Use a multi-axis flow meter or another method to verify that the fan’s air flow 

perpendicular to the axial air flow is less than 10% of the axial air flow, consistent with 

good engineering judgment. Demonstrate this by comparing the perpendicular air flow 

velocity to the mean air flow velocities determined in paragraph (c)(2)(iv) of this section 

at vehicle speeds of 20 and 40 mph.
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(iv) In addition to the road-speed modulated fan, we may approve the use of one or more 

fixed-speed fans to provide proper cooling to represent in-use operation, but only up to a 

total of 2.50 m3/s for all additional fans.

(d) Allowable cooling fans for vehicles above 14,000 pounds GVWR. For all testing, use 

a road-speed modulated fan system that achieves a linear speed of cooling air at the 

blower outlet that is within ±3.0 mph (±1.3 m/s) of the corresponding roll speed when 

vehicle speeds are between 5 and 30 mph, and within ±10 mph (±4.5 m/s) of the 

corresponding roll speed at higher vehicle speeds. For vehicles above 19,500 pounds 

GVWR, we recommend that the cooling fan have a minimum opening of 2.75 m2, a 

minimum flow rate of 60 m

3

/s at a fan speed of 50 mph, and a minimum speed profile in 

the free stream flow, across the duct, that is ±15 % of the target flow rate.

§1066.110 Equipment specifications for emission sampling systems.

(a) This section specifies equipment related to emission testing, other than measurement 

instruments. This equipment includes dynamometers (described further in subpart C of 

this part) and various emission-sampling hardware.

(b) The following equipment specifications apply for testing under this part:

(1) Connect a vehicle’s exhaust system to any dilution stage as follows:

(i) Minimize lengths of laboratory exhaust tubing. You may use a total length of 

laboratory exhaust tubing up to 4 m without needing to heat or insulate the tubing. 

However, you may use a total length of laboratory exhaust tubing up to 10 m if you 

insulate and/or heat the tubing to minimize the temperature difference between the 

exhaust gas and the whole tubing wall over the course of the emission test. The 

laboratory exhaust tubing starts at the end of the vehicle’s tailpipe and ends at the first 

sample point or the first dilution point. The laboratory exhaust tubing may include

flexible sections, but we recommend that you limit the amount of flexible tubing to the 

extent practicable. For multiple-tailpipe configurations where the tailpipes combine into 

a single flow path for emission sampling, the start of the laboratory exhaust tubing may

be taken at the last joint where the exhaust flow first becomes a single, combined flow.

(ii) You may insulate or heat any laboratory exhaust tubing. 

(iii) Use laboratory exhaust tubing materials that are smooth-walled and not chemically

reactive with exhaust constituents. (For purposes of this paragraph (b)(1), nominally

smooth spiral-style and accordion-style flexible tubing are considered to be smoothwalled.) For measurements involving PM, tubing materials must also be electrically 

conductive. Stainless steel is an acceptable material for any testing. You may use short 

sections of nonconductive flexible tubing to connect a PM sampling system to the 

vehicle’s tailpipe; use good engineering judgment to limit the amount of nonconductive 

surface area exposed to the vehicle’s exhaust.

(iv) We recommend that you use laboratory exhaust tubing that has either a wall 

thickness of less than 2 mm or is air gap-insulated to minimize temperature differences 

between the wall and the exhaust.

(v) You must seal your system to the extent necessary to ensure that any remaining leaks 

do not affect your ability to demonstrate compliance with the applicable standards. We 

recommend that you seal all known leaks.

(vi) Electrically ground the entire exhaust system, with the exception of nonconductive 

flexible tubing, as allowed under paragraph (b)(1)(iii) of this section.
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(vii) For vehicles with multiple tailpipes, route the exhaust into a single flow. To ensure 

mixing of the multiple exhaust streams before emission sampling, we recommend a 

minimum Reynolds number, Re#, of 4000 for the combined exhaust stream, where Re#is 

based on the inside diameter of the combined flow at the first sampling point. You may

configure the exhaust system with turbulence generators, such as orifice plates or fins, to 

achieve good mixing; this may be necessary for good mixing if Re#is less than 4000. Re#

is defined in 40 CFR 1065.640.

(2) Use equipment specifications in 40 CFR 1065.140 through 40 CFR 1065.190, except 

as follows:

(i) For PM background measurement, the following provisions apply instead of the 

analogous provisions in 40 CFR 1065.140(b):

(A) You need not measure PM background for every test. You may apply PM 

background correction for a single site or multiple sites using a moving-average 

background value as long as your background PM sample media (e.g., filters) were all 

made by the same manufacturer from the same material. Use good engineering judgment 

to determine how many background samples make up the moving average and how 

frequently to update those values. For example, you might take one background sample 

per week and average that sample into previous background values, maintaining five 

observations for each calculated average value. Background sampling time should be 

representative of the duration of the test interval to which the background correction is 

applied.

(B) You may sample background PM from the dilution tunnel at any time before or after

an emission test using the same sampling system used during the emission test. For this 

background sampling, the dilution tunnel blower must be turned on, the vehicle must be 

disconnected from the laboratory exhaust tubing, and the laboratory exhaust tubing must 

be capped.

(C) The duration of your background sample may be different than that of the test cycle 

in which you are applying the background correction, consistent with good engineering 

judgment.

(D) Your PM background correction may not exceed 5 μg or 5 % of the net PM mass 

expected at the standard, whichever is greater.

(ii) The provisions of 40 CFR 1065.140(d)(2)(iv) do not apply.

(iii) For PM samples, configure dilution systems using the following limits:

(A) Control the dilution air temperature as described in 40 CFR 1065.140(e)(1), except 

that the temperature may be set to (15 to 52) °C. Use good engineering judgment to 

control PM sample temperature as required under 40 CFR 1065.140(e)(4).

(B) Apply the provisions of this paragraph (b)(2)(iii)(B) instead of 40 CFR 

1065.140(e)(2). Add dilution air to the raw exhaust such that the overall dilution factor

of diluted exhaust to raw exhaust, as shown in Eq. 1066.610-2 or 1066.610-3, is within 

the range of (7:1 to 20:1). Compliance with this dilution factor range may be determined 

for an individual test interval or as a time-weighted average over the entire duty cycle as 

determined in Eq. 1066.610-4. The maximum dilution factor limit of 20:1 does not apply

for hybrid electric vehicles (HEVs), since the dilution factor is infinite when the engine is 

off; however we strongly recommend that you stay under the specified maximum dilution 

factor limit when the engine is running. For partial-flow sampling systems, determine 

dilution factor using Eq. 1066.610-3. To determine the overall dilution factor for PM 
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samples utilizing secondary dilution air, multiply the dilution factor from the CVS by the 

dilution ratio of secondary dilution air to primary diluted exhaust.

(iv) In addition to the allowances in 40 CFR 1065.140(c)(6), you may heat the dilution air 

as described in paragraph (b)(2)(iii)(A) of this section to prevent or limit aqueous 

condensation.

(v) If you choose to dilute the exhaust by using a remote mix tee, which dilutes the 

exhaust at the tailpipe, you may use the following provisions consistent with good 

engineering judgment, as long as they do not affect your ability to demonstrate 

compliance with the applicable standards:

(A) You may use smooth-walled flexible tubing (including accordion-style) in the 

dilution tunnel upstream of locations for flow measurement or gaseous emission 

measurement.

(B) You may use smooth-walled electrically conductive flexible tubing in the dilution 

tunnel upstream of the location for PM emission measurements.

(C) All inside surfaces upstream of emission sampling must be made of 300 series 

stainless steel or polymer-based materials.

(D) Use good engineering judgment to ensure that the materials you choose do not cause 

significant loss of PM from your sample.

(vi) Paragraph (b)(1)(vi) of this section applies instead of 40 CFR 1065.145(b).

(vii) Vehicles other than HEVs that apply technology involving engine shutdown during 

idle may apply the sampling provisions of §1066.501(c).

(c) The following table summarizes the requirements of paragraph (b)(2) of this section:

TABLE 1 OF §1066.110–SUMMARY OF EQUIPMENT SPECIFICATIONS FROM 40 CFR PART 

1065, SUBPART B, THAT APPLY FOR CHASSIS TESTING

40 CFR part 1065 

references Applicability for chassis testing under this part

40 CFR 1065.140

Use all except as noted:

40 CFR 1065.140(b) applies as described in this 

section.

Use 40 CFR 1065.140(c)(6), with the additional 

allowance described in this section.

Do not use 40 CFR 1065.140(d)(2)(iv).

Use 40 CFR 1065.140(e)(1) as described in this 

section.

Do not use 40 CFR 1065.140(e)(2).

40 CFR 1065.145 Use all except 40 CFR 1065.145(b).

40 CFR 1065.150 

through 1065.190 Use all.

§1066.120 Measurement instruments.

The measurement instrument requirements in 40 CFR part 1065, subpart C, apply with 

the following exceptions:

(a) The provisions of §1066.125 apply instead of 40 CFR 1065.202.

(b) The provisions of 40 CFR 1065.210 and 1065.295 do not apply.

§1066.125 Data updating, recording, and control.
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This section specifies criteria that your test system must meet for updating and recording

data. It also specifies criteria for controlling the systems related to driver demand, the 

dynamometer, sampling equipment, and measurement instruments.

(a) Read and record values and calculate mean values relative to a specified frequency as 

follows:

(1) This paragraph (a)(1) applies where we specify a minimum command and control 

frequency that is greater than the minimum recording frequency, such as for sample flow 

rates from a CVS that does not have a heat exchanger. For these measurements, the rate 

at which you read and interpret the signal must be at least as frequent as the minimum

command and control frequency. You may record values at the same frequency, or you 

may record them as mean values, as long as the frequency of the mean values meets the 

minimum recording frequency. You must use all read values, either by recording them or 

using them to calculate mean values. For example, if your system reads and controls the 

sample flow rate at 10 Hz, you may record these values at 10 Hz, record them at 5 Hz by

averaging pairs of consecutive points together, or record them at 1 Hz by averaging five 

consecutive points together. 

(2) For all other measured values covered by this section, you may record the values 

instantaneously or as mean values, consistent with good engineering judgment. 

(3) You may not use rolling averages of measured values where a given measured value 

is included in more than one recorded mean value. 

(b) Use data acquisition and control systems that can command, control, and record at the 

following minimum frequencies:
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TABLE 1 OF §1066.125–DATA RECORDING AND CONTROL MINIMUM FREQUENCIES

Applicable 

Section Measured Values

Minimum 

Command and 

Control 

Frequencya

Minimum 

Recording 

Frequencyb,c

§1066.310

§1066.315 Vehicle speed — 10 Hz

§1066.425 Continuous concentrations of raw or dilute 

analyzers — 1 Hz

§1066.425

§1066.501 Power analyzer — 1 Hz

§1066.425 Bag concentrations of raw or dilute analyzers —

1 mean value 

per test interval

40 CFR 1065.545

§1066.425

Diluted exhaust flow rate from a CVS with a 

heat exchanger upstream of the flow

measurement

— 1 Hz

40 CFR 1065.545

§1066.425

Diluted exhaust flow rate from a CVS without 

a heat exchanger upstream of the flow 

measurement

5 Hz 1 Hz means

40 CFR 1065.545

§1066.425

Dilution air flow if actively controlled (for 

example, a partial-flow PM sampling system)

d 5 Hz 1 Hz means

40 CFR 1065.545

§1066.425

Sample flow from a CVS that has a heat 

exchanger 1 Hz 1 Hz

40 CFR 1065.545

§1066.425

Sample flow from a CVS that does not have a 

heat exchanger 5 Hz 1 Hz means

§1066.420 Ambient temperature — 1 Hze

§1066.420 Ambient humidity — 1 Hze

§1066.420 Heated sample system temperatures, including 

PM filter face — 1 Hz

aCFVs that are not using active control are exempt from meeting this requirement due to their operating 

principle.

b

1 Hz means are data reported from the instrument at a higher frequency, but recorded as a series of 1 s 

mean values at a rate of 1 Hz.

c

For CFVs in a CVS, the minimum recording frequency is 1 Hz. For CFVs used to control sampling from a 

CFV CVS, the minimum recording frequency is not applicable..

dThis is not applicable to CVS dilution air.

eUnless specified elsewhere in this part or the standard-setting part. Note that this provision does not apply 

to soak periods where recording frequencies are not specified. For these instances, we recommend a 

recording frequency of ≥ 0.016 Hz.

§1066.130 Measurement instrument calibrations and verifications.

The measurement instrument calibration and verification requirements in 40 CFR part 

1065, subpart D, apply with the following exceptions:

(a) The calibration and verification provisions of 40 CFR 1065.303 do not apply for 

engine speed, torque, fuel rate, or intake air flow.

(b) The linearity verification provisions of 40 CFR 1065.307 do not apply for engine 

speed, torque, fuel rate, or intake air flow. Section 1066.135 specifies additional linearity

verification provisions that apply specifically for chassis testing.

(c) The provisions of §1066.220 apply instead 40 CFR 1065.310.

(d) The provisions of 40 CFR 1065.320, 1065.325, and 1065.395 do not apply.

(e) If you are measuring flow volumetrically (rather than measuring based on molar

values), the provisions of §1066.140 apply instead of 40 CFR 1065.340.
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(f) The provisions of §1066.150 apply instead 40 CFR 1065.350(c), 1065.355(c),

1065.370(c), and 1065.375(c).

(g) Table 1 of this section summarizes the required and recommended calibrations and 

verifications that are unique to testing under this part and indicates when these must be 

performed. Perform other required or recommended calibrations and verifications as 

described in 40 CFR 1065.303, with the exceptions noted in this section. Table 1 

follows:

TABLE 1 OF §1066.130–SUMMARY OF REQUIRED CALIBRATIONS AND VERIFICATIONS

Type of calibration or 

verification Minimum frequencya

40 CFR 1065.307: Linearity 

verification

The linearity verifications from 40 CFR part 1065 do not apply under this part for 

engine speed, torque, fuel rate, or intake air flow; the linearity verification described in 

§1066.135 applies for the following measurements:

Dynamometer Speed: See §1066.220.

Dynamometer Torque: See §1066.220.

40 CFR 1065.310: Torque This calibration does not apply for testing under this part; see §1066.220.

40 CFR 1065.320: Fuel 

flow This calibration does not apply for testing under this part.

40 CFR 1065.325: Intake 

flow This calibration does not apply for testing under this part.

40 CFR 1065.340: CVS 

calibration

This calibration does not apply for CVS flow meters calibrated volumetrically as 

described in §1066.140.

40 CFR 1065.345: Vacuum 

leak

Required upon initial installation of the sampling system; recommended within 35 days

before the start of an emissions test and after maintenance such as pre-filter changes.

40 CFR 1065.350(c), 

1065.355(c), 1065.370(c), 

and 1065.375(c)

These provisions do not apply for testing under this part; see §1066.150.

40 CFR 1065.395: Inertial 

PM balance and weighing These verifications do not apply for testing under this part.

a

Perform calibrations and verifications more frequently if needed to conform to the measurement system 

manufacturer’s instructions and good engineering judgment.

§1066.135 Linearity verification.

This section describes requirements for linearity verification that are unique to testing 

under this part. (Note: see the definition of “linearity” in 40 CFR 1065.1001, where we 

explain that linearity means the degree to which measured values agree with respective 

reference values and that the term “linearity” is not used to refer to the shape of a 

measurement instrument's unprocessed response curve.) Perform other required or 

recommended calibrations and verifications as described in 40 CFR 1065.307, with the 

exceptions noted in this section. 

(a) For gas analyzer linearity, use one of the following options:

(1) Use instrument manufacturer recommendations and good engineering judgment to 

select at least ten reference values, yrefi, that cover the range of values that you expect 

during testing (to prevent extrapolation beyond the verified range during emission 

testing). We recommend selecting zero as one of your reference values. For each range 

calibrated, if the deviation from a least-squares best-fit straight line is 2 % or less of the 

value at each data point, concentration values may be calculated by use of a straight-line 

curve fit for that range. If the deviation exceeds 2 % at any point, use the best-fit 

nonlinear equation that represents the data to within 2 % of each test point to determine 

concentration. If you use a gas divider to blend calibration gases, verify that the 

calibration curve produced names a calibration gas within 2 % of its certified 
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concentration. Perform this verification between 15 and 50 % of the full-scale analyzer 

range.

(2) Use the linearity requirements of 40 CFR 1065.307, except for CO2 measurements 

used for determining fuel economy and GHG emissions for motor vehicles at or below 

14,000 pounds GVWR. If you choose this linearity option, you must use the provisions 

of 40 CFR 1065.672 to check for drift and make appropriate drift corrections.

(b) For dilution air, diluted exhaust, and raw exhaust sample flow, use a reference flow 

meter with a blower or pump to simulate flow rates. Use a restrictor, diverter valve,

variable-speed blower, or variable-speed pump to control the range of flow rates. Use the 

reference meter’s response for the reference values.

(1) Reference flow meters. Because of the large range in flow requirements, we allow a 

variety of reference meters. For example, for diluted exhaust flow for a full-flow dilution 

system, we recommend a reference subsonic venturi flow meter with a restrictor valve 

and a blower to simulate flow rates. For dilution air, diluted exhaust for partial-flow 

dilution, and raw exhaust, we allow reference meters such as critical flow orifices, critical 

flow venturis, laminar flow elements, master mass flow standards, or Roots meters. 

Make sure the reference meter is calibrated and its calibration is NIST-traceable. If you 

use the difference of two flow measurements to determine a net flow rate, you may use 

one of the measurements as a reference for the other.

(2) Reference flow values. Because the reference flow is not absolutely constant, sample 

and record values of Qrefi



for 30 seconds and use the arithmetic mean of the values, Qref

 , 

as the reference value. Refer to 40 CFR 1065.602 for an example of calculating an 

arithmetic mean.

(3) Linearity criteria. The values measured during linearity verification for flow meters 

must meet the following criteria: | xmin(a1-1)+a0 | ≤ 1 % ∙ Qmax



; a1 = 0.98-1.02; SEE = ≤ 2 

% ∙ Qmax



; and r

2

≥ 0.990.

(c) Perform linearity verifications for the following temperature measurements instead of 

those specified at 40 CFR 1065.307(e)(7):

(1) Test cell ambient air.

(2) Dilution air for PM sampling, including CVS, double-dilution, and partial-flow 

systems.

(3) PM sample.

(4) Chiller sample, for gaseous sampling systems that use thermal chillers to dry samples,

and that use chiller temperature to calculate dewpoint at the chiller outlet. For testing, if 

you choose to use the high alarm temperature setpoint for the chiller temperature as a 

constant value in determining the amount of water removed from the emission sample, 

you may verify the accuracy of the high alarm temperature setpoint using good 

engineering judgment without following the linearity verification for chiller temperature. 

We recommend that you input a simulated reference temperature signal below the alarm 

setpoint, increase this signal until the high alarm trips, and verify that the alarm setpoint 

value is no less than 2 °C below the reference value at the trip point.

(5) CVS flow meter inlet temperature.

(d) Perform linearity verifications for the following pressure measurements instead of 

those specified at 40 CFR 1065.307(e)(8):

(1) Exhaust back pressure at the tailpipe exit.
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(2) Barometric pressure.

(3) CVS flow meter inlet pressure.

(4) Sample dryer, for gaseous sampling systems that use either osmotic-membrane dryers

or thermal chillers to dry samples. For your testing, if you choose to use a low alarm 

pressure setpoint for the sample dryer pressure as a constant value in determining the 

amount of water removed from the emission sample, you may verify the accuracy of the 

low alarm pressure setpoint using good engineering judgment without following the 

linearity verification for sample dryer pressure. We recommend that you input a 

reference pressure signal above the alarm setpoint, decrease this signal until the low 

alarm trips, and verify that the alarm setpoint value is no more than 4 kPa above the 

reference value at the trip point.

(e) When following procedures or practices that we incorporate by reference in 

§1066.1010, you must meet the linearity requirements given by the procedure or practice 

for any analytical instruments not covered under 40 CFR 1065.307, such as GC-FID or 

HPLC.

§1066.140 Diluted exhaust flow calibration.

(a) Overview. This section describes how to calibrate flow meters for diluted exhaust 

constant-volume sampling (CVS) systems. We recommend that you also use this section 

to calibrate flow meters that use a subsonic venturi or ultrasonic flow to measure raw 

exhaust flow. You may follow the molar flow calibration procedures in 40 CFR 

1065.340 instead of the procedures in this section.

(b) Scope and frequency. Perform this calibration while the flow meter is installed in its 

permanent position, except as allowed in paragraph (c) of this section. Perform this 

calibration after you change any part of the flow configuration upstream or downstream 

of the flow meter that may affect the flow-meter calibration. Perform this calibration 

upon initial CVS installation and whenever corrective action does not resolve a failure to 

meet the diluted exhaust flow verification (i.e., propane check) in 40 CFR 1065.341.

(c) Ex-situ CFV and SSV calibration. You may remove a CFV or SSV from its 

permanent position for calibration as long as the flow meter meets the requirements in 40 

CFR 1065.340(c).

(d) Reference flow meter. Calibrate each CVS flow meter using a reference flow meter 

such as a subsonic venturi flow meter, a long-radius ASME/NIST flow nozzle, a smooth 

approach orifice, a laminar flow element, or an ultrasonic flow meter. Use a reference 

flow meter that reports quantities that are NIST-traceable within ±1 % uncertainty. Use 

this reference flow meter’s response to flow as the reference value for CVS flow-meter 

calibration.

(e) Configuration. Calibrate the system with any upstream screens or other restrictions 

that will be used during testing and that could affect the flow ahead of the reference flow 

meter. You may not use any upstream screen or other restriction that could affect the 

flow ahead of the reference flow meter, unless the flow meter has been calibrated with 

such a restriction.

(f) PDP calibration. Calibrate each positive-displacement pump (PDP) to determine a 

flow-versus-PDP speed equation that accounts for flow leakage across sealing surfaces in 

the PDP as a function of PDP inlet pressure. Determine unique equation coefficients for 

each speed at which you operate the PDP. Calibrate a PDP flow meter as follows:
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(1) Connect the system as shown in Figure 1 of this section.

(2) Leaks between the calibration flow meter and the PDP must be less than 0.3 % of the 

total flow at the lowest calibrated flow point; for example, at the highest restriction and 

lowest PDP-speed point. 

(3) While the PDP operates, maintain a constant temperature at the PDP inlet within ±2 

% of the mean absolute inlet temperature, Tin .

(4) Set the PDP speed to the first speed point at which you intend to calibrate.

(5) Set the variable restrictor to its wide-open position.

(6) Operate the PDP for at least 3 min to stabilize the system. Continue operating the 

PDP and record the mean values of at least 30 seconds of sampled data of each of the 

following quantities:

(i) The mean flow rate of the reference flow meter, Qref



. This may include several 

measurements of different quantities, such as reference meter pressures and temperatures, 

for calculating Qref



.

(ii) The mean temperature at the PDP inlet, Tin .

(iii) The mean static absolute pressure at the PDP inlet, in p .

(iv) The mean static absolute pressure at the PDP outlet, out p .

(v) The mean PDP speed, nPDP f .

(7) Incrementally close the restrictor valve to decrease the absolute pressure at the inlet to 

the PDP, in p .

(8) Repeat the steps in paragraphs (f)(6) and (7) of this section to record data at a 

minimum of six restrictor positions ranging from the wide-open restrictor position to the 

minimum expected pressure at the PDP inlet.

(9) Calibrate the PDP by using the collected data and the equations in §1066.625(a).

(10) Repeat the steps in paragraphs (f)(6) through (9) of this section for each speed at 

which you operate the PDP.

(11) Use the equations in §1066.630(a) to determine the PDP flow equation for emission 

testing.

(12) Verify the calibration by performing a CVS verification (i.e., propane check) as 

described in 40 CFR 1065.341.

(13) Ensure that the lowest inlet pressure tested during calibration is at least as low as the 

lowest PDP inlet pressure that will occur during emission testing. You may not use the 

PDP below the lowest inlet pressure tested during calibration.

(g) SSV calibration. Calibrate each subsonic venturi (SSV) to determine its discharge

coefficient, Cd, for the expected range of inlet pressures. Calibrate an SSV flow meter as 

follows:

(1) Configure your calibration system as shown in Figure 1 of this section.

(2) Verify that any leaks between the calibration flow meter and the SSV are less than 0.3 

% of the total flow at the highest restriction.

(3) Start the blower downstream of the SSV.

(4) While the SSV operates, maintain a constant temperature at the SSV inlet within ±2 

% of the mean absolute inlet temperature, Tin .
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(5) Set the variable restrictor or variable-speed blower to a flow rate greater than the 

greatest flow rate expected during testing. You may not extrapolate flow rates beyond 

calibrated values, so we recommend that you make sure the Reynolds number, Re#, at the 

SSV throat at the greatest calibrated flow rate is greater than the maximum Re#expected 

during testing.

(6) Operate the SSV for at least 3 min to stabilize the system. Continue operating the 

SSV and record the mean of at least 30 seconds of sampled data of each of the following 

quantities:

(i) The mean flow rate of the reference flow meter, Qref



. This may include several 

measurements of different quantities for calculating Qref



, such as reference meter 

pressures and temperatures.

(ii) The mean temperature at the venturi inlet, Tin .

(iii) The mean static absolute pressure at the venturi inlet, in p .

(iv) Mean static differential pressure between the static pressure at the venturi inlet and 

the static pressure at the venturi throat, SSV p .

(7) Incrementally close the restrictor valve or decrease the blower speed to decrease the 

flow rate.

(8) Repeat the steps in paragraphs (g)(6) and (7) of this section to record data at a 

minimum of ten flow rates.

(9) Determine an equation to quantify Cd as a function of Re#by using the collected data 

and the equations in §1066.625(b). Section 1066.625 also includes statistical criteria for 

validating the Cd versus Re#equation.

(10) Verify the calibration by performing a CVS verification (i.e., propane check) as 

described in 40 CFR 1065.341 using the new Cd versus Re#equation.

(11) Use the SSV only between the minimum and maximum calibrated flow rates. If you 

want to use the SSV at a higher or lower flow rate, you must recalibrate the SSV.

(12) Use the equations in §1066.630(b) to determine SSV flow during a test.

(h) CFV calibration. The calibration procedure described in this paragraph (h) 

establishes the value of the calibration coefficient, Kv, at measured values of pressure, 

temperature and air flow. Calibrate the CFV at the lowest expected static differential 

pressure between the CFV inlet and outlet. Calibrate the CFV as follows:

(1) Configure your calibration system as shown in Figure 1 of this section.

(2) Verify that any leaks between the calibration flow meter and the CFV are less than 

0.3 % of the total flow at the highest restriction.

(3) Start the blower downstream of the CFV.

(4) While the CFV operates, maintain a constant temperature at the CFV inlet within ±2 

% of the mean absolute inlet temperature, Tin .

(5) Set the variable restrictor to its wide-open position. Instead of a variable restrictor, 

you may alternately vary the pressure downstream of the CFV by varying blower speed 

or by introducing a controlled leak. Note that some blowers have limitations on 

nonloaded conditions.

(6) Operate the CFV for at least 3 min to stabilize the system. Continue operating the 

CFV and record the mean values of at least 30 seconds of sampled data of each of the 

following quantities:
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(i) The mean flow rate of the reference flow meter, Qref



. This may include several 

measurements of different quantities, such as reference meter pressures and temperatures, 

for calculating Qref



.

(ii) The mean temperature at the venturi inlet, Tin .

(iii) The mean static absolute pressure at the venturi inlet, in p .

(iv) The mean static differential pressure between the CFV inlet and the CFV outlet, 

CFV p .

(7) Incrementally close the restrictor valve or decrease the downstream pressure to 

decrease the differential pressure across the CFV, CFV p .

(8) Repeat the steps in paragraphs (h)(6) and (7) of this section to record mean data at a 

minimum of ten restrictor positions, such that you test the fullest practical range of 

CFV p expected during testing. We do not require that you remove calibration 

components or CVS components to calibrate at the lowest possible restriction.

(9) Determine Kv and the lowest allowable pressure ratio, r, according to §1066.625.

(10) Use Kv to determine CFV flow during an emission test. Do not use the CFV below 

the lowest allowed r, as determined in §1066.625.

(11) Verify the calibration by performing a CVS verification (i.e., propane check) as 

described in 40 CFR 1065.341.

(12) If your CVS is configured to operate multiple CFVs in parallel, calibrate your CVS 

using one of the following methods:

(i) Calibrate every combination of CFVs according to this section and §1066.625(c). 

Refer to §1065.652(c) for instructions on calculating flow rates for this option.

(ii) Calibrate each CFV according to this section and §1066.625. Refer to §1066.630 for 

instructions on calculating flow rates for this option.

(i) [Reserved]

(j) Ultrasonic flow meter calibration. [Reserved]
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Figure 1 of 1066.140—CVS calibration configurations

reference

flow meter PDP

variable

restrictor

12

6

ref n

atmos p

in p out p Tin

PDP

f

t

reference

flow meter PDP

variable

restrictor

12

6

ref n

atmos p

in p out p Tin

PDP

f

t

reference

flow meter PDP

variable

restrictor

12

6

ref n

atmos p

in p out p Tin

PDP

f

t

reference SSV

flow meter

ref n

atmos p

in p Tin

Tdew

p

variable speed

blower

reference SSV

flow meter

ref n

atmos p

in p Tin

Tdew

p

variable speed

blower

reference CFV

flow meter

variable

restrictor

ref n

in p Tin

atmos p Tdew

blower

downstream

pressure

control

reference CFV

flow meter

variable

restrictor

ref n

in p Tin

atmos p Tdew

blower

downstream

pressure

control

§1066.145 Test fuel, engine fluids, analytical gases, and other calibration standards.

(a) Test fuel. Use test fuel as specified in the standard-setting part, or as specified in 40 

CFR part 1065, subpart H, if it is not specified in the standard-setting part.
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(b) Lubricating oil. Use lubricating oil as specified in 40 CFR 1065.740. For two-stroke 

engines that involve a specified mixture of fuel and lubricating oil, mix the lubricating oil 

with the fuel according to the manufacturer’s specifications.

(c) Coolant. For liquid-cooled engines, use coolant as specified in 40 CFR 1065.745.

(d) Analytical gases. Use analytical gases that meet the requirements of 40 CFR 

1065.750.

(e) Mass standards. Use mass standards that meet the requirements of 40 CFR 1065.790.

§1066.150 Analyzer interference and quench verification limit.

Analyzers must meet the interference and quench verification limits in the following table 

on the lowest, or most representative, instrument range that will be used during emission 

testing, instead of those specified in 40 CFR part 1065, subpart D:

TABLE 1 OF §1066.150–ANALYZER INTERFERENCE AND QUENCH VERIFICATION LIMITS

Verification Limit

40 CFR 1065.350 ±2 % of full scale

40 CFR 1065.355 ±2 % of full scale

40 CFR 1065.370 ±2 % of full scale

40 CFR 1065.375 ±2 % of the flow-weighted mean concentration of 

N2O expected at the standard

Subpart C—DYNAMOMETER SPECIFICATIONS

§1066.201 Dynamometer overview.

This subpart addresses chassis dynamometers and related equipment.

§1066.210 Dynamometers.

(a) General requirements. A chassis dynamometer typically uses electrically generated 

load forces combined with its rotational inertia to recreate the mechanical inertia and 

frictional forces that a vehicle exerts on road surfaces (known as “road load”). Load 

forces are calculated using vehicle-specific coefficients and response characteristics. The 

load forces are applied to the vehicle tires by rolls connected to motor/absorbers. The 

dynamometer uses a load cell to measure the forces the dynamometer rolls apply to the 

vehicle’s tires.

(b) Accuracy and precision. The dynamometer’s output values for road load must be 

NIST-traceable. We may determine traceability to a specific national or international 

standards organization to be sufficient to demonstrate NIST-traceability. The forcemeasurement system must be capable of indicating force readings as follows:

(1) For dynamometer testing of vehicles at or below 20,000 pounds GVWR, the 

dynamometer force-measurement system must be capable of indicating force readings

during a test to a resolution of ±0.05 % of the maximum load-cell force simulated by the 

dynamometer or ±9.8 N (±2.2 lbf), whichever is greater.

(2) For dynamometer testing of vehicles above 20,000 pounds GVWR, the forcemeasurement system must be capable of indicating force readings during a test to a 

resolution of ±0.05 % of the maximum load-cell force simulated by the dynamometer or 

±39.2 N (±8.8 lbf), whichever is greater.
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(c) Test cycles. The dynamometer must be capable of fully simulating vehicle 

performance over applicable test cycles for the vehicles being tested as referenced in the 

corresponding standard-setting part, including operation at the combination of inertial 

and road-load forces corresponding to maximum road-load conditions and maximum 

simulated inertia at the highest acceleration rate experienced during testing.

(d) Component requirements. The following specifications apply:

(1) The nominal roll diameter must be 120 cm or greater. The dynamometer must have 

an independent drive roll for each drive axle as tested under §1066.410(g), except that 

two drive axles may share a single drive roll. Use good engineering judgment to ensure 

that the dynamometer roll diameter is large enough to provide sufficient tire-roll contact 

area to avoid tire overheating and power losses from tire-roll slippage.

(2) Measure and record force and speed at 10 Hz or faster. You may convert measured 

values to 1-Hz, 2-Hz, or 5-Hz values before your calculations, using good engineering 

judgment.

(3) The load applied by the dynamometer simulates forces acting on the vehicle during 

normal driving according to the following equation:

2 i i-1

i i i

i i-1

v v FR A B v C v M

t t



    



Eq. 1066.210-1

Where:

FR = total road-load force to be applied at the surface of the roll. The total force is the 

sum of the individual tractive forces applied at each roll surface.

i = a counter to indicate a point in time over the driving schedule. For a dynamometer 

operating at 10-Hz intervals over a 600-second driving schedule, the maximum value of i

should be 6,000.

A = a vehicle-specific constant value representing the vehicle’s frictional load in lbf or 

newtons. See subpart D of this part.

B = a vehicle-specific coefficient representing load from drag and rolling resistance, 

which are a function of vehicle speed, in lbf/mph or N∙s/m. See subpart D of this part.

v = linear speed at the roll surfaces as measured by the dynamometer, in mph or m/s. Let 

vi-1 = 0 for i = 0.

C = a vehicle-specific coefficient representing aerodynamic effects, which are a function 

of vehicle speed squared, in lbf/mph2or N∙s

2

/m2. See subpart D of this part.

M = mass of the vehicle in lbm or kg based on its test weight, including the effect of 

rotating axles as specified in §1066.310(b)(7), divided by the acceleration due to gravity

as specified in 40 CFR 1065.630. 

t = elapsed time in the driving schedule as measured by the dynamometer, in seconds. 

Let ti-1 = 0 for i = 0.

(4) We recommend that a dynamometer capable of testing vehicles at or below 20,000 

pounds GVWR be designed to apply an actual road-load force within ±1 % or ±9.8 N 

(±2.2 lbf) of the reference value, whichever is greater. Note that slightly higher errors 

may be expected during highly transient operation for vehicles above 8,500 pounds

GVWR.
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(e) Dynamometer manufacturer instructions. This part specifies that you follow the 

dynamometer manufacturer’s recommended procedures for things such as calibrations 

and general operation. If you perform testing with a dynamometer that you manufactured 

or if you otherwise do not have these recommended procedures, use good engineering 

judgment to establish the additional procedures and specifications we specify in this part, 

unless we specify otherwise. Keep records to describe these recommended procedures 

and how they are consistent with good engineering judgment, including any quantified 

error estimates.

§1066.215 Summary of verification procedures for chassis dynamometers.

(a) Overview. This section describes the overall process for verifying and calibrating the 

performance of chassis dynamometers.

(b) Scope and frequency. The following table summarizes the required and 

recommended calibrations and verifications described in this subpart and indicates when 

they must occur:

TABLE 1 OF §1066.215–SUMMARY OF REQUIRED DYNAMOMETER VERIFICATIONS

Type of verification Minimum frequencya

§1066.220: Linearity verification

Speed: Upon initial installation, within 370 days before testing, and after 

major maintenance.

Torque (load): Upon initial installation and after major maintenance.

§1066.225: Roll runout and diameter 

verification Upon initial installation and after major maintenance.

§1066.230: Time verification Upon initial installation and after major maintenance.

§1066.235: Speed measurement 

verification

Upon initial installation, within 370 days before testing, and after major 

maintenance.

§1066.240: Torque (load) transducer

verification Upon initial installation, within 7 days of testing, and after major maintenance.

§1066.245: Response time 

verification

Upon initial installation, within 370 days before testing, and after major 

maintenance.

§1066.250: Base inertia verification Upon initial installation and after major maintenance.

§1066.255: Parasitic loss verification Upon initial installation, after major maintenance, and upon failure of a

verification in §1066.270 or §1066.275.

§1066.260: Parasitic friction 

compensation verification

Upon initial installation, after major maintenance, and upon failure of a

verification in §1066.270 or §1066.275.

§1066.265: Acceleration and 

deceleration verification Upon initial installation and after major maintenance.

§1066.270: Unloaded coastdown 

verification Upon initial installation, within 7 days of testing, and after major maintenance.

§1066.275 Dynamometer readiness 

verification

Upon initial installation, within 1 day before testing, and after major 

maintenance.

a

Perform calibrations and verifications more frequently, according to measurement system manufacturer instructions 

and good engineering judgment.

(c) Automated dynamometer verifications and calibrations. In some cases, 

dynamometers are designed with internal diagnostic and control features to accomplish 

the verifications and calibrations specified in this subpart. You may use these automated 

functions instead of following the procedures we specify in this subpart to demonstrate 

compliance with applicable requirements, consistent with good engineering judgment. 

(d) Sequence of verifications and calibrations. Upon initial installation and after major 

maintenance, perform the verifications and calibrations in the same sequence as noted in 

Table 1 of this section, except that you may perform speed linearity verification after the 
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verifications in §§1066.225 and 1066.230. At other times, you may need to perform 

specific verifications or calibrations in a certain sequence, as noted in this subpart. If you 

perform major maintenance on a specific component, you are required to perform 

verifications and calibrations only on components or parameters that are affected by the 

maintenance.

(e) Corrections. Unless the regulation directs otherwise, if the dynamometer fails to meet 

any specified calibration or verification, make any necessary adjustments or repairs such 

that the dynamometer meets the specification before running a test. Repairs required to 

meet specifications are generally considered major maintenance under this part.

§1066.220 Linearity verification for chassis dynamometer systems.

(a) Scope and frequency. Perform linearity verification for dynamometer speed and 

torque at least as frequently as indicated in Table 1 of §1066.215. The intent of linearity

verification is to determine that the system responds accurately and proportionally over 

the measurement range of interest. Linearity verification generally consists of 

introducing a series of at least 10 reference values to a measurement system. The 

measurement system quantifies each reference value. The measured values are then 

collectively compared to the reference values by using a least-squares linear regression 

and the linearity criteria specified in Table 1 of this section.

(b) Performance requirements. If a measurement system does not meet the applicable 

linearity criteria in Table 1 of this section, correct the deficiency by re-calibrating, 

servicing, or replacing components as needed. Repeat the linearity verification after 

correcting the deficiency to ensure that the measurement system meets the linearity

criteria. Before you may use a measurement system that does not meet linearity criteria, 

you must demonstrate to us that the deficiency does not adversely affect your ability to 

demonstrate compliance with the applicable standards.

(c) Procedure. Use the following linearity verification protocol, or use good engineering 

judgment to develop a different protocol that satisfies the intent of this section, as 

described in paragraph (a) of this section:

(1) In this paragraph (c), the letter “y” denotes a generic measured quantity, the 

superscript over-bar denotes an arithmetic mean (such as y ), and the subscript “ref” 

denotes the known or reference quantity being measured.

(2) Operate the dynamometer system at the specified operating conditions. This may

include any specified adjustment or periodic calibration of the dynamometer system.

(3) Set dynamometer speed and torque to zero.

(4) Verify the dynamometer speed or torque signal based on the dynamometer 

manufacturer’s recommendations.

(5) After verification, check for zero speed and torque. Use good engineering judgment 

to determine whether or not to rezero or re-verify speed and torque before continuing.

(6) For both speed and torque, use the dynamometer manufacturer’s recommendations 

and good engineering judgment to select reference values, yrefi, that cover a range of 

values that you expect would prevent extrapolation beyond these values during emission 

testing. We recommend selecting zero speed and zero torque as reference values for the 

linearity verification.

(7) Use the dynamometer manufacturer’s recommendations and good engineering 

judgment to select the order in which you will introduce the series of reference values. 
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For example, you may select the reference values randomly to avoid correlation with 

previous measurements and to avoid the influence of hysteresis; you may select reference 

values in ascending or descending order to avoid long settling times of reference signals;

or you may select values to ascend and then descend to incorporate the effects of any 

instrument hysteresis into the linearity verification.

(8) Set the dynamometer to operate at a reference condition.

(9) Allow time for the dynamometer to stabilize while it measures the reference values.

(10) At a recording frequency of at least 1 Hz, measure speed and torque values for 30 

seconds and record the arithmetic mean of the recorded values, i

y . Refer to 40 CFR 

1065.602 for an example of calculating an arithmetic mean.

(11) Repeat the steps in paragraphs (c)(8) though (10) of this section until you measure 

speeds and torques at each of the reference settings.

(12) Use the arithmetic means, i

y , and reference values, yrefi , to calculate least-squares 

linear regression parameters and statistical values to compare to the minimum 

performance criteria specified in Table 1 of this section. Use the calculations described 

in 40 CFR 1065.602. Using good engineering judgment, you may weight the results of 

individual data pairs (i.e., (yrefi, i

y )), in the linear regression calculations. Table 1 

follows:

TABLE 1 OF §1066.220–

DYNAMOMETER MEASUREMENT SYSTEMS THAT REQUIRE LINEARITY VERIFICATIONS

Measurement 

system Quantity Linearity criteria

| ymin∙(a1-1)+a0| a1 SEE r

2

Speed v <0.05 % ∙ max v 0.98-1.02 <2 % ∙ max v >0.990

Torque (load) T <1 % ∙ Tmax 0.99-1.01 <1 % ∙ Tmax >0.990

(d) Reference signals. Generate reference values for the linearity-verification protocol in 

paragraph (c) of this section as described for speed and torque in 40 CFR 1065.307(d). 

§1066.225 Roll runout and diameter verification procedure.

(a) Overview. This section describes the verification procedure for roll runout and roll 

diameter. Roll runout is a measure of the variation in roll radius around the 

circumference of the roll.

(b) Scope and frequency. Perform these verifications upon initial installation and after 

major maintenance that could affect roll surface finish or dimensions (such as resurfacing 

or polishing).

(c) Roll runout procedure. Verify roll runout based on the following procedure, or an 

equivalent procedure based on good engineering judgment:

(1) Perform this verification with laboratory and dynamometer temperatures stable and at 

equilibrium. Release the roll brake and shut off power to the dynamometer. Remove any 

dirt, rubber, rust, and debris from the roll surface. Mark measurement locations on the 

roll surface using a marker. Mark the roll at a minimum of four equally spaced locations 

across the roll width; we recommend taking measurements every 150 mm across the roll. 

Secure the marker to the deck plate adjacent to the roll surface and slowly rotate the roll 
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to mark a clear line around the roll circumference. Repeat this process for all 

measurement locations.

(2) Measure roll runout using an indicator with a probe that allows for measuring the 

position of the roll surface relative to the roll centerline as it turns through a complete 

revolution. The indicator must have some means of being securely mounted adjacent to 

the roll. The indicator must have sufficient range to measure roll runout at all points, 

with a minimum accuracy of ±0.025 mm. Calibrate the indicator according to the 

instrument manufacturer’s instructions.

(3) Position the indicator adjacent to the roll surface at the desired measurement location. 

Position the shaft of the indicator perpendicular to the roll such that the point of the 

indicator is slightly touching the surface of the roll and can move freely through a full 

rotation of the roll. Zero the indicator according to the instrument manufacturer’s 

instructions. Avoid distortion of the runout measurement from the weight of a person 

standing on or near the mounted dial indicator.

(4) Slowly turn the roll through a complete rotation and record the maximum and 

minimum values from the indicator. Calculate runout as the difference between these 

maximum and minimum values. 

(5) Repeat the steps in paragraphs (c)(3) and (4) of this section for all measurement 

locations.

(6) The roll runout must be less than 0.254 mm (0.0100 inches) at all measurement 

locations.

(d) Diameter procedure. Verify roll diameter based on the following procedure, or an 

equivalent procedure based on good engineering judgment: 

(1) Prepare the laboratory and the dynamometer as specified in paragraph (c)(1) of this 

section. 

(2) Measure roll diameter using a Pi Tape®. Orient the Pi Tape®to the marker line at the 

desired measurement location with the Pi Tape®hook pointed outward. Temporarily

secure the Pi Tape®to the roll near the hook end with adhesive tape. Slowly turn the roll, 

wrapping the Pi Tape®around the roll surface. Ensure that the Pi Tape®is flat and 

adjacent to the marker line around the full circumference of the roll. Attach a 2.26-kg 

weight to the hook of the Pi Tape®and position the roll so that the weight dangles freely. 

Remove the adhesive tape without disturbing the orientation or alignment of the Pi 

Tape®.

(3) Overlap the gage member and the vernier scale ends of the Pi Tape®to read the 

diameter measurement to the nearest 0.01 mm. Follow the manufacturer’s 

recommendation to correct the measurement to 20 °C, if applicable. 

(4) Repeat the steps in paragraphs (d)(2) and (3) of this section for all measurement 

locations.

(5) The measured roll diameter must be within ±0.254 mm of the specified nominal value 

at all measurement locations. You may revise the nominal value to meet this 

specification, as long as you use the corrected nominal value for all calculations in this 

subpart.

§1066.230 Time verification procedure.

(a) Overview. This section describes how to verify the accuracy of the dynamometer’s 

timing device.
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(b) Scope and frequency. Perform this verification upon initial installation and after 

major maintenance.

(c) Procedure. Perform this verification using one of the following procedures:

(1) WWV method. You may use the time and frequency signal broadcast by NIST from 

radio station WWV as the time standard if the trigger for the dynamometer timing circuit 

has a frequency decoder circuit, as follows:

(i) Contact station WWV by telephone by dialing (303) 499-7111 and listen for the time 

announcement. Verify that the trigger started the dynamometer timer. Use good 

engineering judgment to minimize error in receiving the time and frequency signal.

(ii) After at least 1000 seconds, re-dial station WWV and listen for the time 

announcement. Verify that the trigger stopped the dynamometer timer.

(iii) Compare the measured elapsed time, yact, to the corresponding time standard, yref, to 

determine the time error, yerror, using the following equation:

act ref

error

ref

100 %

y y

y

y



 

Eq. 1066.230-1

(2) Ramping method. You may use an operator-defined ramp function to serve as the 

time standard as follows:

(i) Set up a signal generator to output a marker voltage at the peak of each ramp to trigger 

the dynamometer timing circuit. Output the designated marker voltage to start the 

verification period.

(ii) After at least 1000 seconds, output the designated marker voltage to end the 

verification period.

(iii) Compare the measured elapsed time between marker signals, yact, to the 

corresponding time standard, yref, to determine the time error, yerror, using Eq. 1066.230-1.

(3) Dynamometer coastdown method. You may use a signal generator to output a known 

speed ramp signal to the dynamometer controller to serve as the time standard as follows:

(i) Generate upper and lower speed values to trigger the start and stop functions of the 

coastdown timer circuit. Use the signal generator to start the verification period. 

(ii) After at least 1000 seconds, use the signal generator to end the verification period. 

(iii) Compare the measured elapsed time between trigger signals, yact, to the 

corresponding time standard, yref, to determine the time error, yerror, using Eq. 1066.230-1.

(d) Performance evaluation. The time error determined in paragraph (c) of this section 

may not exceed ±0.001 %. 

§1066.235 Speed verification procedure.

(a) Overview. This section describes how to verify the accuracy of the dynamometer 

speed determination. When performing this verification, you must also ensure the 

dynamometer speed at any devices used to display or record vehicle speed (such as a 

driver’s aid) is representative of the speed input from the dynamometer speed 

determination.

(b) Scope and frequency. Perform this verification upon initial installation, within 370 

days before testing, and after major maintenance.

(c) Procedure. Use one of the following procedures to verify the accuracy and resolution 

of the dynamometer speed simulation:
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(1) Pulse method. Connect a universal frequency counter to the output of the 

dynamometer’s speed-sensing device in parallel with the signal to the dynamometer 

controller. The universal frequency counter must be calibrated according to the counter 

manufacturer’s instructions and be capable of measuring with enough accuracy to 

perform the procedure as specified in this paragraph (c)(1). Make sure the 

instrumentation does not affect the signal to the dynamometer control circuits. 

Determine the speed error as follows:

(i) Set the dynamometer to speed-control mode. Set the dynamometer speed to a value of 

approximately 4.5 m/s (10 mph); record the output of the frequency counter after 10 

seconds. Determine the roll speed, vact, using the following equation:

roll

act

f d

v

n

 



Eq. 1066.235-1

Where:

f = frequency of the dynamometer speed sensing device, accurate to at least four 

significant figures.

droll = nominal roll diameter, accurate to the nearest 1.0 mm, consistent with 

§1066.225(d).

n = the number of pulses per revolution from the dynamometer roll speed sensor.

Example:

f = 2.9231 Hz = 2.9231 s-1

droll = 904.40 mm = 0.90440 m

n = 1 pulse/rev

act

2.9231 0.90440

1

v

 



vact = 8.3053 m/s

(ii) Repeat the steps in paragraph (c)(1)(i) of this section for the maximum speed 

expected during testing and at least two additional evenly spaced speed points between 

the starting speed and the maximum speed point.

(iii) Compare the calculated roll speed, vact, to each corresponding speed set point, vref, to 

determine values for speed error at each set point, verror, using the following equation:

verror = vact - vref

Eq. 1066.235-2

Example:

vact = 8.3053 m/s

vref = 8.3000 m/s

verror = 8.3053 – 8.3000 = 0.0053 m/s

(2) Frequency method. Install a piece of tape in the shape of an arrowhead on the surface 

of the dynamometer roll near the outer edge. Put a reference mark on the deck plate in 

line with the tape. Install a stroboscope or photo tachometer on the deck plate and direct 

the flash toward the tape on the roll. The stroboscope or photo tachometer must be 
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calibrated according to the instrument manufacturer’s instructions and be capable of 

measuring with enough accuracy to perform the procedure as specified in this paragraph 

(c)(2). Determine the speed error as follows:

(i) Set the dynamometer to speed-control mode. Set the dynamometer speed to a speed 

value of approximately 4.5 m/s (10 mph). Tune the stroboscope or photo tachometer 

until the signal matches the dynamometer roll speed. Record the frequency. Determine 

the roll speed, yact, using Eq. 1066.235-1, using the stroboscope or photo tachometer’s 

frequency for f.

(ii) Repeat the steps in paragraph (c)(2)(i) of this section for the maximum speed 

expected during testing and at least two additional evenly spaced speed points between 

the starting speed and the maximum speed point.

(iii) Compare the calculated roll speed, vact, to each corresponding speed set point, vref, to 

determine values for speed error at each set point, yerror, using Eq. 1066.235-2.

(d) Performance evaluation. The speed error determined in paragraph (c) of this section 

may not exceed ±0.02 m/s at any speed set point. 

§1066.240 Torque transducer verification.

Verify torque-measurement systems by performing the verifications described in 

§§1066.270 and 1066.275.

§1066.245 Response time verification.

(a) Overview. This section describes how to verify the dynamometer’s response time to a 

step change in tractive force.

(b) Scope and frequency. Perform this verification upon initial installation, within 370 

days before testing (i.e., annually), and after major maintenance.

(c) Procedure. Use the dynamometer’s automated process to verify response time. You 

may perform this test either at two different inertia settings corresponding approximately

to the minimum and maximum vehicle weights you expect to test or using base inertia 

and two acceleration rates that cover the range of acceleration rates experienced during 

testing (such as 0.5 and 8 mph/s). Use good engineering judgment to select road-load 

coefficients representing vehicles of the appropriate weight. Determine the 

dynamometer’s settling response time, ts, based on the point at which there are no 

measured results more than 10 % above or below the final equilibrium value, as 

illustrated in Figure 1 of this section. The observed settling response time must be less 

than 100 milliseconds for each inertia setting. 
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Figure 1 of §1066.245—Example of a settling response time diagram

Time (t)

ts

Response

1.1

1.0

0.9

§1066.250 Base inertia verification.

(a) Overview. This section describes how to verify the dynamometer’s base inertia.

(b) Scope and frequency. Perform this verification upon initial installation and after 

major maintenance, such as maintenance that could affect roll inertia. 

(c) Procedure. Verify the base inertia using the following procedure:

(1) Warm up the dynamometer according to the dynamometer manufacturer’s 

instructions. Set the dynamometer’s road-load inertia to zero, turning off any electrical 

simulation of road load and inertia so that the base inertia of the dynamometer is the only

inertia present. Motor the rolls to 5 mph. Apply a constant force to accelerate the roll at 

a nominal rate of 1 mph/s. Measure the elapsed time to accelerate from 10 to 40 mph, 

noting the corresponding speed and time points to the nearest 0.01 mph and 0.01 s. Also 

determine average force over the measurement interval.

(2) Starting from a steady roll speed of 45 mph, apply a constant force to the roll to 

decelerate the roll at a nominal rate of 1 mph/s. Measure the elapsed time to decelerate 

from 40 to 10 mph, noting the corresponding speed and time points to the nearest 0.01 

mph and 0.01 s. Also determine average force over the measurement interval.

(3) Repeat the steps in paragraphs (c)(1) and (2) of this section for a total of five sets of 

results at the nominal acceleration rate and the nominal deceleration rate.

(4) Use good engineering judgment to select two additional acceleration and deceleration 

rate pairs that cover the middle and upper rates expected during testing. Repeat the steps 

in paragraphs (c)(1) through (3) of this section at each of these additional acceleration 

and deceleration rates.

(5) Determine the base inertia, Ib, for each measurement interval using the following 

equation:
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b

final init

F

I

v v

t







Eq. 1066.250-1

Where:

F = average dynamometer force over the measurement interval as measured by the 

dynamometer.

vfinal = roll surface speed at the end of the measurement interval to the nearest 0.01 mph.

vinit = roll surface speed at the start of the measurement interval to the nearest 0.01 mph.

t = elapsed time during the measurement interval to the nearest 0.01 s.

Example:

F = 1.500 lbf = 48.26 ft∙lbm/s2

vfinal = 40.00 mph = 58.67 ft/s

vinit = 10.00 mph = 14.67 ft/s

t = 30.00 s

b

48.26

58.67 14.67

30.00

I 



Ib = 32.90 lbm

(6) Calculate the base inertia error, Iberror, for each of the thirty measured base inertia 

values, Ib, by comparing it to the manufacturer’s stated base inertia, Ibref, using the 

following equation:

bref bact

berror

bref

100 % I I I

I



 

Eq. 1066.250-2

Example:

Ibref = 32.96 lbm

bact I = 32.90 lbm (from paragraph (c)(5) of this section)

berror

32.96 32.90 100 %

32.96

I



 

Iberror = 0.18 %

(7) Determine the base inertia mean value, b

I , from the ten acceleration and deceleration 

interval base inertia values for each of the three acceleration/deceleration rates. Then 

determine the base inertia mean value, b

I , from the base inertia values corresponding to

acceleration/deceleration rates. Calculate base inertia mean values as described in 40 

CFR 1065.602(b)
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(8) Calculate the inertia error for the final base inertia mean value from paragraph (c)(7) 

of this section. Use Eq. 1066.250-2, substituting the final base inertia mean value from 

paragraph (c)(7) of this section for the individual base inertia.

(d) Performance evaluation. The dynamometer must meet the following specifications to 

be used for testing under this part:

(1) All base inertia errors determined under paragraph (c)(6) of this section may not 

exceed ±1.0 %. 

(2) The inertia error for the final base inertia mean value determined under paragraph 

(c)(8) of this section may not exceed ±0.20 %.

§1066.255 Parasitic loss verification.

(a) Overview. Verify the dynamometer’s parasitic loss as described in this section, and 

correct as necessary. This procedure determines the dynamometer’s internal losses that it 

must overcome to simulate road load. Characterize these losses in a parasitic loss curve 

that the dynamometer uses to apply compensating forces to maintain the desired roadload force at the roll surface.

(b) Scope and frequency. Perform this verification upon initial installation, after major 

maintenance, and upon failure of a verification in either §1066.270 or §1066.275. 

(c) Procedure. Perform this verification by following the dynamometer manufacturer’s 

specifications to establish a parasitic loss curve, taking data at fixed speed intervals to 

cover the range of vehicle speeds that will occur during testing. You may zero the load 

cell at a selected speed if that improves your ability to determine the parasitic loss. 

Parasitic loss forces may never be negative. Note that the torque transducers must be 

zeroed and spanned prior to performing this procedure.

(d) Performance evaluation. Some dynamometers automatically update the parasitic loss 

curve for further testing. If this is not the case, compare the new parasitic loss curve to 

the original parasitic loss curve from the dynamometer manufacturer or the most recent 

parasitic loss curve you programmed into the dynamometer. You may reprogram the 

dynamometer to accept the new curve in all cases, and you must reprogram the 

dynamometer if any point on the new curve departs from the earlier curve by more than 

±9.0 N for dynamometers capable of testing vehicles at or below 20,000 pounds GVWR,

or ±36.0 N (±8.0 lbf) for dynamometers not capable of testing vehicles at or below 

20,000 pounds GVWR. 

§1066.260 Parasitic friction compensation evaluation.

(a) Overview. This section describes how to verify the accuracy of the dynamometer’s 

friction compensation.

(b) Scope and frequency. Perform this verification upon initial installation, after major 

maintenance, and upon failure of a verification in either §1066.270 or §1066.275. Note 

that this procedure relies on proper verification of speed and torque, as described in 

§§1066.235 and 1066.240. You must also first verify the dynamometer’s parasitic loss 

curve as specified in §1066.255.

(c) Procedure. Use the following procedure to verify the accuracy of the dynamometer’s 

friction compensation:

(1) Warm up the dynamometer as specified by the dynamometer manufacturer. 
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(2) Perform a torque verification as specified by the dynamometer manufacturer. For 

torque verifications relying on shunt procedures, if the results do not conform to 

specifications, recalibrate the dynamometer using NIST-traceable standards as 

appropriate until the dynamometer passes the torque verification. Do not change the 

dynamometer’s base inertia to pass the torque verification.

(3) Set the dynamometer inertia to the base inertia with the road-load coefficients A, B, 

and C set to 0. Set the dynamometer to speed-control mode with a target speed of 50 

mph or a higher speed recommended by the dynamometer manufacturer. Once the speed 

stabilizes at the target speed, switch the dynamometer from speed-control to torquecontrol and allow the roll to coast for 60 seconds. Record the initial and final speeds and 

the corresponding start and stop times. If friction compensation is executed perfectly, 

there will be no change in speed during the measurement interval.

(4) Calculate the power equivalent of friction compensation error, FCerror, using the 

following equation:

 

2 2

error init final 2

I

FC v v

t

  



Eq. 1066.260-1

Where:

I = dynamometer inertia setting.

t = duration of the measurement interval, accurate to at least 0.01 s.

vinit = the roll speed corresponding to the start of the measurement interval, accurate to at 

least 0.05 mph.

vfinal = the roll speed corresponding to the end of the measurement interval, accurate to at 

least 0.05 mph.

Example:

I = 2000 lbm = 62.16 lbf·s2/ft

t = 60.0 s

vinit = 9.2 mph = 13.5 ft/s

vfinal = 10.0 mph = 14.7 ft/s

 

2 2

error

62.16 13.5 14.7

2 60.00

FC   



FCerror = –16.5 ft∙lbf/s = –0.031 hp

(5) The friction compensation error may not exceed ±0.15 hp for dynamometers capable 

of testing vehicles at or below 20,000 pounds GVWR, or ±0.6 hp for dynamometers not 

capable of testing vehicles at or below 20,000 pounds GVWR. 

§1066.265 Acceleration and deceleration verification.

(a) Overview. This section describes how to verify the dynamometer’s ability to achieve 

targeted acceleration and deceleration rates. Paragraph (c) of this section describes how 

this verification applies when the dynamometer is programmed directly for a specific 

acceleration or deceleration rate. Paragraph (d) of this section describes how this 

verification applies when the dynamometer is programmed with a calculated force to 

achieve a targeted acceleration or deceleration rate.
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(b) Scope and frequency. Perform this verification or an equivalent procedure upon 

initial installation and after major maintenance that could affect acceleration and 

deceleration accuracy. Note that this procedure relies on proper verification of speed as 

described in §1066.235.

(c) Verification of acceleration and deceleration rates. Activate the dynamometer’s 

function generator for measuring roll revolution frequency. If the dynamometer has no 

such function generator, set up a properly calibrated external function generator 

consistent with the verification described in this paragraph (c). Use the function 

generator to determine actual acceleration and deceleration rates as the dynamometer 

traverses speeds between 10 and 40 mph at various nominal acceleration and deceleration 

rates. Verify the dynamometer’s acceleration and deceleration rates as follows:

(1) Set up start and stop frequencies specific to your dynamometer by identifying the rollrevolution frequency, f, in revolutions per second (or Hz) corresponding to 10 mph and 

40 mph vehicle speeds, accurate to at least four significant figures, using the following 

equation:

roll

v n f

d 







Eq. 1066.265-1

Where:

v = the target roll speed, in inches per second (corresponding to drive speeds of 10 mph 

or 40 mph).

n = the number of pulses from the dynamometer’s roll-speed sensor per roll revolution.

droll = roll diameter, in inches.

(2) Program the dynamometer to accelerate the roll at a nominal rate of 1 mph/s from 10 

mph to 40 mph. Measure the elapsed time to reach the target speed, to the nearest 0.01 s. 

Repeat this measurement for a total of five runs. Determine the actual acceleration rate 

for each run, aact, using the following equation:

final init

act

v v

a

t





Eq. 1066.265-2

Where:

aact = acceleration rate (decelerations have negative values).

vfinal = the target value for the final roll speed.

vinit = the setpoint value for the initial roll speed.

t = time to accelerate from vinit to vfinal.

Example:

vfinal = 40 mph

vinit = 10 mph

t = 30.003 s

act

40.00 10.00

30.03

a





aact = 0.999 mph/s
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(3) Program the dynamometer to decelerate the roll at a nominal rate of 1 mph/s from 40 

mph to 10 mph. Measure the elapsed time to reach the target speed, to the nearest 0.01 s. 

Repeat this measurement for a total of five runs. Determine the actual acceleration rate, 

aact, using Eq. 1066.265-2

(4) Repeat the steps in paragraphs (c)(2) and (3) of this section for additional acceleration 

and deceleration rates in 1 mph/s increments up to and including one increment above the 

maximum acceleration rate expected during testing. Average the five repeat runs to 

calculate a mean acceleration rate, act a , at each setting.

(5) Compare each mean acceleration rate, act a , to the corresponding nominal acceleration 

rate, aref, to determine values for acceleration error, aerror, using the following equation:

act ref

error

ref

100 % a aa

a



 

Eq. 1066.265-3

Example:

act a = 0.999 mph/s

aref = 1 mph/s

error

0.999 1

100 %

1

a



 

aerror = –0.100 %

(d) Verification of forces for controlling acceleration and deceleration. Program the 

dynamometer with a calculated force value and determine actual acceleration and 

deceleration rates as the dynamometer traverses speeds between 10 and 40 mph at 

various nominal acceleration and deceleration rates. Verify the dynamometer’s ability to 

achieve certain acceleration and deceleration rates with a given force as follows:

(1) Calculate the force setting, F, using the following equation:

FIa   b

Eq. 1066.265-4

Where:

Ib = the dynamometer manufacturer’s stated base inertia, in lbf·s2/ft.

a = nominal acceleration rate, in ft/s2.

Example:

Ib = 2967 lbm = 92.217 lbf·s2/ft

a = 1 mph/s = 1.4667 ft/s2

F   92.217 1.4667

F = 135.25 lbf

(2) Set the dynamometer to road-load mode and program it with a calculated force to 

accelerate the roll at a nominal rate of 1 mph/s from 10 mph to 40 mph. Measure the 

elapsed time to reach the target speed, to the nearest 0.01 s. Repeat this measurement for 

a total of five runs. Determine the actual acceleration rate, aact, for each run using Eq. 
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1066.265-2. Repeat this step to determine measured “negative acceleration” rates using a 

calculated force to decelerate the roll at a nominal rate of 1 mph/s from 40 mph to 10 

mph. Average the five repeat runs to calculate a mean acceleration rate, act a , at each 

setting.

(3) Repeat the steps in paragraph (d)(2) of this section for additional acceleration and 

deceleration rates as specified in paragraph (c)(4) of this section.

(4) Compare each mean acceleration rate, act a , to the corresponding nominal acceleration 

rate, aref, to determine values for acceleration error, aerror, using Eq. 1066.265-3

(e) Performance evaluation. The acceleration error from paragraphs (c)(5) and (d)(4) of 

this section may not exceed ±1.0 %.

§1066.270 Unloaded coastdown verification.

(a) Overview. Use force measurements to verify the dynamometer’s settings based on 

coastdown procedures.

(b) Scope and frequency. Perform this verification upon initial installation, within 7 days 

of testing, and after major maintenance.

(c) Procedure. This procedure verifies the dynamometer’s settings derived from 

coastdown testing. For dynamometers that have an automated process for this procedure, 

perform this evaluation by setting the initial speed, final speed, inertial coefficients, and 

road-load coefficients as required for each test, using good engineering judgment to 

ensure that these values properly represent in-use operation. Use the following procedure 

if your dynamometer does not perform this verification with an automated process:

(1) Warm up the dynamometer as specified by the dynamometer manufacturer.

(2) With the dynamometer in coastdown mode, set the dynamometer inertia for the 

smallest vehicle weight that you expect to test and set A, B, and C road-load coefficients 

to values typical of those used during testing. Program the dynamometer to coast down 

over the dynamometer operational speed range (typically from a speed of 80 mph through 

a minimum speed at or below 10 mph). Perform at least one coastdown over this speed 

range, collecting data over each 10 mph interval.

(3) Repeat the steps in paragraph (c)(2) of this section with the dynamometer inertia and 

road-load coefficients set for the largest vehicle weight that you expect to test.

(4) Determine the average coastdown force, F, for each speed and inertia setting for each 

of the coastdowns performed using the following equation:

I v init vfinal

F

t

 



Eq. 1066.270-1

Where:

F = the average force measured during the coastdown for each speed interval and inertia 

setting, expressed in lbf·s2/ft and rounded to four significant figures.

I = the dynamometer’s inertia setting, in lbf· s

2

/ft.

vinit = the speed at the start of the coastdown interval, expressed in ft/s to at least four 

significant figures.

vfinal = the speed at the end of the coastdown interval, expressed in ft/s to at least four 

significant figures.

t = coastdown time for each speed interval and inertia setting, accurate to at least 0.01 s.
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Example:

I = 2000 lbm = 65.17 lbf·s2/ft

vinit = 25 mph = 36.66 ft/s

vfinal = 15 mph = 22.0 ft/s

t = 5.00 s

65.17 36.66 22.0

5.00

F

 



F = 191.1 lbf

(5) Calculate the target value of coastdown force, Fref, based on the applicable 

dynamometer parameters for each speed interval and inertia setting.

(6) Compare the mean value of the coastdown force measured for each speed interval and 

inertia setting, Fact , to the corresponding Fref to determine values for coastdown force 

error, Ferror, using the following equation:

act ref

error

ref

100 % F F F

F



 

Eq. 1066.270-2

Example:

Fref = 192 lbf

F act = 191 lbf

error

191 192 100 %

192

F



 

Ferror = 0.5 %

(d) Performance evaluation. The coastdown force error determined in paragraph (c) of 

this section may not exceed the following:

(1) For vehicles at or below 20,000 pounds GVWR, calculate Ferrormax for all speed and 

inertia settings from the following formula:

Ferrormax (%) = (2.2 lbf/Fref)·100

Eq. 1066.270-3

Example:

Fref = 192 lbf

Ferrormax (%) = (2.2/192)·100 = 1.14%

(2) For vehicles above 20,000 pounds GVWR, the maximum allowable error, Ferrormax, for 

all speed intervals and inertia settings is ±1.0 % or ±39.2 N, whichever is greater.

(e) If the dynamometer is not able to meet this requirement, diagnose and repair the 

dynamometer before continuing with emission testing. Diagnosis should include 

performing the verifications in §1066.255 and §1066.260.

§1066.275 Daily dynamometer readiness verification.
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(a) Overview. This section describes how to verify that the dynamometer is ready for 

emission testing.

(b) Scope and frequency. Perform this verification upon initial installation, within 1 day

before testing, and after major maintenance.

(c) Procedure. For dynamometers that have an automated process for this verification 

procedure, perform this evaluation by setting the initial speed and final speed and the 

inertial and road-load coefficients as required for the test, using good engineering 

judgment to ensure that these values properly represent in-use operation. Use the 

following procedure if your dynamometer does not perform this verification with an 

automated process:

(1) With the dynamometer in coastdown mode, set the dynamometer inertia to the base 

inertia with the road-load coefficient A set to 20 lbf (or a force that results in a coastdown 

time of less than 10 minutes) and coefficients B and C set to 0. Program the 

dynamometer to coast down for one 10 mph interval from 55 mph down to 45 mph. If 

your dynamometer is not capable of performing one discrete coastdown, then coast down 

with preset 10 mph intervals that include a 55 mph to 45 mph interval.

(2) Perform the coastdown.

(3) Determine the coastdown force and coastdown force error using Eqs. 1066.270-1 and 

1066.270-2.

(d) Performance evaluation. The coastdown force error determined in paragraph (c) of 

this section may not exceed the following:

(1) For vehicles at or below 20,000 pounds GVWR, ±1.0 % or ±9.8 N (±2.2 lbf), 

whichever is greater. 

(2) For vehicles above 20,000 pounds GVWR, ±1.0 % or ±39.2 N (±8.8 lbf), whichever 

is greater.

(e) If the verification results fail to meet the performance criteria in paragraph (d) of this 

section, perform the procedure up to two additional times. If the dynamometer is 

consistently unable to meet the performance criteria, diagnose and repair the 

dynamometer before continuing with emission testing. Diagnosis should include 

performing the verifications in §1066.255 and §1066.260.

§1066.290 Verification of speed accuracy for the driver’s aid.

Use good engineering judgment to provide a driver’s aid that facilitates compliance with 

the requirements of §1066.425. Verify the speed accuracy of the driver’s aid as described 

in §1066.235. 

Subpart D—COASTDOWN

§1066.301 Overview of coastdown procedures.

(a) The coastdown procedures described in this subpart are used to determine the load 

coefficients (A, B, and C) for the simulated road-load equation in §1066.210(d)(3).

(b) The general procedure for performing coastdown tests and calculating load 

coefficients is described in SAE J1263 and SAE J2263 (incorporated by reference in 

§1066.1010). This subpart specifies certain deviations from those procedures for certain 

applications.
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(c) Use good engineering judgment for all aspects of coastdown testing. For example, 

minimize the effects of grade by performing coastdown testing on reasonably level 

surfaces and determining coefficients based on average values from vehicle operation in 

opposite directions over the course.

§1066.305 Coastdown procedures for motor vehicles at or below 14,000 pounds 

GVWR.

For motor vehicles at or below 14,000 pounds GVWR, develop representative road-load 

coefficients to characterize each test vehicle. Calculate road-load coefficients by

performing coastdowns using the provisions of SAE J1263 and SAE J2263 (incorporated 

by reference in §1066.1010). Perform coastdowns at a starting speed as specified in SAE 

J2263, or at the highest speed from the range of applicable duty cycles. Use the same 

road-load coefficients for all duty cycles. However, if your test conditions are 

substantially different from the conditions represented by your road-load coefficients, 

such as cold temperature testing, you may use good engineering judgment to develop 

separate road-load coefficients.

§1066.310 Coastdown procedures for vehicles above 14,000 pounds GVWR.

This section describes coastdown procedures that are unique to vehicles above 14,000 

pounds GVWR. These procedures are valid for calculating road-load coefficients for 

chassis and post-transmission powerpack testing and for calculating drag area (CDA) for 

use in the GEM simulation tool under 40 CFR part 1037.

(a) Determine road-load coefficients by performing a minimum of 16 valid coastdown 

runs (8 in each direction). 

(b) Follow the provisions of Sections 1 through 9 of SAE J1263 and SAE J2263 

(incorporated by reference in §1066.1010), except as described in this paragraph (b). The 

terms and variables identified in this paragraph (b) have the meaning given in SAE J1263 

or J2263 unless specified otherwise.

(1) The test condition specifications of SAE J1263 apply except as follows for wind and 

road conditions:

(i) We recommend that you do not perform coastdown testing on days for which winds 

are forecast to exceed 6.0 mph.

(ii) The grade of the test track or road must not be excessive (considering factors such as 

road safety standards and effects on the coastdown results). Road conditions should 

follow Section 7.4 of SAE J1263, except that road grade may exceed 0.5%. If road grade 

is greater than 0.02% over the length of the test surface, you must incorporate into the 

analysis road grade as a function of distance along the length of the test surface. Use 

Section 11.5 of SAE J2263 to calculate the force due to grade.

(2) Operate the vehicle at a top speed above 70 mph, or at its maximum achievable speed 

if it cannot reach 70 mph. If a vehicle is equipped with a vehicle speed limiter that is set 

for a maximum speed below 70 mph, you must disable the vehicle speed limiter. Start 

the test at or above 70 mph, or at the vehicle’s maximum achievable speed if it cannot 

reach 70 mph. Collect data through a minimum speed at or below 15 mph. Data analysis 

for valid coastdown runs must include the range of vehicle speeds specified in this 

paragraph (b)(2).
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(3) Gather data regarding wind speed and direction, in coordination with time-of-day

data, using at least one stationary electro-mechanical anemometer and suitable data 

loggers meeting the specifications of SAE J1263, as well as the following additional 

specifications for the anemometer placed adjacent to the test surface:

(i) Calibrate the equipment by running the zero-wind and zero-angle calibrations within 

24 hours before conducting the coastdown procedures. If the coastdown procedures are 

not complete 24 hours after calibrating the equipment, repeat the calibration for another 

24 hours of data collection.

(ii) Record the location of the anemometer using a GPS measurement device adjacent to 

the test surface (approximately) at the midway distance along the test surface used for 

coastdowns.

(iii) Position the anemometer such that it will be at least 2.5 but not more than 3.0 vehicle 

widths from the test vehicle’s centerline as the test vehicle passes the anemometer.

(iv) Mount the anemometer at a height that is within 6 inches of half the test vehicle’s 

maximum height.

(v) Place the anemometer at least 50 feet from the nearest tree and at least 25 feet from 

the nearest bush (or equivalent roadside features).

(vi) The height of the grass surrounding the stationary anemometer may not exceed 10% 

of the anemometer’s mounted height, within a radius equal to the anemometer’s mounted 

height.

(4) You may split runs as per Section 9.3.1 of SAE J2263, but we recommend whole 

runs. If you split a run, analyze each portion separately, but count the split runs as one 

run with respect to the minimum number of runs required.

(5) You may perform consecutive runs in a single direction, followed by consecutive runs 

in the opposite direction, consistent with good engineering judgment. Harmonize starting 

and stopping points to the extent practicable to allow runs to be paired.

(6) All valid coastdown run times in each direction must be within 2.0 standard 

deviations of the mean of the valid coastdown run times (from the specified maximum 

speed down to 15 mph) in that direction. Eliminate runs outside this range. After 

eliminating these runs you must have at least eight valid runs in each direction. You may

use coastdown run times that do not meet these standard deviation requirements if we 

approve it in advance. In your request, describe why the vehicle is not able to meet the 

specified standard deviation requirements and propose an alternative set of requirements.

(7) Analyze data for chassis and post-transmission powerpack testing or for use in the 

GEM simulation tool as follows:

(i) Follow the procedures specified in Section 10 of SAE J1263 or Section 11 of SAE 

J2263 to calculate coefficients for chassis and post-transmission powerpack testing.

(ii) Determine drag area, CDA, as follows instead of using the procedure specified in 

Section 10 of SAE J1263:

(A) Measure vehicle speed at fixed intervals over the coastdown run (generally at 10 Hz), 

including speeds at or above 15 mph and at or below the specified maximum speed. 

Establish the elevation corresponding to each interval as described in SAE J2263 if you 

need to incorporate the effects of road grade.

(B) Calculate the vehicle’s effective mass, Me, in kg by adding 56.7 kg to the measured 

vehicle mass for each tire making road contact. This accounts for the rotational inertia of 

the wheels and tires.
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(C) Calculate the road-load force for each measurement interval, Fi, using the following 

equation:

i i 1

i e

v v F M

t

    



Eq. 1066.310-1

Where:

i = an interval counter, starting with i=1 for the first interval. The designation (i-1) 

corresponds to the end of the previous interval or, for the first interval, to the start of the 

test run.

Me = the vehicle’s effective mass, expressed to at least the nearest 0.1 kg. 

v = vehicle speed at the beginning and end of the measurement interval.

Δt = elapsed time over the measurement interval, in seconds.

(D) Plot the data from all the coastdown runs on a single plot of Fi vs. vi

2

to determine the 

slope correlation, D, based on the following equation:

2

i e m i

h

F M g A D v

s



     



Eq. 1066.310-2

Where:

g = gravitational acceleration = 9.81 m/s2.

Δh = change in elevation over the measurement interval, in m. Assume Δh = 0 if you are 

not correcting for grade. 

Δs = distance the vehicle travels down the road during the measurement interval, in m.

Am = the calculated value of the y-intercept based on the curve-fit.

(E) Calculate drag area, CDA, in m2using the following equation:

adj

D

2 D

C A







Eq. 1066.310-3

Where:

ρ = air density at reference conditions = 1.17 kg/m3.

adj

act

98.21

293

T

D D

p

   

          

Eq. 1066.310-4

T = mean ambient absolute temperature during testing, in K.

act p = average ambient pressuring during the test, in kPa.

(8) Determine the A, B, and C coefficients identified in §1066.210 as follows:

(i) For chassis and post-transmission powerpack testing, follow the procedures specified 

in Section 10 of SAE J1263 or Section 12 of SAE J2263.

(ii) For the GEM simulation tool, use the following values:

A = Am

B = 0

C = Dadj
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§1066.315 Dynamometer road-load setting.

Determine dynamometer road-load settings for chassis testing by following SAE J2264 

(incorporated by reference in §1066.1010).

Subpart E— PREPARING VEHICLES AND RUNNING AN EXHAUST 

EMISSION TEST

§1066.401 Overview.

(a) Use the procedures detailed in this subpart to measure vehicle emissions over a 

specified drive schedule. Different procedures may apply for criteria pollutants and 

greenhouse gas emissions as described in the standard-setting part. This subpart 

describes how to-

(1) Determine road-load power, test weight, and inertia class.

(2) Prepare the vehicle, equipment, and measurement instruments for an emission test.

(3) Perform pre-test procedures to verify proper operation of certain equipment and 

analyzers and to prepare them for testing.

(4) Record pre-test data.

(5) Sample emissions.

(6) Record post-test data.

(7) Perform post-test procedures to verify proper operation of certain equipment and 

analyzers.

(8) Weigh PM samples.

(b) The overall test generally consists of prescribed sequences of fueling, parking, and 

driving at specified test conditions. An exhaust emission test generally consists of 

measuring emissions and other parameters while a vehicle follows the drive schedules

specified in the standard-setting part. There are two general types of test cycles:

(1) Transient cycles. Transient test cycles are typically specified in the standard-setting 

part as a second-by-second sequence of vehicle speed commands. Operate a vehicle over 

a transient cycle such that the speed follows the target values. Proportionally sample 

emissions and other parameters and calculate emission rates as specified in subpart G of 

this part to calculate emissions. The standard-setting part may specify three types of 

transient testing based on the approach to starting the measurement, as follows:

(i) A cold-start transient cycle where you start to measure emissions just before starting 

an engine that has not been warmed up.

(ii) A hot-start transient cycle where you start to measure emissions just before starting a 

warmed-up engine.

(iii) A hot-running transient cycle where you start to measure emissions after an engine is 

started, warmed up, and running.

(2) Cruise cycles. Cruise test cycles are typically specified in the standard-setting part as 

a discrete operating point that has a single speed command.

(i) Start a cruise cycle as a hot-running test, where you start to measure emissions after 

the engine is started and warmed up and the vehicle is running at the target test speed.

(ii) Sample emissions and other parameters for the cruise cycle in the same manner as a 

transient cycle, with the exception that the reference speed value is constant. Record 

instantaneous and mean speed values over the cycle.
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§1066.405 Vehicle preparation and preconditioning.

Prepare the vehicle for testing (including measurement of evaporative and refueling 

emissions if appropriate), as described in the standard-setting part.

§1066.410 Dynamometer test procedure.

(a) Dynamometer testing may consist of multiple drive cycles with both cold-start and 

hot-start portions, including prescribed soak times before each test interval. The 

standard-setting part identifies the driving schedules and the associated sample intervals,

soak periods, engine startup and shutdown procedures, and operation of accessories, as 

applicable. Not every test interval includes all these elements.

(b) Place the vehicle onto the dynamometer without starting the engine (for cold-start test 

cycles) or drive the vehicle onto the dynamometer (for hot-start and hot-running cycles 

only) and position a fan that directs cooling air to the vehicle during dynamometer 

operation as described in this paragraph (b). This generally requires squarely positioning 

the fan in front of the vehicle and directing the airflow to the vehicle’s radiator. Use 

good engineering judgment to design and configure fans to cool the test vehicle in a way

that properly simulates in-use operation, consistent with the specifications of §1066.105.

Except for the following special cases, use a road-speed modulated fan meeting the 

requirements of §1066.105(c)(2) that is placed within 90 cm of the front of the vehicle 

and ensure that the engine compartment cover (i.e., hood) is closed:

(1) For vehicles above 14,000 pounds GVWR, use a fan meeting the requirements of 

§1066.105(d) that is placed within 90 cm of the front of the vehicle and ensure that the 

engine compartment cover is closed.

(2) For FTP, LA-92, US06, or HFET testing of vehicles at or below 14,000 pounds 

GVWR, you may use a fixed-speed fan as specified in the following table, with the 

engine compartment cover open:

TABLE 1 OF §1066.410–FIXED-SPEED FAN CAPACITY AND

POSITION SPECIFICATIONS FOR VEHICLES AT OR BELOW 14,000 POUNDS GVWR

Test cycle Maximum fan capacity Approximate distance from the 

front of the vehicle

FTP Up to 2.50 m

3

/s 0 to 30 cm

US06 Up to 7.10 m

3

/s 0 to 60 cm

LA-92 Up to 7.10 m

3

/s 0 to 60 cm

HFET Up to 2.50 m

3

/s 0 to 30 cm

(3) For SC03 and AC17 testing, use a road-speed modulated fan meeting the 

requirements of §1066.105(c)(5) that is placed within 60 to 90 cm of the front of the 

vehicle and ensure that the engine compartment cover is closed. Position the discharge 

nozzle such that its lowest point is not more than 16 cm above the floor of the test cell.

(c) Record the vehicle’s speed trace based on the time and speed data from the 

dynamometer at the recording frequencies given in Table 1 of §1066.125. Record speed 

to at least the nearest 0.01 mph and time to at least the nearest 0.1 s.

(d) You may perform practice runs for operating the vehicle and the dynamometer 

controls to meet the driving tolerances specified in §1066.425 or adjust the emission 
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sampling equipment. Verify that the accelerator pedal allows for enough control to 

closely follow the prescribed driving schedule. We recommend that you verify your 

ability to meet the minimum dilution factor requirements of §1066.110(b)(2)(iii)(B) 

during these practice runs.

(e) Inflate tires on drive wheels according to the vehicle manufacturer’s specifications. 

The tire pressure for drive wheels must be the same for dynamometer operation and for

dynamometer coastdown procedures used for determining road-load coefficients. Report 

these measured tire pressure values with the test results. 

(f) Tie down or load the test vehicle as needed to provide a normal force at the tire and 

dynamometer roll interface to prevent wheel slip. For vehicles above 14,000 pounds 

GVWR, report this measured force with the test results.

(g) Use good engineering judgment when testing vehicles in four-wheel drive or allwheel drive mode. (For purposes of this paragraph (g), the term four-wheel drive 

includes other multiple drive-axle configurations.) This may involve testing on a 

dynamometer with a separate dynamometer roll for each drive axle; or two drive axles 

may use a single roll, as described in §1066.210(d)(1); or you may deactivate the second 

set of drive wheels and operate the vehicle on a single roll. For all vehicles at or below 

14,000 GVWR, we will test your vehicle using the same dynamometer roll arrangement

that you used. We may also test your vehicle using another dynamometer roll 

arrangement for information-gathering purposes. If we choose to perform additional 

testing that requires vehicle modifications, we will ask you to configure the vehicle 

appropriately.

(h) Determine test weight as follows:

(1) For vehicles at or below 14,000 pounds GVWR, determine ETW as described in 

§1066.805. Set dynamometer vehicle inertia, I, based on dynamometer type, as follows: 

(i) For two-wheel drive dynamometers, set I = ETW.

(ii) For four-wheel drive dynamometers, set I = 0.985∙ETW.

(2) For vehicles above 14,000 pounds GVWR, determine the vehicle’s effective mass as 

described in §1066.310 and use this as the test weight.

(i) Warm up the dynamometer as recommended by the dynamometer manufacturer.

(j) Following the test, determine the actual driving distance by counting the number of 

dynamometer roll or shaft revolutions, or by integrating speed over the course of testing 

from a high-resolution encoder system.

§1066.415 Vehicle operation.

This section describes how to test a conventionally configured vehicle (vehicles with 

transmission shifters, foot pedal accelerators, etc). You may ask us to modify these

procedures for vehicles that do not have these control features. 

(a) Start the vehicle as follows:

(1) At the beginning of the test cycle, start the vehicle according to the procedure 

described in the owners manual. In the case of HEVs, this would generally involve 

activating vehicle systems such that the engine will start when the vehicle’s control 

algorithms determine that the engine should provide power instead of or in addition to 

power from the rechargeable energy storage system (RESS). Unless we specify

otherwise, engine starting throughout this part generally refers to this step of activating 

the system on HEVs, whether or not that causes the engine to start running.
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(2) Place the transmission in gear as described by the test cycle in the standard-setting 

part. During idle operation, apply the brakes if necessary to keep the drive wheels from 

turning.

(b) If the vehicle does not start after your recommended maximum cranking time, wait 

and restart cranking according to your recommended practice. If you do not recommend 

such a cranking procedure, stop cranking after 10 seconds, wait for 10 seconds, then start 

cranking again for up to 10 seconds. You may repeat this for up to three start attempts.

If the vehicle does not start after three attempts, you must determine and record the

reason for failure to start. Shut off sampling systems and either turn the CVS off or 

disconnect the laboratory exhaust tubing from the tailpipe during the diagnostic period to 

prevent flow through the exhaust system. Reschedule the vehicle for testing. This may

require performing vehicle preparation and preconditioning if the testing needs to be 

rerun from a cold start. If failure to start occurs during a hot-start test, you may 

reschedule the hot-start test without repeating the cold-start test, as long as you bring the 

vehicle to a hot-start condition before starting the hot-start test.

(c) Repeat the recommended starting procedure if the engine has a false start (i.e., an 

incomplete start).

(d) Take the following steps if the engine stalls:

(1) If the engine stalls during an idle period, restart the engine immediately and continue 

the test. If you cannot restart the engine soon enough to allow the vehicle to follow the 

next acceleration, stop the driving schedule indicator and reactivate it when the vehicle 

restarts.

(2) Void the test if the vehicle stalls during vehicle operation. If this happens, remove the 

vehicle from the dynamometer, take corrective action, and reschedule the vehicle for 

testing. Record the reason for the malfunction (if determined) and any corrective action. 

See the standard-setting part for instructions about reporting these malfunctions.

(e) Operate vehicles during testing as follows:

(1) Where we do not give specific instructions, operate the vehicle according to the 

recommendations in the owners manual, unless those recommendations are 

unrepresentative of what may reasonably be expected for in-use operation.

(2) If vehicles have features that preclude dynamometer testing, you may modify these 

features as necessary to allow testing, consistent with good engineering judgment, as long 

as it does not affect your ability to demonstrate that your vehicles comply with the 

applicable standards. Send us written notification describing these changes along with 

supporting rationale.

(3) Operate vehicles during idle as follows:

(i) For vehicles with automatic transmission, operate at idle with the transmission in 

“Drive” with the wheels braked, except that you may shift to “Neutral” for the first idle 

period and for any idle period longer than one minute. If you put the vehicle in “Neutral” 

during an idle, you must shift the vehicle into “Drive” with the wheels braked at least 5 

seconds before the end of the idle period. Note that this does not preclude vehicle 

designs involving engine shutdown during idle.

(ii) For vehicles with manual transmission, operate at idle with the transmission in gear 

with the clutch disengaged, except that you may shift to “Neutral” with the clutch 

engaged for the first idle period and for any idle period longer than one minute. If you 

put the vehicle in “Neutral” during idle, you must shift to first gear with the clutch 
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disengaged at least 5 seconds before the end of the idle period. Note that this does not 

preclude vehicle designs involving engine operation with shutdown during idle.

(4) Operate the vehicle with the appropriate accelerator pedal movement necessary to 

follow the scheduled speeds in the driving schedule. Avoid smoothing speed variations 

and unnecessary movement of the accelerator pedal.

(5) Operate the vehicle smoothly, following representative shift speeds and procedures. 

For manual transmissions, the operator shall release the accelerator pedal during each 

shift and accomplish the shift without delay. If the vehicle cannot accelerate at the 

specified rate, operate it at maximum available power until the vehicle speed reaches the 

value prescribed in the driving schedule.

(6) Decelerate as follows:

(i) For vehicles with automatic transmission, use the brakes or accelerator pedal as 

necessary, without manually changing gears, to maintain the desired speed.

(ii) For vehicles with manual transmission, shift gears in a way that represents reasonable 

shift patterns for in-use operation, considering vehicle speed, engine speed, and any other 

relevant variables. Disengage the clutch when the speed drops below 15 mph, when 

engine roughness is evident, or when good engineering judgment indicates the engine is 

likely to stall. Manufacturers may recommend shift guidance in the owners manual that 

differs from the shift schedule used during testing, as long as both shift schedules are 

described in the application for certification; in this case, we may shift during testing as

described in the owners manual.

§1066.420 Test preparation.

(a) Follow the procedures for PM sample preconditioning and tare weighing as described 

in 40 CFR 1065.590 if you need to measure PM emissions.

(b) For vehicles above 14,000 pounds GVWR with compression-ignition engines, verify

the amount of nonmethane hydrocarbon contamination as described in 40 CFR 

1065.520(g).

(c) Unless the standard-setting part specifies different tolerances, verify at some point 

before the test that ambient conditions are within the tolerances specified in this 

paragraph (c). For purposes of this paragraph (c), “before the test” means any time from 

a point just prior to engine starting (excluding engine restarts) to the point at which 

emission sampling begins.

(1) Ambient temperature must be (20 to 30) °C. See §1066.425(h) for circumstances 

under which ambient temperatures must remain within this range during the test. 

(2) Dilution air conditions must meet the specifications in §1066.110(b)(2). We 

recommend verifying dilution air conditions just before starting each test interval.

(d) Control test cell ambient air humidity as follows:

(1) For vehicles at or below 14,000 pounds GVWR, follow the humidity requirements in

Table 1 of this section, unless the standard-setting part specifies otherwise. When 

complying with humidity requirements in the table, where no tolerance is specified, use 

good engineering judgment to maintain the humidity level near the specified value within 

the limitations of your test facility.

(2) For vehicles above 14,000 pounds GVWR, you may test vehicles at any humidity.
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TABLE 1 OF §1066.420–TEST CELL HUMIDITY REQUIREMENTS

Test cycle

Humidity requirement 

(grains H2O per 

pound dry air)

Tolerance (grains H2O 

per pound dry air)

AC17 69 ± 5 average, 

± 10 instantaneous

FTP1and LA-92 50

HFET 50

SC03 100 ± 5

US06 50

1

FTP humidity requirement does not apply for cold (-7°C), 

intermediate (10 °C), and hot (35 °C) temperature testing.

(e) You may perform a final calibration of proportional-flow control systems, which may

include performing practice runs.

(f) You may perform the following procedure to precondition sampling systems:

(1) Operate the vehicle over the test cycle.

(2) Operate any dilution systems at their expected flow rates. Prevent aqueous 

condensation in the dilution systems as described in 40 CFR 1065.140(c)(6), taking into 

account allowances given in §1066.110(b)(2)(iv). 

(3) Operate any PM sampling systems at their expected flow rates.

(4) Sample PM using any sample media. You may change sample media during 

preconditioning. You must discard preconditioning samples without weighing them.

(5) You may purge any gaseous sampling systems during preconditioning.

(6) You may conduct calibrations or verifications on any idle equipment or analyzers 

during preconditioning.

(g) Take the following steps before emission sampling begins:

(1) For batch sampling, connect clean storage media, such as evacuated bags or tareweighed filters.

(2) Start all measurement instruments according to the instrument manufacturer’s 

instructions and using good engineering judgment.

(3) Start dilution systems, sample pumps, and the data-collection system.

(4) Pre-heat or pre-cool heat exchangers in the sampling system to within their operating 

temperature tolerances for a test.

(5) Allow heated or cooled components such as sample lines, filters, chillers, and pumps 

to stabilize at their operating temperatures.

(6) Adjust the sample flow rates to desired levels using bypass flow, if desired. 

(7) Zero or re-zero any electronic integrating devices before the start of any test interval.

(8) Select gas analyzer ranges. You may not switch the gain of an analyzer’s analog 

operational amplifier(s) during a test. However, you may switch (automatically or 

manually) gas analyzer ranges during a test if such switching changes only the range over 

which the digital resolution of the instrument is applied. For batch analyzers, select 

ranges before final bag analysis.

(9) Zero and span all continuous gas analyzers using gases that meet the specifications of 

40 CFR 1065.750. For FID analyzers, you may account for the carbon number of your 

span gas either during the calibration process or when calculating your final emission 

value. For example, if you use a C3H8 span gas of concentration 200 ppm (mol/mol), 

you may span the FID to respond with a value of 600 ppm (mol/mol) of carbon or 200 
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ppm of propane. However, if your FID response is equivalent to propane, include a 

factor of three to make the final calculated hydrocarbon mass consistent with a molar 

mass of 13.875389. When utilizing an NMC-FID, span the FID analyzer consistent with 

the determination of their respective response factors, RF, and penetration fractions, PF, 

according to 40 CFR 1065.365.

(10) We recommend that you verify gas analyzer responses after zeroing and spanning by

sampling a calibration gas that has a concentration near one-half of the span gas

concentration. Based on the results, use good engineering judgment to decide whether or 

not to re-zero, re-span, or re-calibrate a gas analyzer before starting a test.

(11) If you correct for dilution air background concentrations of associated engine 

exhaust constituents, start sampling and recording background concentrations at the same 

time you start sampling exhaust gases.

(12) Turn on cooling fans immediately before starting the test.

(h) Proceed with the test sequence described in §1066.425.

§1066.425 Performing emission tests.

(a) See the standard-setting part for drive schedules. These are defined by a smooth fit of 

a specified speed vs. time sequence.

(b) The driver must attempt to follow the target schedule as closely as possible, consistent 

with the specifications in paragraph (b) of this section. Instantaneous speeds must stay

within the following tolerances:

(1) The upper limit is 2.0 mph higher than the highest point on the trace within 1.0 s of 

the given point in time.

(2) The lower limit is 2.0 mph lower than the lowest point on the trace within 1.0 s of the 

given time.

(3) The same limits apply for vehicle operation without exhaust measurements, such as 

vehicle preconditioning and warm-up, except that the upper and lower limits for speed 

values are ±4.0 mph. In addition, up to three occurrences of speed variations greater than 

the tolerance are acceptable for vehicle operation in which no exhaust emission standards 

apply, as long as they occur for less than 15 seconds on any occasion and are clearly 

documented as to the time and speed at that point of the driving schedule.

(4) Void the test if you do not maintain speed values as specified in this paragraph (b), 

except as allowed by this paragraph (b)(4). Speed variations (such as may occur during

gear changes or braking spikes) may occur as follows, as long as such variations are 

clearly documented, including the time and speed values and the reason for the deviation:

(i) Speed variations greater than the specified limits are acceptable for up to 2.0 seconds 

on any occasion.

(ii) For vehicles that are not able to maintain acceleration as specified in §1066.415(e)(5), 

do not count the insufficient acceleration as being outside the specified limits.

(5) We may approve an alternate test cycle and cycle-validation criteria for vehicles that 

do not have enough power to follow the specified driving trace. The alternate driving 

specifications must be based on making best efforts to maintain acceleration and speed to 

follow the specified test cycle. We must approve these alternate driving specifications 

before you perform this testing.

(c) Figure 1 and Figure 2 of this section show the range of acceptable speed tolerances for 

typical points during testing. Figure 1 of this section is typical of portions of the speed 
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curve that are increasing or decreasing throughout the 2-second time interval. Figure 2 of 

this section is typical of portions of the speed curve that include a maximum or minimum 

value.

Figure 1 of §1066.425—Example of the allowable ranges for the driver’s trace

Figure 2 of §1066.425—Example of the allowable ranges for the driver’s trace

(d) Start testing as follows:

(1) If a vehicle is already running and warmed up, and starting is not part of the test

cycle, operate the vehicle as follows:

1.0 s

Time

S

p

e

e

d

Allowable 

Range

2.0 mph

2.0 mph

1.0 s

1.0 s

Time

S

p

e

e

d

Allowable 

Range

2.0 mph

2.0 mph

1.0 s
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(i) For transient test cycles, control vehicle speeds to follow a drive schedule consisting 

of a series of idles, accelerations, cruises, and decelerations.

(ii) For cruise test cycles, control the vehicle operation to match the speed of the first 

interval of the test cycle. Follow the instructions in the standard-setting part to determine 

how long to stabilize the vehicle during each interval, how long to sample emissions at 

each interval, and how to transition between intervals.

(2) If engine starting is part of the test cycle, start recording continuous data, turn on any 

electronic integrating devices, and start batch sampling before starting the engine. 

Initiate the driver’s trace when the engine starts.

(e) Perform the following at the end of each test interval, except as specified in standardsetting part:

(1) Shut down the vehicle if it is part of the test cycle or if testing is complete.

(2) Continue to operate all sampling and dilution systems to allow the response times to 

elapse. Then stop all sampling and recording, including background sampling. Finally, 

stop any integrating devices and indicate the end of the duty cycle in the recorded data.

(f) If testing involves engine shutdown followed by another test interval, start a timer for 

the vehicle soak when the engine shuts down. Turn off cooling fans, close the engine 

compartment cover (if applicable), and turn off the CVS or disconnect the exhaust tube 

from the vehicle’s tailpipe(s) unless otherwise instructed in the standard-setting part. If 

testing is complete, disconnect the laboratory exhaust tubing from the vehicle’s

tailpipe(s) and drive the vehicle from the dynamometer.

(g) Take the following steps after emission sampling is complete:

(1) For any proportional batch sample, such as a bag sample or PM sample, verify that 

proportional sampling was maintained according to 40 CFR 1065.545. Void any samples 

that did not maintain proportional sampling according to those specifications.

(2) Place any used PM samples into covered or sealed containers and return them to the 

PM-stabilization environment. Follow the PM sample post-conditioning and total 

weighing procedures in 40 CFR 1065.595. 

(3) As soon as practical after the interval or test cycle is complete, or optionally during 

the soak period if practical, perform the following:

(i) Begin drift check for all continuous gas analyzers as described in paragraph (g)(5) of 

this section and zero and span all batch gas analyzers as soon as practical before any 

batch sample analysis. You may perform this batch analyzer zero and span before the 

end of the test interval.

(ii) Analyze any conventional gaseous batch samples (HC, CH4, CO, NOx, and CO2) no 

later than 30 minutes after a test interval is complete, or during the soak period if 

practical. Analyze background samples no later than 60 minutes after the test interval is 

complete.

(iii) Analyze nonconventional gaseous batch samples (including background), such as 

NMHCE, N2O, or NMOG sampling with ethanol, as soon as practicable using good 

engineering judgment.

(4) If an analyzer operated above 100 % of its range at any time during the test, perform 

the following steps:

(i) For batch sampling, re-analyze the sample using the lowest analyzer range that results 

in a maximum instrument response below 100 %. Report the result from the lowest range 

from which the analyzer operates below 100 % of its range.
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(ii) For continuous sampling, repeat the entire test using the next higher analyzer range. 

If the analyzer again operates above 100 % of its range, repeat the test using the next 

higher range. Continue to repeat the test until the analyzer consistently operates at less 

than 100 % of its range. Keep records of any tests where the analyzer exceeds its range. 

We may consider these results to determine tht the test vehicle exceeded an emission 

standard, consistent with good engineering judgment.

(5) After quantifying exhaust gases, verify drift as follows:

(i) For batch and continuous gas analyzers, record the mean analyzer value after 

stabilizing a zero gas to the analyzer. Stabilization may include time to purge the 

analyzer of any sample gas, plus any additional time to account for analyzer response. 

(ii) Record the mean analyzer value after stabilizing the span gas to the analyzer. 

Stabilization may include time to purge the analyzer of any sample gas, plus any

additional time to account for analyzer response. 

(iii) Use these data to verify that analyzer drift does not exceed 2.0 % of the analyzer full 

scale.

(h) Measure and record ambient pressure. Measure and record ambient temperature 

continuously to verify that it remains within the temperature range specified in 

§1066.420(c)(1) throughout the test. Also measure humidity if required, such as for 

correcting NOx emissions, or meeting the requirements of §1066.420(d).

(i) [Reserved]

(j) For vehicles at or below 14,000 pounds GVWR, determine overall driver accuracy as 

follows:

(1) Compare the following drive-cycle metrics, based on measured vehicle speeds, to a 

reference value based on the target cycle that would have been generated by driving 

exactly to the target trace as described in SAE J2951 (incorporated by reference in 

§1066.1010):

(i) Determine the Energy Economy Rating as described in Section 5.4 of SAE J2951. 

(ii) Determine the Absolute Speed Change Rating as described in Section 5.5 of SAE 

J2951.

(iii) Determine the Inertia Work Rating as described in Section 5.6 of SAE J2951.

(iv) Determine the phase-weighted composite Energy Based Drive Metrics for the criteria 

specified in this paragraph (j)(1) as described in Section 5.7 of SAE J2951.

(2) The standard-setting part may require you to give us 10 Hz data to characterize both 

target and actual values for cycle energy. Calculate target values based on the vehicles 

speeds from the specified test cycle.

Subpart F—ELECTRIC VEHICLES AND HYBRID ELECTRIC VEHICLES

§1066.501 Overview.

Use the following procedures to test EVs and HEVs (including PHEVs):

(a) Correct the results for Net Energy Change of the RESS as follows: 

(1) For all sizes of EVs, follow SAE J1634 (incorporated by reference in §1066.1010). 

(2) For HEVs at or below 14,000 pounds GVWR, follow SAE J1711 (incorporated by 

reference in §1066.1010) except as described in this paragraph (a). Disregard provisions 

of SAE J1711 that differ from this part or the standard-setting part if they are not specific 

to HEVs. Apply the following adjustments and clarifications to SAE J1711:
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(i) If the procedure calls for charge-sustaining operation, start the drive with a State of 

Charge that is appropriate to ensure charge-sustaining operation for the duration of the 

drive. Take steps other than emission measurements to confirm that vehicles are in 

charge-sustaining mode for the duration of the drive.

(ii) We may approve the use of the alternate End-of-Test criterion in Section 3.9.1 of 

SAE J1711 and the Net Energy Change correction in Appendix C of SAE J1711 if the 

specified criterion and correction are insufficient or inappropriate for establishing the 

transition between charge-depleting and charge-sustaining operation.

(iii) Appendix C of SAE J1711 may be used to correct final fuel economy values, CO2

emissions, and carbon-related exhaust emissions, but may not be used to correct 

measured values for criteria pollutant emissions.

(iv) You may test subject to a measurement accuracy of ±0.3 % of full scale in place of 

the measurement accuracy specified in Section 4.2a of SAE J1711.

(3) For HEVs above 14,000 pounds GVWR, follow SAE J2711 (incorporated by 

reference in §1066.1010) for requirements related to charge-sustaining operation.

(4) Use an integration frequency of 1 to 20 Hz for power analyzers to verify compliance 

with current and voltage specifications.

(b) This paragraph (b) applies for vehicles that include an engine-powered generator or 

other auxiliary power unit that provides motive power. For example, this would include a 

vehicle that has a small gasoline engine that generates electricity to charge batteries. 

Unless we approve otherwise, measure emissions for all test cycles when such an engine 

is operating. For each test cycle for which emissions are not measured, you must validate 

that such engines are not operating at any time during the test cycle.

(c) You may stop emission sampling anytime the engine is turned off, consistent with 

good engineering judgment. This is intended to allow for higher concentrations of dilute 

exhaust gases and more accurate measurements. Take steps to account for exhaust 

transport delay in the sampling system, and be sure to integrate over the actual sampling 

duration when determining Vmix.

Subpart G—CALCULATIONS

§1066.601 Overview.

(a) This subpart describes calculations used to determine emission rates. See the 

standard-setting part and the other provisions of this part to determine which equations 

apply for your testing. This subpart describes how to–

(1) Use the signals recorded before, during, and after an emission test to calculate 

distance-specific emissions of each regulated pollutant.

(2) Perform calculations for calibrations and performance checks.

(3) Determine statistical values.

(b) You may use data from multiple systems to calculate test results for a single emission 

test, consistent with good engineering judgment. You may also make multiple 

measurements from a single batch sample, such as multiple weighing of a PM filter or 

multiple readings from a bag sample. Although you may use an average of multiple 

measurements from a single test, you may not use test results from multiple emission 

tests to report emissions. We allow weighted means where appropriate, such as for 

sampling onto a PM filter over the FTP. You may discard statistical outliers, but you 
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must report all results.

§1066.605 Mass-based and molar-based exhaust emission calculations.

(a) Calculate your total mass of emissions over a test cycle as specified in paragraph (c) 

of this section or in 40 CFR part 1065, subpart G, as applicable.

(b) See the standard-setting part for composite emission calculations over multiple test

intervals and the corresponding weighting factors.

(c) Perform the following sequence of preliminary calculations to correct recorded 

concentration measurements before calculating mass emissions in paragraphs (d) and (e) 

of this section:

(1) For vehicles above 14,000 pounds GVWR, correct all THC and CH4 concentrations

for initial contamination as described in 40 CFR 1065.660(a), including continuous 

readings, sample bag readings, and dilution air background readings. This correction is 

optional for vehicles at or below 14,000 pounds GVWR.

(2) Correct all concentrations measured on a “dry” basis to a “wet” basis, including 

dilution air background concentrations.

(3) Calculate all NMHC and CH4 concentrations, including dilution air background 

concentrations, as described in 40 CFR 1065.660.

(4) For vehicles at or below 14,000 pounds GVWR, calculate HC concentrations, 

including dilution air background concentrations, as described in this section, and as 

described in §1066.635 for NMOG. For emission testing of vehicles above 14,000 

pounds GVWR, with fuels that contain 25 % or more oxygenated compounds by volume, 

calculate THCE and NMHC concentrations, including dilution air background 

concentrations, as described in 40 CFR part 1065, subpart I.

(5) Correct NOx emission values for intake-air humidity as described in §1066.615.

(6) Correct all gaseous concentrations for dilution air background as described in 

§1066.610.

(7) Correct all PM filter masses for sample media buoyancy as described in 40 CFR 

1065.690.

(d) Calculate the emission mass of each gaseous pollutant using the following equation:

m V [emission] mix [emission] [emission]      x c

Eq. 1066.605-1

Where:

m[emission] = emission mass over the test interval.

Vmix = total dilute exhaust volume over the test interval, corrected to standard reference 

conditions, and corrected for any volume removed for emission sampling and for any 

volume change from adding secondary dilution air.

ρ[emission] = density of the appropriate chemical species as given in §1066.1005(f).

x[emission] = measured emission concentration in the sample, after dry-to-wet and 

background corrections.

c = 10-2for emission concentrations in %, and 10-6for emission concentrations in ppm.

Example:

Vmix = 170.878 m3(from paragraph (f) of this section) 
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ρNOx = 1913 g/m3

xNOx = 0.9721 ppm

c = 10-6

6

NOx m 170.878 1913 0.9721 10 0.3177 g 

    

(e) Calculation of the emission mass of PM, mPM, is dependent on how many PM filters 

you use, as follows:

(1) Except as specified in paragraphs (e)(2) and (3) of this section, calculate mPM using 

the following equation:

 

mix

PM PMfil PMbkgnd

PMstd sdastd

V

m m m

V V

 

    

  

Eq. 1066.605-2

Where:

mPM = mass of particulate matter emissions over the test interval, as described in 

§1066.815(b)(1), (2), and (3).

Vmix = total dilute exhaust volume over the test interval, corrected to standard reference 

conditions, and corrected for any volume removed for emission sampling and for any 

volume change from adding secondary dilution air.

Vsdastd = total volume of secondary dilution air sampled through the filter over the test 

interval, corrected to standard temperature and pressure.

mPMfil = mass of particulate matter emissions on the filter over the test interval.

mPMbkgnd = mass of particulate matter on the background filter.

Example:

Vmix = 170.878 m

3

(from paragraph (f) of this section)

VPMstd = 0.925 m

3

(from paragraph (f) of this section)

Vsdastd = 0.527 m3(from paragraph (f) of this section)

mPMfil = 0.0000045 g

mPMbkgnd = 0.0000014 g

PM  

170.878 0.0000045 0.0000014 0.00133 g

0.925 0.527

m

 

        

(2) If you sample PM onto a single filter as described in §1066.815(b)(4), calculate mPM

using the following equation:

 

 

 

 

mix

PM PMfil PMbkgnd

ct-PMstd ct-sdastd ht-PMstd ht-sdastd

s-PMstd s-sdastd 0.43 0.57

V

m m m

V V V V

V V

   

  

 

  

 

Eq. 1066.605-3

Where:

mPM = mass of particulate matter emissions over the entire FTP as sampled according to 

§1066.815(b)(4).
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Vmix = total dilute exhaust volume over the test interval, corrected to standard reference 

conditions, and corrected for any volume removed for emission sampling and for any 

volume change from adding secondary dilution air.

V[interval]-PMstd = total volume of dilute exhaust sampled through the filter over the test 

interval (ct = cold transient, s = stabilized, ht = hot transient), corrected to standard 

reference conditions.

V[interval]-sdastd = total volume of secondary dilution air sampled through the filter over the 

test interval (ct = cold transient, s = stabilized, ht = hot transient), corrected to standard 

reference conditions.

mPMfil = mass of particulate matter emissions on the filter over the test interval.

mPMbkgnd = mass of particulate matter on the background filter over the test interval.

Example:

Vmix = 633.691 m

3

Vct-PMstd = 0.925 m

3

Vct-sdastd = 0.527 m

3

Vs-PMstd = 1.967 m

3

Vs-sdastd = 1.121 m

3

Vht-PMstd = 1.122 m

3

Vht-sdastd = 0.639 m

3

mPMfil = 0.0000106 g

mPMbkgnd = 0.0000014 g

 

 

 

PM  

633.691 0.0000106 0.0000014

0.925 0.527 1.122 0.639

1.967 1.121

0.43 0.57

m

   

  

 

  

 

mPM = 0.00222 g

(3) If you sample PM onto a single filter as described in §1066.815(b)(5), calculate mPM

using the following equation:

       

 

mix

PM PMfil PMbkgnd

ct-PMstd ct-sdastd cs-PMstd cs-sdastd ht-PMstd ht-sdastd hs-PMstd hs-sdastd

0.43 0.57

V

m m m

V V V V V V V V

   

  

     



 

Eq. 1066.605-4

Where:

mPM = mass of particulate matter emissions over the entire FTP as sampled according to 

§1066.815(b)(5).

Vmix = total dilute exhaust volume over the test interval, corrected to standard reference 

conditions, and corrected for any volume removed for emission sampling and for any 

volume change from secondary dilution air.
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V[interval]-PMstd = total volume of dilute exhaust sampled through the filter over the test 

interval (ct = cold transient, cs = cold stabilized, ht = hot transient, hs = hot stabilized), 

corrected to standard reference conditions.

V[interval]-sdastd = total volume of secondary dilution air sampled through the filter over the 

test interval (ct = cold transient, cs = cold stabilized, ht = hot transient, hs = hot 

stabilized), corrected to standard reference conditions.

mPMfil = mass of particulate matter emissions on the filter over the test interval.

mPMbkgnd = mass of particulate matter on the background filter over the test interval.

Example:

Vmix = 972.121 m

3

Vct-PMstd = 0.925 m

3

Vct-sdastd = 0.529 m

3

Vcs-PMstd = 1.968 m

3

Vcs-sdastd = 1.123 m

3

Vht-PMstd = 1.122 m

3

Vht-sdastd = 0.641 m

3

Vhs-PMstd = 1.967 m

3

Vhs-sdastd = 1.121 m

3

mPMfil = 0.0000229 g

mPMbkgnd = 0.0000014 g

       

PM  

972.121 0.0000229 0.0000014

0.925 0.529 1.968 1.123 1.122 0.641 1.967 1.121

0.43 0.57

m

   

  

     



 

mPM = 0.00401 g

(f) This paragraph (f) describes how to correct flow and flow rates to standard reference 

conditions and provides an example for determining Vmix based on CVS total flow and 

the removal of sample flow from the dilute exhaust gas. You may use predetermined 

nominal values for removed sample volumes, except for flows used for batch sampling.

(1) Correct flow and flow rates to standard reference conditions as needed using the 

following equation:

[flow]act in std

[flow]std

std in

V p T

V

p T

 





Eq. 1066.605-5

Where:

V[flow]std = total flow volume at the flow meter, corrected to standard reference conditions.

V[flow]act = total flow volume at the flow meter at test conditions.

pin = absolute static pressure at the flow meter inlet, measured directly or calculated as 

the sum of atmospheric pressure plus a differential pressure referenced to atmospheric 

pressure.

Tstd = standard temperature.

pstd = standard pressure.

Tin = temperature of the dilute exhaust sample at the flow meter inlet.
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Example:

VPMact = 1.071 m

3

pin = 101.7 kPa

Tstd = 293.15 K

pstd = 101.325 kPa

Tin = 340.5 K

3

PMstd

1.071 101.7 293.15 0.925 m

101.325 340.5

V

 

 



(2) The following example provides a determination of Vmix based on CVS total flow and 

the removal of sample flow from one dilute exhaust gas analyzer and one PM sampling 

system that is utilizing secondary dilution. Note that your Vmix determination may vary

from Eq. 1066.605-6 based on the number of flows that are removed from your dilute 

exhaust gas and whether your PM sampling system is using secondary dilution. For this 

example, Vmix is governed by the following equation:

V V mix   CVSstd V V gasstd   PMstd Vsdastd

Eq. 1066.605-6

Where:

VCVSstd = total dilute exhaust volume over the test interval at the flow meter, corrected to

standard reference conditions.

Vgasstd = total volume of sample flow through the gaseous emission bench over the test 

interval, corrected to standard reference conditions.

VPMstd = total volume of dilute exhaust sampled through the filter over the test interval , 

corrected to standard reference conditions.

Vsdastd = total volume of secondary dilution air flow sampled through the filter over the 

test interval, corrected to standard reference conditions.

Example:

Using Eq. 1066.605-5

VCVSstd = 170.451 m

3

, where VCVSact = 170.721 m

3

, pin = 101.7 kPa, and Tin = 294.7 K

Using Eq. 1066.605-5

Vgasstd = 0.028 m

3

, where Vgasact = 0.033 m

3

, pin = 101.7 kPa, and Tin = 340.5 K

Using Eq. 1066.605-5

VPMstd = 0.925 m

3

, where VPMact = 1.071 m

3

, pin = 101.7 kPa, and Tin = 340.5 K

Using Eq. 1066.605-5

Vsdastd = 0.527 m3, where Vsdaact = 0.531 m3, pin = 101.7 kPa, and Tin = 296.3 K

Vmix = 170.451 + 0.028 + 0.925 – 0.527 = 170.878 m

3

(g) Calculate total flow volume over a test interval, V[flow], for a CVS or exhaust gas 

sampler as follows: 

(1) Varying versus constant flow rates. The calculation methods depend on 

differentiating varying and constant flow, as follows:

(i) We consider the following to be examples of varying flows that require a continuous 

multiplication of concentration times flow rate: raw exhaust, exhaust diluted with a 

constant flow rate of dilution air, and CVS dilution with a CVS flow meter that does not 

have an upstream heat exchanger or electronic flow control.
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(ii) We consider the following to be examples of constant exhaust flows: CVS diluted 

exhaust with a CVS flow meter that has an upstream heat exchanger, an electronic flow 

control, or both.

(2) Continuous sampling. For continuous sampling, you must frequently record a 

continuously updated flow signal. This recording requirement applies for both varying 

and constant flow rates.

(i) Varying flow rate. If you continuously sample from a varying exhaust flow rate, 

calculate V[flow] using the following equation:

[flow] i

i 1

N

V Q t



    

Eq. 1066.605-7

Where:

∆t = 1/frecord Eq. 1066.605-8

Example:

N = 505

QCVS1

 = 0.276 m3

/s

QCVS2

 = 0.294 m3

/s

frecord = 1 Hz

Using Eq. 1066.605-8,

t = 1/1 = 1 s

CVS CVS505 V Q   (0.276 0.294   ... ) 1



VCVS = 170.721 m3

(ii) Constant flow rate. If you continuously sample from a constant exhaust flow rate, use 

the same calculation described in paragraph (g)(2)(i) of this section or calculate the mean 

flow recorded over the test interval and treat the mean as a batch sample, as described in 

paragraph (g)(3)(ii) of this section. 

(3) Batch sampling. For batch sampling, calculate total flow by integrating a varying flow 

rate or by determining the mean of a constant flow rate, as follows:

(i) Varying flow rate. If you proportionally collect a batch sample from a varying 

exhaust flow rate, integrate the flow rate over the test interval to determine the total flow 

from which you extracted the proportional sample, as described in paragraph (g)(2)(i) of 

this section. 

(ii) Constant flow rate. If you batch sample from a constant exhaust flow rate, extract a 

sample at a proportional or constant flow rate and calculate V[flow] from the flow from 

which you extract the sample by multiplying the mean flow rate by the time of the test 

interval using the following equation: 

V Q [flow]  t



Eq. 1066.605-9

Example:

QCVS

 = 0.338 m

3

/s

t = 505 s 
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CVS V   0.338 505

VCVS = 170.69 m3

§1066.610 Dilution air background correction.

(a) Correct the emissions in a gaseous sample for background using the following 

equation:

[emission] [emission]dexh [emission]bkgnd

1

x x x 1

DF

   

           

Eq. 1066.610-1

Where:

x[emission]dexh = measured emission concentration in dilute exhaust (after dry-to-wet 

correction, if applicable).

x[emission]bkgnd = measured emission concentration in the dilution air (after dry-to-wet 

correction, if applicable).

DF = dilution factor, as determined in paragraph (b) of this section.

Example:

xNOxdexh = 1.08305 ppm

xNOxbkgnd = 0.12456 ppm

DF = 9.14506

NOx

1

1.08305 0.12456 1 0.97211 ppm

9.14506

x

   

         

(b) Except as specified in paragraph (c) of this section, determine the dilution factor, DF, 

over the test interval using the following equation:

Eq. 1066.610-2

Where:

xCO2 = amount of CO2 measured in the sample over the test interval.

xNMHC = amount of C1-equivalent NMHC measured in the sample over the test interval.

xCH4 = amount of CH4 measured in the sample over the test interval.

xCO = amount of CO measured in the sample over the test interval.

 = atomic hydrogen-to-carbon ratio of the test fuel. You may measure  or use default 

values from Table 1 of 40 CFR 1065.655.

 = atomic oxygen-to-carbon ratio of the test fuel. You may measure  or use default 

values from Table 1 of 40 CFR 1065.655.

Example:

xCO2 = 1.456 % = 0.01456

CO2 NMHC CH4 CO

1

1 3.76 1 ( )

2 4 2

DF

x x x x

  



   

                
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xNMHC = 0.84 ppm = 0.00000084

xCH4 = 0.26 ppm = 0.00000026

xCO = 80.4 ppm = 0.0000804

 = 1.92

 = 0.03

 

1

9.14506

1.92 1.92 0.03 1 3.76 1 0.01456 0.00000084 0.00000026 0.0000804

2 4 2

DF      

              

(c) Determine the dilution factor, DF, over the test interval for partial-flow dilution 

sample systems using the following equation:

dexhstd

exhstd

V

DF

V



Eq. 1066.610-3

Where:

Vdexhstd = total dilute exhaust volume sampled over the test interval, corrected to standard 

reference conditions.

Vexhstd = total exhaust volume sampled from the vehicle, corrected to standard reference 

conditions.

Example:

Vdexhstd = 170.9 m3

Vexhstd = 15.9 m3

170.9 11.1

15.4

DF  

(d) Determine the time-weighted dilution factor, DFw, over the duty cycle using the 

following equation:

i

i 1

w

i

i 1 i

1

N

N

t

DF

t

DF













Eq. 1066.610-4

Where:

N = number of test intervals.

i = test interval number

t = duration of the test interval.

DF = dilution factor over the test interval.

Example:

N = 3

DF1 = 14.40

t1 = 505 s

DF2 = 24.48

t2 = 867 s
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DF3 = 17.28

t3 = 505 s

w

505 867 505 18.82

111 505 867 505

14.40 24.48 17.28

DF         

                

§1066.615 NOx intake-air humidity correction.

You may correct NOx emissions for intake-air humidity as described in this section if the 

standard-setting part allows it. See §1066.605(c)(1) for the proper sequence for applying 

the NOx intake-air humidity correction.

(a) For vehicles at or below 14,000 pounds GVWR, apply a correction for vehicles with

reciprocating engines operating over specific test cycles as follows:

(1) Calculate a humidity correction using a time-weighted mean value for ambient 

humidity over the test interval. Calculate absolute ambient humidity, H, using the 

following equation:

 

H2O d

air atmos d

1000 %

%

M p RH H

M p p RH

  



  

Eq. 1066.615-1

Where:

MH2O = molar mass of H2O.

pd = saturated vapor pressure at the ambient dry bulb temperature.

RH = relative humidity of ambient air

Mair = molar mass of air.

patmos = atmospheric pressure.

Example:

MH2O = 18.01528 g/mol

pd = 2.93 kPa

RH = 37.5 %

Mair = 28.96559 g/mol

patmos = 96.71 kPa

 

2

1000 18.01528 2.93 37.5 0.01 7.14741 g H O vapor kg dry air

28.96559 96.71 2.93 37.5 0.01

H

   

 

   

(2) Use the following equation to correct measured concentrations to a reference 

condition of 10.71 grams H2O vapor per kilogram of dry air for the FTP, US06, LA-92, 

SC03, and HFET test cycles:

 

s

NOxdexhcor NOxdexh 1 0.0329 10.71

H

x x

H

 

  

Eq. 1066.615-2

Where:

xNOxdexh = measured dilute NOx emissions.

Hs = humidity scale. Set = 1 for FTP, US06, LA-92, and HFET test cycles. Set = 0.8825 

for the SC03 test cycle.
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H = ambient humidity, as determined in paragraph (a)(1) of this section.

Example:

H = 7.14741 g H2O vapor/kg dry air time weighted over the FTP test cycle

xNOxdexh = 1.21 ppm

 

NOxdexhcor

1

1.21 1.08305 ppm

1 0.0329 7.14741 10.71

x   

  

(b) For vehicles above 14,000 pounds GVWR, apply correction factors as described in 40 

CFR 1065.670.

§1066.620 Removed water correction.

Correct for removed water if water removal occurs upstream of a concentration 

measurement and downstream of a flow meter used to determine mass emissions over a 

test interval. Perform this correction based on the amount of water at the concentration 

measurement and on the amount of water at the flow meter.

§1066.625 Flow meter calibration calculations.

This section describes how to calibrate various flow meters based on mass flow rates. 

Calibrate your flow meter according to 40 CFR 1065.640 instead if you calculate 

emissions based on molar flow rates.

(a) PDP calibration. Perform the following steps to calibrate a PDP flow meter:

(1) Calculate PDP volume pumped per revolution, Vrev, for each restrictor position from 

the mean values determined in §1066.140:

ref in std

rev

nPDP in std

Q T p

V

f p T

 



 



Eq. 1066.625-1

Where:

Qref

 = mean flow rate of the reference flow meter.

Tin = mean temperature at the PDP inlet.

pstd = standard pressure = 101.325 kPa.

nPDP f = mean PDP speed.

in p = mean static absolute pressure at the PDP inlet.

Tstd = standard temperature = 293.15 K.

Example:

Qref

 = 0.1651 m3

/s

Tin = 299.5 K

pstd = 101.325 kPa

nPDP f = 1205.1 r/min = 20.085 r/s

in p = 98.290 kPa
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Tstd = 293.15 K

0.1651 299.5 101.3

20.085 98.290 293.15

Vrev

 



 

Vrev = 0.00866 m3/r

(2) Calculate a PDP slip correction factor, Ks for each restrictor position from the mean 

values determined in §1066.140:

out in

s

nPDP out

1 p p K

f p



 

Eq. 1066.625-2

Where:

nPDP f = mean PDP speed.

out p = mean static absolute pressure at the PDP outlet.

in p = mean static absolute pressure at the PDP inlet.

Example:

nPDP f = 1205.1 r/min = 20.085 r/s

out p = 100.103 kPa

in p = 98.290 kPa

s

1 100.103 98.290

20.085 100.103

K



 

Ks = 0.006700 s/r

(3) Perform a least-squares regression of Vrev, versus Ks, by calculating slope, a1, and 

intercept, a0, as described in 40 CFR 1065.602.

(4) Repeat the procedure in paragraphs (a)(1) through (3) of this section for every speed 

that you run your PDP.

(5) The following example illustrates a range of typical values for different PDP speeds:

TABLE 1 OF §1066.625–

EXAMPLE OF PDP CALIBRATION DATA

nPDP f

(revolution/s)

a1 

(m3/s)

a0 

(m3/revolution)

12.6 0.841 0.056

16.5 0.831 -0.013

20.9 0.809 0.028

23.4 0.788 -0.061

(6) For each speed at which you operate the PDP, use the appropriate regression equation 

from this paragraph (a) to calculate flow rate during emission testing as described in 

§1066.630.

(b) SSV calibration. The equations governing SSV flow assume one-dimensional 

isentropic inviscid flow of an ideal gas, except that the equations can account for 

compressible flow. Paragraph (b)(2)(iv) of this section describes other assumptions that 
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may apply. If good engineering judgment dictates that you account for gas 

compressibility, you may either use an appropriate equation of state to determine values 

of Z as a function of measured pressure and temperature, or you may develop your own 

calibration equations based on good engineering judgment. Note that the equation for the 

flow coefficient, Cf, is based on the ideal gas assumption that the isentropic exponent, , 

is equal to the ratio of specific heats, Cp/Cv. If good engineering judgment dictates using 

a real gas isentropic exponent, you may either use an appropriate equation of state to 

determine values of  as a function of measured pressure and temperature, or you may

develop your own calibration equations based on good engineering judgment.

(1) Calculate volume flow rate, Q, as follows

t in std

d f

std mix in

A R p T Q C C

p Z M R T

  

  

   



Eq. 1066.625-3

Where:

Cd = discharge coefficient, as determined in paragraph (b)(2)(i) of this section.

Cf = flow coefficient, as determined in paragraph (b)(2)(ii) of this section.

At = cross-sectional area at the venturi throat.

R = molar gas constant.

pin = static absolute pressure at the venturi inlet.

Tstd = standard temperature.

pstd = standard pressure.

Z = compressibility factor.

Mmix = molar mass of gas mixture.

Tin = absolute temperature at the venturi inlet.

(2) Perform the following steps to calibrate an SSV flow meter:

(i) Using the data collected in §1066.140, calculate Cd for each flow rate using the 

following equation:

std mix in

d ref

f t in std

p Z M R T

C Q

C A R p T

   

 

   



Eq. 1066.625-4

Where: 

Qref

 = measured volume flow rate from the reference flow meter.

(ii) Use the following equation to calculate Cf for each flow rate:

 

   

1

2

1

2

f

4

2 1

1

r

C

r









 





 

  

 



  

 

Eq. 1066.625-5

Where:

 = isentropic exponent. For an ideal gas, this is the ratio of specific heats of the gas 

mixture, Cp/Cv.

r = pressure ratio, as determined in paragraph (b)(2)(iii) of this section.
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 = ratio of venturi throat diameter to inlet diameter.

(iii) Calculate r using the following equation:

in

1

p

r

p



 

Eq. 1066.625-6

Where:

Δp = differential static pressure, calculated as venturi inlet pressure minus venturi throat 

pressure.

(iv) You may apply any of the following simplifying assumptions or develop other values 

as appropriate for your test configuration, consistent with good engineering judgment:

(A) For raw exhaust, diluted exhaust, and dilution air, you may assume that the gas 

mixture is incompressible and therefore behaves as an ideal gas (Z=1).

(B) For raw exhaust, you may assume =1.385.

(C) For diluted exhaust and dilution air, you may assume =1.399.

(D) For diluted exhaust and dilution air, you may assume Mmix is a function only of the 

amount of water in the dilution air or calibration air, as follows:

  mix 2

air H2O H O H2O M M  1  x M  x

Eq. 1066.625-7

Where:

Mair = 28.96559 g/mol

xH2O = amount of H2O in the dilution air or calibration air, determined as described in 40 

CFR 1065.645.

MH2O = 18.01528 g/mol

Example:

xH2O = 0.0169 mol/mol

M mix   28.96559 1 0   .0169 18.01528  0.0169

Mmix = 28.7805 g/mol

(E) For diluted exhaust and dilution air, you may assume a constant molar mass of the 

mixture, Mmix, for all calibration and all testing if you control the amount of water in 

dilution air and in calibration air, as illustrated in the following table:
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TABLE 2 OF §1066.625–

EXAMPLES OF DILUTION AIR AND CALIBRATION AIR 

DEWPOINTS AT WHICH YOU MAY ASSUME A CONSTANT MMIX

If calibration 

Tdew (C) is...

assume the following 

constant Mmix (g/mol)...

for the following ranges of Tdew

(C) during emission testsa

< 0 28.96559 < 18

0 28.89263 < 21

5 28.86148 < 22

10 28.81911 < 24

15 28.76224 < 26

20 28.68685 -8 to 28

25 28.58806 12 to 31

30 28.46005 23 to 34

aThe specified ranges are valid for all calibration and emission testing over the 

atmospheric pressure range (80.000 to 103.325) kPa.

(v) The following example illustrates the use of the governing equations to calculate Cd

of an SSV flow meter at one reference flow meter value:

Example:

Qref

 = 2.395 m

3

/s

Z = 1

Mmix = 28.7805 g/mol = 0.0287805 kg/mol

R = 8.314472 J/(mol∙K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

Tin = 298.15 K

At = 0.01824 m2

pin = 99.132 kPa = 99132 Pa = 99132 kg/(m∙s2)

 = 1.399

 = 0.8

Δp = 7.653 kPa

2.312 1 0.922

99.132

r   

 

   

1.399 1

1.399

2

1.399

1

2

f

4

2 1.399 0.922 1

1.399 1 0.8 0.922

C





    

  

  

 

Cf = 0.472

d

101325 1 0.0287805 8.314472 298.15 2.395

0.472 0.01824 8.314472 99132 293.15

C

   

 

   

Cd = 0.985

(vi) Calculate the Reynolds number, Re#, for each reference flow rate, Qref



, using the 

throat diameter of the venturi, dt, and the uncorrected air density, . Because the 

dynamic viscosity, μ, is needed to compute Re#, you may use your own fluid viscosity
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model to determine μ for your calibration gas (usually air), using good engineering 

judgment. Alternatively, you may use the Sutherland three-coefficient viscosity model to 

approximate μ, as shown in the following sample calculation for Re#:

# ref

t

4 Q

Re =

d



 

 

 



Eq. 1066.625-8

Where, using the Sutherland three-coefficient viscosity model:

3

2

in 0

0

0 in

T T S

T T S

 

    

           

Eq. 1066.625-9

Where:

0 = Sutherland reference viscosity.

T0 = Sutherland reference temperature.

S = Sutherland constant.

TABLE 3 OF §1065.640–

SUTHERLAND THREE-COEFFICIENT VISCOSITY MODEL PARAMETERS

Gasa μ0 T0 S

Temperature

range within ±2 

% errorb

Pressure 

limitb

kg/(m∙s) K K K kPa

Air 1.716∙10-5273 111 170 to 1900 ≤ 1800

CO2 1.370∙10-5273 222 190 to 1700 ≤ 3600

H2O 1.12∙10-5350 1064 360 to 1500 ≤ 10000 

O2 1.919∙10-5273 139 190 to 2000 ≤ 2500

N2 1.663∙10-5273 107 100 to 1500 ≤ 1600

aUse tabulated parameters only for the pure gases, as listed. Do not combine 

parameters in calculations to calculate viscosities of gas mixtures.

bThe model results are valid only for ambient conditions in the specified ranges.

Example:

μ0 = 1.716∙10-5kg/(m∙s)

T0 = 273 K

S = 111 K

3

2

5 298.15 273 111 1.716 10

273 298.15 111



     

            

μ = 1.838∙10-5kg/(m∙s)

Tin = 298.15 K

dt = 152.4 mm = 0.1524 m

 = 1.1509 kg/m3
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#

5

4 1.1509 2.395

3.14159 0.1524 1.838 10

Re = 

 

  

Re#= 1.2531∙106

(vii) Calculate ρ using the following equation:

in mix

in

p MW

R T









Eq. 1066.625-10

Example:

99132 0.0287805

8.314472 298.15









ρ = 1.1509 kg/m3

(viii) Create an equation for Cd as a function of Re#, using paired values of the two 

quantities. The equation may involve any mathematical expression, including a 

polynomial or a power series. The following equation is an example of a commonly used 

mathematical expression for relating Cd and Re#:

6

d 0 1 #

10 C a a

Re

  

Eq. 1066.625-11

(ix) Perform a least-squares regression analysis to determine the best-fit coefficients for 

the equation and calculate SEE as described in 40 CFR 1065.602.

(x) If the equation meets the criterion of SEE ≤ 0.5 %, you may use the equation for the 

corresponding range of Re#, as described in §1066.652.

(xi) If the equation does not meet the specified statistical criteria, you may use good 

engineering judgment to omit calibration data points; however, you must use at least 

seven calibration data points to demonstrate that you meet the criterion. For example, 

this may involve narrowing the range of flow rates for a better curve fit.

(xii) Take corrective action if the equation does not meet the specified statistical criterion

even after omitting calibration data points. For example, select another mathematical 

expression for the Cd versus Re#equation, check for leaks, or repeat the calibration 

process. If you must repeat the calibration process, we recommend applying tighter 

tolerances to measurements and allowing more time for flows to stabilize.

(xiii) Once you have an equation that meets the specified statistical criterion, you may

use the equation only for the corresponding range of flow rates.

(c) CFV calibration. Some CFV flow meters consist of a single venturi and some consist 

of multiple venturis where different combinations of venturis are used to meter different 

flow rates. For CFV flow meters that consist of multiple venturis, either calibrate each 

venturi independently to determine a separate calibration coefficient, Kv, for each venturi, 

or calibrate each combination of venturis as one venturi by determining Kv for the 

system.

(1) To determine Kv for a single venturi or a combination of venturis, perform the 

following steps:

(i) Calculate an individual Kv for each calibration set point for each restrictor position 

using the following equation:
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refstd in

v

in

Q T

K =

p





Eq. 1066.625-12

Where:

Qrefstd

 = mean flow rate from the reference flow meter, corrected to standard reference 

conditions.

Tin = mean temperature at the venturi inlet.

in p = mean static absolute pressure at the venturi inlet.

(ii) Calculate the mean and standard deviation of all the Kv values (see 40 CFR 

1065.602). Verify choked flow by plotting Kv as a function of in p . Kv will have a 

relatively constant value for choked flow; as vacuum pressure increases, the venturi will 

become unchoked and Kv will decrease. Paragraphs (c)(1)(iii) through (viii) of this 

section describe how to verify your range of choked flow.

(iii) If the standard deviation of all the Kv values is less than or equal to 0.3 % of the 

mean Kv, use the mean Kv in Eq. 1066.630-7, and use the CFV only up to the highest

venturi pressure ratio, r, measured during calibration using the following equation:

CFV

in

1

p

r

p



 

Eq. 1066.625-13

Where:

pCFV = differential static pressure; venturi inlet minus venturi outlet.

(iv) If the standard deviation of all the Kv values exceeds 0.3 % of the mean Kv, omit the 

Kv value corresponding to the data point collected at the highest r measured during 

calibration.

(v) If the number of remaining data points is less than seven, take corrective action by 

checking your calibration data or repeating the calibration process. If you repeat the 

calibration process, we recommend checking for leaks, applying tighter tolerances to 

measurements and allowing more time for flows to stabilize.

(vi) If the number of remaining Kv values is seven or greater, recalculate the mean and 

standard deviation of the remaining Kv values.

(vii) If the standard deviation of the remaining Kv values is less than or equal to 0.3 % of 

the mean of the remaining Kv, use that mean Kv in Eq 1066.630-7, and use the CFV 

values only up to the highest r associated with the remaining Kv.

(viii) If the standard deviation of the remaining Kv still exceeds 0.3 % of the mean of the 

remaining Kv values, repeat the steps in paragraph (c)(1)(iv) through (vii) of this section.

(2) During exhaust emission tests, monitor sonic flow in the CFV by monitoring r. Based 

on the calibration data selected to meet the standard deviation criterion in paragraphs 

(c)(1)(iv) and (vii) of this section, in which Kv is constant, select the data values 

associated with the calibration point with the lowest absolute venturi inlet pressure to 

determine the r limit. Calculate r during the exhaust emission test using Eq. 1066.625-8 
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to demonstrate that the value of r during all emission tests is less than or equal to the r

limit derived from the CFV calibration data.

§1066.630 PDP, SSV, and CFV flow rate calculations.

This section describes the equations for calculating flow rates from various flow meters. 

After you calibrate a flow meter according to §1066.625, use the calculations described 

in this section to calculate flow during an emission test. Calculate flow according to 40 

CFR 1065.642 instead if you calculate emissions based on molar flow rates.

(a) PDP. (1) Based on the speed at which you operate the PDP for a test interval, select 

the corresponding slope, a1, and intercept, a0, as determined in §1066.625(a), to calculate 

PDP flow rate, Q, as follows:

rev std in

nPDP

in std

V T p

Q f

T p

 

 





Eq. 1066.630-1

Where:

fnPDP = pump speed.

Vrev = PDP volume pumped per revolution, as determined in paragraph (a)(2) of this 

section.

Tstd = standard temperature = 293.15 K.

pin = static absolute pressure at the PDP inlet.

Tin = absolute temperature at the PDP inlet.

pstd = standard pressure= 101.325 kPa.

(2) Calculate Vrev using the following equation:

1 out in

rev 0

nPDP out

a p p V a

f p



  

Eq. 1066.630-2

pout = static absolute pressure at the PDP outlet.

Example:

a1 = 50.43 m3/min = 0.8405 m3/s

fnPDP = 755.0 r/min = 12.58 r/s

pout = 99.950 kPa

pin = 98.575 kPa 

a0 = 0.056 m3/r

Tin = 323.5 K

rev

0.8405 99.950 98.575 0.056

12.58 99.950

V



  

Vrev = 0.063 m3/r

0.06383 293.15 98.575 12.58

323.5 101.3

Q

 

 





Q = 0.7079 m

3

/s

(b) SSV. Calculate SSV flow rate, Q, as follows: 
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t in std

d f

std mix in

A R p T Q C C

p Z M R T

  

  

   



Eq. 1066.630-3

Where:

Cd = discharge coefficient, as determined based on the Cd versus Re#equation in 

§1066.625(b)(2)(viii).

Cf = flow coefficient, as determined in §1066.625(b)(2)(ii).

At = venturi throat cross-sectional area.

R = molar gas constant.

pin = static absolute pressure at the venturi inlet.

Tstd = standard temperature.

pstd = standard pressure.

Z = compressibility factor.

Mmix = molar mass of gas mixture.

Tin = absolute temperature at the venturi inlet.

Example: 

Cd = 0.890

Cf = 0.472

At = 0.01824 m2

R = 8.314472 J/(mol∙K) = 8.314472 (m2∙kg)/(s2∙mol∙K)

pin = 98.496 kPa

Tstd = 293.15 K

pstd = 101.325 kPa

Z = 1

Mmix = 28.7789 g/mol = 0.0287789 kg/mol

Tin = 296.85 K

0.01824 8.314472 98.496 293.15 0.89 0.472

101.325 1 0.0287805 8.314472 296.85

Q

  

  

   



Q = 2.155 m3

/s

(c) CFV. If you use multiple venturis and you calibrated each venturi independently to 

determine a separate calibration coefficient, Kv, for each venturi, calculate the individual 

volume flow rates through each venturi and sum all their flow rates to determine CFV 

flow rate, Q. If you use multiple venturis and you calibrated venturis in combination, 

calculate Q using the Kv that was determined for that combination of venturis.

(1) To calculate Qthrough one venturi or a combination of venturis, use the mean Kv you 

determined in §1066.625(c) and calculate the appropriate quantity for Q as follows:

v in

in

K p Q=

T





Eq. 1066.630-7

Where:

Kv = flow meter calibration coefficient.
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Tin = temperature at the venturi inlet.

pin = absolute static pressure at the venturi inlet.

Example: 

Kv = 0.074954 m3∙K0.5/(kPa∙s)

pin = 99.654 kPa

Tin = 353.15 K

0.074954 99.654

353.15

Q







Q = 0.39748 m

3

/s

(2) [Reserved]

§1066.635 NMOG determination.

For vehicles subject to an NMOG standard, determine NMOG as described in paragraph 

(a) of this section. Except as specified in the standard-setting part, you may alternatively 

calculate NMOG results based on measured NMHC emissions as described in paragraphs 

(c) through (f) of this section.

(a) Determine NMOG by independently measuring alcohols and carbonyls as described 

in 40 CFR 1065.805 and 1065.845. Use good engineering judgment to determine which 

alcohols and carbonyls you need to measure. This would typically require you to 

measure all alcohols and carbonyls that you expect to contribute 1% or more of total 

NMOG. Calculate the mass of NMOG in the exhaust, mNMOG, with the following 

equation, using density values specified in §1066.1005(f):

OHCi

NMOG NMHC NMHC OHCi[THC-FID] OHCi

1 1 OHCi

N N

i i

m

m m  RF m

  

     

Eq. 1066.635-1

Where:

mNMHC = the mass of NMHC and all oxygenated hydrocarbons (OHCs) in the exhaust, as 

determined using Eq. 1066.605-1. Calculate NMHC mass based on ρNMHC.

ρNMHC = the effective C1-equivalent density of NMHC as specified in §1066.1005(f).

mOHCi = the mass of oxygenated species i in the exhaust calculated using Eq. 1066.605-1.

ρOCHi = the C1-equivalent density of oxygenated species i.

RFOHCi[THC-FID] = the response factor of a THC-FID to oxygenated species i relative to 

propane on a C1-equivalent basis as determined in 40 CFR 1065.845.

(b) The following example shows how to determine NMOG as described in paragraph (a) 

of this section for (OHC) compounds including ethanol (C2H5OH), methanol (CH3OH), 

acetaldehyde (C2H4O), and formaldehyde (CH2O) as C1-equivalent concentrations:

mNMHC = 0.0125 g

mCH3OH = 0.0002 g

mC2H5OH = 0.0009 g

mCH2O = 0.0001 g

mC2H4O = 0.00005 g

RFCH3OH[THC-FID] = 0.63

RFC2H5OH[THC-FID] = 0.75
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RFCH2O[THC-FID] = 0.00

RFC2H4O[THC-FID] = 0.50

ρNMHC-liq = 576.816 g/m3

ρCH3OH = 1332.02 g/m3

ρC2H5OH = 957.559 g/m3

ρCH2O = 1248.21 g/m3

ρC2H4O = 915.658 g/m3

NMOG

0.0002 0.0009 0.63 0.75

1332.02 957.559 0.0125 576.816

0.0001 0.00005 0.00 0.5

1248.21 915.658

0.0002 0.0009 0.0001 0.00005

m

 

     

   

  

 

  

mNMOG = 0.013273

(c) For ethanol-gasoline blends with less than 25 % ethanol by volume, you may

calculate NMOG from measured NMHC emissions as follows:

(1) For hot-start and hot-running test cycles or intervals other than the FTP, you may

determine NMOG based on the NMHC emission rate using the following equation:

NMOGh NMHCh e e  1.03

Eq. 1066.635-2

Where:

eNMOGh = mass emission rate of NMOG from the hot-running test cycle.

eNMHCh = mass emission rate of NMHC from the hot-running test cycle, calculated using

ρNMHC-liq.

Example:

eNMHCh = 0.025 g/mi

NMOGh e   0.025 1.03  0.026 g/mi

(2) You may determine weighted composite NMOG for FTP testing based on the 

weighted composite NMHC emission rate and the volume percent of ethanol in the fuel 

using the following equation:

e e NMOGcomp   NMHCcomp 1.0302   0.0071 VPEtOH 

Eq. 1066.635-3

Where:

eNMOGcomp = weighted FTP composite mass emission rate of NMOG.

eNMHCcomp = weighted FTP composite mass emission rate of NMHC, calculated using

ρNMHC-liq.

VPEtOH = volume percentage of ethanol in the test fuel. Use good engineering judgment 

to determine this value either as specified in 40 CFR 1065.710 or based on blending 

volumes, taking into account any denaturant.

Example:

eNMHCcomp = 0.025 g/mi

VPEtOH = 10.1 %
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eNMOGcomp   0.025 1.0302   0.0071 10.1  0.0275 g/mi

(3) You may determine NMOG for the transient portion of the FTP cold-start test for use 

in fuel economy and CREE calculations based on the NMHC emission rate for the test 

interval and the volume percent of ethanol in the fuel using the following equation:

e e NMOG-FTPct   NMHC-FTPct 1.0246   0.0079 VPEtOH 

Eq. 1066.635-4

Where:

eNMOG-FTPct = mass emission rate of NMOG from the transient portion of the FTP coldstart test ( generally known as bag 1).

eNMHC-FTPct = mass emission rate of NMHC from the transient portion of the FTP coldstart test (bag 1), calculated using ρNMHC-liq.

Example:

eNMHC-FTPct = 0.052 g/mi

VPEtOH = 10.1 %

eNMOG-FTPct   0.052 1.0246   0.0079 10.1  0.0574 g/mi

(4) You may determine NMOG for the stabilized portion of the FTP test for either the 

cold-start test or the hot-start test (bag 2 or bag 4) for use in fuel economy and CREE 

calculations based on the corresponding NMHC emission rate and the volume percent of 

ethanol in the fuel using the following equation:

e e NMOG-FTPcs-hs   NMHC-FTPcs-hs 1.1135   0.001 VPEtOH 

Eq. 1066.635-5

Where:

eNMOG-FTPcs-hs = mass emission rate of NMOG from the stabilized portion of the FTP test 

(bag 2 or bag 4).

eNMHC-FTPcs-hs = mass emission rate of NMHC from the stabilized portion of the FTP test 

(bag 2 or bag 4), calculated using ρNMHC-liq.

(5) You may determine NMOG for the transient portion of the FTP hot-start test for use 

in fuel economy and CREE calculations based on the NMHC emission rate for the test 

interval and the volume percent of ethanol in the fuel using the following equation:

e e NMOG-FTPht   NMHC-FTPht 1.0195   0.0031 VPEtOH 

Eq. 1066.635-6

Where:

eNMOG-FTPht = mass emission rate of NMOG from the transient portion of the FTP hot-start 

test (bag 3).

eNMHC-FTPht = mass emission rate of NMHC from the transient portion of the FTP hot-start 

test (bag 3), calculated using ρNMHC-liq.

(d) You may take the following alternative steps when determining fuel economy and 

CREE under 40 CFR part 600 for testing with ethanol-gasoline blends that have up to 25 

% ethanol by volume:
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(1) Calculate NMOG by test interval using Eq. 1066.635-3 for individual bag 

measurements from the FTP.

(2) For HEVs, calculate NMOG for two-bag FTPs using Eq. 1066.635-3 as described in 

40 CFR 600.114.

(e) We consider NMOG values for diesel-fueled vehicles, CNG-fueled vehicles, LNGfueled vehicles, and LPG-fueled vehicles to be equivalent to NMHC emission values for 

all test cycles.

(f) For all fuels not covered by paragraphs (c) and (e) of this section, manufacturers may

propose a methodology to calculate NMOG results from measured NMHC emissions. 

We will approve adjustments based on comparative testing that demonstrates how to 

properly represent NMOG based on measured NMHC emissions.

§1066.695 Data requirements.

Record information for each test as follows:

(a) Test number.

(b) A brief description of the test vehicle (or other system/device tested).

(c) Date and time of day for each part of the test sequence.

(d) Test results. Also include a validation of driver accuracy as described in 

§1066.425(j).

(e) Driver and equipment operators.

(f) Vehicle information as applicable, including identification number, model year, 

applicable emission standards(including bin standards or family emission limits, as 

applicable), vehicle model, vehicle class, test group, durability group, engine family, 

evaporative/refueling emission family, basic engine description (including displacement, 

number of cylinders, turbocharger/supercharger used, and catalyst type), fuel system 

(type of fuel injection and fuel tank capacity and location), engine code, GVWR, 

applicable test weight, inertia weight class, actual curb weight at zero miles, actual road 

load at 50 mph, transmission class and configuration, axle ratio, odometer reading, idle 

rpm, and measured drive wheel tire pressure.

(g) Dynamometer identification, inertia weight setting, indicated power absorption 

setting, and records to verify compliance with the driving distance and cycle-validation 

criteria as calculated from measured roll or shaft revolutions.

(h) Analyzer bench identification, analyzer ranges, recordings of analyzer output during 

zero, span, and sample readings.

(i) Associate the following information with the test record: test number, date, vehicle 

identification, vehicle and equipment operators, and identification of the measurements 

recorded.

(j) Test cell barometric pressure and humidity. You may use a central laboratory

barometer if the barometric pressure in each test cell is shown to be within ±0.1 % of the 

barometric pressure at the central barometer location.

(k) Records to verify compliance with the ambient temperature requirements throughout 

the test procedure and records of fuel temperatures during the running loss test.

(l) [Reserved]

(m) For CVS systems, record dilution factor for each test interval and the following 

additional information:

(1) For CFV and SSV testing, Vmix for each interval of the exhaust test.
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(2) For PDP testing, test measurements required to calculate Vmix for each test interval.

(n) The humidity of the dilution air, if you remove H2O from an emission sample before 

measurement.

(o) Temperature of the dilute exhaust mixture and secondary dilution air (in the case of a 

double-dilution system) at the inlet to the respective gas meter or flow instrumentation 

used for PM sampling. Determine minimum values, maximum values, mean values, and 

percent of time outside of the tolerance over each test interval.

(p) The maximum exhaust gas temperature over the course of the test interval within 20 

cm upstream or downstream of PM sample media.

(q) If applicable, the temperatures of the heated FID, the gas in the heated sample line, 

and the heated filter. Determine minimum values, maximum values, average values, and 

percent of time outside of the tolerance over each test interval.

(r) Gas meter or flow measurement instrumentation readings used for batch sampling

over each test interval. Determine minimum, maximum, and average values over each 

test interval.

(s) The stabilized pre-test weight and post-test weight of each particulate sample media 

(e.g., filter).

(t) Continuous temperature and humidity of the ambient air in which the PM sample 

media are stabilized. Determine minimum values, maximum values, average values, and 

percent of time outside of the tolerance over each test interval.

(u) For vehicles fueled by natural gas, the test fuel composition, including all carboncontaining compounds (including CO2, but excluding CO). Record C1 and C2

compounds individually. You may record C3 through C5 hydrocarbons together, and you 

may record C6 and heavier hydrocarbon compounds together.

(v) For vehicles fueled by liquefied petroleum gas, the test fuel composition, including all 

carbon-containing compounds (including CO2, but excluding CO). Record C1 through C4

compounds individually. You may record C5 and heavier hydrocarbons together.

(w) For the AC17 test in §1066.845, interior volume, climate control system type and 

characteristics, refrigerant used, compressor type, and evaporator/condenser 

characteristics.

(x) Additional information related to evaporative emissions. [Reserved]

(y) Additional information related to refueling emissions. [Reserved]

Subpart H—COLD TEMPERATURE TEST PROCEDURES

§1066.701 Applicability and general provisions.

(a) The procedures of this part 1066 may be used for testing at any ambient temperature. 

Section 1066.710 describes the provisions that apply for testing vehicles at a nominal 

temperature of 20 °C (68 °F); these procedures apply for motor vehicles as described in 

40 CFR part 86, subpart S, and 40 CFR part 600. For other vehicles, see the standardsetting part to determine if your vehicle is required to meet emission standards outside the 

normal (20 to 30) °C ((68 to 86) °F) temperature range.

(b) Do not apply the humidity correction factor in §1066.615(a) for cold temperature 

testing.
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§1066.710 Cold temperature testing procedures for measuring CO and NMHC

emissions and determining fuel economy.

This section describes procedures for measuring carbon monoxide (CO) and nonmethane 

hydrocarbon (NMHC) emissions and determining fuel economy on a cold day using the 

FTP test cycle (see §1066.801). The following figure illustrates the test procedure:
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Figure 1 of §1066.710— Cold temperature testing sequence for measuring CO and NMHC emissions and determining fuel economy
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(a) Follow the exhaust emission measurement procedures specified in §§1066.410 

through 1066.425 and §1066.815(d), subject to the following exceptions and additional 

provisions:

(1) Measure and control ambient conditions as specified in paragraph (b) of this section.

(2) Use the vehicle’s heater and defroster as specified in paragraph (c) of this section.

(3) Precondition and stabilize the vehicle as specified in paragraphs (d) and (e) of this 

section. Ensure that there is no precipitation or dew on the vehicle before the emission 

test.

(4) For dynamometers that have independently heated bearings, start the emission test 

within 20 minutes after warming up the dynamometer; for other types of dynamometers, 

start the emission test within 10 minutes after warming up the dynamometer.

(5) Adjust the dynamometer to simulate vehicle operation on the road at −7 °C. Base this

adjustment on the road-load force profile at −7 °C, or on a 10 percent decrease in the 

target coastdown time used for FTP testing.

(6) Analyze samples for NMHC, CO, and CO2. You do not need to analyze samples for 

other pollutants.

(b) Maintain ambient conditions as follows instead of following the specifications in 

subpart E of this part:

(1) Ambient temperature for emission tests. Measure and record ambient temperature in 

the test cell at least once every 60 seconds during the sampling period. The temperature 

must be (−7.0 ±1.7) °C at the start of the test and average temperature must be (−7.0 

±2.8) °C during the test. Instantaneous temperature values may be above −4.0 °C or 

below −9.0 °C, but not for more than 3 minutes at a time during the test.

(2) Ambient temperature for preconditioning. Instantaneous ambient temperature values 

may be above −4.0 °C or below −9.0 °C but not for more than 3 minutes at a time during 

the preconditioning period. At no time may the ambient temperatures be below −12.0 °C

or above −1.0 °C. The average ambient temperature during preconditioning must be 

(−7.0 ±2.8) °C. You may precondition vehicles at temperatures above −7.0 °C or with a 

temperature tolerance greater than that described in this section (or both) if you determine 

that this will not cause NMHC, CO, or CO2 emissions to decrease; if you modify the 

temperature specifications for vehicle preconditioning, adjust the procedures described in 

this section appropriately for your testing.

(3) Ambient humidity. Maintain humidity low enough to prevent condensation on the 

dynamometer rolls during testing.

(c) Heater and defroster. During the test, operate the vehicle’s interior climate control 

system with the heat on and set to primarily defrost the front window. Turn air 

conditioning off. You may not use any supplemental auxiliary heat during this testing. 

You may set the heater to any temperature and fan setting during vehicle preconditioning. 

(1) Manually controlled systems. (i) Prior to the first acceleration, 20 seconds after the 

start of the UDDS, set the climate control as follows (these settings may be initiated prior 

to starting the vehicle if allowed by the vehicle’s climate control system):

(A) Temperature. Set controls to maximum heat.

(B) Fan speed. Set the fan speed to full off or the lowest available speed if a full off 

position is not available.

(C) Airflow direction. Direct airflow to the front window (window defrost mode).

(D) Air source. If independently controllable, set the system to draw in outside air.
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(ii) At the second idle of the test cycle, which occurs 125 seconds after the start of the 

test, set the fan speed to maximum. Complete by 130 seconds after the start of the test.

Leave temperature and air source settings unchanged

(iii) At the sixth idle of the test interval, which occurs at the deceleration to zero miles per 

hour 505 seconds after the start of the test, set the fan speed to the lowest setting that 

maintains air flow. Complete these changes by 510 seconds after the start of the test. 

You may use different vent and fan speed settings for the remainder of the test. Leave 

the temperature and air source settings unchanged.

(2) Automatic control systems. For vehicles with automatic control systems, you may

follow the provisions of paragraph (c)(1) of this section or you may set the temperature to

72 °F and the air flow control to the front window defrost mode for the whole test.

(3) Multiple-zone systems. For vehicles that have separate driver and passenger controls

or separate front and rear controls, you must set all temperature and fan controls as 

described in paragraphs (c)(1) and (2) of this section, except that rear controls need not be 

set to defrost the front window.

(4) Alternative test procedures. We may approve the use of other settings under 40 CFR 

86.1840 if a vehicle’s climate control system is not compatible with the provisions of this 

section.

(d) Take the following steps to prepare and precondition vehicles for testing under this 

section:

(1) Prepare the vehicle as described in §1066.810(a). 

(2) Fill the fuel tank to approximately 40 % of the manufacturer’s nominal fuel tank 

capacity with the appropriate test fuel for cold temperature testing as specified 40 CFR 

part 1065, subpart H. The temperature of the dispensed test fuel must be at or below 15.5 

°C. If the leftover fuel in the fuel tank before the refueling event does not meet these 

specifications, drain the fuel tank before refueling. You may operate the vehicle prior to 

the preconditioning drive to eliminate fuel effects on adaptive memory systems.

(3) You may start the preconditioning drive once the fuel in the fuel tank reaches (12.6 to 

-1.4) °C. Precondition the vehicle as follows:

(i) Push or drive the vehicle onto the dynamometer.

(ii) Operate the vehicle over one UDDS. You may perform additional vehicle 

preconditioning with repeated driving over the UDDS, subject to our advance approval. 

(iii) Turn off the test vehicle and any cooling fans within 5 minutes after completing the 

preconditioning drive. Ambient temperature must be between (−12.0 and −1.0) °C in the 

5 minutes following the preconditioning drive.

(iv) Do not manually purge or load the evaporative canister.

(e) Soak the vehicle for (12 to 36) hours to stabilize it at test temperatures before starting 

the emission test as described in this paragraph (e). If you move a stabilized vehicle 

through a warm area when transporting it to the dynamometer for testing, you must 

restabilize the vehicle by holding it at an ambient temperature within the range specified 

in paragraph (b)(1) of this section for at least six times as long as the vehicle was exposed 

to warmer temperatures. Use one of the following methods to reach a stabilized 

condition:

(1) Cold storage. Measure and record ambient temperature in the test cell at least once 

every 60 seconds during the ambient cold soak period. These ambient temperatures may

be above −4.0 °C or below −9.0 °C, but not for more than 3 minutes at a time. Use
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measured values to calculate an hourly average temperature. Each hourly average 

temperature must be (−7.0 °C ±2.8) °C.

(2) Forced-cooling or warming. Position fans to blow temperature-controlled air onto the 

vehicle to stabilize the vehicle at the specified temperatures for emission testing. Position 

fans to target the vehicle’s drive train, engine block, and radiator rather than the oil pan. 

You may not place fans under the vehicle. You may consider the vehicle to be stabilized 

at the test temperature when the bulk oil temperature reaches (-8.7 to -5.3) °C; measure 

oil temperature at one or more points away from the side or bottom surfaces of the oil 

pan. Each oil temperature measurement must be within the specified range before 

stabilization is complete. Once the vehicle reaches this stabilized condition, cold soak 

the vehicle within the stabilized temperature range for at least one hour before starting the 

emission test. During this time, keep the ambient temperature within the range specified 

in paragraph (b)(1) of this section.

Subpart I—EXHAUST EMISSION TEST PROCEDURES FOR MOTOR 

VEHICLES

§1066.801 Applicability and general provisions.

This subpart I specifies how to apply the test procedures of this part for light-duty

vehicles, light-duty trucks, and heavy-duty vehicles at or below 14,000 pounds GVWR 

that are subject to chassis testing for exhaust emissions under 40 CFR part 86, subpart S. 

For these vehicles, references in this part 1066 to the standard-setting part include this 

subpart I.

(a) Use the procedures detailed in this subpart to measure vehicle emissions over a 

specified drive schedule in conjunction with subpart E of this part. Where the procedures 

of subpart E of this part differ from this subpart I, the provisions in this subpart I take 

precedence.

(b) Collect samples of every pollutant for which an emission standard applies, unless 

specified otherwise.

(c) This subpart covers the following test procedures:

(1) The Federal Test Procedure (FTP), which includes the general driving cycle. This 

procedure is also used for measuring evaporative emissions. This may be called the 

conventional test since it was adopted with the earliest emission standards.

(i) The FTP consists of one Urban Dynamometer Driving Schedule (UDDS) as specified 

in paragraph (a) of Appendix I of 40 CFR part 86, followed by a 10-minute soak with the 

engine off and repeat driving through the first 505 seconds of the UDDS. Note that the 

UDDS represents about 7.5 miles of driving in an urban area. Engine startup (with all 

accessories turned off), operation over the initial UDDS, and engine shutdown make a 

complete cold-start test. The hot-start test consists of the first 505 seconds of the UDDS

following the 10-minute soak and a hot-running portion of the UDDS after the first 505 

seconds. The first 505 seconds of the UDDS is considered the transient portion; the 

remainder of the UDDS is considered the stabilized (or hot-stabilized) portion. The hotstabilized portion for the hot-start test is generally measured during the cold-start test; 

however, in certain cases, the hot-start test may involve a second full UDDS following 

the 10-minute soak, rather than repeating only the first 505 seconds. See §§1066.815 and 

1066.820.
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(ii) Evaporative emission testing includes a preconditioning drive with the UDDS and a 

full FTP cycle, including exhaust measurement, followed by evaporative emission 

measurements. In the three-day diurnal test sequence, the exhaust test is followed by a

running loss test consisting of a UDDS, then two New York City Cycles as specified in 

paragraph (e) of Appendix I of 40 CFR part 86, followed by another UDDS; see 40 CFR 

86.134. Note that the New York City Cycle represents about 1.18 miles of driving in a 

city center. The running loss test is followed by a high-temperature hot soak test as 

described in 40 CFR 86.138 and a three-day diurnal emission test as described in 40 CFR 

86.133. In the two-day diurnal test sequence, the exhaust test is followed by a lowtemperature hot soak test as described in 40 CFR 86.138-96(k) and a two-day diurnal 

emission test as described in 40 CFR 86.133-96(p). 

(iii) Refueling emission tests for vehicles that rely on integrated control of diurnal and 

refueling emissions includes vehicle operation over the full FTP test cycle corresponding 

to the three-day diurnal test sequence to precondition and purge the evaporative canister. 

For non-integrated systems, there is a preconditioning drive over the UDDS and a 

refueling event, followed by repeated UDDS driving to purge the evaporative canister.

The refueling emission test procedures are described in 40 CFR 86.150 through 86.157.

(2) The Supplemental Federal Test Procedure (SFTP) measures the emission effects from 

aggressive driving and operation with the vehicle’s air conditioner. The SFTP is based 

on a composite of three different test elements. In addition to the FTP, vehicles generally 

operate over the US06 and SC03 driving schedules as specified in paragraphs (g) and (h) 

of Appendix I of 40 CFR part 86, respectively. In the case of heavy-duty vehicles above 

10,000 pounds GVWR and at or below 14,000 pounds GVWR, SFTP testing involves 

additional driving over the LA-92 driving schedule specified in paragraph (c) of 40 CFR 

part 86, Appendix I, instead of the US06 driving schedule. Note that the US06 driving 

schedule represents about 8.0 miles of relatively aggressive driving; the SC03 driving 

schedule represents about 3.6 miles of urban driving with the air conditioner operating; 

and the LA-92 driving schedule represents about 9.8 miles of relatively aggressive 

driving for commercial trucks. See §§1066.815 and 1066.820.

(3) The Highway Fuel Economy Test (HFET) is specified in Appendix I of 40 CFR part 

600. Note that the HFET represents about 10.2 miles of rural and freeway driving with 

an average speed of 48.6 mph and a maximum speed of 60.0 mph. See §1066.840.

(4) Cold temperature standards apply for CO and NMHC emissions when vehicles 

operate over the FTP at a nominal temperature of -7 °C. See 40 CFR part 86, subpart C,

and subpart H of this part.

(5) Emission measurement to determine air conditioning credits for greenhouse gas 

standards. In this optional procedure, manufacturers operate vehicles over repeat runs of 

the AC17 test sequence to allow for calculating credits as part of demonstrating 

compliance with CO2 emission standards. The AC17 test sequence consists of a UDDS 

preconditioning drive, followed by emission measurements over the SC03 and HFET 

driving schedules. See §1066.845.

(d) The following provisions apply for all testing:

(1) Ambient temperatures encountered by the test vehicle must be (20 to 30) °C, unless 

otherwise specified. Where ambient temperature specifications apply before or between 

test measurements, the vehicle may be exposed to temperatures outside of the specified 

range for up to 10 minutes to account for vehicle transport or other actions to prepare for 
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testing. The temperatures monitored during testing must be representative of those 

experienced by the test vehicle. For example, do not measure ambient temperatures near 

a heat source.

(2) Do not operate or store the vehicle at an incline if good engineering judgment 

indicates that it would affect emissions.

(3) If a test is void after collecting emission data from previous test segments, the test 

may be repeated to collect only those data points needed to complete emission 

measurements. You may combine emission measurements from different test runs to 

demonstrate compliance with emission standards. 

(4) Prepare vehicles for testing as described in §1066.810.

(e) The following figure illustrates the FTP test sequence for measuring exhaust and 

evaporative emissions:
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Figure 1 of §1066.801–FTP test sequence
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§1066.805 Road-load power, test weight, and inertia weight class determination.

(a) Simulate a vehicle’s test weight on the dynamometer using the appropriate equivalent 

test weight shown in Table 1 of this section. Equivalent test weights are established 

according to each vehicle’s test weight basis, as described in paragraph (b) of this section. 

Table 1 also specifies the inertia weight class corresponding to each equivalent test 

weight; the inertia weight class allows for grouping vehicles with a range of equivalent 

test weights. Table 1 follows:
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TABLE 1 OF §1066.805–EQUIVALENT TEST WEIGHTS (POUNDS)

Test weight Equivalent test Inertia weight 

Up to 1062 1000 1000

1063 to 1187 1125 1000

1188 to 1312 1250 1250

1313 to 1437 1375 1250

1438 to 1562 1500 1500

1563 to 1687 1625 1500

1688 to 1812 1750 1750

1813 to 1937 1875 1750

1938 to 2062 2000 2000

2063 to 2187 2125 2000

2188 to 2312 2250 2250

2313 to 2437 2375 2250

2438 to 2562 2500 2500

2563 to 2687 2625 2500

2688 to 2812 2750 2750

2813 to 2937 2875 2750

2938 to 3062 3000 3000

3063 to 3187 3125 3000

3188 to 3312 3250 3000

3313 to 3437 3375 3500

3438 to 3562 3500 3500

3563 to 3687 3625 3500

3688 to 3812 3750 3500

3813 to 3937 3875 4000

3938 to 4125 4000 4000

4126 to 4375 4250 4000

4376 to 4625 4500 4500

4626 to 4875 4750 4500

4876 to 5125 5000 5000

5126 to 5375 5250 5000

5376 to 5750 5500 5500

5751 to 6250 6000 6000

6251 to 6750 6500 6500

6751 to 7250 7000 7000

7251 to 7750 7500 7500

7751 to 8250 8000 8000

8251 to 8750 8500 8500

8751 to 9250 9000 9000

9251 to 9750 9500 9500

9751 to 10250 10000 10000

10251 to 10750 10500 10500

10751 to 11250 11000 11000

11251 to 11750 11500 11500

11751 to 12250 12000 12000

12251 to 12750 12500 12500

12751 to 13250 13000 13000

13251 to 13750 13500 13500

13751 to 14000 14000 14000

(b) The test weight basis for non-MDPV heavy-duty vehicles is “adjusted loaded vehicle 

weight”. For all other vehicles, the test weight basis for establishing equivalent test 

weight is “loaded vehicle weight”. These load terms are defined in 40 CFR 86.1803.
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(c) For FTP, SFTP, New York City Cycle, HFET, and LA-92 testing, determine roadload forces for each test vehicle at speeds between 9.3 and 71.5 miles per hour. The 

road-load force must represent vehicle operation on a smooth, level road with no wind or 

calm winds, no precipitation, an ambient temperature of approximately 20 °C, and 

atmospheric pressure of 98.21 kPa. You may extrapolate road-load force for speeds 

below 9.3 mph.

§1066.810 Vehicle preparation.

(a) Include additional fittings and adapters as required to accommodate a fuel drain at the 

lowest point possible in the tank(s) as installed on the vehicle.

(b) For preconditioning that involves loading an evaporative emission canister with 

butane, provide valving or other means to allow for purging and loading the canister.

(c) For vehicles to be tested for running loss emissions (40 CFR 86.134), prepare the fuel 

tank for measuring temperature and pressure as specified in 40 CFR 86.107–98(e) and (f)

and 40 CFR 86.134. Vapor temperature measurement is optional during the running loss 

test.

(d) For vehicles to be tested for running loss emissions, prepare the exhaust system by

sealing or plugging all detectable sources of exhaust gas leaks. Inspect or test the exhaust 

system to ensure that there are no leaks that would cause exhaust hydrocarbon emissions 

to be detected as running losses.

(e) The following provisions apply for preconditioning steps to reduce nonfuel emissions 

to normal vehicle background levels for vehicles subject to Tier 3 evaporative emission 

standards under 40 CFR 86.1813:

(1) You must notify us in advance if you plan to perform such preconditioning. This 

notice must include a detailed description of the intended procedures and any

measurements or thresholds for determining when stabilization is complete. You need 

not repeat this notification for additional vehicle testing in the same or later model years 

as long as your preconditioning practice conforms to these procedures.

(2) You may precondition a vehicle as described in paragraph (e)(1) of this section only

within 12 months after the vehicle’s original date of manufacture, except that you may

ask us to approve further preconditioning steps for any testing to address identifiable 

sources of nonfuel emissions beyond what would generally occur with an appropriately 

aged in-use vehicle. For example, you may clean up fluid leaks and you may perform 

further off-vehicle preconditioning for tires or other replacement parts that are less than 

12 months old. You may also replace the spare tire with an aged spare tire, and you may

replace the windshield washer fluid with water.

§1066.815 Exhaust emission test procedures for FTP testing.

(a) General. The FTP exhaust emission test sequence consists of a cold-start test and a 

hot-start test as described in §1066.801.

(b) PM sampling options. Collect PM using any of the procedures specified in 

paragraphs (b)(1) through (5) of this section and use the corresponding equation in 

§1066.820 to calculate FTP composite emissions. Testing must meet the requirements 

related to filter face velocity as described in 40 CFR 1065.170(c)(1)(vi), except as 

specified in paragraphs (b)(4) and (5) of this section. For procedures involving flow 

weighting, set the filter face velocity to a weighting target of 1.0 to meet the requirements 
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of 40 CFR 1065.170(c)(1)(vi). Allow filter face velocity to decrease as a percentage of 

the weighting factor if the weighting factor is less than 1.0. Use the appropriate 

equations in §1066.610 to show that you meet the dilution factor requirements of 

§1066.110(b)(2)(iii)(B).

(1) You may collect a separate PM sample for transient and stabilized portions of the 

cold-start UDDS and the hot-start UDDS. This may either be done by sampling with 

three bags or four bags. You may omit the stabilized portion of the hot-start test (bag 4)

and use the stabilized portion of the cold-start test (bag 2) in its place.

(2) You may collect PM on one filter over the cold-start UDDS and on a separate filter 

over the hot-start UDDS.

(3) You may collect PM on one filter over the cold-start UDDS (bag 1 and bag 2) and on 

a separate filter over the 867 seconds of the stabilized portion of the cold-start UDDS and 

the first 505 seconds of the hot-start UDDS (bag 2 and bag 3). Note that this option 

involves duplicate measurements during the stabilized portion of the cold-start UDDS.

(4) You may collect PM on a single filter over the cold-start UDDS and the first 505 

seconds of the hot-start UDDS. If you use this method, adjust your sampling system flow 

rate to weight the filter face velocity over the three intervals of the FTP based on 

weighting targets of 0.43 for bag 1, 1.0 for bag 2, and 0.57 for bag 3.

(5) You may collect PM on a single filter over the cold-start UDDS and the full hot-start 

UDDS. If you use this method, adjust your sampling system flow rate to weight the filter 

face velocity based on weighting targets of 0.75 for the cold-start UDDS and 1.0 for the 

hot-start UDDS.

(c) Gaseous sampling options. Collect gaseous samples using any of the following 

procedures:

(1) You may collect a single sample for a full UDDS (cold-start or hot-start).

(2) You may sample emissions separately for transient and stabilized portions of any 

UDDS.

(3) You may omit the stabilized portion of the hot-start test (bag 4) and use the stabilized 

portion of the cold-start test (bag 2) in its place.

(d) Test sequence. Follow the exhaust emission measurement procedures specified in 

§§1066.410 through 1066.425, subject to the following exceptions and additional 

provisions:

(1) Take the following steps for the cold-start test:

(i) Precondition the vehicle as described in §1066.816. Initiate the cold-start test 

following the 12 to 36 hour soak period.

(ii) Start sampling and recording simultaneously with starting the vehicle. Place the 

vehicle in gear 15 seconds after engine starting, which is 5 seconds before the first 

acceleration.

(iii) At the end of the deceleration scheduled to occur 505 seconds into the cold-start 

UDDS, simultaneously switch all the sample flows from the cold-start transient interval 

to the stabilized interval, stopping all cold-start transient interval sampling and recording, 

including background sampling. Reset integrating devices for the stabilized interval and 

indicate the end of the cold-start interval in the recorded data. Operate the vehicle over 

the remainder of the UDDS. Turn the engine off 2 seconds after the end of the last 

deceleration in the stabilized interval (1,369 seconds after the start of the driving 

schedule).
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(iv) Five seconds after the engine stops running, stop all stabilized interval sampling and 

recording, including background sampling. Stop any integrating devices for the 

stabilized interval and indicate the end of the stabilized interval in the recorded data. 

Note that the 5 second delay is intended to account for sampling system transport.

(2) Take the following steps for the hot-start test:

(i) Initiate the hot-start test (9 to 11) minutes after the end of the sample period for the 

cold-start UDDS. 

(ii) Repeat the steps in paragraph (d)(1)(ii) of this section. Operate the vehicle over the 

first 505 seconds of the UDDS. At the end of the deceleration scheduled to occur 505 

seconds into the hot-start UDDS, turn off the engine and simultaneously stop all hot-start 

sampling and recording, including background sampling, and any integrating devices.

(iii) For tests that do not include bag 4 operation, turn the engine off. To include bag 4 

measurement, operate the vehicles over the remainder of the UDDS and conclude the 

testing as described in paragraphs (d)(1)(iii) and (iv) of this section.

(3) This completes the procedure for measuring FTP exhaust emissions. See §1066.801 

and subpart J of this part for continuing the test sequence to measure evaporative or 

refueling emissions. 

§1066.816 Vehicle preconditioning for FTP testing.

Precondition the test vehicle before the FTP exhaust measurement as described in 40 

CFR 86.132. 

§1066.820 Composite calculations for FTP exhaust emissions.

(a) Determine the mass of exhaust emissions of each pollutant for each FTP test interval

as described in §1066.605.

(b) Calculate the final composite gaseous test results as a mass-weighted value, e[emission]-

FTPcomp, in grams per mile using the following equation:

c h

[emission]-FTPcomp

ct cs ht hs

0.43 0.57 m me

D D D D

   

             

Eq. 1066.820-1

Where:

mc = the combined mass emissions determined from the cold-start UDDS test interval

(generally known as bag 1 and bag 2), in grams.

Dct = the measured driving distance from the transient portion of the cold-start test (bag 

1), in miles.

Dcs = the measured driving distance from the stabilized portion of the cold-start test (bag 

2), in miles.

mh = the combined mass emissions determined from the hot-start UDDS test interval in 

grams. This is the hot-stabilized portion from either the first or second UDDS (bag 2, 

unless you measure bag 4), in addition to the hot transient portion (bag 3).

Dht = the measured driving distance from the transient portion of the hot-start test (bag 3), 

in miles.

Dhs = the measured driving distance from the stabilized portion of the hot-start test (bag 

4), in miles. Set Dhs = Dcs for testing where the hot-stabilized portion of the UDDS is not 

run.
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(c) Calculate the final composite PM test results as a mass-weighted value, ePM-FTPcomp, in 

grams per mile as follows:

(1) Use the following equation for PM measured as described in §1066.815(b)(1), (2), or 

(3):

PM-cUDDS PM-hUDDS

PM-FTPcomp

ct cs ht hs

0.43 0.57 m me

D D D D

   

             

Eq. 1066.820-2

Where:

mPM-cUDDS = the combined PM mass emissions determined from the cold-start UDDS test 

interval (bag 1 and bag 2), in grams, as calculated using Eq. 1066.605-2.

mPM-hUDDS = the combined PM mass emissions determined from the hot-start UDDS test 

interval (bag 3 and bag 4), in grams, as calculated using Eq. 1066.605-2. This is the hotstabilized portion from either the first or second UDDS (bag 2, unless you measure bag 

4), in addition to the hot transient portion (bag 3).

(2) Use the following equation for PM measured as described in §1066.815(b)(4):

   

PM

PM-FTPcomp

ct cs ht 0.43 0.57

m

e

D D D



   

Eq. 1066.820-3

Where:

mPM = the combined PM mass emissions determined from the cold-start UDDS test 

interval and the first 505 seconds of the hot-start UDDS test interval (bag 1, bag 2, and 

bag 3), in grams, as calculated using Eq. 1066.605-3.

(3) Use the following equation for PM measured as described in §1066.815(b)(5):

   

PM

PM-FTPcomp

ct cs ht hs 0.43 0.57

m

e

D D D D



    

Eq. 1066.820-4

Where:

mPM = the combined PM mass emissions determined from the cold-start UDDS test 

interval and the hot-start UDDS test interval (bag 1, bag 2, bag 3, and bag 4), in grams, as 

calculated using Eq. 1066.605-4.

§1066.830 Supplemental Federal Test Procedures; overview.

Sections 1066.831 and 1066.835 describe the detailed procedures for the Supplemental 

Federal Test Procedure (SFTP). This testing applies for all vehicles subject to the SFTP 

standards in 40 CFR part 86, subpart S. The SFTP test procedure consists of FTP testing 

and two additional test elements—a sequence of vehicle operation with more aggressive 

driving and a sequence of vehicle operation that accounts for the impact of the vehicle’s 

air conditioner. 

(a) The SFTP standard applies as a composite representing the three test elements. The 

emission results from the aggressive driving test element (§1066.831), the air 

conditioning test element (§1066.835), and the FTP test element (§1066.820) are 
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analyzed according to the calculation methodology and compared to the applicable SFTP 

emission standards as described in 40 CFR part 86, subpart S.

(b) The test elements of the SFTP may be run in any sequence that includes the specified 

preconditioning steps.

§1066.831 Exhaust emission test procedures for aggressive driving.

(a) This section describes how to test using the US06 or LA-92 driving schedule. The 

US06 driving schedule can be divided into two test intervals—the US06 City cycle 

comprises the combined portions of the cycle from 1 to 130 seconds and from 495 to 596 

seconds, and the US06 Highway cycle comprises the portion of the cycle between 130 

and 495 seconds. See §1066.801 for further information on the driving schedules.

(b) Take the following steps to precondition vehicles for testing under this section:

(1) Drain and refill the vehicle’s fuel tank(s) in any of the following cases:

(i) For aggressive-driving tests that do not follow FTP or HFET testing.

(ii) For a test element that starts more than 72 hours after the most recent FTP or HFET 

measurement (with or without evaporative emission measurements).

(iii) For testing in which the test vehicle has not remained in an area where ambient 

temperatures were within the range specified for testing since the previous FTP or HFET.

(2) Keep ambient temperatures within the ranges specified for test measurements 

throughout the preconditioning sequence.

(3) Warm up the vehicle to a stabilized condition as follows:

(i) Push or drive the vehicle onto the dynamometer.

(ii) Operate the vehicle one time over one of the driving schedules specified in this 

paragraph (b)(3)(ii). You may ask us to use a particular preconditioning driving schedule 

if that is related to fuel effects on adaptive memory systems. For our testing, we will 

generally operate the vehicle over the same preconditioning cycle that will be used for 

testing in this section. You may exercise your sampling equipment, but you may not 

determine emissions results during preconditioning. Choose from the following driving 

schedules:

(A) The first 505 seconds of the UDDS (bag 1)

(B) The last 867 seconds of the UDDS (bag 2).

(C) The HFET driving schedule.

(D) US06 driving schedule or, for heavy-duty vehicles above 10,000 pounds GVWR with 

a power-to-weight ratio at or below 0.024 hp/lbm, just the highway portion of the US06 

driving schedule. 

(E) The SC03 driving schedule.

(F) The LA-92 driving schedule. 

(4) Allow the vehicle to idle for (1 to 2) minutes. This leads directly into the test 

measurements described in paragraph (c) of this section.

(c) For testing involving the full US06 driving schedule, you may collect emissions from 

separate city and highway test intervals (see 40 CFR part 600), or you may collect 

emissions over the full US06 driving schedule as a single test interval. Take the 

following steps to measure emissions over separate city and highway test intervals:

(1) At 130 seconds, simultaneously stop all US06 City, and start all US06 Highway

sampling, recording, and integrating (including background sampling). At 136 seconds 

(before the acceleration), record the measured dynamometer roll revolutions.
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(2) At 495 seconds, simultaneously stop all US06 Highway, and start all US06 City

sampling, recording, and integrating (including background sampling). At 500 seconds 

(before the acceleration), record the measured dynamometer roll revolutions.

(3) Except as specified in paragraph (c)(4) of this section, treat the emissions from the 

first and second portions of the US06 City test interval as a single sample.

(4) If you collect gaseous emissions over separate city and highway test intervals, you 

may still collect PM over the full US06 driving schedule as a single test interval. If you 

do this, calculate a composite dilution factor based on city and highway emissions using 

Eq. 1066.610-4 to show that you meet the dilution factor requirements of 

§1066.110(b)(2)(iii)(B). 

(d) For diesel-fueled vehicles, measure THC emissions on a continuous basis as 

described in 40 CFR part 1065. For separate measurement of the city and highway test 

intervals as described in paragraph (c) of this section, perform separate calculations for 

each portion of the test cycle.

(e) Follow the exhaust emission measurement procedures specified in §§1066.410 

through 1066.425, subject to the following exceptions and additional provisions:

(1) Following the preconditioning specified in paragraph (b) of this section, place the 

vehicle in gear and simultaneously start sampling and recording. Begin the first 

acceleration 5 seconds after placing the vehicle in gear.

(2) Operate the vehicle over the full US06 driving schedule, except as follows:

(i) For heavy-duty vehicles above 10,000 pounds GVWR, operate the vehicle over the 

LA-92 driving schedule.

(ii) Heavy-duty vehicles at or below 10,000 pounds GVWR with a power-to-weight ratio 

at or below 0.024 hp/lbm may be certified using only the highway portion of the US06 

driving schedule as described in 40 CFR 86.1816.

(iii) All heavy-duty vehicles shall be tested at their adjusted loaded vehicle weight as 

described in 40 CFR 86.1816.

(3) Turn the engine off 2 seconds after the end of the last deceleration. Five seconds after 

the engine stops running, stop all sampling and recording, including background

sampling. Stop any integrating devices and indicate the end of the test cycle in the 

recorded data. Note that the 5 second delay is intended to account for sampling system 

transport.

(4) Correct calculated NOx emissions as described in §1066.615(a)(1).

§1066.835 Exhaust emission test procedure for SC03 emissions.

This section describes how to test using the SC03 driving schedule (see §1066.801). This 

procedure is designed to determine gaseous exhaust emissions while simulating an urban 

trip on a hot summer day. The provisions of 40 CFR part 86 and 40 CFR part 600 waive 

SC03 testing for some vehicles; in those cases, calculate SFTP composite emissions by

adjusting the weighting calculation as specified in 40 CFR part 86, subpart S.

(a) Drain and refill the vehicle’s fuel tank(s) if testing starts more than 72 hours after the 

last drain and fill operation.

(b) Keep the vehicle in an environment meeting the conditions described in paragraph (f) 

of this section throughout the preconditioning sequence. 

(c) Warm up the vehicle to a stabilized condition as follows: 

(1) Push or drive the test vehicle onto the dynamometer.
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(2) Close the vehicle’s windows before testing.

(3) The test cell and equipment must meet the specifications in paragraph (e) of this 

section. Measure and control ambient conditions as specified in paragraph (f) of this 

section.

(4) Set the vehicle’s air conditioning controls by selecting A/C mode and “maximum”, 

setting airflow to “recirculate” (if so equipped), selecting the highest fan setting, and 

turning the A/C temperature to full cold (or 72 °F for automatic systems). Turn the 

control to the “on” position before testing so the air conditioning system is active 

whenever the engine is running.

(5) Perform a preconditioning drive by operating the test vehicle one time over the first 

505 seconds of the UDDS (bag 1), the last 867 seconds of the UDDS (bag 2), or the SC03 

driving schedule. If the air conditioning test sequence starts more than 2 hours after a 

different exhaust emission test, you may instead operate the vehicle one time over the full 

UDDS.

(6) Following the preconditioning drive, turn off the test vehicle and the vehicle cooling 

fan(s) and allow the vehicle to soak for (9 to 11) minutes.

(d) Follow the exhaust emission measurement procedures specified in §§1066.410 

through 1066.425, subject to the following exceptions and additional provisions:

(1) Place the vehicle in gear 15 seconds after engine starting, which is 3 seconds before 

the first acceleration. Follow the SC03 driving schedule. 

(2) Turn the engine off 2 seconds after the end of the last deceleration. Five seconds after 

the engine stops running, stop all sampling and recording, including background

sampling. Stop any integrating devices any indicate the end of the test cycle in the 

recorded data. Note that the 5 second delay is intended to account for sampling system 

transport.

(3) Correct calculated NOx emissions as described in §1066.615(a)(2).

(e) The following requirements apply for the test cell and cooling fan configuration:

(1) Minimum test cell size. The test cell must be at least 20 feet wide, 40 feet long, and 

10 feet high, unless we approve the use of a smaller test cell. We will approve this only

if you demonstrate that the smaller test cell is capable of meeting all the requirements of 

this section.

(2) Vehicle frontal air flow. Verify that the fan configuration meets the requirements of 

§1066.105(c)(3).

(f) Maintain ambient conditions as follows: 

(1) Ambient temperature and humidity. Measure and record ambient temperature and 

humidity in the test cell at least once every 30 seconds during the sampling period.

Alternatively, if you collect data of at least once every 12 seconds, you may use a moving 

average of up to 30 second intervals to measure and record ambient temperature and 

humidity. Control ambient temperature throughout the test sequence to 35.0 ±3.0 °C.

Control ambient temperature during emission sampling to (33.6 to 36.4) °C on average. 

Control ambient humidity during emission sampling as described in §1066.420(d).

(2) Conditions before and after testing. Use good engineering judgment to demonstrate 

that you meet the specified instantaneous temperature and humidity tolerances in 

paragraphs (f)(1) of this section at all times before and between emission measurements.

(3) Solar heat load. Simulate solar heating as follows:
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(i) You may use a metal halide lamp, a sodium lamp, or a quartz halogen lamp with 

dichroic mirrors as a radiant energy emitter. We may also approve the use of a different 

type of radiant energy emitter if you demonstrate that it meets the requirements of this 

section.

(ii) We recommend achieving radiant heating with spectral distribution characteristics as 

described in the following table:

TABLE 1 OF §1066.835–RECOMMENDED SPECTRAL DISTRIBUTION

Band width (nm) Percent of total spectrum

Lower limit (%) Upper limit (%)

<320a — 0

320–400 0 7

400–780 45 55

>780 35 53

aNote that you may need to filter the UV region between 280 and 320 nm.

(iii) Determine radiant energy intensity experienced by the vehicle as the average value 

between two measurements along the vehicle’s centerline, one at the base of the 

windshield and the other at the bottom of the rear window (or equivalent location for 

vehicles without a rear window). This value must be 850 ±45 W/m2. Instruments for 

measuring radiant energy intensity must meet the following minimum specifications:

(A) Sensitivity of 9 microvolts per W/m2.

(B) Response time of 5 seconds. For purposes of this requirement, “response time” 

means the time for the instrument to reach 95 percent of its equilibrium response after a 

step change in radiant intensity.

(C) Cosine response error of no more than ± 1 % for 0–70 degree zenith angles. The 

cosine response error is the percentage difference between the intensity measured at a 

given angle and a reference value, where the reference value is the intensity predicted 

from the zero-degree intensity and the cosine of the incident angle.

(D) When comparing measured values for radiant energy to reference values, each 

measured value over the full range of measurement may not deviate from the 

corresponding reference value by more than ±0.5 % of the analyzer range’s maximum 

value.

(iv) Check the uniformity of radiant energy intensity at least every 500 hours of emitter 

usage or every 6 months, whichever is sooner, and after any major modifications 

affecting the solar simulation. Determine uniformity by measuring radiant energy

intensity as described in paragraph (f)(4)(iii) of this section at each point of a 0.5 m grid 

over the vehicle’s full footprint, including the edges of the footprint, at an elevation 1 m 

above the floor. Measured values of radiant energy intensity must be between (722 and 

978) W/m2at all points.

§1066.840 Highway fuel economy test procedure.

This section describes the procedure for the highway fuel economy test (HFET). This 

test involves emission sampling and fuel economy measurement for certain vehicles as 

described in 40 CFR part 86, subpart S, and in 40 CFR part 600. See §1066.801 for 

further information on the driving schedules. Follow the exhaust emission measurement 
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procedures specified in §§1066.410 through 1066.425, subject to the following 

exceptions and additional provisions:

(a) Perform the HFET immediately following the FTP when this is practical. If the 

HFET procedure starts more than 3 hours after an FTP (including evaporative emission 

measurements, if applicable), operate it over one UDDS to precondition the vehicle. We 

may approve additional preconditioning in unusual circumstances.

(b) Operate the vehicle over the HFET driving schedule for preconditioning. Allow the 

vehicle to idle for 15 seconds (with the vehicle in gear), then start a repeat run of the 

HFET driving schedule and simultaneously start sampling and recording. 

(c) Turn the engine off at the end of the HFET driving schedule and stop all sampling and 

recording, including background. Stop any integrating devices and indicate the end of 

the test cycle in the recorded data.

§1066.845 AC17 air conditioning efficiency test procedure.

(a) Overview. This section describes a voluntary procedure for measuring the net impact 

of air conditioner operation on CO2 emissions. See 40 CFR 86.1868 for provisions 

describing how to use these procedures to calculate credits and otherwise comply with 

emission standards. 

(b) Test cell. Operate the vehicle in a test cell meeting the specifications described in 

§1066.832(e). You may add airflow up to at a maximum of 4 miles per hour during 

engine idling and when the engine is off if that is needed to meet ambient temperature or 

humidity requirements.

(c) Ambient conditions. Measure and control ambient conditions as specified in 

§1066.832(f), except that you must control ambient temperature during emission 

sampling to (22.0 to 28.0) °C throughout the test and (23.5 to 26.5) °C on average. These 

tolerances apply to the combined SC03 and HFET drive cycles during emission 

sampling. Note that you must set the same ambient temperature target for both the air 

conditioning on and off portions of emission sampling. Control ambient temperature 

during the preconditioning cycle and 30 minute soak to 25.0 ±5.0 °C. For these same 

modes with no emission sampling, target the specified ambient humidity levels, but you 

do not need to meet the humidity tolerances. Note that solar heating is disabled for 

certain test intervals as described in this section.

(d) Interior air temperature measurement. Measure and record the vehicle’s interior air 

temperature at least once every 5 seconds during the sampling period. Measure 

temperature at the outlet of the center-most duct on the dashboard, and approximately 30 

mm behind the driver’s headrest and passenger’s headrest. 

(e) Air conditioning system settings. For testing that requires the air conditioning to be 

operating, set the vehicle’s air conditioning controls as follows: 

(1) For automatic systems, set the temperature control to 72 °F (22 °C).

(2) For manual systems, select A/C mode, set the temperature to full cold and 

“maximum”, set airflow to “recirculate” (if so equipped), and select the highest fan 

setting. During the first idle period of the SC03 driving schedule (between 186 and 204 

seconds), reduce the fan speed setting to nominally 50 % of maximum fan speed, set 

airflow to “fresh air” (if so equipped), and adjust the temperature setting to target a 

temperature of 55° F (13 °C) at the dashboard air outlet. Maintain these settings for the 

remainder of the test. You may rely on prior temperature measurements to determine the
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temperature setting; however, if the system is unable to meet the 55 °F (13 °C) target, 

you may instead set airflow to “fresh air” and temperature to full cold. If the vehicle is 

equipped with technology that defaults to recirculated air at ambient temperatures above 

75 °F (22 °C), that technology should remain enabled throughout the test; this may mean 

not setting the airflow to “recirculate” at the start and not setting the airflow to "fresh air" 

during the first idle period of the SCO3 driving schedule.

(f) Test procedure. Follow the exhaust emission measurement procedures specified in 

§§1066.410 through 1066.425, subject to the following exceptions and additional 

provisions:

(1) Prepare each test vehicle for a series of tests according to 40 CFR 86.132-00(a) 

through (g). If the vehicle has been tested within the last 36 hours concluding with a 12 

to 36 hour soak, continue to paragraph (f)(2) of this section; otherwise perform an 

additional UDDS preconditioning cycle that concludes with a 12 to 36 hour soak. You 

may use a forced cooldown system to bring critical vehicle temperatures to within soak 

temperature limits. Critical temperatures include transmission oil, engine oil, engine 

coolant, and cabin air temperatures.

(2) Open the vehicle’s windows and operate the vehicle over a preconditioning UDDS 

with no solar heating and with the air conditioning off. At the end of the preconditioning 

drive, turn off the test vehicle and all cooling fans. 

(3) Turn on solar heating within one minute after turning off the engine. Once the solar 

energy intensity reaches 805 W/m2, let the vehicle soak for 30 ±1 minutes. You may

alternatively rely on prior measurements to start the soak period after a defined period of 

warming up to the specified solar heat load. Close the vehicle’s windows at the start of 

the soak period; ensure that the windows are adequately closed where instrumentation 

and wiring pass through to the interior.

(4) Turn the air conditioning control to the “on” position before testing so the air 

conditioning system is active whenever the engine is running. Place the vehicle in gear 

15 seconds after engine starting, which is 3 seconds before the first acceleration. At the 

end of the driving schedule, simultaneously switch all the sampling, recording, and 

integrating from SC03 to HFET, including background sampling. Indicate the end of the 

test cycle in the recorded data. Record the measured dynamometer roll revolutions 

corresponding to the SC03 driving schedule.

(5) Directly following the SC03 driving schedule, operate the vehicle over the HFET 

driving schedule. Turn the vehicle off at the end of the driving schedule and 

simultaneously stop all sampling, recording, and integrating, including background 

sampling. Indicate the end of the test cycle in the recorded data. Record the measured 

dynamometer roll revolutions corresponding to the HFET drive schedule. Turn off the 

solar heating.

(6) Allow the vehicle to remain on the dynamometer for (10 to 15) minutes after emission 

sampling has concluded. Repeat the testing described in paragraphs (f)(1) through (5) of 

this section and turn off the vehicle’s air conditioner and the solar heating throughout the 

test run. The windows may be open or closed.

(g) Calculations. (1) Determine the mass of CO2 emissions for each of the two test 

intervals as described in §1066.605.

(2) Calculate the composite mass-weighted emissions of CO2, eCO2-AC17comp, representing 

the average of the SC03 and HFET emissions, in grams per mile using the following 
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equation:

SC03 HFET

CO2-AC17comp

SC03 HFET

0.5 0.5 m me

D D

   

           

Eq. 1066.845-1

Where:

mSC03 = mass emissions from the SC03 test interval, in grams.

DSC03 = measured driving distance during the SC03 test interval, in miles.

mHFET = mass emissions from the HFET test interval, in grams.

DHFET = measured driving distance during the HFET test interval, in miles.

Subpart J—EVAPORATIVE EMISSION TEST PROCEDURES

§1066.901 Applicability and general provisions.

This subpart describes how to measure evaporative and refueling emissions from test 

vehicles. The provisions of §§1066.910 through 1066.930 include general provisions for 

equipment and calculations related to evaporative and refueling emissions. The 

provisions of §§1066.950 through 1066.985 describe provisions that apply specifically to 

motor vehicles subject to standards under 40 CFR part 86, subpart S, or 40 CFR part 

1037. 

TEST EQUIPMENT AND CALCULATIONS FOR EVAPORATIVE AND REFUELING EMISSIONS

1066.910 SHED enclosure specifications.

Enclosures for evaporative and refueling emissions must meet the specifications 

described in 40 CFR 86.106-96, 86.107-96(a), and 86.107-98(a).

1066.915 Enclosures; auxiliary systems and equipment.

Enclosures for evaporative and refueling emissions must be equipped with fans, blowers, 

and measurement and data recording equipment as described in 40 CFR 86.107-98(b) 

through (h) and (j).

1066.920 Enclosure calibrations.

Enclosures for evaporative and refueling emissions must meet the calibration 

specifications described in 40 CFR 86.116-94 and 86.117-96.

1066.925 Enclosure calculations for evaporative and refueling emissions.

Calculate emissions for evaporative emissions as described in 40 CFR 86.143-96. 

Calculate emissions for refueling emissions as described in 40 CFR 86.143-96 and 

86.156-98.

1066.930 Equipment for point-source measurement of running losses.

For point-source measurement of running loss emissions, use equipment meeting the 

specifications in 40 CFR 86.107-96(i)
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EVAPORATIVE AND REFUELING EMISSION TEST PROCEDURES FOR MOTOR VEHICLES

1066.950 Fuel temperature profile.

Develop fuel temperature profiles for running loss testing as described in 40 CFR 86.129-

94(d).

1066.955 Diurnal emission test.

Test vehicles for diurnal emissions as described in 40 CFR 86.133-96.

1066.960 Running loss test.

Test vehicles for running loss emissions as described in 40 CFR 86.134-96.

1066.965 Hot soak test.

Test vehicles for hot soak emissions as described in 40 CFR 86.138-96.

1066.970 Refueling test for liquid fuels.

Except as described in §1066.975, test vehicles for refueling emissions as described in 40 

CFR 86.150-98, 86.151-98, 86.152-98, and 86.154-98. Keep records as described in 40 

CFR 86.155-98.

1066.971 Vehicle and canister preconditioning for the refueling test.

Precondition vehicles for the refueling emission test as described in 40 CFR 86.153-98.

1066.975 Refueling test for LPG.

For vehicles designed to operate on liquefied petroleum gas, measure refueling emissions 

as described in 40 CFR 86.157-98.

1066.980 Fuel dispensing spitback procedure.

Test vehicles for spitback emissions as described in 40 CFR 86.146-96.

§1066.985 Fuel storage system leak test procedure.

(a) Scope. Perform this test as required in the standard-setting part to verify that there are 

no significant leaks in your fuel storage system.

(b) Measurement principles. Leaks are detected by measuring pressure, temperature, and 

flow to calculate an equivalent orifice diameter for the system. Use good engineering 

judgment to develop and implement leak test equipment. You may not tighten fittings or 

connections in the vehicle’s fuel system to prepare the vehicle for testing. 

(c) Measurement equipment. Your leak test equipment must meet the following 

requirements:

(1) Pressure, temperature, and flow sensors must be calibrated with NIST-traceable 

standards. 

(2) Correct flow measurements to standard reference conditions.

(3) Leak test equipment must have the ability to pressurize fuel storage systems to at least 

4.1 kPa and have an internal leak rate of less than 0.20 standard liters per minute.

(4) You must be able to attach the test equipment to the vehicle without permanent 

alteration of the fuel storage or evaporative emission control systems. For any testing that 
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involves pressurizing the fuel system and detecting leaks at access points away from the 

fuel fill pipe, the gas cap must be installed in the production configuration. For the test 

point at or near the fuel fill pipe, attaching the test equipment may involve adding an 

extension to the fuel fill pipe that incorporates the access point to the fuel system. If the 

extension apparatus has a fixed cap, the vehicle’s gas cap must be tested separately as 

described in paragraph (d)(9) of this section. This separate testing is not required if the 

extension apparatus incorporates the vehicle’s gas cap.

(5) The point of attachment to the fuel storage system must allow pressurization to test 

system integrity of the fuel tank and of fuel lines and vapor lines reaching up to and 

including the gas cap and the evaporative canister. The evaporative system test port 

available on some vehicles is an example of an effective attachment point.

(d) Leak test procedure. Test a vehicle’s fuel storage system for leaks as follows:

(1) Refuel vehicle to 40 % of its nominal fuel tank capacity.

(2) Soak the vehicle for 6 to 24 hours at a temperature between (20 and 30) °C; record 

this setpoint temperature and maintain temperatures throughout the leak test at this 

setpoint temperature within a tolerance ±2 °C.

(3) Before performing the test, purge the fuel storage system of any residual pressure, 

bringing the system into equilibrium with ambient pressure.

(4) Seal the evaporative canister’s vent to atmosphere and ensure that the vehicle’s purge 

valve is closed.

(5) Attach the leak test equipment to the vehicle.

(6) Pressurize the fuel storage system with N2 or another inert gas to at least 2.4 kPa. Use 

good engineering judgment to avoid overpressurizing the system.

(7) Maintain gas flow through the system for at least 180 seconds, ensuring that the flow 

reading is stable for an effective leak diameter of ±0.002 inches.

(8) Use the following equation, or a different equation you develop based on good

engineering judgment, to calculate the effective leak diameter, deff:

   

2

0.5057

gas

eff

in atmos in atmos

N

7.844

V

d

p p p p

SG T

   

 

  



 

Where:

deff = effective leak diameter, in inches, expressed to at least two decimal places.

Vgas = volumetric flow of gas, in m3/s.

pin = inlet pressure to orifice, in kPa.

patmos = atmospheric pressure, in kPa.

SGN2 = specific gravity of N2 relative to air at 101.325 kPa and 15.5 °C = 0.967.

T = temperature of flowing medium, in K.

(9) Repeat the test described in this paragraph (c) for each access point described in the 

application for certification. Use each test result (without averaging) to determine 

whether the vehicle passes the leak standard.

(10) Gas caps may need to be tested separately for leaks as described in paragraph (c)(4) 

of this section. Test the gas caps using commercially available flow equipment such as 
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that used for inspection-and-maintenance programs for motor vehicles to determine a 

leak rate in cubic centimeters per minute resulting from a sustained tank pressure of 7.5 

kPa. Correct the leak rate to standard reference conditions, based on the measured leak 

rate corresponding to atmospheric pressure. The corrected leak value may not exceed 60 

cubic centimeters per minute.

(11) You may use special or alternative test procedures as described in 40 CFR 

1065.10(c).

(e) Equipment calibration. Use good engineering judgment to calibrate the leak check 

device.

Subpart K—DEFINITIONS AND OTHER REFERENCE MATERIAL

§1066.1001 Definitions.

The definitions in this section apply to this part. The definitions apply to all subparts 

unless we note otherwise. Other terms have the meaning given in 40 CFR part 1065. 

The definitions follow:

Average means the arithmetic mean of a sample.

Bag 1 means relating to the first 505 seconds of the FTP cold-start test interval. 

Note that the term bag 1 may also apply to measurement of constituents that are not 

collected in a bag, such as PM and continuously measured THC.

Bag 2 means relating to the last 867 seconds of the FTP cold-start test interval.

Bag 3 means relating to the first 505 seconds of the FTP hot-start test interval. 

Bag 4 means relating to the last 867 seconds of the FTP hot-start test interval, if 

run. Note that bag 2 is generally used in place of bag 4.

Base inertia means a value expressed in mass units to represent the rotational 

inertia of the rotating dynamometer components between the vehicle driving tires and the 

dynamometer torque-measuring device, as specified in §1066.250.

C1-equivalent means a convention of expressing HC concentrations based on the 

total number of carbon atoms present, such that the C1-equivalent of an HC concentration 

equals the concentration multiplied by the mean number of carbon atoms in each HC 

molecule. For example, the C1-equivalent of 10 ppm of propane (C3H8) is 30 ppm. C1-

equivalent concentration values may be denoted as “ppmC” in the standard-setting part. 

Densities may also be expressed on a C1 basis. Note that calculating HC masses from 

concentrations and densities is only valid where they are each expressed on the same 

carbon basis.

Driving schedule means a series of vehicle speeds that a vehicle must follow during a 

test. Driving schedules are specified in the standard-setting part. A driving schedule may

consist of multiple test intervals.

Duty cycle means a set of weighting factors and the corresponding test cycles, where the 

weighting factors are used to combine the results of multiple test intervals into a 

composite result.

FTP means one of the following:

(1) The test cycle consisting of one UDDS as specified in paragraph (a) of Appendix I of 

40 CFR part 86, followed by a 10-minute soak with the engine off and repeat driving 

through the first 505 seconds of the UDDS. See §1066.801(c)(1).
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(2) The entire test procedure for measuring exhaust and/or evaporative emissions as 

described in §1066.801(c).

Footprint has the meaning given in the standard-setting part.

HFET means the test cycle specified in Appendix I of 40 CFR part 600.

LA-92 means the test cycle specified in Appendix I, paragraph (c), of 40 CFR part 

86.

Nonmethane organic gas (NMOG) means the combination of organic gases other than 

methane as calculated in §1066.635. Note that for this part, the organic gases are 

summed on a mass basis without any adjustment for photochemical reactivity.

Parts-per-million (ppm) means ppm on a molar basis. For hydrocarbon concentrations 

including HC, THC, NMHC, and NMOG, ppm means ppm on a C1-equivalent molar 

basis.

Road-load coefficients means sets of A, B, and C road-load force coefficients that are 

used in the dynamometer road-load simulation, where road-load force at speed v equals A 

+ B∙v + C∙v

2

.

SC03 means the test cycle specified in Appendix I, paragraph (h), of 40 CFR part 

86.

SFTP means the collection of test cycles as given in 1066.801(c)(2).

Standard reference conditions means the following:

(1) Standard pressure is 101.325 kPa.

(2) Standard temperature is 293.15 K.

Test interval means a period over which a vehicle’s emission rates are determined 

separately. For many standards, compliance with the standard is based on a weighted 

average of the mass emissions from multiple test intervals. For example, the standardsetting part may specify a complete duty cycle as a cold-start test interval and a hot-start 

test interval. In cases where multiple test intervals occur over a duty cycle, the standardsetting part may specify additional calculations that weight and combine results to arrive 

at composite values for comparison against the applicable standards.

Test weight has the meaning given in §§1066.410(b) or 1066.805.

UDDS means the test cycle specified in Appendix I, paragraph (a), of 40 CFR 

part 86.

US06 means the test cycle specified in Appendix I, paragraph (g), of 40 CFR part 

86.

Unloaded coastdown means a dynamometer coastdown run with the vehicle 

wheels removed from the roll surface.

We (us, our) means the Administrator of the Environmental Protection Agency

and any authorized representatives.

§1066.1005 Symbols, abbreviations, acronyms, and units of measure.

The procedures in this part generally follow either the International System of Units (SI)

or the United States customary units, as detailed in NIST Special Publication 811, which 

we incorporate by reference in §1066.1010. See 40 CFR 1065.20 for specific provisions 

related to these conventions. This section summarizes the way we use symbols, units of 

measure, and other abbreviations.

(a) Symbols for quantities. This part uses the following symbols and units of measure for 

various quantities:

Symbol Quantity Unit Unit symbol Unit in terms of SI 
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base units

 atomic hydrogen to carbon ratio mole per mole mol/mol 1

A area square meter m

2 m2

A vehicle frictional load pound force or newton lbf or N kg∙s-2

Am calculated vehicle frictional load pound force or newton lbf or N kg∙s-2

a0

intercept of least squares 

regression

a1 slope of least squares regression

a acceleration feet per second squared or 

meters per second squared ft/s2

or m/s2 m∙s-2

B

vehicle load from drag and 

rolling resistance

pound force per mile per hour 

or newton second per meter lbf/mph or N∙s/m kg∙s-1

∙m

-1

 ratio of diameters meter per meter m/m 1

 atomic oxygen to carbon ratio mole per mole mol/mol 1

c conversion factor

C

vehicle-specific aerodynamic 

effects

pound force per mile per hour 

squared or newton second 

squared per meter squared

lbf/mph2or N∙s2/m2kg∙m

-2

C#

number of carbon atoms in a 

molecule C#

number of carbon 

atoms in a molecule C#

Cd discharge coefficient

CDA drag area meter squared m

2 m2

Cfflow coefficient

Cp heat capacity at constant pressure joule per kelvin J/K J∙K

-1

Cv heat capacity at constant volume joule per kelvin J/K J∙K

-1

d diameter meters m m

D distance miles or meters mi or m m

D slope correlation

pound force per mile per hour 

squared or newton second 

squared per meter squared

lbf/mph2or N∙s2/m2kg∙m

-2

DF dilution factor 1

e mass weighted emission result grams/mile g/mi

F force pound force or newton lbf or N kg∙s-2

f frequency hertz Hz s

-1

fn angular speed (shaft) revolutions per minute r/min 2∙π∙60-1∙m·m-1·s-1

FC friction compensation error horsepower or watt W kg·m

2

·s

-3

FR Road-load force pound force or newton lbf or N kg∙s-2

g gravitational acceleration meters per second squared m/s2 m∙s-2

 ratio of specific heats

(joule per kilogram kelvin) 

per (joule per kilogram 

kelvin) 

(J/(kg∙K))/(J/(kg∙K)) 1

 ambient humidity grams water vapor per 

kilogram dry air

g H2O vapor/kg dry 

air

g H2O vapor/kg dry 

air

h change in height meters m m

I inertia pound mass or kilogram lbm or kg kg

I current ampere A A

i indexing variable

IR inertia work rating

K correction factor 1

Kv calibration coefficient m

4

∙s∙K0.5/kg m

4

∙s∙K0.5∙kg-1

 viscosity, dynamic pascal second Pa∙s m

-1

∙kg∙s-1

M molar mass gram per mole g/mol 10-3∙kg∙mol-1

Me effective mass kilogram kg kg

m mass pound mass or kilogram lbm or kg kg

N total number in series

n total number of pulses in a series

p pressure pascal Pa m

-1

∙kg∙s-2

p differential static pressure pascal Pa m

-1

∙kg∙s-2
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pd

saturated vapor pressure at 

ambient dry bulb temperature kilopascal kPa m

-1

∙kg∙s-2

PF penetration fraction

Q flow cubic feet or cubic meter ft3or m3 m

3

Q flow rate cubic feet per minute or cubic 

meter per second ft3

/min or m3/s m

3

/s

ρ mass density kilogram per cubic meter kg/m3

kg∙m

-3

R dynamometer roll revolutions revolutions per minute rpm 2∙π∙60-1∙ m·m

-1

·s

-1

r ratio of pressures pascal per pascal Pa/Pa 1

r

2

coefficient of determination

Re# Reynolds number

RF response factor

RH relative humidity

S Sutherland constant kelvin K K

SEE standard estimate of error

SG specific gravity

s

distance traveled during 

measurement interval meters m m

T absolute temperature kelvin K K

T Celsius temperature degree Celsius °C K – 273.15

T torque (moment of force) newton meter N∙m m

2

∙kg∙s-2

t time second s s

Δt time interval, period, 1/frequency second s s

U voltage volt V m

2

∙kg∙s

-3

∙A

-1

v speed miles per hour or meters per 

second mph or m/s m∙s-1

V volume cubic meter m

3 m3

VP volume percent

x

concentration of emission over a 

test interval part per million ppm

y generic variable

Z compressibility factor Z

compressibility 

factor Z

(b) Symbols for chemical species. This part uses the following symbols for chemical 

species and exhaust constituents:

Symbol Species

CH4 methane

CH3OH methanol

CH2O formaldehyde

C2H4O acetaldehyde

C2H5OH ethanol

C2H6 ethane

C3H7OH propanol

C3H8 propane

C4H10 butane

C5H12 pentane

CO carbon monoxide

CO2 carbon dioxide

H2O water

HC hydrocarbon

N2 molecular nitrogen

NMHC nonmethane hydrocarbon

NMHCE nonmethane hydrocarbon equivalent

NMOG nonmethane organic gas

NO nitric oxide

NO2 nitrogen dioxide
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NOx oxides of nitrogen

N2O nitrous oxide

O2 molecular oxygen

OHC oxygenated hydrocarbon

PM particulate matter

THC total hydrocarbon

THCE total hydrocarbon equivalent

(c) Superscripts. This part uses the following superscripts to define a quantity:

Superscript Quantity

overbar (such as y ) arithmetic mean

overdot (such as y ) quantity per unit time

(d) Subscripts. This part uses the following subscripts to define a quantity:

Subscript Quantity

0 reference

abs absolute quantity

AC17 air conditioning 2017 test interval

act actual or measured condition

actint actual or measured condition over the speed interval

adj adjusted

air air, dry

atmos atmospheric

b base

bkgnd background

c cold

comp composite

cor corrected

cs cold stabilized

ct cold transient

cUDDS cold-start UDDS

D driven

dew dewpoint

dexh dilute exhaust quantity

dil dilute

e effective

emission emission specie

error error

EtOH ethanol

exh raw exhaust quantity

exp expected quantity

fil filter

final final

flow flow measurement device type

gas gaseous

h hot

HFET highway fuel economy test 

hs hot stabilized

ht hot transient

hUDDS hot-start UDDS

i an individual of a series

ID driven inertia

in inlet

int intake

init initial quantity, typically before an emission test
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IT target inertia

liq liquid

max

the maximum (i.e. peak) value expected at the standard over a test 

interval; not the maximum of an instrument range

meas measured quantity

mix dilute exhaust gas mixture

out outlet

PM particulate matter

record record

ref reference quantity

rev revolution

roll dynamometer roll

s settling

s slip

s stabilized

sat saturated condition

SC03 air conditioning driving schedule

span span quantity

sda secondary dilution air

std standard conditions

T target

t throat

test test quantity

uncor uncorrected quantity

w weighted

zero zero quantity

(e) Other acronyms and abbreviations. This part uses the following additional 

abbreviations and acronyms: 

A/C air conditioning

AC17 air conditioning 2017 test interval

ALVW adjusted loaded vehicle weight

ASME American Society of Mechanical Engineers

CFR Code of Federal Regulations

CFV critical-flow venturi

CNG compressed natural gas

CVS constant-volume sampler

EPA Environmental Protection Agency

ETW equivalent test weight

EV electric vehicle

FID flame-ionization detector

FTP Federal test procedure

GC gas chromatograph

GEM greenhouse gas emissions model

GHG greenhouse gas (including CO2, N2O, and CH4)

GPS global positioning system

GVWR gross vehicle weight rating

HEV hybrid electric vehicle, including plug-in hybrid electric 

vehicles

HFET highway fuel economy test

HLDT heavy light-duty truck

HPLC high pressure liquid chromatography

IBR incorporated by reference

LA-92 Los Angeles 1992 driving schedule

MDPV medium-duty passenger vehicle

NIST National Institute for Standards and Technology

NMC nonmethane cutter
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PDP positive-displacement pump

PHEV plug-in hybrid electric vehicle

PM particulate matter

RESS rechargeable energy storage system

ppm parts per million

SAE Society of Automotive Engineers

SC03 air conditioning driving schedule

SEA selective enforcement audit

SFTP supplemental federal test procedure

SI International System of Units

SSV subsonic venturi

UDDS urban dynamometer driving schedule

US06 aggressive driving schedule

U.S.C. United States Code

WWV NIST radio station call sign

(f) This part uses the following densities of chemical species:

Symbol Quantity1,2 g/m3g/ft3

ρCH4 density of methane 666.905 18.8847

ρCH3OH density of methanol 1332.02 37.7185

ρC2H5OH C1-equivalent density of ethanol 957.559 27.1151

ρC2H4O C1-equivalent density of acetaldehyde 915.658 25.9285

ρC3H8 density of propane 611.035 17.3026

ρC3H7OH C1-equivalent density of propanol 832.74 23.5806

ρCO density of carbon monoxide 1164.41 32.9725

ρCO2 density of carbon dioxide 1829.53 51.8064

ρHC-gas effective density of hydrocarbon - gaseous fuel3(see 3) (see 3)

ρCH2O density of formaldehyde 1248.21 35.3455

ρHC-liq effective density of hydrocarbon - liquid fuel4576.816 16.3336

ρNMHC-gas effective density of nonmethane hydrocarbon - gaseous fuel3(see 3) (see 3)

ρNMHC-liq effective density of nonmethane hydrocarbon - liquid fuel4576.816 16.3336

ρNMHCE-gas effective density of nonmethane equivalent hydrocarbon -

gaseous fuel3 (see 3) (see 3)

ρNMHCE-liq effective density of nonmethane equivalent hydrocarbon -

liquid fuel4 576.816 16.3336

ρNOx effective density of oxides of nitrogen51912.5 54.156

ρN2O density of nitrous oxide 1829.66 51.8103

ρTHC-liq effective density of total hydrocarbon - liquid fuel4576.816 16.3336

ρTHCE-liq effective density of total equivalent hydrocarbon - liquid fuel4576.816 16.3336

1Densities are given at 20 °C and 101.325 kPa.

2Densities for all hydrocarbon containing quantities are given in g/m3

-carbon atom and g/ft3-

carbon atom.

3The effective density for natural gas fuel and liquefied petroleum gas fuel are defined by an 

atomic hydrogen-to-carbon ratio, , of the hydrocarbon components of the test fuel. ρHCgas = 

41.57∙(12.011 + (∙1.008)).

4The effective density for gasoline and diesel fuel are defined by an atomic hydrogen-to-carbon 

ratio, , of 1.85.

5The effective density of NOx

is defined by the molar mass of nitrogen dioxide, NO2.

(g) Constants. (1) This part uses the following constants for the composition of dry air:

Symbol Quantity mol/mol 

xArair amount of argon in dry air 0.00934

xCO2air amount of carbon dioxide in dry air 0.000375

xN2air amount of nitrogen in dry air 0.78084

xO2air amount of oxygen in dry air 0.209445
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(2) This part uses the following molar masses or effective molar masses of chemical 

species:

Symbol Quantity g/mol

(10-3·kg·mol-1)

Mair molar mass of dry air128.96559

MH2O molar mass of water 18.01528

1

See paragraph (g)(1) of this section for the composition of dry air.

(3) This part uses the following molar gas constant for ideal gases:

Symbol Quantity J/(mol∙K)

(m2∙kg∙s-2∙mol-1∙K-1)

R molar gas constant 8.314472

(h) Prefixes. This part uses the following prefixes to define a quantity:

Symbol Quantity Value

 micro 10-6

m milli 10-3

c centi 10-2

k kilo 103

M mega 106

n nano 10-9

§1066.1010 Reference materials.

(a) Certain material is incorporated by reference into this part with the approval of the 

Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. To enforce any 

edition other than that specified in this section, a document must be published in the 

Federal Register and the material must be available to the public. All approved material 

is available for inspection at U.S. EPA, Air and Radiation Docket and Information 

Center, 1301 Constitution Ave., NW., Room B102, EPA West Building, Washington, 

DC 20460, (202) 202-1744, and is available from the sources listed below. It is also 

available for inspection at the National Archives and Records Administration (NARA). 

For information on the availability of this material at NARA, call 202–741–6030, or go to 

http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

To enforce any edition other than that specified in this section, a document must be 

published in the Federal Register and the material must be available to the public.

(b) SAE International material. The following standards are available from SAE 

International, 400 Commonwealth Dr., Warrendale, PA 15096–0001, (877) 606–7323 

(U.S. and Canada) or (724) 776–4970 (outside the U.S. and Canada), or 

http://www.sae.org:

(1) SAE J1263, Road Load Measurement and Dynamometer Simulation Using 

Coastdown Techniques, revised March 2010, IBR approved for §§1066.301(b), 

1066.305, and 1066.310(b).

(2) SAE J1634, Battery Electric Vehicle Energy Consumption and Range Test Procedure, 

revised October 2012, IBR approved for §1066.501(a).

(3) SAE J1711, Recommended Practice for Measuring the Exhaust Emissions and Fuel 

Economy of Hybrid-Electric Vehicles, Including Plug-In Hybrid Vehicles, revised June 

2010, IBR approved for §§1066.125 and 1066.501(a).
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(4) SAE J2263, Road Load Measurement Using Onboard Anemometry and Coastdown 

Techniques, revised December 2008, IBR approved for §§1066.301(b), 1066.305, and 

1066.310(b).

(5) SAE J2264, Chassis Dynamometer Simulation of Road Load Using Coastdown 

Techniques, revised January 2014, IBR approved for §1066.315.

(6) SAE J2711, Recommended Practice for Measuring Fuel Economy and Emissions of 

Hybrid-Electric and Conventional Heavy-Duty Vehicles, issued September 2002, IBR 

approved for §1066.501(a).

(7) SAE J2951, Drive Quality Evaluation for Chassis Dynamometer Testing, revised 

January 2014, IBR approved for §1066.425(j).

(c) National Institute of Standards and Technology material. The following documents 

are available from National Institute of Standards and Technology, 100 Bureau Drive, 

Stop 1070, Gaithersburg, MD 20899-1070, (301) 975-6478, or www.nist.gov:

(1) NIST Special Publication 811, 2008 Edition, Guide for the Use of the International 

System of Units (SI), Ambler Thompson and Barry N. Taylor, Physics Laboratory, 

March 2008, IBR approved for §§1066.20(a) and 1066.1005.

(2) [Reserved]