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Appendix C 

PROPOSED REGULATION ORDER 

Amend section 1971.5, title 13, California Code of Regulations, to read as follows:

Note: The proposed amendments are shown in underline to indicate additions and 

strikeout to indicate deletions from the existing regulatory text. Various portions of the 

regulations that are not modified by the proposed amendments are omitted from the text 

shown and indicated by “ * * * * ”. 

§ 1971.5. Enforcement of Malfunction and Diagnostic System Requirements for 

2010 and Subsequent Model-Year Heavy-Duty Engines. 

(a) General. 

* * * * 

(3) Definitions. 

The definitions applicable to these rules include those set forth in Health and 

Safety Code section 39010 et seq. and in Cal. Code Regs., title 13, section 

1900(b) and section 1971.1(c), which are incorporated by reference herein. The 

following definitions are specifically applicable to section 1971.5 and take 

precedence over any contrary definitions. 

* * * * 

“OBD Emission Testing” refers to testing conducted to determine compliance 

with the malfunction criteria in Cal. Code Regs., title 13, section 1971.1(e) 

through (g) that are based on a multiple of, or an additive to, a tailpipe emission 

standard or an absolute measurement from an applicable emission test cycle 

(e.g., 1.5 times the applicable federal test procedure (FTP) emission standards, 

PM standard plus 0.02 g/bhp-hr, PM level of 0.03 g/bhp-hr as measured from an 

applicable emission test cycle). 

* * * * 

(b) Testing Procedures for ARB-Conducted Testing. 

* * * * 

(3) Engine Selection for ARB-Conducted Enforcement Testing. 

* * * * 

(C) Protocol for Procuring Engines for Test Sample Group. 

 (i) For OBD emission and ratio testing, the Executive Officer shall determine 

the appropriate manner for procuring engines. In making his or her 

determination, the Executive Officer shall consider the nature of the 

nonconformance and the scope of the engine class. The method used 

shall ensure that engines are recruited from more than one source. 

Methods used may include obtaining lists of engine owners from specific 
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sources (e.g., engine manufacturers, motor vehicle registration records) 

and soliciting participation from owners, discussing with fleet or rental 

operations to locate engines in the engine class, or using methods used 

by the manufacturer to procure engines for the manufacturer-run heavy 

duty diesel in-use testing program established pursuant to 70 Federal 

Register 34594 to procure engines consistent with the procurement 

process followed by the Executive Officer under Cal. Code Regs., title 13, 

section 2137 (e.g., obtaining lists of all vehicles in the motor vehicle class 

within a specified geographical area, mailing postcards soliciting 

participation of vehicles within the specified area, selecting vehicles from 

those that responded to the solicitation, inspecting selected vehicles to 

determine whether appropriate to include in sample group, etc.). In 

selecting engines for OBD emission testing, the Executive Officer shall 

include only engines meeting the criteria set forth in section (b)(3)(D)(i) 

below. For OBD ratio testing, the Executive Officer shall include only 

engines meeting the criteria set forth in section (b)(3)(D)(ii) below. 

* * * * 

(D) Engines to be included in a Test Sample Group. 

* * * * 

(ii) In selecting engines to be included in a test sample group for enforcement 

OBD ratio testing, the Executive Officer shall include only engines that: 

a. Are certified to the requirements of Cal. Code Regs., title 13, section 

1971.1. 

b. Have collected sufficient engine operation data for the monitor to be 

tested. For monitors required to meet the in-use monitor performance 

ratio and to track and report ratio data pursuant to Cal. Code Regs., title 

13, section 1971.1(d)(3.2), sufficient engine operation data shall mean 

the denominator meets the criteria set forth in sections (b)(3)(D)(ii)1. 

through 5. below. For monitors required to meet the in-use monitor 

performance ratio but not required to track and report ratio data 

pursuant to Cal. Code Regs., title 13, section 1971.1(d)(3.2), sufficient 

engine operation data shall mean that engines that have a denominator 

that meets the criteria set forth in sections (b)(3)(D)(ii)1. through 5. 

below after undergoing testing as set forth in section (b)(4)(C)(ii) below. 

Specifically, the denominator, as defined in Cal. Code Regs., title 13, 

section 1971.1(d)(4.3), for the monitor to be tested must have a value 

equal to or greater than: 

1. 150 for gasoline evaporative system and secondary air system 

monitors, and gasoline monitors utilizing a denominator 

incremented in accordance with Cal. Code Regs., title 13, section 

1971.1(d)(4.3.2)(D), (E), and (F) (e.g., cold start monitors, variable 

valve timing and/or control system monitors, etc.), or 

2. 300 for gasoline catalyst, oxygen sensor, EGR, and all other 

component monitors. 
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3. 50 for diesel PM filter monitors, and NMHC converting catalyst 

monitors, PM sensor monitors, and PM sensor heater monitors and 

other diesel monitors using a denominator incremented in 

accordance with Cal. Code Regs., title 13, section 

1971.1(d)(4.3.2)(E), (F), (G) or (H), or 

4. 150 for diesel monitors utilizing a denominator incremented in 

accordance with Cal. Code Regs., title 13, section 

1971.1(d)(4.3.2)(D), (E), or (F) (e.g., cold start monitors, 

comprehensive component output component monitors, etc.) and 

not covered in section (b)(3)(D)(ii)3. above, or 

5. 300 for all other diesel monitors not covered under sections 

(b)(3)(D)(ii)3. and 4. above. 

* * * * 

(6) Finding of Nonconformance after Enforcement Testing. 

After conducting enforcement testing pursuant to section (b)(4) above, the 

Executive Officer shall make a finding of nonconformance of the OBD system in 

the identified engine class under the respective tests for the applicable model 

year(s) as follows: 

(A) OBD Emission Testing. 

(i) For 2010 through 2012 model year engines: 

a. Engines certified as an OBD parent rating (i.e., the engine rating subject 

to the “full OBD” requirement under Cal. Code Regs., title 13, section 

1971.1(d)(7.1.1)), shall be considered nonconforming if the emission 

test results indicate that 50 percent or more of the engines in the test 

sample group do not properly illuminate the MIL when emissions 

exceed 2.0 times the malfunction criteria (e.g., 5.0 times the standard if 

the malfunction criterion is 2.5 times the standard) on the applicable 

standard (i.e., FTP or SET). 

* * * * 

(ii) For 2013 through 2015 model year engines: 

a. All engines classified as OBD parent and child ratings subject to Cal. 

Code Regs., title 13, section 1971.1(d)(7.2.2) shall be considered to be 

nonconforming if the emission test results indicate that 50 percent or 

more of the engines in the test sample group do not properly illuminate 

the MIL when emissions exceed 2.0 times the malfunction criteria (e.g., 

4.0 times the standard if the malfunction criterion is 2.0 times the 

standard) on the applicable standard (i.e., FTP or SET). 

* * * * 

(iii) For 2016 through 2018 model year engines: 

a. PM filter monitors on engines subject to the malfunction criteria of Cal. 

Code Regs., title 13, sections 1971.1(e)(8.2.1)(CD) and (E) shall be 

considered to be nonconforming if the emission test results indicate that 

50 percent or more of the engines in the test sample group do not 

properly illuminate the MIL when emissions exceed 2.0 times the 

malfunction criteria (e.g., PM emission level of 0.06 g/bhp-hr if the 
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malfunction criterion is 0.03 g/bhp-hr) on either any of the applicable 

standards (i.e., FTP or SET). 

b. Monitors on engines and engine ratings previously certified to Cal. 

Code Regs., title 13, section 1971.1(d)(7.2.3) for extrapolated OBD in 

the 2013 through 2015 model years shall be considered nonconforming 

if the emission test results indicate that 50 percent or more of the 

engines in the test sample group do not properly illuminate the MIL 

when emissions exceed 2.0 times the malfunction criteria (e.g., 4.0 

times the standard if the malfunction criterion is 2.0 times the standard) 

on either any of the applicable standards (i.e., FTP or SET). 

c. Monitors on engines not covered under sections (b)(6)(A)(iii)a. and b. 

above shall be considered nonconforming if the emission test results 

indicate that 50 percent or more of the engines in the test sample group 

do not properly illuminate the MIL when emissions exceed the 

malfunction criteria on either any of the applicable standards (i.e., FTP 

or SET). 

(iv) For 2019 and subsequent model year engines, any engine shall be 

considered nonconforming if the results of the tests indicate that 50 

percent or more of the engines in the test sample do not properly 

illuminate the MIL when emissions exceed the malfunction criteria on 

either any of the applicable standards (i.e., FTP or SET). 

(v) The Executive Officer may not consider an OBD system nonconforming 

solely due to a failure or deterioration mode of a monitored component or 

system that could not have been reasonably foreseen to occur by the 

manufacturer. 

(B) OBD Ratio Testing. 

(i) 2013 through 2015 model year engines certified to a ratio of 0.100 in 

accordance with Cal. Code Regs., title 13, section 1971.1(d)(3.2.2) and 

PM filter filtering performance monitors (section 1971.1(e)(8.2.1)) and 

missing substrate monitors (section 1971.1(e)(8.2.5)) on 2016 through 

2018 model year engines shall be considered nonconforming if the data 

collected from the engines in the test sample group indicate either that the 

average in-use monitor performance ratio for one or more of the monitors 

in the test sample group is less than 0.050 or that 66.0 percent or more of 

the engines in the test sample group have an in-use monitor performance 

ratio of less than 0.050 for the same monitor. 

(ii) Except as provided above in section (b)(6)(B)(i) above, 2016 and 

subsequent model year engines certified to a ratio of 0.100 in accordance 

with Cal. Code Regs., title 13, section 1971.1(d)(3.2.2) shall be considered 

nonconforming if the data collected from the engines in the test sample 

group indicate either that the average in-use monitor performance ratio for 

one or more of the monitors in the test sample group is less than 0.088 or 

that 66.0 percent or more of the engines in the test sample group have an 

in-use monitor performance ratio of less than 0.100 for the same monitor. 

(C) All Other OBD Testing. 

* * * * 
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(ii) Engines shall be considered nonconforming if the results of the testing 

indicate that at least 30 percent of the engines in the test sample group do 

not comply with one or more of the requirements of Cal. Code Regs., title 

13, section 1971.1 while the engine is running and while in the key on, 

engine off position such that off-board equipment designed to access the 

following parameters via the standards referenced in Cal. Code Regs., title 

13, section 1971.1 for 2013 and subsequent model year engines cannot 

obtain valid and correct data for the following parameters: 

* * * * 

b. The current MIL command status while the MIL is commanded off and 

while the MIL is commanded on in accordance with SAE J1979/J1939 

and Cal. Code Regs., title 13, section 1971.1(h)(4.2), and in accordance 

with SAE J1979/J1939 and Cal. Code Regs., title 13, section 

1971.1(d)(2.1.2) during the MIL functional check and, if applicable Cal. 

Code Regs., title 13, section 1971.1(h)(4.1.36) during the MIL readiness 

status check; 

* * * * 

(d) Remedial Action. 

* * * * 

(3) Ordered Remedial Action-Mandatory Recall. 

(A) Except as provided in sections (d)(3)(B) below, the Executive Officer shall 

order the recall and repair of all engines in an engine class that have been 

determined to be equipped with a nonconforming OBD system if enforcement 

testing conducted pursuant to sections (b) or (c) above or information 

received from the manufacturer indicates that: 

(i) For major monitors required to meet the in-use performance ratio pursuant 

to Cal. Code Regs., title 13, section 1971.1(d)(3.2) and subject to the 

nonconformance criteria of section (b)(6)(B)(ii) on 2016 and subsequent 

model year engines, the average in-use monitor performance ratio for one 

or more of the major monitors in the test sample group is less than or 

equal to 33.0 percent of the applicable required minimum ratio established 

in Cal. Code Regs., title 13, section 1971.1(d)(3.2.2) (e.g., if the required 

ratio is 0.100, less than or equal to a ratio of 0.033) or 66.0 percent or 

more of the vehicles in the test sample group have an in-use monitor 

performance ratio of less than or equal to 33.0 percent of the applicable 

required minimum ratio established in Cal. Code Regs., title 13, section 

1971.1(d)(3.2.2) for the same major monitor. 

(ii) For major monitors required to indicate a malfunction before emissions 

exceed a certain emission threshold, when the engine is tested in a 

vehicle and operated so as to reasonably encounter all monitoring 

conditions disclosed in the manufacturer’s certification application, the 

OBD system is unable to detect and illuminate the MIL for a malfunction of 

a component/system monitored by the major monitor prior to emissions 

exceeding: 
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a. For 2013 through 2015 model year OBD parent and child ratings 

subject to the “full OBD” requirement under Cal. Code Regs., title 13, 

section 1971.1(d)(7.2.2), three times the applicable major monitor 

malfunction criteria (e.g., if the malfunction criteria is 2.5 times the 

applicable standard, recall would be required when emissions exceed 

7.5 times the applicable standard, or if the malfunction criteria is the PM 

standard plus 0.02 g/bhp-hr and the PM standard is 0.01 g/bhp-hr, 

recall would be required when emissions exceeded 0.09 g-bhp-hr). 

b. For 2016 through 2018 model year engines: 

1. For engine ratings previously certified to Cal. Code Regs., title 13, 

section 1971.1(d)(7.2.3) for “extrapolated OBD” in the 2013 through 

2015 model years, three times the applicable major monitor 

malfunction criteria (e.g., if the malfunction criteria is 2.5 times the 

applicable standard, recall would be required when emissions 

exceed 7.5 times the applicable standard, or if the malfunction 

criteria is the PM standard plus 0.02 g/bhp-hr and the PM standard 

is 0.01 g/bhp-hr, recall would be required when emissions exceeded 

0.09 g-bhp-hr), and 

2. For all other engine ratings, three times the malfunction criteria for 

PM filter monitors subject to Cal. Code Regs., title 13, sections 

1971.1(e)(8.2.1)(CD) and (E) (e.g., if the malfunction criteria is the 

PM standard plus 0.02 g/bhp-hr and the PM standard is 0.01 g/bhphr, recall would be required when emissions exceeded 0.09 g-bhphr) and two times the malfunction criteria for all other applicable 

major monitors. 

c. For 2019 and subsequent model year engines, two times the applicable 

major monitor malfunction criteria (e.g., if the malfunction criteria is 2.5 

times the applicable standards, recall would be required when 

emissions exceed 5.0 times the applicable standards). 

(iii) For misfire monitor: 

a. Gasoline misfire monitor: For 2016 and subsequent model year 

gasoline engines, the monitor for misfire causing catalyst damage is 

unable to properly detect and illuminate the MIL for misfire rates that 

are more than 20 percentage points greater than the misfire rates 

disclosed by the manufacturer in its certification application as causing 

catalyst damage (e.g., if the disclosed misfire rate is 12 percent, recall 

would be required if the misfire rate is greater than 32 percent without 

proper detection). 

b. Diesel misfire monitor: For 2019 and subsequent model year diesel 

engines, the misfire monitor is unable to properly detect and illuminate 

the MIL for misfire rates that are more than 10 percentage points 

greater than the misfire malfunction criteria specified in section Cal. 

Code Regs., title 13, section 1971.1(e)(2.2.2) (e.g., misfire rate more 

than 15 percent if the misfire malfunction criteria is 5 percent). 

(iv) For 2016 and subsequent model year gasoline engines, when the engine 

is tested in a vehicle and operated so as to reasonably encounter all 
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monitoring conditions disclosed in the manufacturer’s certification 

application, the evaporative system monitor is unable to detect and 

illuminate the MIL for a cumulative leak or leaks in the evaporative system 

equivalent to that caused by an orifice with a diameter of at least 1.5 times 

the diameter of the required orifice in Cal. Code Regs., title 13, section 

1971.1(f)(7.2.2)(B). 

(v) When the engine is tested in a vehicle and operated so as to reasonably 

encounter all monitoring conditions disclosed in the manufacturer’s 

certification application, the OBD system cannot detect and illuminate the 

MIL for a malfunction of a component that effectively disables a major 

monitor and the major monitor, by being disabled, meets the criteria for 

recall identified in sections (d)(3)(A)(ii) or (iv) above (e.g. is unable to 

detect and illuminate the MIL for malfunctions that cause FTP emissions 

to exceed two times the malfunction criteria). 

(vi) For 2013 and subsequent model year diesel engines, when the engine is 

tested in a vehicle and operated so as to reasonably encounter all 

monitoring conditions disclosed in the manufacturer’s certification 

application, the PM filter monitor is unable to detect and illuminate the MIL 

for any of the following: 

a. a missing substrate fault in accordance with title 13, CCR section 

1971.1(e)(8.2.5); or 

b. a malfunction of the PM filter that causes PM emissions to be equal to 

or greater than the emission level of the engine, as measured from an 

applicable emission test cycle (i.e., FTP or SET), with the PM filter 

substrate completely removed. 

(vi)(vii) The engine class cannot be tested so as to obtain valid test results in 

accordance with the criteria identified in section (b)(6)(C)(ii) due to the 

nonconforming OBD II system. 

* * * * 

 

NOTE: Authority cited: Sections 39010, 39600, 39601, 43000.5, 43013, 43016, 43018, 43100, 43101, 

43104, 43105, 43105.5, 43106, 43154, 43211, and 43212, Health and Safety Code. Reference: 

Sections 39002, 39003, 39010, 39018, 39021.5, 39024, 39024.5, 39027, 39027.3, 39028, 39029, 

39031, 39032, 39032.5, 39033, 39035, 39037.05, 39037.5, 39038, 39039, 39040, 39042, 

39042.5, 39046, 39047, 39053, 39054, 39058, 39059, 39060, 39515, 39600, 39601, 43000, 

43000.5, 43004, 43006, 43013, 43016, 43018, 43100, 43101, 43102, 43104, 43105, 43105.5, 

43106, 43150, 43151, 43152, 43153, 43154, 43155, 43156, 43204, 43211, and 43212, Health 

and Safety Code.