State of California

AIR RESOURCES BOARD

Notice of Public Availability of Modified Text and

Availability of Additional Documents

PUBLIC HEARING TO CONSIDER TECHNICAL STATUS AND PROPOSED 

REVISIONS TO ON-BOARD DIAGNOSTIC SYSTEM REQUIREMENTS FOR 

HEAVY-DUTY ENGINES, PASSENGER CARS, LIGHT-DUTY TRUCKS, MEDIUMDUTY VEHICLES AND ENGINES

Public Hearing Date: August 23, 2012

Public Availability Date: January 4, 2013

Deadline for Public Comment: January 25, 2013

At its August 23, 2012 public hearing, the Air Resources Board (ARB or Board) 

approved for adoption amendments with modifications to the California Code of 

Regulations, title 13, sections 1968.2, 1968.5, 1971.1, and 1971.5. Upon becoming 

operative, the amendments would update the on-board diagnostic (OBD II) 

requirements for light-duty and medium-duty vehicles and engines and the heavy-duty 

on-board diagnostic (HD OBD) requirements for heavy-duty vehicles and engines, as 

well as the associated enforcement requirements. 

At the hearing, the Board adopted Resolution 12-29 in which it approved for adoption 

amendments to sections 1968.2, 1968.5, 1971.1, and 1971.5, as modified by staff’s 

suggested modifications presented to the Board at the August 23, 2012 hearing. The 

modifications were made in response to comments received since the Staff Report was 

published on July 5, 2012, as part of the 45-day notice. These modifications include 

changes to the required monitoring conditions for the diesel misfire monitor 

requirements in the HD OBD and OBD II regulations, clarifications to the readiness 

status and test results requirements in the HD OBD regulation, deletion of the service 

information requirements in the HD OBD regulation, and various changes to correct 

errors and improve clarity. The resolution and all other regulatory documents for this 

rulemaking are available online at the following ARB website:

http://www.arb.ca.gov/regact/2012/hdobd12/hdobd12.htm

In accordance with the Government Code, section 11346.8, the Board directed the 

Executive Officer to adopt the approved amendments after making them available to the 

public for comment for a period of at least fifteen days. The Board further provided that 

the Executive Officer shall consider such written comments as may be submitted during 

this period, shall make such modifications as may be appropriate in light of the 

comments received, and shall present the regulations to the Board for further 

consideration if warranted. 
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Modifications to the proposed text are set forth in Attachment A to this notice, which

contains relevant portions of sections 1971.1, 1968.2, 1971.5, and 1968.5 affected by 

the modifications being proposed with this notice. For sections 1971.1, 1971.5, and 

1968.5, the amendments proposed with the 45-day notice are shown in single underline

to indicate additions and single strikeout to indicate deletions from the existing 

regulatory text, while amendments proposed with this 15-day notice are shown in 

double underline to indicate additions and double strikeout to indicate deletions from the 

existing regulatory text. For section 1968.2, the amendments that were approved by the 

Board at the January 26-27, 2012 board hearing are shown in single underline to 

indicate additions and single strikeout to indicate deletions from the existing regulatory 

text. These amendments were formally approved by the Office of Administrative Law 

on August 7, 2012, and became operative on that date. The amendments proposed 

with the 45-day notice are shown in double underline to indicate additions and double 

strikeout to indicate deletions from the existing regulatory text, while new amendments 

proposed with this 15-day notice are shown in bold italic double underline to indicate 

additions and bold italic double strikeout to indicate deletions from the existing 

regulatory text.

Summary of Proposed Modifications

Modifications to HD OBD Regulation (section 1971.1)

1. Section 1971.1(c): As part of the 45-day notice, staff proposed a new definition of 

“alternate phase-in” that is similar to that currently provided in the OBD II regulation 

and would provide manufacturers with compliance flexibility in meeting some 

regulation requirements with prescribed phase-in schedules. As part of this 15-day 

notice, staff corrected a mistake in the example calculation in the last paragraph of 

the definition that referred to “2013”; the amendment has been corrected to indicate

“2016”. 

Additionally, as part of the 45-day notice, staff proposed modifications to the

definition of “diagnostic or emission critical” electronic control unit to clarify which 

control units would fall under this definition and thus would be required to report a 

calibration identification number (CAL ID) and calibration verification number (CVN) 

combination. With the advent of more and more electronic controllers or ‘smart’ 

sensors that have integrated controllers on vehicles, the existing definition resulted 

in many modules with relatively minor roles in the OBD system having to support 

CAL ID and CVN. To better realign the requirements to the original intent of having 

this apply only to the controllers with the most critical OBD content, the proposal in 

the 45-day notice attempted to increase the amount of OBD content in a controller 

that would trigger the need for CAL ID and CVN. However, manufacturers have 

expressed concern that some elements of the proposed definition would increase 

the number of controllers subject to the requirement, including those that had 

relatively minor roles, and that some language in the definition was too broad to 

interpret consistently. After discussions with manufacturers, staff has revised the 
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definition to address both of these concerns. The latest revision does increase the 

amount of OBD content for most controllers before CAL ID and CVN would be 

required while still providing assurance that the controllers with the most critical OBD 

content will have CAL ID and CVN. The revision more directly targets inclusion of 

controllers that are at higher risk for being modified or tampered by including 

controllers that are reprogrammable and have material OBD content.

Finally, in the 45-day notice, staff proposed for the purposes of HD OBD compliance 

the addition of a definition of “emission standard” that differs from the definition of 

that term as set forth in Health and Safety Code section 39027. Health and Safety 

Code sections 39010 and 39601(b) authorizes the use of such revised definitions in 

ARB-adopted regulations for the purpose of conforming definitions to federal laws, 

rules and regulations. The definition proposed in the 45-day notice conforms to the 

federal definition of that term as interpreted by the U.S. Supreme Court in Engine 

Manufacturers Association v. South Coast Air Quality Management District (2004) 

541 U.S. 246, 253, 124 S.Ct. 1756, 1762. The proposed definition makes it clear 

that OBD systems, in general, and OBD design-feature requirements of sections 

1971.1 and 1968.2, specifically, are emission standards. Health and Safety Code 

section 39010 further provides that the definitions set forth in the Health and Safety 

Code govern the construction of Division 26 of the Health and Safety Code, 

including and until ARB revises those definitions in its regulations. The revised 

definition of emission standard would thus govern the construction of that term as

used in the Division 26. To make this clear, staff is proposing that the definition be 

further modified to specifically reference that the definition not only applies to OBD 

compliance but also to the remedies provided in the Health and Safety Code for 

noncompliance

2. Section 1971.1(e)(1.4.2)(D): As part of the 45-day notice, staff proposed 

modifications to the freeze frame requirements for engines using the International 

Organization for Standardization (ISO) 15765-4 protocol to require storage of freeze 

frame conditions when storing pending fault codes under section 

1971.1(d)(2.2.1)(D)(iii). In making this change, staff mistakenly did not align the

proposed amendments with the freeze frame requirements under the diesel fuel 

system monitor section, which currently allows storage of freeze frame conditions in 

conjunction with storage of a confirmed fault code. Modifications are being 

proposed to address this error. 

3. Section 1971.1(e)(2.3.3)(A): As part of the 45-day notice, staff proposed that

manufacturers begin to phase-in monitors starting in the 2016 model year to detect a 

misfire fault when the percentage of misfire exceeds a certain level and to 

continuously monitor for diesel misfire under nearly all positive torque conditions up 

to 75 percent of the maximum engine speed and load. Further, the 45-day proposed 

modifications included a phase-in starting in the 2019 model year to expand the 

monitoring to all positive torque engine speed and load conditions up to 100 percent 

of the maximum rated engine speed and load. Manufacturers have commented that 
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it would be more consistent with terminology of the heavy-duty industry to limit 

monitoring to under 75 percent of the peak torque instead of 75 percent of the 

maximum load, and that it would also be beneficial during the initial phase-in starting 

in 2016 to limit monitoring to above a minimum torque condition because they 

anticipate robust detection of misfire at the lower torque ranges will be difficult. In 

response, staff is proposing to modify section 1971.1(e)(2.3.3)(A)(i) for the initial 

phase-in to require manufacturers to continuously monitor for diesel misfire under 

positive torque conditions between 20 and 75 percent of peak torque and up to 75 

percent of the maximum engine speed. The proposed inclusion of the minimum 

torque enablement criterion would effectively cover a limited disablement area of 

very low torque and high engine speed conditions, which was initially proposed as 

part of the 45-day notice, making the initial proposal unnecessary. Staff is 

consequently proposing to delete the originally proposed disablement area from 

section 1971.1(e)(2.3.3)(A)(i). For the final phase-in to full-range misfire monitors 

beginning in 2019, staff mistakenly forgot to add the limited disablement area that is

necessary to avoid false detections. Staff is now proposing to add this disablement 

allowance to section 1971.1(e)(2.3.3)(A)(ii).

4. Section 1971.1(e)(2.3.3)(C): In response to requests from industry wanting more 

specific language regarding diesel misfire monitor disablement, staff is proposing 

new language similar to the language currently in the gasoline misfire monitoring 

section, which allows manufacturers to disable diesel misfire monitoring or use an 

alternate malfunction criteria during certain conditions. The proposed language 

specifies that disablement may be approved under conditions such as rough road, 

fuel cut, and when intrusive diagnostics or infrequent regeneration events may

significantly affect engine stability. 

5. Section 1971.1(e)(2.4.2)(B)(i): As with proposed modification 2. above, as part of the 

45-day notice, staff proposed modifications to the freeze frame requirements for 

engines using the ISO 15765-4 protocol to require storage of freeze frame 

conditions when storing pending fault codes under section 1971.1(d)(2.2.1)(D)(iii). 

In making this change, staff again mistakenly did not align these amendments with 

the freeze frame requirements under the diesel misfire monitor section. 

Modifications are now being proposed to address this.

6. Sections 1971.1(e)(5.2.3)(B), (e)(8.2.4)(A)(iii), (e)(8.2.4)(B), and (g)(3.2.2)(F)(ii): As 

part of the 45-day notice, staff proposed language allowing manufacturers to be 

exempt from specific monitoring requirements if certain conditions are met related to 

the “applicable full useful life standard.” Manufacturers have indicated that there is

only one set of applicable standards for heavy-duty engines, and thus the term “full 

useful life” is not necessary and may cause confusion. Staff therefore is proposing 

to delete the phrase “full useful life” from these sections. Further, staff is proposing 

modifications to improve the clarity and address confusion about the criteria 

manufacturers have to meet to be exempt from monitoring. Specifically, the 

proposed modifications would make clearer that exemption is only allowed if (1) no 
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fault can cause emissions to increase by 15 percent or more of the applicable 

standard, and (2) no fault can cause emissions to exceed the applicable standard.

7. Section 1971.1(g)(5.7): As part of the 45-day notice, staff proposed language that 

would allow manufacturers to request Executive Officer approval to be exempt from 

monitoring a component if a failure only affects emissions or other diagnostics when 

the ambient temperature is below 20 degrees Fahrenheit. There has been some 

confusion about the language, and staff believes additional modifications are needed

to ensure consistent interpretation and implementation by manufacturers. 

Specifically, staff is proposing to delete the requirement that manufacturers request 

Executive Officer approval and provide supporting data for such exemptions. 

Instead, manufacturers would be required to provide supporting data only when staff 

reasonably believes a manufacturer has inappropriately determined that a 

component falls under the exemption criteria. Staff additionally proposed that 

manufacturers provide more details about the supporting data; specifically the 

Executive Officer would be able to request emission data for any reasonable driving 

condition above 20 degrees Fahrenheit.

8. Section 1971.1(g)(5.8): As part of the 45-day notice, staff proposed a new definition 

of “alternate phase-in” and new prescribed phase-in schedules for requirements 

under the oxides of nitrogen (NOx) catalyst and NOx and particulate matter (PM)

sensor monitoring requirements. However, as proposed, the alternate phase-in 

calculation methodology under the “alternate phase-in” definition was difficult to 

directly apply to the required phase-ins for the monitors listed above. The 

referenced phase-ins are more complicated than typical phase-ins because they 

include a partial phase-in requiring less than 100 percent of the vehicles to meet an 

interim, less stringent malfunction threshold in the first few years and then a second 

phase-in to meet the final malfunction threshold. Specifically, the first phase-in 

requires a minimum of 20 and 50 percent of diesel engines to comply with an interim 

threshold of +0.3 g/bhp-hr NOx in the 2014 and 2015 model years, respectively. 

The second phase-in requires 100 percent compliance to a final threshold of +0.2 

g/bhp-hr NOx in the 2016 model year. To provide additional flexibility to 

manufacturers, the proposed regulatory language allows engines phased-in during 

the 2014 or 2015 model years to the interim threshold of +0.3 g/bhp-hr NOx to be 

carried over into the 2016 model year and not required to meet the final +0.2 g/bhphr NOx threshold until the 2017 model year, which further complicates the second 

phase-in. Given the additional complexities of these two overlapping phase-ins, 

additional clarifying language is being proposed so manufacturers will have clear 

direction as to how to apply the alternate phase-in calculations for these specific 

monitors. Specifically, staff is proposing language (newly proposed section 

1971.1(g)(5.8.3)) that would allow manufacturers to use, with Executive Officer 

approval, a manufacturer-defined phase-in that would provide an equivalent 

compliance volume of engines meeting the requirement as the prescribed phase-in 

for these monitors. The manufacturer-defined phase-in would be approved provided 

the calculated compliance volume met or exceeded the required phase-in 
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compliance volume and the manufacturer met several criteria specifically identified 

in the proposed language regarding which engines to include and exclude from the 

calculation of the equivalent compliance volume. 

For the first phase-in at the interim threshold of +0.3 g/bhp-hr NOx, the language 

clarifies that the compliance volume for the required phase-in is calculated with 20 

and 50 percent in the 2014 and 2015 model years, respectively, and engines 

meeting this threshold no earlier than the 2013 model year would be counted 

towards meeting the requirements. Also consistent with the methodology of typical 

alternate phase-ins, all manufacturer-defined phase-ins would need to result in “full”

compliance (i.e., 50 percent at +0.3 g/bhp-hr) no later than the 2017 model year, and 

for those manufacturer-defined phase-ins that result in less than 50 percent of the 

diesel engines complying in the 2016 model year, engines not meeting the 

+0.3 g/bhp-hr threshold in the 2015 and 2016 model years would need to be 

subtracted from the compliance volume calculation. Lastly, because engines 

meeting the final +0.2 g/bhp-hr threshold are meeting a more stringent threshold 

than engines meeting the interim +0.3 g/bhp-hr threshold, the language would clarify 

that engines meeting the +0.2 g/bhp-hr threshold during the 2013 through 2017 

model years would also be deemed as complying with the +0.3 g/bhp-hr threshold 

and would not be counted against the manufacturer. 

For the second phase-in at the final threshold of +0.2 g/bhp-hr NOx, the language 

clarifies that this is considered a second stand-alone phase-in for which the 

compliance volume is calculated with 100 percent in the 2016 model year for the 

required phase-in. As such, engines meeting the +0.2 g/bhp-hr threshold no earlier 

than the 2015 model year would be counted towards meeting the second phase-in 

and all engines would need to comply with the threshold by the 2018 model year. 

Further, for manufacturer-defined phase-ins that do result in some engines not 

complying in the 2017 model year, those engines not meeting the +0.2 g/bhp-hr

threshold in the 2016 and 2017 model years would be subtracted from the 

compliance volume calculation. And lastly, to address the additional flexibility 

mentioned above in which engines previously certified in the 2014 or 2015 model 

years to the interim +0.3 g/bhp-hr threshold are allowed to be carried over into the 

2016 model year and not certified to the final +0.2 g/bhp-hr threshold until the 2017 

model year, the language clarifies that all 2016 model year engines using this carryover provision would also be deemed as complying with the +0.2 g/bhp-hr final 

threshold and would not be counted against the manufacturer.

9. Section 1971.1(h)(4.1.1) and (h)(4.1.3)(B): As part of the 45-day notice, staff 

proposed changes to the readiness status requirements, including identifying 

specific monitored component/systems for which the readiness status shall always 

indicate “complete” and identifying the specific monitors that are required to be 

included in the readiness status for other monitored component/systems. 

Additionally, staff proposed that for the diesel misfire monitor, the readiness status 

would indicate “complete” if the idle-only misfire monitor (i.e., the monitor that meets 
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section 1971.1(e)(2.2.1)) has fully executed. Manufacturers, however, have 

indicated that they may not have a separate monitor for the idle-only monitoring 

requirement. Instead, they may use the continuous misfire monitor that runs during 

all required driving conditions, including idle. Monitored component/systems that 

only have continuous monitors are generally required to have their readiness status 

always indicate “complete” since the monitors should run all the time. Thus, staff is 

proposing to require manufacturers with a separate monitor designed to detect 

misfires identified in section 1971.1(e)(2.2.1) to set the diesel misfire readiness 

status to “complete” if this separate monitor has fully executed, while manufacturers 

without a separate monitor would be required to always set the diesel misfire 

readiness status to “complete” since they would only have the continuous misfire 

monitor.

10.Section 1971.1(h)(4.5.5): This section covers test results requirements, specifically 

requiring test results and limits to report values of zero after the OBD system fault 

memory is cleared. Manufacturers have indicated that the requirements are not 

aligned with the current specifications in Society of Automotive Engineers (SAE)

J1939-73, which require test results and limits to report specific non-zero values that 

correspond to “test not complete” after the fault memory is cleared. Thus, for the 

2010 through 2015 model years, staff is proposing that manufacturers be allowed to 

have the test results and limits report either values of zero as originally specified in 

the regulation or the specific non-zero values corresponding to “test not complete” in 

accordance with SAE J1939-73. Further, staff is proposing that 2016 and 

subsequent model year engines be required to align with SAE J1939-73 and only 

report the specific non-zero values for test results and limits corresponding to “test 

not complete.”

11.Section 1971.1(h)(6): This section covers the service information requirements for 

HD OBD. At the time this section was first adopted in 2005, there were no separate 

service information requirements specific to heavy-duty engines. Since then, the 

Board has adopted a separate ARB regulation (California Code of Regulations, title 

13, section 1969) that prescribes service information requirements for heavy-duty 

engines. Thus, staff is proposing to delete the service information requirements 

under section 1971.1(h)(6). 

12.Section 1971.1(i)(3.1.2): The HD OBD regulation requires manufacturers to perform 

demonstration testing on monitors to ensure they are able to detect faults before the 

required emission thresholds are exceeded. As part of the 45-day notice, staff 

proposed changes to require manufacturers to detect diesel misfire when the 

percentage of misfire exceeds a certain percentage instead of when specific 

emission thresholds are exceeded. With this change, staff also proposed to exempt 

manufacturers from performing demonstration testing on the diesel misfire monitor. 

In making this latter change, staff, however, mistakenly overlooked proposed section 

1971.1(e)(2.2.5), which would allow manufacturers to use an alternative malfunction 

criterion that would be calibrated to an emission level if emissions are below a 
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certain emission threshold. To correct this oversight, staff is proposing that

manufacturers be required to perform demonstration testing on the diesel misfire 

monitor if it is calibrated using the alternative emission threshold of section 

1971.1(e)(2.2.5).

13.Section 1971.1(k)(4): This section covers the carryover provisions for deficiencies

that allow deficiencies to be carried over if manufacturers have met certain criteria. 

Manufacturers may carry over deficiencies in such cases for a maximum of two 

model years from the first year the deficiency was originally granted, unless 

hardware changes are needed, in which case the deficiency can be carried over for 

a maximum of three model years. Manufacturers have expressed concern that they 

have not been able to correct some deficiencies that were first granted in the 2010 

or 2011 model years in time for the 2013 or 2014 model year and they will be 

prohibited from carrying those deficiencies over to those model years. To address 

this, staff recognizes that in many cases, manufacturers have been making a good 

faith effort to bring their systems into full compliance but that the workload of 

addressing all of the identified deficiencies on their first-ever OBD systems at the 

same time they are expanding implementation from one engine family in 2010 to all 

engine families in 2013 has been taxing. Thus, staff is proposing to allow 

manufacturers to request Executive Officer approval to carryover deficiencies first 

granted in the 2010 model year up through the 2013 model year if no hardware 

changes are needed and through the 2014 model year if hardware changes are 

needed. For deficiencies first granted in 2011, manufacturers would be allowed to 

carryover deficiencies through the 2014 model year. 

Modifications to OBD II Regulation (section 1968.2)

14.Section 1968.2(c): See discussion of further modifications to the definition of 

“emission standard,” at 1. above, which applies equally to the proposed 

modifications to the same term in the OBD II regulation.

15.Sections 1968.2(e)(15.4.3), (f)(1.2.2)(A)(ii), (f)(2.2.2)(A)(ii), (f)(4.2.1)(A)(ii), 

(f)(5.2.1)(A)(i)b., (f)(5.2.1)(B)(i)b., (f)(5.2.2)(A)(ii), (f)(6.2.1)(A)(ii), (f)(7.2.1)(A)(ii), 

(f)(8.2.1)(A)(ii), (f)(9.2.2)(A)(ii), (f)(12.2.2)(B)(i), (f)(13.2.1)(B), (f)(15.4.3), and 

(f)(17.1.3): As part of the 45-day notice, staff proposed a new definition for “emission 

standard” to clarify that the OBD regulations include emission standards, and 

proposed new definitions for “exhaust emission standards” and “tailpipe emission 

standards” to identify respective subcategories of the new definition of “emission 

standard” that had previously merely been identified in the regulation as emission 

standards. Staff, however, mistakenly failed to make specific all of the previous 

general references to emission standards to align those references with the new 

subcategory definitions. It is now proposing to specifically identify the appropriate 

subcategory references. 
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16.Sections 1968.2(f)(1.2.3)(B), (f)(9.2.4)(A), and (f)(15.2.2)(F)(ii): As part of the 45-day 

notice, staff proposed language allowing manufacturers to be exempt from specific 

monitoring requirements if certain conditions are met. Staff is proposing 

modifications to improve the clarity and address confusion about the criteria 

manufacturers have to meet to be exempt from monitoring. Specifically, the 

proposed modifications would make it clearer that exemption is allowed if (1) no fault 

can cause emissions to increase by 15 percent or more of the applicable full useful 

life standard, and (2) no fault can cause emissions to exceed the applicable full 

useful life standard.

17.Section 1968.2(f)(2.3): As part of the 45-day notice, staff proposed a change to the 

HD OBD regulation to only require the NOx converting catalyst reductant delivery 

performance monitor to run once per trip instead of continuously, since the original 

requirement was found to be inappropriate and too stringent. Staff mistakenly did 

not include this change in the OBD II regulation for medium-duty diesels; it is now

proposing the same change to the OBD II regulation. 

18.Section 1968.2(f)(3.3.3)(B): As part of the 45-day notice, staff proposed 

modifications requiring manufacturers to phase-in monitors starting in the 2016 

model year for medium-duty diesel vehicles to detect a misfire fault when the 

percentage of misfire exceeds a certain level and to continuously monitor for diesel 

misfire under nearly all positive torque conditions up to 75 percent of the maximum 

engine speed and load. Further, the 45-day proposed modifications included a 

phase-in starting in the 2019 model year to expand the monitoring to all positive 

torque engine speed and load conditions (up to 100 percent of the maximum rated 

engine speed and load). Manufacturers have commented that it would be more 

consistent with terminology in the heavy-duty industry to limit monitoring to under 75 

percent of the peak torque instead of 75 percent of the maximum load. Staff is thus 

proposing to modify section 1968.2(f)(3.3.3)(B)(i) for the initial phase-in starting in 

2016 to require manufacturers to continuously monitor for diesel misfire under 

positive torque conditions up to 75 percent of the peak torque with engine speed 

below 75 percent of the maximum speed. Additionally, staff has found that the

limited low torque and high engine speed disablement area allowed under section 

1968.2(f)(3.3.3)(B)(i) would be necessary both during the 2016 phase-in and for the 

final phase-in starting in 2019 when the monitors are enabled under all positive 

torque engine speed and load conditions, and is proposing to add this disablement 

allowance to section 1968.2(f)(3.3.3)(B)(ii).

19.Section 1968.2(f)(3.3.3)(D): In response to requests from industry wanting more 

specific language regarding diesel misfire monitor disablement, staff is proposing 

new language similar to the language currently in the gasoline misfire monitoring 

section, which allows manufacturers to disable diesel misfire monitoring or use an 

alternate malfunction criteria during certain conditions. The proposed language 

specifies that disablement may be approved under conditions, such as rough road, 
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fuel cut, and when intrusive diagnostics or infrequent regeneration events may 

significantly affect engine stability.

20.Section 1968.2(f)(5.3.1)(A): As part of the 45-day notice, staff proposed to require 

manufacturers to track and report the in-use monitoring performance data of the 

diesel NOx sensor monitoring capability monitor on 2016 and subsequent model 

year “medium-duty vehicles certified to an engine dynamometer tailpipe emission 

standard.” Staff mistakenly meant to require this on all medium-duty vehicles and is 

proposing to delete the phrase “certified to an engine dynamometer tailpipe emission 

standard” from this section.

21.Section 1968.2(f)(6.2.6): As part of the 45-day notice, staff proposed to allow 

manufacturers to be exempt from monitoring the diesel exhaust gas recirculation 

(EGR) catalyst if a fault of the catalyst could not cause a measurable emission 

impact on the criteria pollutants in the HD OBD regulation. Staff mistakenly did not 

include this change in the OBD II regulation; it is proposing to allow this same 

exemption criterion in the OBD II regulation. 

22.Section 1968.2(f)(9.2.4)(B): As part of the 45-day notice, staff proposed to require 

manufacturers to monitor the catalyzed PM filter for proper feedgas generation 

starting with the 2016 model year in the HD OBD regulation. Staff mistakenly did not 

include this change in the OBD II regulation and is proposing to require 2016 and 

subsequent model year medium-duty vehicles to monitor the catalyzed PM filter for 

proper feedgas generation.

23.Section 1968.2(h)(4.3): The OBD II regulation requires manufacturers to perform 

demonstration testing on monitors to ensure they are able to detect faults before the 

required emission thresholds are exceeded. As part of the 45-day notice, staff 

proposed changes to require manufacturers to detect diesel misfire on medium-duty 

vehicles when the percentage of misfire exceeds a certain percentage instead of 

when specific emission thresholds are exceeded. With this change, staff also 

proposed changes to the demonstration testing requirements for diesel misfire 

monitoring which would specifically require testing only for those vehicles with 

misfire monitors calibrated to an emission malfunction threshold (i.e., those meeting 

section 1968.2(f)(3.2.2)(A)(i)). Staff, however, mistakenly overlooked proposed 

section 1968.2(f)(3.2.5), which would allow manufacturers to use an alternative 

malfunction criterion that would be calibrated to an emission level if emissions are 

below a certain emission threshold. To correct this oversight, staff is proposing that

manufacturers be required to perform demonstration testing on the diesel misfire 

monitor if it is subject to section 1968.2(f)(3.2.2)(A)(i) or calibrated using the 

alternative emission threshold of section 1968.2(f)(3.2.5).
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Modifications to HD OBD and OBD II Enforcement Regulations (sections 1971.5 and 

1968.5)

24.Sections 1971.5(a)(3) and 1968.5(a)(3), definitions of “Nonconforming OBD 

System”: The HD OBD and OBD II enforcement regulations respectively establish 

procedures to ensure that vehicles and engines certified for sale in California are 

equipped with OBD systems that properly function and meet the purposes and 

respective requirements of sections 1971.1 and 1968.2, and that OBD systems that 

fail to meet those requirements are nonconforming and subject to remedial action, 

including recall. In the 45-day notice, ARB staff proposed, for the purposes of OBD 

compliance, that a specific definition of “emission standard” (different from the 

definition set forth in Health and Safety Code section 39027) be added to the HD 

OBD and OBD II regulations. (See discussion in 1. above regarding rationale for 

amended definition of “emission standard” and Initial Statement of Reasons: Staff 

Report issued with 45-day notice, at pages 8 and 18.) ARB staff is now proposing 

that the definitions of “nonconforming OBD system” in the associated enforcement 

regulations be modified to reference this new emission standard definition. 

Specifically, that a nonconforming OBD system is an OBD system on a production 

engine/vehicle that has been determined not to meet the emission standards of 

sections 1971.1 and 1968.2. Additionally, for purposes of clarity, the reference in 

the definitions to tailpipe emission standards has been replaced with the term 

“exhaust emission standards,” a term that is more generally used but has the same 

meaning.

Other Minor Modifications

25.In addition to the modifications described above, staff is proposing various 

nonsubstantive modifications to the regulatory text in sections 1971.1 and 1968.2 to 

improve clarity and to correct errors that have found by staff and industry.

Additional Document(s) Added to the Record

In the interest of completeness, staff has also added to the rulemaking record and 

invites comments on Attachment B, “Additional Supporting Documents and Information” 

and Attachment C, “S&P 500 Index: Annual Returns.” These documents are also 

available at the following website:

http://www.arb.ca.gov/regact/2012/hdobd12/hdobd12.htm

Written comments will only be accepted on the modifications and document identified in 

this notice and may be submitted by postal mail or electronic mail submittal as follows:

Postal mail: Clerk of the Board, Air Resources Board

1001 I Street, Sacramento, California 95814

Electronic submittal: http://www.arb.ca.gov/lispub/comm/bclist.php
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Please note that under the California Public Records Act (Gov. Code § 6250 et seq.), 

your written and verbal comments, attachments, and associated contact information 

(e.g., your address, phone, email, etc.) become part of the public record and can be 

released to the public upon request. 

In order to be considered by the Executive Officer, comments must be directed to ARB 

in one of the two forms described above and received by ARB by 5:00 p.m., on the 

deadline date for public comment listed at the beginning of this notice. Only comments 

relating to the above-described modifications to the text of the regulations shall be 

considered by the Executive Officer.

If you need this document in an alternate format or another language, please contact 

the Clerk of the Board at (916) 322-5594 or by facsimile at (916) 322-3928 no later than 

five (5) business days from the release date of this notice. TTY/TDD/Speech to Speech 

users may dial 711 for the California Relay Service.

Si necesita este documento en un formato alterno u otro idioma, por favor llame a la 

oficina del Secretario del Consejo de Recursos Atmosféricos al (916) 322-5594 o envíe 

un fax al (916) 322-3928 no menos de cinco (5) días laborales a partir de la fecha del 

lanzamiento de este aviso. Para el Servicio Telefónico de California para Personas con 

Problemas Auditivos, ó de teléfonos TDD pueden marcar al 711. 

Attachments

The energy challenge facing California is real. Every Californian needs to take immediate action to 

reduce energy consumption. For a list of simple ways you can reduce demand and cut your energy 

costs, see ARB’s website at www.arb.ca.gov.
Attachment A

PROPOSED 15-DAY MODIFIED REGULATION ORDER

Amend section 1971.1, title 13, California Code of Regulations, to read as follows: 

Note: The amendments proposed with the 45-day notice are shown in single underline

to indicate additions and single strikeout to indicate deletions from the existing 

regulatory text, while amendments proposed with this 15-day notice are shown in 

double underline to indicate additions and double 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 “ * * * * ”. 

§1971.1. On-Board Diagnostic System Requirements--2010 and Subsequent 

Model-Year Heavy-Duty Engines

(c) Definitions.

* * * *

“Alternate phase-in”, as allowed in section (g)(5.8), is a phase-in schedule that 

achieves equivalent compliance volume by the end of the last year of a scheduled 

phase-in provided in this regulation. The compliance volume is the number 

calculated by multiplying the percent of engines (based on the manufacturer’s 

projected sales volume of all engines unless specifically stated otherwise in section 

(e), (f), or (g)) meeting the new requirements per year by the number of years 

implemented prior to and including the last year of the scheduled phase-in and then 

summing these yearly results to determine a cumulative total (e.g., a three year, 

20/50/100 percent scheduled phase-in would be calculated as (20*3 years) + (50*2 

years) + (100*1 year) = 260; a two-year 20/50 percent scheduled phase-in would be 

calculated as (20*2 years) + (50*1 year) = 90). Manufacturers are allowed to include 

engines introduced before the first year of the scheduled phase-in (e.g., in the 

previous example, 10 percent introduced one year before the scheduled phase-in 

begins would be calculated as (10*4 years) and added to the cumulative total). 

However, manufacturers are only allowed to include engines introduced up to one 

model year before the first year of the scheduled phase-in. The Executive Officer 

shall consider acceptable any alternate phase-in that results in an equal or larger 

cumulative total by the end of the last year of the scheduled phase-in and ensures 

that all engines subject to the phase-in will comply with the respective requirements 

no later than two model years following the last year of the scheduled phase-in.

For alternate phase-in schedules resulting in all engines complying one model 

year following the last year of the scheduled phase-in, the compliance volume 

shall be calculated as described directly above. For example, a 20/50/100 

percent scheduled phase-in during the 2016-2018 model years would have a 

cumulative total of 260. If the manufacturer’s planned alternate phase-in 

schedule is 40/50/80/100 percent during the 2016-2019 model years, the final 
2

compliance volume calculation would be (40*3 years) + (50*2 years) + (80*1 

year) = 300, which is greater than 260 and therefore would be acceptable as an 

alternate phase-in schedule.

For alternate phase-in schedules resulting in all engines complying two model 

years following the last year of the scheduled phase-in, the compliance volume 

calculation shall be calculated as described directly above and shall also include 

a negative calculation for engines not complying until one or two model years 

following the last year of the scheduled phase-in. The negative calculation shall 

be calculated by multiplying the percent of engines not meeting the new 

requirements in the final year of the phase-in by negative one and the percent of 

engines not meeting the new requirements in the one year after the final year of 

the phase-in by negative two. For example, if 10 percent of a manufacturer’s 

engines did not comply by the final year of the scheduled phase-in and 5 percent 

did not comply by the end of the first year after the final year of the scheduled 

phase-in, the negative calculation result would be (10*(-1 years)) + (5*(-2 years)) 

= -20. The final compliance volume calculation is the sum of the original 

compliance volume calculation and the negative calculation. For example, a 

20/50/100 percent scheduled phase-in during the 2016-2018 model years would 

have a cumulative total of 260. If a manufacturer’s planned alternate phase-in 

schedule is 40/70/80/90/100 percent during the 20132016-2020 model years, the 

final compliance volume calculation would be (40*3 years) + (70*2 years) + (80*1 

year) + (20*(-1 year)) + (10*(-2 years)) = 300, which is greater than 260 and 

therefore would be acceptable as an alternate phase-in schedule.

* * * *

“Diagnostic or emission critical” electronic control unit refers to the engine control 

unit and any other on-board electronic powertrain control unit containing software

that: 

(1) determines the commanded value(s) for any of the following:

(a) Fuel injection quantity

(b) Fuel injection timing and/or valve timing

(c) NOx catalyst reductant (e.g., urea) injection quantity; or

(2) is used to control or determine the measured value of an exhaust gas sensor 

subject to monitoring in section (e)(9) or (f)(8) (e.g., NOx or PM sensor 

module); or

(31) has primary control over any of the monitors required by sections (e)(1) 

through (f)(9), (g)(1) through (g)(2), and (g)(4), but does not include circuit or 

out-of-range fault monitors required by sections (e)(9.2.1)(A)(ii), 

(e)(9.2.1)(B)(ii), (e)(9.2.2)(B), (e)(9.2.4)(B), (f)(8.2.1)(B), (f)(8.2.2)(B), 

(f)(8.2.2)(D), (f)(8.2.3)(A), (f)(8.2.3)(B), and (g)(1.1.2); or 

(242) excluding except for anti-lock brake system (ABS) control units or 

stability/traction control units,:

(a) has primary control over the any rationality fault diagnostics or functional 

check for more than two four of the input components or more than two output 

components required to be monitored by section (g)(3).; or
3

(b) for 2016 and subsequent model year engines, is field reprogrammable 

and has primary control over any rationality fault diagnostic or function check

for any input or output component required to be monitored by section (g)(3).

For purposes of criteria (31) and (42) above, “primary control” over a monitor means 

the control unit does any of the following: (a) determines if any enable conditions are 

satisfied; (b) calculates all or part of the diagnostic decision the value or statistic or 

metric by which pass or fail decisions are made (e.g., the comparison of a 

component’s measured or calculated level of performance to a fault threshold) that 

represents the component/system’s level of performance; or (c) makes or processes 

pass or fail decisions (e.g., debounces diagnostic decision statistics or commands 

MIL illumination or fault code storage). Further, fFor purposes of criteriaon (422)(a)

above, all glow plugs in an engine shall be considered “one” output component in 

lieu of each glow plug being considered a separate component. Additionally, for 

purposes of criterion (2)(b) above, “field reprogrammable” means a control unit that 

is capable of supporting a manufacturer service procedure intended to be executed 

in a dealership or other vehicle service environment that results in the downloading 

of new software and/or calibration data into the control unit.

* * * *

“Emission standard,” as it applies to OBD compliance and the remedies provided 

for in the Health and Safety Code for noncompliance, relates to the emission 

characteristics of a motor vehicle and engine and means:

(1) a numerical limit on the amount of a given pollutant that a motor vehicle or 

motor vehicle engine may emit into the atmosphere; or

(2) a requirement that a motor vehicle or motor vehicle engine be equipped with 

a certain type of pollution-control device or some other design feature related 

to the control of emissions.

* * * *

(d) General Requirements.

Section (d) sets forth the general requirements of the OBD system. Specific 

performance requirements for components and systems that shall be monitored are 

set forth in sections (e) through (g) below. The OBD system is required to detect all 

malfunctions specified in sections (e) through (g). However, except as specified 

elsewhere, the OBD system is not required to use a unique monitor to detect each 

malfunction specified.

* * * *

(2) MIL and Fault Code Requirements.

* * * *

(2.2) MIL Illumination and Fault Code Storage Protocol.

(2.2.1) For vehicles using the ISO 15765-4 protocol for the standardized functions 

required in section (h):

* * * *

(D)Storage and erasure of freeze frame conditions.

* * * *
4

(ii) The storage and erasure of For 2010 through 2015 model year 

engines, the OBD system shall store and erase freeze frame 

conditions shall be done in conjunction with the storage and erasure of 

either pending or confirmed fault codes as required elsewhere in 

section (d)(2.2).

(iii) For 2016 and subsequent model year engines, except as provided for 

in section (d)(2.2.1)(D)(iv), the OBD system shall store freeze frame 

conditions in conjunction with the storage of a pending fault code. 

a. If the pending fault code is erased in the next driving cycle in which 

monitoring occurs and a malfunction is not detected (as described 

in section (d)(2.2.1)(B)), the OBD system may erase the 

corresponding freeze frame conditions. 

b. If the pending fault code matures to a confirmed fault code (as 

described in section (d)(2.2.1)(B)), the OBD system shall either 

retain the currently stored freeze frame conditions or replace the 

stored freeze frame conditions with freeze frame conditions 

regarding the confirmed fault code. The OBD system shall erase 

the freeze frame information in conjunction with the erasure of the 

confirmed fault code (as described under section (d)(2.3.1)(B)).

* * * *

(2.2.2) For vehicles using the SAE J1939 protocol for the standardized functions 

required in section (h):

* * * *

(D)Storage and erasure of freeze frame conditions.

(i) The OBD system shall store and erase “freeze frame” conditions (as 

defined in section (h)(4.3)) present at the time a malfunction is 

detected. 

(ii) The OBD system shall store freeze frame conditions in conjunction with 

the storage of a pending fault code.

(iii) If the pending fault code is erased in the next driving cycle in which 

monitoring occurs and a malfunction is not detected (as described 

under section (d)(2.2.2)(B)), the OBD system may erase the 

corresponding freeze frame conditions.

(iv) If the pending fault code matures to a MIL-on fault code (as described 

under section (d)(2.2.2)(B)), the OBD system shall either retain the 

currently stored freeze frame conditions or replace the stored freeze 

frame conditions with freeze frame conditions regarding the MIL-on 

fault code. The OBD system shall erase the freeze frame information 

in conjunction with the erasure of the previously MIL-on fault code (as 

described under section (d)(2.3.2)(C)).

* * * *

(e) Monitoring Requirements for Diesel/Compression-Ignition Engines.

(1) Fuel System Monitoring

* * * *

(1.4) MIL Illumination and Fault Code Storage: 
5

* * * *

(1.4.2) Additionally, for malfunctions identified in section (e)(1.2.1) (i.e., fuel 

pressure control) on all 2013 and subsequent model year vehicles 

engines:

* * * *

(D)Storage of freeze frame conditions.

(i) For 2013 through 2015 model year engines, aA manufacturer shall 

store and erase freeze frame conditions either in conjunction with 

storing and erasing a pending fault code or in conjunction with storing 

and erasing a confirmed/MIL-on fault code. For 2016 and subsequent 

model year engines, a manufacturer shall store freeze frame 

conditions in conjunction with storing and erasing a pending fault code 

in accordance with section (d)(2.2.1)(D)(iii) or (d)(2.2.2)(D).

(ii) If freeze frame conditions are stored for a malfunction other than 

misfire (see section (e)(2)) or fuel system malfunction when a fault 

code is stored as specified in section (e)(1.4.2) above, the stored 

freeze frame information shall be replaced with freeze frame 

information regarding the fuel system malfunction.

* * * *

(2) Misfire Monitoring

* * * *

(2.2) Malfunction Criteria:

(2.2.1) The OBD system shall detect a misfire malfunction when one or more 

cylinders are continuously misfiring.

(2.2.2) Additionally, for 2013 and subsequentthrough 2015 model year engines 

equipped with sensors that can detect combustion or combustion quality 

(e.g., for use in homogeneous charge compression ignition (HCCI) control 

systems) and for 20 percent of 2016 model year diesel engines, 50 

percent of 2017 model year diesel engines, and 100 percent of 2018 

model year diesel engines (percentage based on the manufacturer’s 

projected California sales volume of all diesel engines subject to this 

regulation), the OBD system shall detect a misfire malfunction when the 

percentage of misfire is equal to or exceeds five percent causing the 

engine’s NMHC, CO, or NOx emissions to exceed 2.0 times the applicable 

standards or the engine’s PM emissions to exceed the applicable standard 

plus 0.02 g/bhp-hr.

* * * *

(2.2.5) Upon request by the manufacturer and upon determining that the 

manufacturer has submitted data and/or engineering evaluation that 

support the request, the Executive Officer shall revise the percentage of 

misfire malfunction criteria in section (e)(2.2.2) upward to exclude 

detection of misfire that cannot cause the engine’s NMHC, CO, and NOx 

emissions to exceed 2.0 times the applicable standards and the engine’s 

PM emissions to exceed the applicable standard plus 0.02 g/bhp-hr. 

* * * *
6

(2.3) Monitoring Conditions: 

(2.3.1) Except as provided in section (e)(2.3.2), Tthe OBD system shall monitor 

for misfires identified in section (e)(2.2.1) during engine idle conditions at 

least once per driving cycle in which the monitoring conditions for misfire 

are met. A manufacturer shall submit monitoring conditions to the 

Executive Officer for approval. The Executive Officer shall approve 

manufacturer-defined monitoring conditions that are determined (based on 

manufacturer-submitted data and/or other engineering documentation) to: 

(i) be technically necessary to ensure robust detection of malfunctions 

(e.g., avoid false passes and false detection of malfunctions), (ii) require 

no more than 1000 cumulative engine revolutions, and (iii) do not require 

any single continuous idle operation of more than 15 seconds to make a 

determination that a malfunction is present (e.g., a decision can be made 

with data gathered during several idle operations of 15 seconds or less); 

or satisfy the requirements of (d)(3.1) with alternative engine operating 

conditions.

(2.3.2) Manufacturers may request Executive Officer approval to use alternate 

monitoring conditions (e.g., off-idle) in lieu of the monitoring conditions 

specified in section (e)(2.3.1). The Executive Officer shall approve 

alternate monitoring conditions that are determined (based on 

manufacturer-submitted data and/or other engineering documentation) to 

ensure equivalent robust detection of malfunctions and equivalent 

timeliness in detection of malfunctions. 

(2.3.3) Additionally, fFor misfires identified in section (e)(2.2.2) 2013 and 

subsequent model year engines equipped with sensors that can detect 

combustion or combustion quality:

(A) The OBD system shall continuously monitor for misfire under the following 

conditions:

(i) For 2013 through 2018 model year engines and 2019 and subsequent 

model year engines that are not included in the phase-in specified in 

section (e)(2.3.3)(A)(ii), all under positive torque conditions between 20 

percent and 75 percent of peak torque with engine speeds up to 75 

percent of the maximum-rated engine speed and engine load up to 75 

percent maximum-rated and load conditions except within the following 

range.: the engine operating region bound by the positive torque line 

(i.e., engine load with transmission in neutral) and the two following 

engine-operating points: engine speed of 50 percent of maximum-rated 

engine speed with the engine load at the positive torque line, and 75 

percent of the maximum-rated engine speed with the engine load 5 

percent above the positive torque line.

(ii) For 20 percent of 2019 model year diesel engines, 50 percent of 2020 

model year diesel engines, and 100 percent of 2021 model year diesel 

engines (percentage based on the manufacturer’s projected California 

sales volume of all diesel engines subject to this regulation), under all 

positive torque engine speed and load conditions except within the 
7

following range: the engine operating region bound by the positive 

torque line (i.e., engine torque with transmission in neutral) and the two 

following points: engine speed of 50 percent of maximum-rated engine 

speed with the engine torque at the positive torque line, and 100 

percent of the maximum-rated engine speed with the engine torque at 

10 percent of peak torque above the positive torque line.

* * * *

(C)A manufacturer may request Executive Officer approval to disable misfire 

monitoring or employ an alternate malfunction criterion when misfire 

cannot be distinguished from other effects. Upon determining that the 

manufacturer has presented documentation that demonstrates the 

disablement interval or period of use of an alternate malfunction criterion 

is limited only to that necessary for avoiding false detection, the Executive 

Officer shall approve the disablement or use of the alternate malfunction 

criterion. Such disablements may include but are not limited to events 

involving:

(i) rough road,

(ii) fuel cut,

(iii) gear changes for manual transmission vehicles,

(iv)traction control or other vehicle stability control activation such as antilock braking or other engine torque modifications to enhance vehicle 

stability,

(v) off-board control or intrusive activation of vehicle components or 

diagnostics during service or assembly plant testing,

(vi)intrusive diagnostics during portions that can significantly affect engine 

stability, or

(vii) infrequent regeneration events during portions that can significantly 

affect engine stability.

* * * *

(2.4) MIL Illumination and Fault Code Storage:

* * * *

(2.4.2) Additionally, for 2013 and subsequent model year engines misfires 

identified in section (e)(2.2.2)equipped with sensors that can detect 

combustion or combustion quality:

* * * *

(B) Storage of freeze frame conditions.

(i) For 2013 through 2015 model year engines, tThe OBD system shall 

store and erase freeze frame conditions either in conjunction with 

storing and erasing a pending fault code or in conjunction with storing 

a confirmed/MIL-on fault code and erasing a confirmed/previously MILon fault code. For 2016 and subsequent model year engines, a

manufacturer shall store freeze frame conditions in conjunction with 

storing and erasing a pending fault code in accordance with section 

(d)(2.2.1)(D)(iii) or (d)(2.2.2)(D).
8

(ii) If freeze frame conditions are stored for a malfunction other than a 

misfire malfunction when a fault code is stored as specified in section 

(e)(2.4.2), the stored freeze frame information shall be replaced with 

freeze frame information regarding the misfire malfunction.

* * * *

(5) Non-Methane Hydrocarbon (NMHC) Converting Catalyst Monitoring

* * * *

(5.2) Malfunction Criteria:

* * * *

(5.2.3) Other Aftertreatment Assistance Functions:

* * * *

(B) For 2013 2015 and subsequent model year engines, for catalysts used to 

generate a feedgas constituency to assist SCR systems (e.g., to increase 

NO2 concentration upstream of an SCR system), the OBD system shall 

detect a malfunction when the catalyst is unable to generate the 

necessary feedgas constituents for proper SCR system operation. 

Catalysts are exempt from feedgas generation this monitoring if both of 

the following criteria are satisfied: (1) no malfunction of the catalyst’s 

feedgas generation ability can cause emissions to (1) increase by 15 

percent or more of the applicable full useful life standard as measured 

from an applicable emission test cycle; or and (2) no malfunction of the 

catalyst’s feedgas generation ability can cause emissions to exceed the 

applicable full useful life standard as measured from an applicable 

emission test cycle.

* * * *

(6) Oxides of Nitrogen (NOx) Converting Catalyst Monitoring

* * * *

(6.2) Malfunction Criteria: For purposes of section (e)(6), each catalyst in a series 

configuration that converts NOx shall be monitored either individually or in 

combination with others.

(6.2.1) Conversion Efficiency: 

* * * *

(B) For all 2013 model year engines and 2014 and 2015 model year engines 

that are not included in the phase-in specified in section (e)(6.2.1)(C): 

(i) The OBD system shall detect a catalyst malfunction when the catalyst 

conversion capability decreases to the point that would cause an 

engine's emissions to exceed the applicable NOx standard by more 

than 0.4 g/bhp-hr (e.g., cause emissions to exceed 0.6 g/bhp-hr if the 

exhaust emission standard is 0.2 g/bhp-hr) as measured from an 

applicable cycle emission test or 2.0 times the applicable NMHC 

standard.

(ii) If no failure or deterioration of the catalyst system NOx conversion 

capability could result in an engine’s NOx or NMHC emissions 

exceeding the applicable malfunction criteria of section (e)(6.2.1)(B)(i), 
9

the OBD system shall detect a malfunction when the catalyst has no 

detectable amount of NOx or NMHC conversion capability.

(C) For at least 20 percent of 2014 model year diesel engines and at least 50 

percent of 2015 model year diesel engines (percentage based on the 

manufacturer’s projected California sales volume of all diesel engines 

subject to this regulation):

(i) The OBD system shall detect a catalyst malfunction when the catalyst 

conversion capability decreases to the point that would cause an 

engine's emissions to exceed the applicable NOx standard by more 

than 0.3 g/bhp-hr (e.g., cause emissions to exceed 0.5 g/bhp-hr if the 

exhaust emission standard is 0.2 g/bhp-hr) as measured from an 

applicable cycle emission test or 2.0 times the applicable NMHC 

standard.

(ii) If no failure or deterioration of the catalyst system NOx conversion 

capability could result in an engine’s NOx or NMHC emissions 

exceeding the applicable malfunction criteria of section (e)(6.2.1)(C)(i), 

the OBD system shall detect a malfunction when the catalyst has no 

detectable amount of NOx or NMHC conversion capability.

(B)(D) Except as provided for below in section (e)(6.2.1)(E), Ffor 20132016

and subsequent model year engines:

(i) The OBD system shall detect a catalyst malfunction when the catalyst 

conversion capability decreases to the point that would cause an 

engine's emissions to exceed the applicable NOx standard by more 

than 0.2 g/bhp-hr (e.g., cause emissions to exceed 0.4 g/bhp-hr if the 

exhaust emission standard is 0.2 g/bhp-hr) as measured from an 

applicable cycle emission test or 2.0 times the applicable NMHC 

standard.

(ii) If no failure or deterioration of the catalyst system NOx conversion 

capability could result in an engine’s NOx or NMHC emissions 

exceeding the applicable malfunction criteria of section 

(e)(6.2.1)(BD)(i), the OBD system shall detect a malfunction when the 

catalyst has no detectable amount of NOx or NMHC conversion 

capability.

(E) In lieu of using the malfunction criteria in section (e)(6.2.1)(D), a 

manufacturer may continue to use the malfunction criteria in section 

(e)(6.2.1)(C) for any 2016 model year engine that was previously certified 

in the 2014 or 2015 model year to the malfunction criteria in section 

(e)(6.2.1)(C) and carried over to the 2016 model year. 

(6.2.2) Selective Catalytic Reduction (SCR) or Other Active/Intrusive Reductant 

Injection System Performance:

(A) Reductant Delivery Performance: 

* * * *

(ii) For all 2013 model year engines and 2014 and 2015 model year 

engines that are not included in the phase-in specified in section 

(e)(6.2.2)(A)(iii):
10

a. The OBD system shall detect a malfunction prior to any failure or 

deterioration of the system to properly regulate reductant delivery 

(e.g., urea injection, separate injector fuel injection, post injection of 

fuel, air assisted injection/mixing) that would cause an engine's 

emissions to exceed the applicable NOx standard by more than 0.4 

g/bhp-hr (e.g., cause emissions to exceed 0.6 g/bhp-hr if the 

exhaust emission standard is 0.2 g/bhp-hr) as measured from an 

applicable cycle emission test or 2.0 times the applicable NMHC 

standard.

b. If no failure or deterioration of the SCR system could result in an 

engine’s NOx or NMHC emissions exceeding the applicable 

malfunction criteria of section (e)(6.2.2)(A)(ii)a., the OBD system 

shall detect a malfunction when the system has reached its control 

limits such that it is no longer able to deliver the desired quantity of 

reductant.

(iii) For at least 20 percent of all 2014 model year diesel engines and at 

least 50 percent of all 2015 model year diesel engines (percentage 

based on the manufacturer’s projected California sales volume of all 

diesel engines subject to this regulation):

a. The OBD system shall detect a malfunction prior to any failure or 

deterioration of the system to properly regulate reductant delivery 

(e.g., urea injection, separate injector fuel injection, post injection of 

fuel, air assisted injection/mixing) that would cause an engine's 

emissions to exceed the applicable NOx standard by more than 0.3 

g/bhp-hr (e.g., cause emissions to exceed 0.5 g/bhp-hr if the 

exhaust emission standard is 0.2 g/bhp-hr) as measured from an 

applicable cycle emission test or 2.0 times the applicable NMHC 

standard.

b. If no failure or deterioration of the SCR system could result in an 

engine’s NOx or NMHC emissions exceeding the applicable 

malfunction criteria of section (e)(6.2.2)(A)(iii)a., the OBD system 

shall detect a malfunction when the system has reached its control 

limits such that it is no longer able to deliver the desired quantity of 

reductant.

(ii)(iv) Except as provided for below in section (e)(6.2.2)(A)(v), Ffor 2013

2016 and subsequent model year engines, the OBD system shall 

detect a system malfunction prior to any failure or deterioration of the 

system to properly regulate reductant delivery (e.g., urea injection, 

separate injector fuel injection, post injection of fuel, air assisted 

injection/mixing) that would cause an engine’s emissions to exceed the 

applicable NOx standard by more than 0.2 g/bhp-hr (e.g., cause 

emissions to exceed 0.4 g/bhp-hr if the exhaust emission standard is 

0.2 g/bhp-hr) as measured from an applicable cycle emission test or 

2.0 times the applicable NMHC standard. If no failure or deterioration 

of the SCR system could result in an engine’s NOx or NMHC 
11

emissions exceeding the applicable malfunction criteria above, the 

OBD system shall detect a malfunction when the system has reached 

its control limits such that it is no longer able to deliver the desired 

quantity of reductant.

(v) In lieu of using the malfunction criteria in section (e)(6.2.2)(A)(iv), a 

manufacturer may continue to use the malfunction criteria in section 

(e)(6.2.2)(A)(iii) for any 2016 model year engine that was previously 

certified in the 2014 or 2015 model year to the malfunction criteria in 

section (e)(6.2.2)(A)(iii) and carried over to the 2016 model year. 

* * * *

(8) Particulate Matter (PM) Filter Monitoring

* * * *

(8.2) Malfunction Criteria:

* * * *

(8.2.4) Catalyzed PM Filter:

(A) NMHC conversion: For 2013 2015 and subsequent model year engines,

for with catalyzed PM filters that convert NMHC emissions,:

(i) tThe OBD system shall monitor the catalyst function of the PM filter 

and detect a malfunction when the NMHC conversion capability 

decreases to the point that NMHC emissions exceed 2.0 times the 

applicable standards. 

(ii) If no failure or deterioration of the NMHC conversion capability could 

result in an engine’s NMHC emissions exceeding 2.0 times the 

applicable standards, the OBD system shall detect a malfunction when 

the system has no detectable amount of NMHC conversion capability.

(iii) Catalyzed PM filters are exempt from NMHC conversion capabilitythis

monitoring if both of the following criteria are satisfied: (1) no

malfunction of the catalyzed PM filter’s NMHC conversion capability 

can cause emissions to (1) increase by 15 percent or more of the 

applicable full useful life standard as measured from an applicable 

emission test cycle; or and (2) no malfunction of the catalyzed PM 

filter’s NMHC conversion capability can cause emissions to exceed the 

applicable full useful life standard as measured from an applicable 

emission test cycle.

(B) Feedgas generation: For 2016 and subsequent model year engines with 

catalyzed PM filters used to generate a feedgas constituency to assist 

SCR systems (e.g., to increase NO2 concentration upstream of an SCR 

system), the OBD system shall detect a malfunction when the system is 

unable to generate the necessary feedgas constituents for proper SCR 

system operation. Catalyzed PM filters are exempt from feedgas 

generation this monitoring if both of the following criteria are satisfied: (1) 

no malfunction of the catalyzed PM filter’s feedgas generation ability can 

cause emissions to (1) increase by 15 percent or more of the applicable 

full useful life standard as measured from an applicable emission test 

cycle; or and (2) no malfunction of the catalyzed PM filter’s feedgas 
12

generation ability can cause emissions to exceed the applicable full useful 

life standard as measured from an applicable emission test cycle.

* * * *

(9) Exhaust Gas Sensor Monitoring

* * * *

(9.2) Malfunction Criteria:

* * * *

(9.2.2) NOx and PM sensors:

(A) Sensor performance faults: 

* * * *

(ii) For all 2013 model year engines and 2014 and 2015 model year 

engines that are not included in the phase-in specified in section 

(e)(9.2.2)(A)(iii), the OBD system shall detect a malfunction prior to any 

failure or deterioration of the sensor voltage, resistance, impedance, 

current, response rate, amplitude, offset, or other characteristic(s) that 

would cause an engine's NOx emissions to exceed the applicable NOx 

standard by more than 0.4 g/bhp-hr (e.g., cause emissions to exceed 

0.6 g/bhp-hr if the exhaust emission standard is 0.2 g/bhp-hr) as 

measured from an applicable cycle emission test or cause an engine's 

PM emissions to exceed (whichever is higher): 0.03 g/bhp-hr as 

measured from an applicable cycle emission test (i.e., FTP or SET); or 

any of the applicable standards by more than 0.02 g/bhp-hr (e.g., 

cause emissions to exceed 0.03 g/bhp-hr if the exhaust emission 

standard is 0.01 g/bhp-hr).

(iii) For at least 20 percent of 2014 model year diesel engines and at least 

50 percent of 2015 model year diesel engines (percentage based on 

the manufacturer’s projected California sales volume of all diesel 

engines subject to this regulation), the OBD system shall detect a 

malfunction prior to any failure or deterioration of the sensor voltage, 

resistance, impedance, current, response rate, amplitude, offset, or 

other characteristic(s) that would cause an engine's NOx emissions to 

exceed the applicable NOx standard by more than 0.3 g/bhp-hr (e.g., 

cause emissions to exceed 0.5 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test or cause an engine's PM emissions to exceed 

(whichever is higher): 0.03 g/bhp-hr as measured from an applicable 

cycle emission test (i.e., FTP or SET); or any of the applicable 

standards by more than 0.02 g/bhp-hr (e.g., cause emissions to 

exceed 0.03 g/bhp-hr if the exhaust emission standard is 0.01 g/bhphr).

(ii)(iv) Except as provided for below in section (e)(9.2.2)(A)(v), Ffor 2013

2016 and subsequent model year engines, the OBD system shall 

detect a malfunction prior to any failure or deterioration of the sensor 

voltage, resistance, impedance, current, response rate, amplitude, 
13

offset, or other characteristic(s) that would cause an engine's NOx 

emissions to exceed any of the applicable NOx standards by more 

than 0.2 g/bhp-hr (e.g., cause emissions to exceed 0.4 g/bhp-hr if the 

exhaust emission standard is 0.2 g/bhp-hr) as measured from an 

applicable cycle emission test (i.e., FTP or SET), cause an engine’s 

NMHC emissions to exceed 2.0 times the applicable NMHC standard, 

or cause an engine's PM emissions to exceed (whichever is higher): 

0.03 g/bhp-hr as measured from an applicable cycle emission test (i.e., 

FTP or SET); or any of the applicable standards by more than 0.02 

g/bhp-hr (e.g., cause emissions to exceed 0.03 g/bhp-hr if the exhaust

emission standard is 0.01 g/bhp-hr).

(v) In lieu of using the malfunction criteria in section (e)(9.2.2)(A)(iv), a 

manufacturer may continue to use the malfunction criteria in section 

(e)(9.2.2)(A)(iii) for any 2016 model year engine that was previously 

certified in the 2014 or 2015 model year to the malfunction criteria in 

section (e)(9.2.2)(A)(iii) and carried over to the 2016 model year. 

* * * *

(g) Monitoring Requirements For All Engines.

(1) Engine Cooling System Monitoring

* * * *

(1.3) Monitoring Conditions:

(1.3.1) Thermostat

* * * *

(D) Manufacturers may request Executive Officer approval to suspend or 

disable thermostat monitoring if the vehicle is subjected to conditions 

which could lead to false diagnosis (e.g., vehicle operation at idle for more 

than 50 percent of the warm-up time, hot restart conditions engine block 

heater operation). In general, the Executive Officer shall not approve 

disablement of the monitor on engine starts where the ECT at engine start 

is more than 35 degrees Fahrenheit lower than the thermostat malfunction 

threshold temperature determined under section (g)(1.2.1)(A). The 

Executive Officer shall approve the request upon determining that the 

manufacturer has provided data and/or engineering analysis that 

demonstrate the need for the request. With respect to disablement on 

driving cycles solely due to warm ECT at engine start conditions, the 

manufacturer shall disable the monitor during driving cycles where the 

ECT at engine start is within 35 degrees Fahrenheit of the thermostat 

malfunction threshold temperature determined under section (g)(1.2.1)(A) 

(e.g., if the malfunction threshold temperature is 160 degrees Fahrenheit, 

the monitor shall be disabled if the ECT at engine start is between above

125 and 160 degrees Fahrenheit).

* * * *

(3) Comprehensive Component Monitoring

* * * *

(3.2) Malfunction Criteria:
14

* * * *

(3.2.2) Output Components/Systems:

* * * *

(F) For 2013 2015 and subsequent model year engines that utilize fuel control 

system components (e.g., injectors, fuel pump) that have tolerance 

compensation features implemented in hardware or software during 

production or repair procedures (e.g., individually coded injectors for flow 

characteristics that are programmed into an electronic control unit to 

compensate for injector to injector tolerances, fuel pumps that use in-line 

resistors to correct for differences in fuel pump volume output), the 

components shall be monitored to ensure the proper compensation is 

being used. 

(i) Except as provided in section (g)(3.2.2)(F)(ii) below, Tthe system shall 

detect a fault if the compensation being used by the control system 

does not match the compensation designated for the installed 

component (e.g., the flow characteristic coding designated on a 

specific injector does not match the compensation being used by the 

fuel control system for that injector). If a manufacturer demonstrates 

that a single component (e.g., injector) using the wrong compensation 

cannot cause a measurable increase in emissions during any 

reasonable driving condition, the manufacturer shall detect a 

malfunction for the minimum number of components using the wrong 

compensation needed to cause an emission increase. Further, the 

stored fault code shall identify the specific component that does not 

match the compensation.

(ii)Monitoring of the fuel control system components under section 

(g)(3.2.2)(F)(i) is not required if the manufacturer demonstrates that 

both of the following criteria are satisfied: (1) no fault of the 

components’ tolerance compensation features (e.g., wrong 

compensation being used) could cause emissions to (1) increase by 15 

percent or more of the applicable full useful life standard as measured 

from an applicable emission test cycle; or and (2) no fault of the 

components’ tolerance compensation features can cause emissions to 

exceed the applicable full useful life standard as measured from an 

applicable emission test cycle. For purposes of determining if the 

emission criteria above are met, the manufacturers shall request 

Executive Officer approval of the test plan for which the emission 

impact will be determined. The test plan shall include the combination 

of failed components and the degree of mismatch (e.g., wrong 

compensation) used as well as the test procedure and emission test 

cycles used to demonstrate the emission impact, including the 

necessary preconditioning cycles used by the system to correct or 

adapt for any mismatch and mitigate the emission impact. Executive 

Officer approval shall be granted upon determining that the 

manufacturer has submitted data and/or engineering analysis that 
15

demonstrate that the conditions necessary for the system to correct or 

adapt will readily occur in a timely manner during in-use operation and 

that the test conditions represent worst case emissions from typical inuse service actions when considering the distribution and variance of 

the compensation values and parts (e.g., replacement of one or more 

plus-one-sigma injectors with minus-one-sigma injectors without 

updating of the compensation value). 

* * * *

(5) Exceptions to Monitoring Requirements

* * * *

(5.7) A manufacturer may request Executive Officer approval to be exempt from 

monitoring a component if both of The OBD system is not required to monitor 

an electronic powertrain component/system if the following criteria are met 

when the ambient temperature is above 20 degrees Fahrenheit: (1) a 

malfunction of the component does not affect emissions during any 

reasonable driving condition, and (2) a malfunction of the component does 

not affect the diagnostic strategy for any other monitored component or 

system,. and (3) tThe ambient temperature shall be is determined based on 

a temperature sensor monitored by the OBD system (e.g., IAT sensor). The 

manufacturer shall determine whether a component/system meets these 

criteria. If the Executive Officer reasonably believes that a manufacturer has 

incorrectly determined that a component/system meets these criteria, the 

Executive Officer shall require the manufacturer to provide emission and/or 

other diagnostic data showing that the component/system, when 

malfunctioning and installed in a suitable test vehicle, does not have an effect 

on emissions or other diagnostic strategies. The Executive Officer may 

request emission data for any reasonable driving condition at ambient 

temperatures above 20 degrees Fahrenheit. The Executive Officer shall 

approve the request upon determining that the manufacturer has submitted 

data and/or engineering evaluation that support these criteria.

(5.8) Whenever the requirements in section (e), (f), or (fg) of this regulation require 

a manufacturer to meet a specific phase-in schedule,: manufacturers may use 

an alternate phase-in schedule in lieu of the required phase-in schedule if the 

alternate phase-in schedule provides for equivalent compliance volume as 

defined in section (c) except as specifically noted for the phase-in for the PM 

filter monitor in section (e)(8.2.1) 

(5.8.1) Except as provided for in section (g)(5.8.3) below for the diesel NOx 

converting catalyst and NOx and PM sensor phase-ins and in section 

(e)(8.2.1) for the PM filter monitor phase-in, Mmanufacturers may use an

alternate phase-in schedule in lieu of the required phase-in schedule set 

forth in sections (e), (f), or (g) if the alternate phase-in schedule provides 

for equivalent compliance volume as defined in section (c) except as 

specifically noted for the phase-in for the PM filter monitor in section 

(e)(8.2.1).
16

(5.8.2) Small volume manufacturers may use an alternate phase-in schedule in 

accordance with section (g)(5.8.1) in lieu of the required phase-in 

schedule or may use a different schedule as follows: 

(A) For the diesel misfire monitor phase-in schedule in section (e)(2.2.2), the 

manufacturer may meet the requirement on all engines by the 2018 model 

year in lieu of meeting the specific phase-in requirements for the 2016 and 

2017 model years.

(B) For the diesel misfire monitor phase-in schedule in section (e)(2.3.3), the 

manufacturer may meet the monitoring conditions requirements of section 

(e)(2.3.3)(A)(i) on all engines subject to (e)(2.2.2) through the 2020 model 

year and the monitoring conditions requirements of section (e)(2.3.3)(A)(ii) 

on all 2021 and subsequent model year engines in lieu of the specific 

phase-in requirements in section (e)(2.3.3)(A) for the 2019 and 2020 

model years.

(C)For the diesel NOx converting catalyst monitor phase-in schedules in 

section (e)(6), the manufacturer may use the malfunction criteria in 

sections (e)(6.2.1)(B) and (e)(6.2.2)(A)(ii) for all 2014 and 2015 model 

year engines in lieu of the malfunction criteria and required phase-in 

schedule in sections (e)(6.2.1)(C) and (e)(6.2.2)(A)(iii).

(D)For the diesel PM filter monitor phase-in schedule in section (e)(8), the 

manufacturer may use the malfunction criteria in section (e)(8.2.1)(B) for 

all 2014 and 2015 model year engines in lieu of the malfunction criteria 

and required phase-in schedule in section (e)(8.2.1)(C).

(E) For the diesel NOx sensor phase-in schedules in section (e)(9), the 

manufacturer may use the malfunction criteria in section (e)(9.2.2)(A)(ii) 

for all 2014 and 2015 model year engines in lieu of the malfunction criteria 

and required phase-in schedule in section (e)(9.2.2)(A)(iii).

(5.8.3) In lieu of meeting the diesel NOx converting catalyst and NOx and PM 

sensor phase-ins set forth in sections (e)(6.2.1), (e)(6.2.2), and (e)(9.2.2), 

a manufacturer may request Executive Officer approval to use a 

manufacturer-defined phase-in for each requirement. The Executive 

Officer shall approve the manufacturer-defined phase-in if it meets the 

following criteria:

(A) For the requirements in sections (e)(6.2.1)(C), (e)(6.2.2)(A)(iii), and 

(e)(9.2.2)(A)(iii) (i.e., requiring a NOx threshold of +0.3 g/bhp-hr):

(i) The phase-in shall provide for a compliance volume of engines 

certified to the +0.3 g/bhp-hr NOx threshold that is equivalent to the 

volume of the required phase-in set forth in each of the abovereferenced sections (i.e., the phase-in of 20 percent of 2014 model 

year diesel engines and 50 percent of 2015 model year diesel 

engines). The compliance volume shall be calculated in accordance 

with the calculation methodology in the definition of “alternate phasein” in section (c) (i.e., (20*2 years) + (50*1 year) = 90 for the required 

phase-in). The compliance volume shall be considered equivalent if 

the calculated total is equal to or greater than 90.
17

(ii) The calculated compliance volume for the manufacturer-defined 

phase-in may not include engines meeting the +0.3 g/bhp-hr NOx 

threshold requirement earlier than the 2013 model year. 

(iii) For the 2013 through 2017 model years, engines meeting the 

requirements in sections (e)(6.2.1)(D), (e)(6.2.2)(A)(iv), and 

(e)(9.2.2)(A)(iv) (i.e., requiring a NOx threshold of +0.2 g/bhp-hr) shall 

also be considered as meeting the +0.3 g/bhp-hr NOx threshold 

requirement and included in the calculated compliance volume and

shall not be subtracted from the calculated compliance volume.

(iv) For the 2016 model year, if the proposed phase-in results in a 

combined percentage of engines meeting the +0.3 g/bhp-hr and the 

+0.2 g/bhp-hr thresholds being less than 50 percent of all diesel 

engines, the manufacturer shall subtract those engines that do not 

meet the above thresholds in both the 2015 and 2016 model years

from the required percentage of 50 percent when calculating the 

compliance volume according to the calculation methodology in the 

definition of “alternate phase-in” section (c). 

(v) All engines shall meet either the +0.3 g/bhp-hr NOx threshold or the 

+0.2 g/bhp-hr NOx threshold no later than the 2017 model year. 

(B) For the requirements in sections (e)(6.2.1)(D), (e)(6.2.2)(A)(iv), and 

(e)(9.2.2)(A)(iv) (i.e., requiring a NOx threshold of +0.2 g/bhp-hr): 

(i) The phase-in shall provide for a compliance volume of engines 

certified to the +0.2 g/bhp-hr NOx threshold that is equivalent to the 

volume of the required phase-in set forth in each of the abovereferenced sections (i.e., 100 percent of 2016 model year diesel 

engines). The compliance volume shall be calculated in accordance 

with the calculation methodology in the definition of “alternate phasein” in section (c) (i.e., (100*1 year) = 100 for the required phase-in). 

The compliance volume shall be considered equivalent if the 

calculated total is equal to or greater than 100.

(ii) The calculated compliance volume for the manufacturer-defined 

phase-in shall not include engines meeting the +0.2 g/bhp-hr NOx 

threshold requirement earlier than the 2015 model year.

(iii) For the 2016 model year only, engines meeting the NOx threshold of 

+0.3 g/bhp-hr and carried over from the 2014 or 2015 model year per 

sections (e)(6.2.1)(E), (e)(6.2.2)(A)(v), and (e)(9.2.2)(A)(v) shall also 

be considered as meeting the +0.2 g/bhp-hr NOx threshold 

requirement and included in the calculated compliance volume and 

shall not be subtracted from the calculated compliance volume.

(iv) If the phase-in includes engines that do not meet the +0.2 g/bhp-hr 

NOx threshold in the 2017 model year, the manufacturer shall subtract 

those engines that do not meet the threshold in the 2016 and 2017 

model years (except as allowed for the 2016 model year in section 

(g)(5.8.3)(B)(iii) above) from the required percentage of 100 percent 
18

when calculating the compliance volume according to the calculation 

methodology in the definition of “alternate phase-in” section (c). 

(v) All engines shall meet the +0.2 g/bhp-hr NOx threshold no later than 

the 2018 model year. 

* * * *

(h) Standardization Requirements.

* * * *

(4) Required Emission Related Functions:

The following standardized functions shall be implemented in accordance with 

the specifications in SAE J1979 or SAE J1939 to allow for access to the required 

information by a scan tool meeting SAE J1978 specifications or designed to 

communicate with an SAE J1939 network: 

(4.1) Readiness Status: In accordance with SAE J1979/J1939-73 specifications, 

the OBD system shall indicate “complete” or “not complete” since the fault 

memory was last cleared for each of the installed monitored components and 

systems identified in sections (e)(1) through (f)(9), and (g)(3) except (e)(11) 

and (f)(4). The readiness status for all components or systems identified in 

(f)(2) and (g)(3) shall always indicate “complete”. The readiness status for all 

other components or systems shall immediately indicate “complete” upon the 

respective monitor(s) (except those monitors specified under section 

(h)(4.1.4) below) determining that the component or system is not 

malfunctioning. The readiness status for a component or system shall also 

indicate “complete” if after the requisite number of decisions necessary for 

determining MIL status has been fully executed, the monitor indicates a 

malfunction for the component or system. The readiness status for each of 

the monitored components or systems shall indicate “not complete” whenever 

fault memory has been cleared or erased by a means other than that allowed 

in section (d)(2). Normal vehicle shut down (i.e., key off, engine off) may not 

cause the readiness status to indicate “not complete”.

(4.1.1) Subject to Executive Officer approval, a manufacturer may request that 

the readiness status for a monitor be set to indicate “complete” without 

monitoring having been completed if monitoring is disabled for a multiple 

number of driving cycles due to the continued presence of extreme 

operating conditions (e.g., cold ambient temperatures, high altitudes). 

Executive Officer approval shall be based on the conditions for monitoring 

system disablement and the number of driving cycles specified without 

completion of monitoring before readiness is indicated as “complete”. The 

readiness status for the following component/system readiness bits shall 

always indicate “complete”:

(A) Diesel misfire (section (e)(2)) for engines without a separate monitor 

designed to detect misfires identified in section (e)(2.2.1) and subject to 

the monitoring conditions of sections (e)(2.3.1) and (e)(2.3.2);

(AB) Gasoline misfire (section (f)(2)); and

(BC) Diesel and gasoline comprehensive component (section (g)(3)).

* * * *
19

(4.1.3) For 2016 and subsequent model year engines, for components and 

systems not listed in section (h)(4.1.1) above, the readiness status for 

each component/system readiness bit listed below shall immediately 

indicate “complete” if any of the following conditions occur: (1) all the 

respective supported monitors listed below for each component/system 

have fully executed and determined that the component or system is not 

malfunctioning, or (2) at least one of the monitors listed below for each 

component/system has determined that the component or system is 

malfunctioning after the requisite number of decisions necessary for 

determining the MIL status have been fully executed, regardless of 

whether or not the other monitors listed have been fully executed:

(A) Diesel Fuel System: sections (e)(1.2.1), (e)(1.2.2), and (e)(1.2.3)

(B) Diesel Misfire: section (e)(2.2.1) for engines with a separate monitor 

designed to detect misfires identified in section (e)(2.2.1) and subject to 

the monitoring conditions of sections (e)(2.3.1) and (e)(2.3.2)

* * * *

(4.2) Data Stream: The following signals shall be made available on demand 

through the standardized data link connector in accordance with SAE 

J1979/J1939 specifications. The actual signal value shall always be used 

instead of a default or limp home value.

* * * *

(4.2.2) For all diesel engines:

* * * *

(E) For 2013 and subsequent model year engines, normalized trigger for PM 

filter regeneration (SPN 54566 defined by SAE J1939 for 2016 and 

subsequent model year engines), PM filter regeneration status (SPN 3700 

defined by SAE J1939 for 2016 and subsequent model year engines); and

* * * *

(4.5) Test Results:

* * * *

(4.5.5) If the OBD system fault memory is cleared,:

(A) For vehicles using the ISO 15765-4 protocol for the standardized functions 

required in section (h), all test results shall report values of zero for the 

test result and test limits. The test results shall be updated once the 

applicable monitor has run and has valid test results and limits to report.

(B) For vehicles using the SAE J1939 protocol for the standardized functions 

required in section (h):

(i) For 2010 through 2015 model year engines, all test results shall either 

(a) report values of zero for the test results and test limits, or (b) report 

values corresponding to ‘test not complete’ in accordance with SAE 

J1939-73 specifications. The test results shall be updated once the 

applicable monitor has run and has valid test results and limits to 

report.

(ii) For 2016 and subsequent model year engines, all test results shall 

report values corresponding to ‘test not complete’ in accordance with 
20

SAE J1939-73 specifications. The test results shall be updated once 

the applicable monitor has run and has valid test results and limits to 

report.

* * * *

(6) Service Information:

(6.1) Engine manufacturers shall provide the aftermarket service and repair 

industry emission-related service information as set forth in sections (h)(6.3) 

through (6.5).

(6.2) The Executive Officer shall waive the requirements of sections (h)(6.3) 

through (6.5) upon determining that ARB or U.S. EPA has adopted a service 

information regulation or rule that is in effect and operative and requires 

engine manufacturers to provide emission-related service information:

(A) of comparable or greater scope than required under these provisions;

(B) in an easily accessible format and in a timeframe that is equivalent to or 

exceeds the timeframes set forth below; and

(C)at fair and reasonable cost.

(6.3) Manufacturers shall make readily available, at a fair and reasonable price to 

the automotive repair industry, vehicle repair procedures which allow effective 

emission-related diagnosis and repairs to be performed using only the SAE 

J1978/J1939 generic scan tool and commonly available, non-microprocessor 

based tools.

(6.4) As an alternative to publishing repair procedures required under section 

(h)(6.3), a manufacturer may publish repair procedures referencing the use of 

manufacturer-specific or enhanced equipment provided the manufacturer 

meets one of the following conditions: 

(6.4.1) makes available to the aftermarket scan tool industry the information 

needed to manufacture scan tools to perform the same emission-related 

diagnosis and repair procedures (excluding any reprogramming) in a 

comparable manner as the manufacturer-specific diagnostic scan tool, or

(6.4.2) makes available for purchase, at a fair and reasonable price to the 

automotive repair industry, a manufacturer-specific or enhanced tool to 

perform the emission-related diagnosis and repair procedures (excluding 

any reprogramming).

(6.5) Manufacturers shall make available:

(6.5.1) Information to utilize the test results reported as required in section 

(h)(4.5). The information must include a description of the test and test 

result, typical passing and failing values, associated fault codes with the 

test result, and scaling, units, and conversion factors necessary to convert 

the results to engineering units.

(6.5.2) A generic description of each of the diagnostics used to meet the 

requirements of this regulation. The generic description must include a 

text description of how the diagnostic is performed, typical enable 

conditions, typical malfunction thresholds, typical monitoring time, fault 

codes associated with the diagnostic, and test results (section (h)(4.5)) 

associated with the diagnostic. Vehicles that have diagnostics not
21

adequately represented by the typical values identified above shall be 

specifically identified along with the appropriate typical values.

(6.5.3) Information necessary to execute each of the diagnostics used to meet the 

requirements of sections (e)(1) through (f)(9). The information must 

include either a description of sample driving patterns designed to be 

operated in-use or a written description of the conditions the vehicle needs 

to operate in to execute each of the diagnostics necessary to change the 

readiness status from “not complete” to “complete” for all monitors. The 

information shall be able to be used to exercise all necessary monitors in 

a single driving cycle as well as be able to be used to exercise the 

monitors to individually change the readiness status for each specific 

monitor from “not complete” to “complete”.

* * * *

(i) Monitoring System Demonstration Requirements for Certification.

* * * *

(3) Required Testing:

Except as provided below, the manufacturer shall perform single-fault testing 

based on the applicable test with the following components/systems set at their 

malfunction criteria limits as determined by the manufacturer for meeting the 

requirements of sections (e), (f), and (g) or sections (d)(7.1.2) and (d)(7.2.3) for 

extrapolated OBD systems.

(3.1) Required testing for Diesel/Compression Ignition Engines: 

* * * *

(3.1.2) Misfire Monitoring: For 2010 through 2012 model year engines, a For 

2013 model year engines subject to section (e)(2.2.5), the manufacturer 

shall perform a test at the malfunction limit specified in section (e)(2.2.5). 

A misfire demonstration test is not required for diesel engines not subject 

to section (e)(2.2.5). For 2013 and subsequent model year engines, the 

manufacturer shall perform a test at the malfunction criteria limit specified 

in section (e)(2.2.2).

* * * *

(j) Certification Documentation.

* * * *

(2) The following information shall be submitted as part of the certification 

application. Except as provided below for demonstration data, the Executive 

Officer will not issue an Executive Order certifying the covered engines without 

the information having been provided. The information must include:

* * * *

(2.19) A list of the test results required to be made available under section (gh)(4.5) 

and the corresponding diagnostic(s) noted by fault code for each test result.

* * * *

(k) Deficiencies.

* * * *
22

(4) Manufacturers must re-apply for Executive Officer approval of a deficiency each 

model year. In considering the request to carry-over a deficiency, the Executive 

Officer shall consider the factors identified in section (k)(1) including the 

manufacturer’s progress towards correcting the deficiency. Except as provided 

for in sections (k)(4.1) and (k)(4.2) below, tThe Executive Officer may not allow 

manufacturers to carry over monitoring system deficiencies for more than two 

model years unless it can be demonstrated that substantial engine hardware 

modifications and additional lead time beyond two years would be necessary to 

correct the deficiency, in which case the Executive Officer shall allow the 

deficiency to be carried over for three model years.

(4.1) For deficiencies first granted in the 2010 model year, the Executive Officer 

may allow manufacturers to carry over the deficiency into the 2013 model 

year unless it can be demonstrated that substantial engine hardware 

modifications and additional lead time beyond the 2013 model year would be 

necessary to correct the deficiency, in which case the Executive Officer shall 

allow the deficiency to be carried over into the 2014 model year.

(4.2) For deficiencies first granted in the 2011 model year, the Executive Officer 

may allow manufacturers to carry over the deficiency into the 2014 model 

year.

* * * *
23

Amend section 1968.2, title 13, California Code of Regulations, to read as follows:

Note: The amendments that were approved by the Board at the January 26-27, 2012 

board hearing are shown in single underline to indicate additions and single strikeout to 

indicate deletions from the existing regulatory text. These amendments were formally 

approved by the Office of Administrative Law on August 7, 2012, and became operative 

on August 7, 2012. The amendments proposed with the 45-day notice are shown in 

double underline to indicate additions and double strikeout to indicate deletions from the 

existing regulatory text. New amendments proposed with this 15-day notice are shown 

in bold italic double underline to indicate additions and bold italic double 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 “ * * * * ”.

§1968.2. Malfunction and Diagnostic System Requirements -- 2004 and 

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

Vehicles and Engines 

(c) Definitions.

* * * * 

“Emission standard,” as it applies to OBD compliance and the remedies 

provided for in the Health and Safety Code for noncompliance, relates to the 

emission characteristics of a motor vehicle and engine and means:

(1) a numerical limit on the amount of a given pollutant that a motor vehicle or 

motor vehicle engine may emit into the atmosphere; or

(2) a requirement that a motor vehicle or motor vehicle engine be equipped with 

a certain type of pollution-control device or some other design feature related 

to the control of emissions.

* * * *

(e) Monitoring Requirements for Gasoline/Spark-Ignited Engines.

* * * *

(15) Comprehensive Component Monitoring

* * * * 

(15.4) MIL Illumination and Fault Code Storage:

* * * * 

(15.4.3)For purposes of determining the emission increase in section 

(e)(15.4.2)(A), the manufacturer shall request Executive Officer approval 

of the test cycle/vehicle operating conditions for which the emission 

increase will be determined. Executive Officer approval shall be granted 

upon determining that the manufacturer has submitted data and/or 

engineering evaluation that demonstrate that the testing conditions 
24

represent in-use driving conditions where emissions are likely to be most 

affected by the malfunctioning component. For purposes of determining 

whether the specified percentages in section (e)(15.4.2)(A) are exceeded, 

if the approved testing conditions are comprised of an emission test cycle 

with an exhaust emission standard, the measured increase shall be 

compared to a percentage of the exhaust emission standard (e.g., if the 

increase is equal to or more than 15 percent of the exhaust emission 

standard for that test cycle). If the approved testing conditions are 

comprised of a test cycle or vehicle operating condition that does not have 

an exhaust emission standard, the measured increase shall be calculated 

as a percentage of the baseline test (e.g., if the increase from a back-toback test sequence between normal and malfunctioning condition is equal 

to or more than 15 percent of the baseline test results from the normal 

condition).

* * * * 

(f) Monitoring Requirements for Diesel/Compression-Ignition Engines. 

(1) Non-Methane Hydrocarbon (NMHC) Converting Catalyst Monitoring

* * * *

(1.2) Malfunction Criteria:

* * * *

(1.2.2) Conversion Efficiency:

(A) The OBD II system shall detect an NMHC catalyst malfunction when the 

catalyst conversion capability decreases to the point that emissions 

exceed:

* * * *

(ii) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

a. 2.5 times the applicable NMHC standards for 2007 through 2012 

model year vehicles; and

b. 2.0 times the applicable NMHC standards or the applicable NOx 

standard by more than 0.2 g/bhp-hr (e.g., cause emissions to 

exceed 0.4 g/bhp-hr if the exhaust emission standard is 0.2 g/bhphr) for 2013 and subsequent model year vehicles.

* * * *

(1.2.3) Other Aftertreatment Assistance Functions. Additionally, for 2010 and 

subsequent model year vehicles, the catalyst(s) shall be monitored for 

other aftertreatment assistance functions:

* * * *

(B) For 20105 and subsequent model year passenger cars, light-duty trucks, 

and MDPVs certified to a chassis dynamometer tailpipe emission standard 

and 20135 and subsequent model year medium-duty vehicles (including 

MDPVs) certified to an engine dynamometer tailpipe emission standard, 

for catalysts used to generate a feedgas constituency to assist SCR 

systems (e.g., to increase NO2 concentration upstream of an SCR 

system), the OBD II system shall detect a malfunction when the catalyst is 
25

unable to generate the necessary feedgas constituents for proper SCR 

system operation. Catalysts are exempt from feedgas generation this

monitoring if both of the following criteria are satisfied: (1) no

malfunction of the catalyst’s feedgas generation ability can cause 

emissions to (1) increase by 15 percent or more of the applicable full 

useful life standard as measured from an applicable emission test cycle; 

or and (2) no malfunction of the catalyst’s feedgas generation ability 

can cause emissions to exceed the applicable full useful life standard as

measured from an applicable emission test cycle.

* * * *

(2) Oxides of Nitrogen (NOx) Converting Catalyst Monitoring

* * * *

(2.2) Malfunction Criteria:

* * * *

(2.2.2) Conversion Efficiency:

(A) The OBD II system shall detect a NOx catalyst malfunction when the 

catalyst conversion capability decreases to the point that NOx or NMHC 

emissions exceed:

* * * *

(ii) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

a. the applicable NOx standard by more than 0.5 g/bhp-hr (e.g., cause 

NOx emissions to exceed 0.7 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test or 3.5 times the applicable NMHC standard for 2007 

through 2009 model year vehicles;

b. the applicable NOx standard by more than 0.4 g/bhp-hr (e.g., cause 

NOx emissions to exceed 0.6 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test or 2.5 times the applicable NMHC standard for 2010 

through 2012 model year vehicles; and

c. the applicable NOx standard by more than 0.3 g/bhp-hr (e.g., cause 

NOx emissions to exceed 0.5 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test or 2.0 times the applicable NMHC standard for 2013 

through 2015 model year vehicles; and

cd. the applicable NOx standard by more than 0.2 g/bhp-hr (e.g., cause 

NOx emissions to exceed 0.4 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test or 2.0 times the applicable NMHC standard for 2013

2016 and subsequent model year vehicles.

* * * *

(2.2.3) Selective Catalytic Reduction (SCR) or Other Active/Intrusive Reductant 

Injection System Performance:
26

(A) Reductant Delivery Performance:

(i) For 2007 and subsequent model year vehicles, the OBD II system 

shall detect a system malfunction prior to any failure or deterioration of 

the system to properly regulate reductant delivery (e.g., urea injection, 

separate injector fuel injection, post injection of fuel, air assisted 

injection/mixing) that would cause a vehicle’s NOx or NMHC emissions 

to exceed the applicable emission levels specified in sections 

(f)(2.2.2)(A).

(ii) If no failure or deterioration of the reductant delivery system could

result in a vehicle’s NOx or NMHC emissions exceeding the applicable 

malfunction criteria specified in section (f)(2.2.3)(A)(i), the OBD II 

system shall detect a malfunction when the system has reached its 

control limits such that it is no longer able to deliver the desired 

quantity of reductant.

* * * *

(2.3) Monitoring Conditions:

(2.3.1) Manufacturers shall define the monitoring conditions for malfunctions 

identified in sections (f)(2.2.2), (f)(2.2.3)(A), and (f)(2.2.3)(C) (i.e., catalyst 

efficiency, reductant delivery performance, and improper reductant) in 

accordance with sections (d)(3.1) and (d)(3.2) (i.e., minimum ratio 

requirements). For purposes of tracking and reporting as required in 

section (d)(3.2.2), all monitors used to detect malfunctions identified in 

section (f)(2.2.2) shall be tracked separately but reported as a single set of 

values as specified in section (d)(5.2.2).

(2.3.2) Except as provided for in section (f)(2.3.3), the OBD II system shall 

monitor continuously for malfunctions identified in sections (f)(2.2.3)(A),

(B), and (D) (e.g.i.e., SCR performance, insufficient reductant, feedback 

control).

(2.3.3) Manufacturers may request Executive Officer approval to temporarily 

disable continuous monitoring under conditions technically necessary to 

ensure robust detection of malfunctions and to avoid false passes and 

false indications of malfunctions. The Executive Officer shall approve the 

request upon determining that the manufacturer has submitted data and/or 

an engineering evaluation which demonstrate that a properly operating 

system cannot be distinguished from a malfunctioning system and that the 

disablement interval is limited only to that which is technically necessary.

* * * *

(3) Misfire Monitoring

* * * *

(3.2) Malfunction Criteria:

(3.2.1) The OBD II system shall detect a misfire malfunction when one or more 

cylinders are continuously misfiring.

(3.2.2) Additionally, for all combustion sensor or combustion quality sensorequipped (e.g., for use in homogeneous charge compression ignition 

control systems) 2010 and subsequent model year vehicles passenger 
27

cars, light-duty trucks, and MDPVs certified to a chassis dynamometer 

tailpipe emission standard, for all combustion sensor or combustion 

quality sensor-equipped and 2010 through 2015 model year mediumduty vehicles equipped with sensors that can detect combustion or 

combustion quality (e.g., for use in homogeneous charge 

compression ignition (HCCI) control systems), and for 20 percent of 

2016 model year, 50 percent of 2017 model year, and 100 percent of 2018 

model year medium-duty vehicles (percentage based on the 

manufacturer’s projected California sales volume for all medium-duty 

diesel vehicles):

(A) The OBD II system shall detect a misfire malfunction that would cause a 

vehicle’s NMHC, CO, NOx, or PM emissions to exceed as follows:

(i) For passenger cars, light-duty trucks, and MDPVs certified to a chassis 

dynamometer tailpipe emission standard, the OBD II system shall 

detect a misfire malfunction that would cause a vehicle’s NMHC, CO, 

NOx, or PM emissions to exceed 1.5 times any of the applicable FTP 

standards.

(ii) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard, the OBD II system shall

detect a misfire malfunction when the percentage of misfire is equal to 

or exceeds five percent 2.0 times any of the applicable NMHC, CO, 

and NOx standards or 0.03 g/bhp-hr PM as measured from an 

applicable cycle emission test.

* * * *

(3.2.5) Upon request by the manufacturer and upon determining that the 

manufacturer has submitted data and/or engineering evaluation which 

support the request, the Executive Officer shall revise the percentage of 

misfire malfunction criteria in section (f)(3.2.2)(A)(ii) upward to exclude 

detection of misfire that cannot cause the vehicle’s NMHC, CO, and NOx 

emissions to exceed 2.0 times the applicable standards and the vehicle’s 

PM emissions to exceed 0.03 g/bhp-hr as measured from an applicable 

cycle emission test. 

* * * *

(3.3) Monitoring Conditions: 

* * * *

(3.3.3) Additionally, fFor misfires identified in section (f)(3.2.2) 2010 and 

subsequent model year vehicles subject to (f)(3.2.2), the OBD II system 

shall monitor for misfire as follows:

(A) For passenger cars, light-duty trucks, and MDPVs certified to a chassis 

dynamometer tailpipe emission standard, Tthe OBD II system shall 

continuously monitor for misfire under all positive torque engine speeds 

and load conditions.

(B) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard, the OBD II system shall 

continuously monitor for misfire under the following conditions:
28

(i) For 2010 through 2018 model year vehicles and 2019 and subsequent 

model year vehicles that are not included in the phase-in specified in

section (f)(3.3.3)(B)(ii), under positive torque conditions up to75 

percent of peak torque with engine speed up to 75 percent of the 

maximum-rated engine speed and engine load up to 75 percent 

maximum-rated load except within the following range: the engine 

operating region bound by the positive torque line (i.e., engine load

torque with transmission in neutral) and the two following engineoperating points: engine speed of 50 percent of maximum-rated

engine speed with the engine load torque at the positive torque line, 

and 75 percent of the maximum-rated engine speed with the engine 

load torque at 5 percent of peak torque above the positive torque 

line.

(ii) For 20 percent of 2019 model year, 50 percent of 2020 model year, 

and 100 percent of 2021 model year medium-duty vehicles 

(percentage based on the manufacturer’s projected California sales 

volume for all medium-duty diesel vehicles), under all positive torque

engine speed and load conditions except within the following 

range: the engine operating region bound by the positive torque 

line (i.e., engine load with transmission in neutral) and the two 

following points: engine speed of 50 percent of maximum engine 

speed with the engine torque at the positive torque line, and 100 

percent of the maximum engine speed with the engine torque at 

10 percent of peak torque above the positive torque line.

* * * *

(D)A manufacturer may request Executive Officer approval to disable 

misfire monitoring or employ an alternate malfunction criterion when 

misfire cannot be distinguished from other effects. Upon 

determining that the manufacturer has presented documentation that 

demonstrates the disablement interval or period of use of an 

alternate malfunction criterion is limited only to that necessary for 

avoiding false detection, the Executive Officer shall approve the 

disablement or use of the alternate malfunction criterion. Such 

disablements may include but are not limited to events involving:

(i) rough road,

(ii) fuel cut,

(iii)gear changes for manual transmission vehicles,

(iv)traction control or other vehicle stability control activation such 

as anti-lock braking or other engine torque modifications to 

enhance vehicle stability,

(v) off-board control or intrusive activation of vehicle components or 

diagnostics during service or assembly plant testing,

(vi)intrusive diagnostics during portions that can significantly affect 

engine stability, or
29

(vii)infrequent regeneration events during portions that can 

significantly affect engine stability.

* * * *

(4) Fuel System Monitoring

* * * *

(4.2) Malfunction Criteria:

(4.2.1) Fuel system pressure control:

(A) The OBD II system shall detect a malfunction of the fuel system pressure 

control system (e.g., fuel, hydraulic fluid) prior to any failure or 

deterioration that would cause a vehicle’s NMHC, CO, NOx, or PM 

emissions to exceed:

* * * *

(ii) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

a. 1.5 times any of the applicable NMHC, CO, and NOx standards or 

0.03 g/bhp-hr PM as measured from an applicable cycle emission 

test for 2007 and subsequent model year vehicles certified to an 

engine dynamometer tailpipe NOx emission standard of greater 

than 0.50 g/bhp-hr NOx;

b. 2.5 times any of the applicable NMHC or CO standards, the 

applicable NOx standard by more than 0.3 g/bhp-hr (e.g., cause 

NOx emissions to exceed 0.5 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test, or 0.03 g/bhp-hr PM as measured from an applicable 

cycle emission test for 2007 through 2012 model year vehicles 

certified to an engine dynamometer tailpipe NOx emission standard 

of less than or equal to 0.50 g/bhp-hr NOx; and

c. 2.0 times any of the applicable NMHC or CO standards, the 

applicable NOx standard by more than 0.2 g/bhp-hr (e.g., cause 

NOx emissions to exceed 0.4 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test, or 0.03 g/bhp-hr PM as measured from an applicable 

cycle emission test for 2013 and subsequent model year vehicles 

certified to an engine dynamometer tailpipe NOx emission standard 

of less than or equal to 0.50 g/bhp-hr NOx;

* * * *

(5) Exhaust Gas Sensor Monitoring

* * * *

(5.2) Malfunction Criteria:

(5.2.1) Air-Fuel Ratio Sensors: 

(A) For sensors located upstream of the exhaust aftertreatment:

(i) Sensor performance faults: The OBD II system shall detect a 

malfunction prior to any failure or deterioration of the sensor voltage, 

resistance, impedance, current, response rate, amplitude, offset, or 
30

other characteristic(s) that would cause a vehicle’s NMHC, CO, NOx, 

or PM emissions to exceed:

* * * *

b. For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

1. 1.5 times the applicable NMHC, CO, and NOx standards or 0.03 

g/bhp-hr PM as measured from an applicable cycle emission 

test for 2007 and subsequent model year vehicles certified to an 

engine dynamometer tailpipe NOx emission standard of greater 

than 0.50 g/bhp-hr NOx;

2. 2.5 times the applicable NMHC or CO standards, the applicable 

NOx standard by more than 0.3 g/bhp-hr (e.g., cause NOx 

emissions to exceed 0.5 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test, or 0.03 g/bhp-hr PM as measured from an 

applicable cycle emission test for 2007 through 2012 model 

year vehicles certified to an engine dynamometer tailpipe NOx 

emission standard of less than or equal to 0.50 g/bhp-hr NOx; 

and

3. 2.0 times the applicable NMHC or CO standards, the applicable 

NOx standard by more than 0.2 g/bhp-hr (e.g., cause NOx 

emissions to exceed 0.4 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test, or 0.03 g/bhp-hr PM as measured from an 

applicable cycle emission test for 2013 and subsequent model 

year vehicles certified to an engine dynamometer tailpipe NOx 

emission standard of less than or equal to 0.50 g/bhp-hr NOx.

* * * *

(B) For sensors located downstream of the exhaust aftertreatment:

(i) Sensor performance faults: The OBD II system shall detect a 

malfunction prior to any failure or deterioration of the sensor voltage, 

resistance, impedance, current, response rate, amplitude, offset, or 

other characteristic(s) that would cause a vehicle’s NMHC, CO, NOx, 

or PM emissions to exceed:

* * * *

b. For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

1. 2.5 times the applicable NMHC or CO standards, the applicable 

NOx standard by more than 0.5 g/bhp-hr (e.g., cause NOx 

emissions to exceed 0.7 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test, or 0.05 g/bhp-hr PM as measured from an 

applicable cycle emission test for 2007 through 2009 model 

year vehicles certified to an engine dynamometer tailpipe NOx 

emission standard of greater than 0.50 g/bhp-hr NOx;
31

2. 2.5 times the applicable NMHC or CO standards, the applicable 

NOx standard by more than 0.3 g/bhp-hr (e.g., cause NOx 

emissions to exceed 0.5 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test, or 0.05 g/bhp-hr PM as measured from an 

applicable cycle emission test for 2007 through 2012 model 

year vehicles certified to an engine dynamometer tailpipe NOx 

emission standard of less than or equal to 0.50 g/bhp-hr NOx; 

and

3. 2.0 times the applicable NMHC or CO standards, the applicable 

NOx standard by more than 0.2 g/bhp-hr (e.g., cause NOx 

emissions to exceed 0.4 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test, or 0.03 g/bhp-hr PM as measured from an 

applicable cycle emission test for 2013 and subsequent model 

year vehicles certified to an engine dynamometer tailpipe NOx 

emission standard of less than or equal to 0.50 g/bhp-hr NOx.

* * * *

(5.2.2) NOx and PM sensors:

(A) Sensor performance faults: The OBD II system shall detect a malfunction 

prior to any failure or deterioration of the sensor voltage, resistance, 

impedance, current, response rate, amplitude, offset, or other 

characteristic(s) that would cause a vehicle’s emissions to exceed:

* * * *

(ii) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

a. 2.5 times the applicable NMHC standards, the applicable NOx 

standard by more than 0.5 g/bhp-hr (e.g., cause NOx emissions to 

exceed 0.7 g/bhp-hr if the exhaust emission standard is 0.2 g/bhphr) as measured from an applicable cycle emission test or 0.05 

g/bhp-hr PM as measured from an applicable cycle emission test 

for 2007 through 2009 model year vehicles;

b. 2.5 times the applicable NMHC standards, the applicable NOx 

standard by more than 0.4 g/bhp-hr (e.g., cause NOx emissions to 

exceed 0.6 g/bhp-hr if the exhaust emission standard is 0.2 g/bhphr) as measured from an applicable cycle emission test or 0.05 

g/bhp-hr PM as measured from an applicable cycle emission test 

for 2010 through 2012 model year vehicles; and

c. 2.0 times the applicable NMHC standard, the applicable NOx 

standard by more than 0.3 g/bhp-hr (e.g., cause NOx emissions to 

exceed 0.5 g/bhp-hr if the exhaust emission standard is 0.2 g/bhphr) as measured from an applicable cycle emission test, or 0.03 

g/bhp-hr PM as measured from an applicable cycle emission test 

for 2013 through 2015 model year vehicles; and
32

cd. 2.0 times the applicable NMHC standards, the applicable NOx 

standard by more than 0.2 g/bhp-hr (e.g., cause NOx emissions to 

exceed 0.4 g/bhp-hr if the exhaust emission standard is 0.2 g/bhphr) as measured from an applicable cycle emission test or 0.03 

g/bhp-hr PM as measured from an applicable cycle emission test 

for 2013 2016 and subsequent model year vehicles.

* * * *

(5.3) Monitoring Conditions:

(5.3.1) Exhaust Gas Sensors

(A) Manufacturers shall define the monitoring conditions for malfunctions 

identified in sections (f)(5.2.1)(A)(i), (5.2.1)(B)(i), and (5.2.2)(A), and 

(5.2.2)(D) (e.g., sensor performance faults) in accordance with sections 

(d)(3.1) and (d)(3.2) (i.e., minimum ratio requirements). For all 2010 and 

subsequent model year vehicles, for purposes of tracking and reporting as 

required in section (d)(3.2.2), all monitors used to detect malfunctions 

identified in sections (f)(5.2.1)(A)(i), (5.2.1)(B)(i), and (5.2.2)(A), and for 

2016 and subsequent model year medium-duty vehicles certified to an 

engine dynamometer tailpipe emission standard, section (f)(5.2.2)(D)

shall be tracked separately but reported as a single set of values as 

specified in section (d)(5.2.2).

* * * *

(6) Exhaust Gas Recirculation (EGR) System Monitoring

* * * *

(6.2) Malfunction Criteria:

(6.2.1) Low Flow:

(A) The OBD II system shall detect a malfunction of the EGR system at or 

prior to a decrease from the manufacturer's specified EGR flow rate that 

would cause a vehicle’s NMHC, CO, NOx, or PM emissions to exceed:

* * * *

(ii) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

a. 1.5 times the applicable FTP standards for 2004 through 2006 

model year vehicles;

b. 1.5 times the applicable NMHC, CO, and NOx standards or 0.03 

g/bhp-hr PM as measured from an applicable cycle emission test 

for 2007 and subsequent model year vehicles certified to an engine 

dynamometer tailpipe NOx emission standard of greater than 0.50 

g/bhp-hr NOx;

c. 2.5 times the applicable NMHC or CO standards, the applicable 

NOx standard by more than 0.3 g/bhp-hr (e.g., cause NOx 

emissions to exceed 0.5 g/bhp-hr if the exhaust emission standard 

is 0.2 g/bhp-hr) as measured from an applicable cycle emission 

test, or 0.03 g/bhp-hr PM as measured from an applicable cycle 

emission test for 2007 through 2012 model year vehicles certified to 
33

an engine dynamometer tailpipe NOx emission standard of less 

than or equal to 0.50 g/bhp-hr NOx; and

d. 2.0 times the applicable NMHC or CO standards, the applicable 

NOx standard by more than 0.2 g/bhp-hr (e.g., cause NOx 

emissions to exceed 0.4 g/bhp-hr if the exhaust emission standard 

is 0.2 g/bhp-hr) as measured from an applicable cycle emission 

test, or 0.03 g/bhp-hr PM as measured from an applicable cycle 

emission test for 2013 and subsequent model year vehicles 

certified to an engine dynamometer tailpipe NOx emission standard 

of less than or equal to 0.50 g/bhp-hr NOx.

* * * *

(6.2.6) EGR Catalyst Performance: For catalysts located in the EGR system on 

2013 and subsequent model year vehicles and used to convert 

constituents to reduce emissions or protect or extend the durability of 

other emission-related components (e.g., to reduce fouling of an EGR 

cooler or valve),:

(A)For 2004 through 2012 model year vehicles, the catalyst shall be 

monitored in accordance with the other emission control or source 

system monitoring requirements under section (f)(16).

(B)For 2013 and subsequent model year vehicles, except as provided 

for in section (f)(6.2.6)(C) below, the OBD II system shall detect a 

malfunction when the catalyst has no detectable amount of constituent 

(e.g., hydrocarbons, soluble organic fractions) oxidation. For 2004 

through 2012 model year vehicles, the catalyst shall be monitored in 

accordance with the other emission control or source system 

monitoring requirements under section (f)(16).

(C)Monitoring of the catalyst is not required if there is no measurable 

emission impact on the criteria pollutants (i.e., NMHC, CO, NOx, and 

PM) during any reasonable driving condition in which the catalyst is 

most likely to affect criteria pollutants.

* * * *

(7) Boost Pressure Control System Monitoring

* * * *

(7.2) Malfunction Criteria:

(7.2.1) Underboost:

(A) The OBD II system shall detect a malfunction of the boost pressure control 

system at or prior to a decrease from the manufacturer's commanded or 

expected boost pressure that would cause a vehicle’s NMHC, CO, NOx, 

or PM emissions to exceed:

* * * *

(ii) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

a. 2.5 times the applicable NMHC or CO standards, the applicable 

NOx standard by more than 0.3 g/bhp-hr (e.g., cause NOx 

emissions to exceed 0.5 g/bhp-hr if the exhaust emission standard 
34

is 0.2 g/bhp-hr) as measured from an applicable cycle emission 

test, or 0.03 g/bhp-hr PM as measured from an applicable cycle 

emission test for 2010 through 2012 model year vehicles; and

b. 2.0 times the applicable NMHC or CO standards, the applicable 

NOx standard by more than 0.2 g/bhp-hr (e.g., cause NOx 

emissions to exceed 0.4 g/bhp-hr if the exhaust emission standard 

is 0.2 g/bhp-hr) as measured from an applicable cycle emission 

test, or 0.03 g/bhp-hr PM as measured from an applicable cycle 

emission test for 2013 and subsequent model year vehicles.

* * * *

(8) NOx Adsorber Monitoring

* * * *

(8.2) Malfunction Criteria:

(8.2.1) NOx adsorber capability:

(A) The OBD II system shall detect a NOx adsorber system malfunction when 

the NOx adsorber system capability decreases to the point that would 

cause a vehicle's NOx or NMHC emissions to exceed:

* * * *

(ii) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

a. the applicable NOx standard by more than 0.5 g/bhp-hr (e.g., cause 

NOx emissions to exceed 0.7 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test or 3.5 times the applicable NMHC standard for 2007 

through 2009 model year vehicles;

b. the applicable NOx standard by more than 0.3 g/bhp-hr (e.g., cause 

NOx emissions to exceed 0.5 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test or 2.5 times the applicable NMHC standard for 2010 

through 2012 model year vehicles; and

c. the applicable NOx standard by more than 0.2 g/bhp-hr (e.g., cause 

NOx emissions to exceed 0.4 g/bhp-hr if the exhaust emission 

standard is 0.2 g/bhp-hr) as measured from an applicable cycle 

emission test or 2.0 times the applicable NMHC standard for 2013 

and subsequent model year vehicles.

* * * *

(9) Particulate Matter (PM) Filter Monitoring

* * * *

(9.2) Malfunction Criteria:

* * * *

(9.2.2) Frequent Regeneration:

(A) For 2010 and subsequent model year vehicles, the OBD II system shall 

detect a malfunction when PM filter regeneration occurs more frequently 

than (i.e., occurs more often than) the manufacturer’s specified 
35

regeneration frequency such that it would cause a vehicle's emissions to 

exceed:

* * * *

(ii) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

a. 2.5 times the applicable NMHC standards or the applicable NOx 

standard by more than 0.3 g/bhp-hr (e.g., cause NOx emissions to 

exceed 0.5 g/bhp-hr if the exhaust emission standard is 0.2 g/bhphr) as measured from an applicable cycle emission test for 2010 

through 2012 model year vehicles; and

b. 2.0 times the applicable NMHC standards or the applicable NOx 

standard by more than 0.2 g/bhp-hr (e.g., cause NOx emissions to 

exceed 0.4 g/bhp-hr if the exhaust emission standard is 0.2 g/bhphr) as measured from an applicable cycle emission test for 2013 

and subsequent model year vehicles.

* * * *

(9.2.4) Catalyzed PM Filter:

(A)NMHC conversion: For 20105 and subsequent model year passenger 

cars, light-duty trucks, and MDPVs certified to a chassis dynamometer 

tailpipe emission standard and 20135 and subsequent model year 

medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard with catalyzed PM filters that 

convert NMHC emissions, the OBD II system shall monitor the catalyst 

function of the PM filter and detect a malfunction when the NMHC 

conversion capability decreases to the point that NMHC emissions exceed 

the applicable emission levels specified in section (f)(9.2.2)(A). If no 

failure or deterioration of the NMHC conversion capability could result in a 

vehicle’s NMHC emissions exceeding these emission levels, the OBD II 

system shall detect a malfunction when the system has no detectable 

amount of NMHC conversion capability. PM filters are exempt from 

NMHC conversion capability this monitoring if both of the following 

criteria are satisfied: (1) no malfunction of the PM filter’s NMHC 

conversion capability can cause emissions to (1) increase by 15 percent 

or more of the applicable full useful life standard as measured from an 

applicable emission test cycle; or and (2) no malfunction of the PM 

filter’s NMHC conversion capability can cause emissions to exceed 

the applicable full useful life standard as measured from an applicable 

emission test cycle.

(B)Feedgas generation: For 2016 and subsequent model year mediumduty vehicles with catalyzed PM filters used to generate a feedgas 

constituency to assist SCR systems (e.g., to increase NO2

concentration upstream of an SCR system), the OBD II system shall 

detect a malfunction when the system is unable to generate the 

necessary feedgas constituents for proper SCR system operation. 

Catalyzed PM filters are exempt from this monitoring if both of the 
36

following criteria are satisfied: (1) no malfunction of the catalyzed PM 

filter’s feedgas generation ability can cause emissions to increase by 

15 percent or more of the applicable full useful life standard as 

measured from an applicable emission test cycle; and (2) no

malfunction of the catalyzed PM filter’s feedgas generation ability 

can cause emissions to exceed the applicable full useful life 

standard as measured from an applicable emission test cycle.

* * * *

(12) Cold Start Emission Reduction Strategy Monitoring

* * * *

(12.2) Malfunction Criteria: The OBD II system shall, to the extent feasible, detect a 

malfunction if either of the following occurs:

* * * *

(12.2.2) Any failure or deterioration of the cold start emission reduction control 

strategy that would cause a vehicle’s NMHC, CO, NOx, or PM emissions 

to exceed:

* * * *

(B) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

(i) 2.0 times the applicable NMHC or CO standards, the applicable NOx 

standard by more than 0.2 g/bhp-hr (e.g., cause NOx emissions to 

exceed 0.4 g/bhp-hr if the exhaust emission standard is 0.2 g/bhp-hr) 

as measured from an applicable cycle emission test, or 0.03 g/bhp-hr 

PM as measured from an applicable cycle emission test for 2013 and 

subsequent model year vehicles.

* * * *

(13) Variable Valve Timing And/Or Control (VVT) System Monitoring

* * * *

(13.2) Malfunction Criteria:

(13.2.1) Target Error: The OBD II system shall detect a malfunction prior to any 

failure or deterioration in the capability of the VVT system to achieve the 

commanded valve timing and/or control within a crank angle or lift 

tolerance that would cause a vehicle's NMHC, CO, NOx, or PM emissions 

to exceed:

* * * *

(B) For medium-duty vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard:

(i) 1.5 times the applicable NMHC, CO, and NOx standards or 0.03 

g/bhp-hr PM as measured from an applicable cycle emission test for 

2006 and subsequent model year vehicles certified to an engine 

dynamometer tailpipe NOx emission standard of greater than 0.50 

g/bhp-hr NOx;

(ii) 2.5 times the applicable NMHC or CO standards, the applicable NOx 

standard by more than 0.3 g/bhp-hr (e.g., cause NOx emissions to 
37

exceed 0.5 g/bhp-hr if the exhaust emission standard is 0.2 g/bhp-hr) 

as measured from an applicable cycle emission test, or 0.03 g/bhp-hr 

PM as measured from an applicable cycle emission test for 2006 

through 2012 model year vehicles certified to an engine dynamometer 

tailpipe NOx emission standard of less than or equal to 0.50 g/bhp-hr 

NOx; and

(iii) 2.0 times the applicable NMHC or CO standards, the applicable NOx 

standard by more than 0.2 g/bhp-hr (e.g., cause NOx emissions to 

exceed 0.4 g/bhp-hr if the exhaust emission standard is 0.2 g/bhp-hr) 

as measured from an applicable cycle emission test, or 0.03 g/bhp-hr 

PM as measured from an applicable cycle emission test for 2013 and 

subsequent model year vehicles certified to an engine dynamometer 

tailpipe NOx emission standard of less than or equal to 0.50 g/bhp-hr 

NOx.

* * * *

(15) Comprehensive Component Monitoring

* * * *

(15.2) Malfunction Criteria:

* * * *

(15.2.2) Output Components/Systems:

* * * *

(F) For 20132015 and subsequent model year vehicles that utilize fuel control 

system components (e.g., injectors, fuel pump) that have tolerance 

compensation features implemented in hardware or software during 

production or repair procedures (e.g., individually coded injectors for flow 

characteristics that are programmed into an electronic control unit to 

compensate for injector to injector tolerances, fuel pumps that use in-line 

resistors to correct for differences in fuel pump volume output), the 

components shall be monitored to ensure the proper compensation is 

being used. 

(i) The system shall detect a fault if the compensation being used by the 

control system does not match the compensation designated for the 

installed component (e.g., the flow characteristic coding designated on 

a specific injector does not match the compensation being used by the 

fuel control system for that injector). If a manufacturer demonstrates 

that a single component (e.g., injector) using the wrong compensation 

cannot cause a measurable increase in emissions during any 

reasonable driving condition, the manufacturer shall detect a 

malfunction for the minimum number of components using the wrong 

compensation needed to cause an emission increase. Further, the 

stored fault code shall identify the specific component that does not 

match the compensation.

(ii)Monitoring of the fuel control system components under section 

(f)(15.2.2)(F)(i) is not required if the manufacturer demonstrates that 

both of the following criteria are satisfied: (1) no fault of the 
38

components’ tolerance compensation features (e.g., wrong 

compensation being used) could cause emissions to (1) increase by 15 

percent or more of the applicable full useful life standard as measured 

from an applicable emission test cycle; or and (2) no fault of the 

components’ tolerance compensation features could cause 

emissions to exceed the applicable full useful life standard as

measured from an applicable emission test cycle. For purposes of 

determining if the emission criteria above are met, the manufacturers 

shall request Executive Officer approval of the test plan for which the 

emission impact will be determined. The test plan shall include the 

combination of failed components and the degree of mismatch (e.g., 

wrong compensation) used as well as the test procedure and emission 

test cycles used to demonstrate the emission impact, including the 

necessary preconditioning cycles used by the system to correct or 

adapt for any mismatch and mitigate the emission impact. Executive 

Officer approval shall be granted upon determining that the 

manufacturer has submitted data and/or engineering analysis that 

demonstrate that the conditions necessary for the system to correct or 

adapt will readily occur in a timely manner during in-use operation and 

that the test conditions represent worst case emissions from typical inuse service actions when considering the distribution and variance of 

the compensation values and parts (e.g., replacement of one or more 

plus-one-sigma injectors with minus-one-sigma injectors without 

updating of the compensation value).

* * * *

(15.4) MIL Illumination and Fault Code Storage:

* * * *

(15.4.3) For purposes of determining the emission increase in section 

(f)(15.4.2)(A), the manufacturer shall request Executive Officer approval of 

the test cycle/vehicle operating conditions for which the emission increase 

will be determined. Executive Officer approval shall be granted upon 

determining that the manufacturer has submitted data and/or engineering 

evaluation that demonstrate that the testing conditions represent in-use 

driving conditions where emissions are likely to be most affected by the 

malfunctioning component. For purposes of determining whether the 

specified percentages in section (f)(15.4.2)(A) are exceeded, if the 

approved testing conditions are comprised of an emission test cycle with 

an exhaust emission standard, the measured increase shall be compared 

to a percentage of the exhaust emission standard (e.g., if the increase is 

equal to or more than 15 percent of the exhaust emission standard for 

that test cycle). If the approved testing conditions are comprised of a test 

cycle or vehicle operating condition that does not have an exhaust

emission standard, the measured increase shall be calculated as a 

percentage of the baseline test (e.g., if the increase from a back-to-back 

test sequence between normal and malfunctioning condition is equal to or 
39

more than 15 percent of the baseline test results from the normal 

condition).

* * * *

(17) Exceptions to Monitoring Requirements

(17.1) Except as provided in sections (f)(17.1.1) through (17.1.4) below, upon 

request of a manufacturer or upon the best engineering judgment of ARB, the 

Executive Officer may revise the emission threshold for a malfunction on any 

diagnostic required in section (f) for medium-duty vehicles if the most reliable 

monitoring method developed requires a higher threshold to prevent 

significant errors of commission in detecting false indications of a malfunction. 

Additionally, except as specified in section (f)(9.2.1)(A)(iii), for 2007 through 

20092013 model year light-duty vehicles and 2007 through 2012 2013 2015

model year medium-duty vehicles, the Executive Officer may revise the PM 

filter malfunction criteria of section (f)(9.2.1) to exclude detection of specific 

failure modes (e.g., combined failure of partially melted and partially cracked 

substrates) if the most reliable monitoring method developed requires the 

exclusion of specific failure modes to prevent significant errors of commission 

in detecting false indications of a malfunction. 

* * * *

(17.1.3) For medium-duty diesel vehicles (including MDPVs) certified to an engine 

dynamometer tailpipe emission standard, the Executive Officer shall 

approve a malfunction criteria of “the applicable PM standard plus 0.02 

g/bhp-hr PM (e.g., unable to maintain PM emissions at or below 0.03 

g/bhp-hr if the exhaust emission standard is 0.01 g/bhp-hr) as measured 

from an applicable cycle emission test” in lieu of “0.03 g/bhp-hr PM as 

measured from an applicable cycle emission test” wherever required in 

section (f). The Executive Officer shall also approve a malfunction criteria 

of “the applicable PM standard plus 0.04 g/bhp-hr PM (e.g., unable to 

maintain PM emissions at or below 0.05 g/bhp-hr if the exhaust emission 

standard is 0.01 g/bhp-hr) as measured from an applicable cycle emission 

test” in lieu of “0.05 g/bhp-hr PM as measured from an applicable cycle 

emission test” wherever required in section (f).

* * * *

(h) Monitoring System Demonstration Requirements For Certification

* * * *

(4) Required Testing for Diesel/Compression-ignition vehicles:

Except as provided below, the manufacturer shall perform single-fault testing 

based on the applicable test with the following components/systems set at their 

malfunction criteria limits as determined by the manufacturer for meeting the 

requirements of section (f).

* * * *

(4.3) Misfire Monitoring: For 2010 and subsequent model year vehicles subject to 

section (f)(3.2.2)(A)(i) or (f)(3.2.5), the manufacturer shall perform a test at 

the malfunction criteria limit specified in section (f)(3.2.2)(A)(i) or (f)(3.2.5). A 

misfire monitor demonstration test is not required for vehicles not subject to 
40

section (f)(3.2.2)(A)(i) and not subject to section (f)(3.2.5).

* * * *
41

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

Note: The amendments proposed with the 45-day notice are shown in single underline

to indicate additions and single strikeout to indicate deletions from the existing 

regulatory text, while amendments proposed with this 15-day notice are shown in 

double underline to indicate additions and double 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.

* * * * 

“Nonconforming OBD System” means an OBD system on a production 

engine that has been determined not to comply with the emission standards as 

defined in requirements of Cal. Code Regs., title 13, section 1971.1(c),. For 

purposes of section 1971.5, an engine class shall be considered nonconforming

irrespective of whether engines in the engine class, on average, meet other 

applicable tailpipe or evaporative emission standards (e.g., exhaust emission 

standards defined in Cal. Code Regs., title 13, section 1956.8, evaporative 

emission standards defined in Cal. Code Regs., title 13, section 1976).

* * * *
42

Amend section 1968.5, title 13, California Code of Regulations, to read as follows: 

Note: The amendments proposed with the 45-day notice are shown in single underline

to indicate additions and single strikeout to indicate deletions from the existing 

regulatory text, while amendments proposed with this 15-day notice are shown in 

double underline to indicate additions and double 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 “ * * * * ”. 

§1968.5. Enforcement of Malfunction and Diagnostic System Requirements for 

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

Medium-Duty Vehicles and 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 title 13, CCR sections 1900(b) and 

1968.2(c), which are incorporated by reference herein. The following definitions 

are specifically applicable to section 1968.5 and take precedence over any 

contrary definitions.

* * * *

“Nonconforming OBD II System” means an OBD II system on a production 

vehicle that has been determined not to comply with the emission standards as 

defined in requirements of title 13, CCR section 1968.2(c),. For purposes of 

section 1968.5, a motor vehicle class shall be considered nonconforming

irrespective of whether vehicles in the motor vehicle class, on average, meet

other applicable tailpipe or evaporative emission standards (e.g., exhaust 

emission standards defined in title 13, CCR section 1960.1, evaporative emission 

standards defined in title 13, CCR section 1976).

* * * *
ATTACHMENT B

ADDITIONAL SUPPORTING DOCUMENTS AND INFORMATION

The following additional supporting documents and information are available for public 

comments during the supplemental public comment period for the 2012 rulemaking 

approving the revisions to on-board diagnostic system requirements for heavy-duty 

engines, passenger cars, light-duty trucks, medium-duty vehicles and engines

regulations.

Additional Rationale for Definition of “Alternate Phase-In”

In the 45-day notice, staff proposed in the amendments to the HD OBD regulation a 

new definition of “alternate phase-in” that is similar to that currently provided in the 

OBD II regulation and would provide manufacturers with compliance flexibility in 

meeting some regulation requirements with prescribed phase-in schedules. The HD 

OBD regulation previously did not include any prescribed phase-in schedules and, thus, 

there was no need for alternate phase-in schedules. However, as part of the 45-day 

notice, staff proposed several phase-in schedules for several different requirements and 

included a new definition for “alternate phase-in” that would provide the same flexibility 

as currently exists under the OBD II regulation.

Additional Information on Costs

Staff is also providing more information concerning the costs attributed to the proposed 

amendments. In the Initial Statement of Reasons: Staff Report (Staff Report) for the 

present amendments, staff described the incremental costs that manufacturers would 

incur under the amendments for heavy-duty diesel engines. Specifically, the Staff 

Report indicated that the proposed amendments would result in some added costs for 

heavy-duty diesel engines attributable to the more comprehensive diesel misfire 

monitoring requirements that begin in the 2016 model year. As stated, the reporting 

requirements for these amendments, when fully phased-in, would result in costs of up to 

$30,000 annually. On a per vehicle basis, a large manufacturer is estimated to have an

incremental retail cost of less than $0.56 per vehicle. Subsequent to the release of the 

Staff Report, staff adjusted the cost analysis to allow for a six percent cost of capital 

recovery for truck builders. This adjustment results in an incremental retail cost of 

$0.59 per vehicle, a $0.03 increase from the cost initially reported (i.e., less than 0.01 

percent increase in the retail price of a typical heavy duty vehicle).

Staff’s analysis took the national sales numbers for the top nine engine manufacturers 

and determined a composite manufacturer average value of 72,440 engines that will be 

annually produced and sold nationwide. This number was rounded to 72,000 for the

analysis. Staff then estimated the incremental costs for an engine manufacturer with 

sales of 72,000 engines. Staff further assumed the hypothetical engine manufacturer 

would have three engine families that would require separate misfire monitoring data to 

be generated. It then calculated the total costs for such a manufacturer using estimated
testing cost information obtained from emission test laboratories and heavy-duty engine 

manufacturers. The data generation and associated reporting costs for the updated 

misfire monitoring requirements was estimated to cost $10,000 per engine family for a 

total cost of $30,000 for a typical large manufacturer. 

The Staff Report did not address how the incremental costs of $0.59 per vehicle

(previously $0.56 per vehicle as described above) were calculated. The incremental 

costs were obtained by adding the testing and reporting costs over four years for all 

eleven heavy-duty diesel engine manufacturers (from the 2016 model year through the 

2019 model year) and dividing the costs by the estimated number of heavy-duty diesel 

engines that are projected to be produced for sale nationwide over the same time period 

by all eleven manufacturers. Nationwide volumes were used instead of California-only 

volumes because it is assumed (and consistent with past practice) that manufacturers 

will make one engine for the entire nation to comply with both the U.S. EPA and ARB 

HD OBD requirements. The total costs consist of the total number of engine families 

estimated to be tested by manufacturers multiplied by $10,000 per engine family. A 

total of 99 engine families are projected to be tested over the four years at a total cost of 

$990,000. The total number of heavy-duty diesel engines was obtained by multiplying 

the projected nationwide sales of 2012 model year diesel engines (479,000) by four

(years). The incremental costs were then adjusted with a six percent profit margin each 

for the engine manufacturer, truck builder, and dealer (assuming trucks are in the 

dealership for three months) to calculate the total incremental costs for consumers (i.e., 

new heavy-duty vehicle purchasers). 

In the Staff Report, staff also estimated the incremental costs that heavy-duty alternatefueled engine manufacturers would incur due to the proposed amendment to move up 

the start date for full OBD systems on heavy-duty alternate-fueled engines by two years 

(from the 2020 to the 2018 model year). Since the amendment would require these 

manufacturers to implement OBD systems two years earlier than previously required, 

the majority of costs were already accounted for in the 2009 HD OBD biennial review 

rulemaking. The only additional costs would be those costs incurred for the proposed 

misfire monitoring requirement amendments described above and the time value of 

money cost that is incurred due to using money two years earlier instead of earning 

investment returns. Specifically, this would cover the earlier hiring of additional staff or 

purchasing of equipment needed for compliance and include some annual costs for 

recalibration within this earlier compliance timeframe. Also, since the alternate-fueled 

engines will have OBD systems on them two years earlier, buyers of such engines in 

these two years will see an incremental price increase that otherwise would not have 

occurred until later. From staff’s analysis, the incremental retail cost to buyers of these 

engines/vehicles for these two years has been estimated to range from $21 per vehicle 

to $207 per vehicle, depending on the size of the manufacturer. Subsequent to the 

release of the Staff Report, staff adjusted the incremental costs to include a six percent 

profit margin for truck builders and dealers. As such, the incremental retail cost to 

buyers of these vehicles for the two years has been adjusted to range from $23 per 

vehicle to $228 per vehicle (less than a 1.0 percent increase in the retail price of the 

vehicle).
The Staff Report did not provide an explanation as to how the incremental costs of $23

per vehicle to $228 per vehicle were calculated. The incremental cost for heavy-duty 

alternate-fueled vehicles was determined separately for small and large manufacturers 

because the resources and production volume of these two industry segments are 

significantly different. Similar to heavy-duty diesel engine manufacturers, the misfire 

monitoring amendments will add testing and reporting costs for alternate-fueled engine 

manufacturers. Staff assumed that heavy-duty alternate-fueled engine manufacturers 

would have one engine family that would require misfire monitoring data to be 

generated. This will result in estimated costs of $10,000 per manufacturer annually. 

The incremental costs per vehicle were then obtained by dividing the testing and 

reporting costs by the assumed production volumes for a typical large and small heavyduty alternate-fueled engine manufacturer. For these calculations, a typical large 

manufacturer was assumed to produce 5,000 engines nationwide per year and a typical 

small manufacturer was assumed to produce 500 engines nationwide per year. These 

costs are expected to be passed on to consumers (new heavy-duty engine/vehicle 

purchasers) so a six percent profit margin for engine builders, truck builders, and 

dealers were each applied to the reporting costs. As a result, the total incremental retail 

cost for the misfire monitoring amendment is estimated at $2.38 per vehicle for a large

alternate-fueled engine manufacturer and $23.82 per vehicle for a small alternate-fueled 

engine manufacturer.

To evaluate the time value money cost for the two year earlier implementation of HD 

OBD for heavy-duty alternate-fueled vehicles, staff estimated the time value of money 

cost to be 13.75 percent over the two years. Although current rates of return in 

investments have been near zero in recent years, staff assumed an annualized return 

rate of 6.65 percent. This annualized return rate was used based on the average 

annualized returns on the Standard and Poor’s (S&P) 500 Index from 2003 through 

2011 (5.92 percent) plus a 25 percent margin to arrive at the 6.65 percent rate. 

Applying the 6.65 percent annual rate of return over two years results in an overall 

return rate of 13.75 percent assuming all moneys are reinvested and interest rate is 

compounded annually. Staff then applied 13.75 percent to the overall incremental costs 

calculated in the 2009 cost analysis, giving an adjusted incremental cost of $18.19 per 

vehicle. This cost is a conservative value considering that the 2009 cost estimates 

included algorithm development and calibration costs to implement all OBD diagnostics

while alternate-fueled engines are expected to be derived from existing diesel or 

gasoline-fueled heavy-duty engines that already have base algorithms and calibrations 

and would only require a portion of the algorithm development and calibration costs. 

Heavy-duty alternate-fueled engine manufacturers will likely only need to recalibrate a 

few of the major monitors such as fuel system, catalyst, and EGR and develop a few 

comprehensive component monitors for added components related to the fuel 

conversion. By adding the $2.38 per vehicle reporting costs to the $18.19 per vehicle 

cost and applying a six percent profit margin for truck builders and another six percent 

profit margin for dealers, a total incremental cost of $23 is obtained for large heavy-duty 

alternate-fueled engine manufacturers.
For small heavy-duty alternate-fueled engine manufacturers, a similar approach was 

used to calculate the incremental costs. A typical small manufacturer is estimated to 

produce 500 engines per year which is a factor of ten less than a typical large 

manufacturer. Assuming the scaling of the volume also affects costs in a similar 

manner, the cost determined above for large alternate-fueled engine manufacturers 

results in an incremental cost of $181.90 per vehicle for small volume manufacturers. 

To obtain the total incremental cost for small heavy-duty alternate-fueled engine

manufacturers of $228 per vehicle, the $23.82 per vehicle reporting cost was added to 

the $181.90 cost after a six percent profit margin was applied to account for truck 

builder and dealer profits. A summary table of the incremental consumer costs for 

alternate-fueled vehicles is shown in Table 1 below. The cost numbers for the 2009 

analysis below were presented in the 2009 HD OBD Staff Report.

Table 1: Incremental Consumer Cost of Heavy-Duty Diesel Vehicles

2009 Analysis 2012 Analysis

1971.1 

Costs

1971.5 

Costs

Total 

HD 

OBD 

Costs

Total Large 

Alt Fuels HD

OBD Costs

Total 

Small 

Alt Fuels 

Costs

(dollars) (dollars) (dollars) (dollars) (dollars)

Variable costs Component $37.18 $0.00 $37.18 $5.12 $51.20

Assembly $0.68 $0.00 $0.68 $0.09 $0.90

Warranty $1.64 $0.00 $1.64 $0.23 $2.30

Shipping $1.20 $0.00 $1.20 $0.17 $1.70

Support costs Research $22.49 $0.00 $22.49 $3.09 $30.90

Engineering Support $0.14 $0.06 $0.20 $0.03 $0.30

Legal $0.35 $0.00 $0.35 $0.05 $0.50

Administrative $2.08 $0.31 $2.39 $0.33 $3.30

Investment Machine & equipment $0.00 $0.00 $0.00 $0.00 $0.00

recovery costs Assembly plant changes $0.00 $0.00 $0.00 $0.00 $0.00

Development/Testing $57.34 $1.22 $58.56 $8.05 $80.50

Engine 

manufacturer profit 

(a) $7.39 $0.10 $7.49 $1.03 $10.30

Truck Builder profit 

(a) $1.09 $10.91

Dealer profit (a) $1.16 $11.57

Misfire Monitor 

costs(a)(b) $2.38 $23.82

Total cost $130.49 $1.69 $132.18 $22.82 $228.20

(a) Profit was calculated at 6% of the total incremental costs.

(b) Engine manufacturer profit, truck builder profit, and dealer profit were all applied.
Market Commentary 11612

October, 2012 Data:

Part 1: SUMMARY RETURNS & RANK

Last Month -3.3% Rank: 19 out of 23

Last Year . . . . . . . . . . . . . . . . 12.7% Rank: 4 out of 23

Last 5 Years -8.9% Rank: 12 out of 23

Last 10 Years . . . . . . . . . . . . 59.4% Rank: 17 out of 23

S&P 500 Index: Annual Returns

Year Percent Year Percent Year Percent Year Percent

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

16.3

11.8

-6.6

45.0

26.4

2.6

-14.3

38.1

8.5

-3.0

23.1

-11.8

18.9

13.0

9.1

-13.1

20.1

7.7

-11.4

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

0.1

10.8

15.6

-17.4

-29.7

31.5

19.1

-11.5

1.1

12.3

25.8

-9.7

14.8

17.3

1.4

26.3

14.6

2.0

12.4

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

27.3

-6.6

26.3

4.5

7.1

-1.5

34.1

20.3

31.0

26.7

19.5

-10.1

-13.0

-23.4

26.4

9.0

3.0

13.6

3.5

2008

2009

2010

2011

-38.5

23.5

12.8

0.0

The annual gain or loss in the S&P 500 Stock index from 1951 to present.

Dividends are not included.

Standard & Poor's 500 Stock Index - 58 Year Graph

S&P 500 Stock Market Index Historical Graph

1/1950 1/1960 1/1970 1/1980 1/1990 1/2000 1/2010

 1/2020 The above graph plots the monthly close for the Standard & Poor's 500 Stock Index in logarithmic

scale. Updated Friday, November 2, 2012. Click the links below for the forecast and other links

related to this stock index.

100

1000

10000

10

S&P 500 Index Forecast

Dow Jones Multi-Index Charts & Analysis

10 Year Chart - S & P 500 Chart

60 Year Graph - S&P 500 Index

Stock Market Performance Ranking: S&P 500 Index

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S&P 500 Stock Market Index Historical Graph http://www.forecast-chart.com/historical-sp-500.html

1 of 3 11/6/2012 10:00 AM
Returns for the Standard & Poor's 500 Stock Index is shown above for four time

periods. For example: the change in the Standard & Poor's 500 Stock Index was

-3.3% in the last month. With that return, the S&P 500 Index was ranked 19th

out of the 23 indexes reviewed in this site for that time period. Dividends are not

included.

Part 2: HISTORICAL HIGHLIGHTS

The performance ranking of the S&P 500 Index relative to the other 23 stock

indexes covered in this site is detailed below. Four different time periods are

reviewed. The Standard & Poor's 500 Stock Index is compared to foreign and

domestic, large cap and small cap indexes. Each paragraph identifies the top

and bottom performers as well as the average and median market performance

for the indexes during in each time period.

Last Month:

During October of 2012, the S&P 500 had a rank of 19 with a return of -3.34%.

The top ranked index during October was the Hang Seng Index, with a return of

3.00%. The worst performing index during that period was the NASDAQ 100

Index with a return of -5.83%.

The median return for all stock market indexes during October was -1.86%. The

average return for the indexes during the month was -1.76%.

Last Year:

During the last 12 months, the S&P 500 had a rank of 4 with a return of 13%.

The top ranked index during the last year was the DAX Stock Index, with a

return of 18%. The worst performing index during that period was the Nikkei 225

Index with a return of -1%.

The median return for the indexes during this period was 10%. The average

return for all stock market indexes over the year was 9%.

Last 5 Years:

Over the 5 years ended October of 2012, the S&P 500 had a rank of 12 with a

return of -9%. The top ranked index during the 5 year period was the Mexico

IPC Index, with a return of 30%. The worst performing index during that period

was the Nikkei 225 Index with a return of -45%.

The median return for all stock market indexes during this time period was -9%.

The average return for the indexes over the 5 years was -9%.

Last 10 Years:

During the 10 years ended October of 2012, the S&P 500 had a rank of 17 with

a return of 59%. The top ranked index during the period was the Mexico IPC

Index, with a return of 587%. The worst performing index during the 10 year

time period was the Nikkei 225 Index with a return of -5%.

The median return for the indexes during the last 10 years was 89%. The

average return for all stock market indexes over that time frame was 108%.

Table:

In this site, you may view the returns for all 23 indexes over all 4 time periods in

one convenient table. Click the Market Trend Analysis link under the chart

(above). The table of contents for Forecast-Chart.com's Market Trend Analysis

will open. Click the link to the Stock Index Return Scoreboard in the table of

contents.

All calculations are based on the monthly market close for each index, excluding

dividends.

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