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OAR Box 1190 

Prepped by Candice Davis 

Document Number: 

46) ll-A-38 

Docket Number: 

A-90-28 

Printed 5/5/2008 9:13:51 AM Sheet 46 of 106 
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— . -/Mo-ay 

MAIL OUT #95-03 " " 

State of California 

AIR RESOURCES BOARD 

Notice of Public Availability of Modified Text 

AMENDMENTS TO REGULATIONS REGARDING ON-BOARD DIAGNOSTIC SYSTEM 

REQUIREMENTS FOR 1994 AND LATER PASSENGER CARS, LIGHT-DUTY TRUCKS, 

AND MEDIUM-DUTY VEHICLES AND ENGINES (OBD II) 

Public Hearing Date: December 8, 1994 

Public Availability Date: January 19, 1995 

Deadline for Public Comment: February 3, 1995 

At a public hearing held on December 8, 1994, the Air Resources Board (the "Board") 

considered amendments to California's On-Board Diagnostic II (OBD II) regulation (Section 

1968.1, Title 1,3, California Code of Regulations ("CCR")). The proposed amendments would 

improve the overall effectiveness of the OBD II requirements while addressing 

implementation concerns expressed by manufacturers. 

The Board adopted Resolution 94-67 approving the proposed amendments with 

modifications. The modifications made by the Board prior to adopting the Resolution are 

summarized below. 

Section (b)( 1.2.2) was modified by the Board to reduce the 1998 and 1999 model year 

phase-in percentages for the low emission vehicle catalyst monitoring requirements. With the 

modification, manufacturers must certify 30 percent of its low emission vehicle applications to 

the 1.5 times the standard emission threshold for the 1998 model year, and 60 percent for the 

1999 model year. The percentages proposed by the staff were 40 and 70 percent, 

respectively. 

The Board modified the implementation dates for the phase-in of evaporative system 

leak detection strategies capable of detecting leaks as small as the equivalent of a 0.020 inch 

diameter hole. Section (b)(4.2.2) has been modified to delay initial introduction of such 

systems from the 1998 model year to the 2000 model year. The projected sales volume 

phase-in percentages would be 50 percent with the 2000 model year, 75 percent for 2001, and 

100 percent compliance for the 2002 model year. Small volume manufacturers would not be 

required to meet the 2000 and 2001 model year phase-in percentages. 

The Board directed the staff to modify the requirements for comprehensive component 

monitoring (section (b)(10) ofthe regulation) to require illumination ofthe Malfunction 
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Indicator Light (MIL) only for affected components and systems that can cause emissions to 

increase by more than 15 percent of the FTP standard. Section (b)(10.4) has been modified to 

state that manufacturers shall^ be required only to store a fault code, and not to illuminate the 

MIL, for affected components and systems that could not cause such an emission increase. 

However, if an electronic component or system is used as part of the diagnostic strategy to 

satisfy another monitoring requirement, MIL illumination would continue to be required for 

those components and systems in order to ensure that the vehicle operator is alerted to 

malfunctions that impair the function of the OBD II system. 

In addition to these modifications, the staff has proposed other minor modifications to 

the OBD II regulation to further address manufacturers concerns and for clarity: 

Section (a)(2.2) has been modified with respect to the requirements for clearing the 

OBD II readiness code when disabling monitoring systems in response to the activation of a 

Power Take-Off (PTO) unit. The section would require that the readiness code be cleared 

(i.e., all bits set to "test not complete") while the PTO unit is active. Once the PTO unit is 

de-activated, the readiness code can be restored to the state that existed prior to activation. 

Section (b)(1.1.2) has been modified to allow manufacturers of spark-ignited lean-bum 

engines to request Executive Officer approval for exemption from the OBD II catalyst 

monitoring requirements if the manufacturer can demonstrate that technology is not available 

that would allow for reliable monitoring of the catalyst system. 

A footnote has been added to section (b)( 1.2.1) to clarify that in instances where the 

malfunction criteria is to be based on the applicable emission standards, the certification 

reactivity adjustment factor shall be applied with respect to hydrocarbon emissions on low 

emission vehicle applications. 

Section (b)(3.2)(B) has been modified to remove an unnecessary restriction on the 

establishment of the malfunction criteria for misfire monitoring. With the modification, 

manufacturers would be permitted, but not required, to use the data from a single durability 

demonstration vehicle for all engines that have the same number of cylinders as the 

demonstration vehicle. 

The title for section (g), and section (g)(1.0) itself have been modified to further make 

clear that the demonstration requirements do not apply solely to engine families for which a 

Durability Demonstration Vehicle (DDV) is available. Similarly, in section (g)(4.5) the term 

"DDV" has been replaced by "vehicle." 

Section (g)(2.6.1) has been modified to clarify the catalyst monitoring demonstration 

requirements for non-low emission vehicles. Consistent with the monitoring requirements for 

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such vehicles, the modification makes clear that the baseline emission test is to be conducted 

with a representative 4000 mile catalyst svstem. 

Section (g)(3.0) has* been modified to further clarify that for successful completion of 

OBD II demonstrations, manufacturers shall not require the demonstration vehicle to be cold 

soaked prior to running preconditioning cycles. 

Section (m)(5.1) has been modified to clarify that the implementation requirements 

specified in the section apply to alternate fuel engines as well as vehicles. 

Resolution 94-67 and the text of Section 1968.1, Title 13, as modified, are attached. 

Comments regarding the modifications to Section 1968.1 must be submitted to the Board 

Secretary, Air Resources Board, P.O. Box 2815, Sacramento, California 95812, no later than 

February 3, 1995, for consideration by the Executive Officer. Questions regarding this mailout may be directed to Allen Lyons, Air Resources Engineer Associate, at (818) '575-6833. 

Sincerely, 

K. D. Drachand, Chief 

Attachments 

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State of Cal ifornia 

AIR RESOURCES BOARD 

Resolution 94-67 

December 8, 1994 

Agenda Item No.: 94-12-2 

WHEREAS, sections 39002 and 39003 of the Health and Safety Code charge the 

Board with the responsibility for systematically attacking the serious air 

pollution problem caused by motor vehicles; 

WHEREAS, sections 39600 and 39601 of the Health and Safety code authorize 

the Board to adopt standards, rules and regulations and to do such acts as 

may be necessary for the proper execution of the powers and duties granted 

to and imposed upon the Board by law; 

WHEREAS, in section 43000 of the Health and Safety Code, the Legislature has 

declared that the emission of air pollutants from motor vehicles is the 

primary cause of air pollution in many parts of the state; 

WHEREAS, in section 43000.5 of the Health and Safety Code, the Legislature 

found and declared that, despite significant reductions in vehicle emissions 

in recent years, continued growth in population and vehicle miles traveled 

throughout California have the potential not only to prevent attainment of 

the state standards, but in some cases, to result in worsening of air 

quality; 

WHEREAS, section 43004 provides that unless expressly exempted, the exhaust 

emissions for gasoline-powered motor vehicles shall apply to motor vehicles 

which have been modified or altered to use a fuel other than gasoline or 

diesel; 

WHEREAS, section 43006 provides that the ARB may certify the fuel system of 

any motor vehicle powered by a fuel other than gasoline or diesel which 

meets the standards specified by section 43004 and adopttest procedures for 

such certification; 

WHEREAS, section 43013 of the Health and Safety Code authorizes the Board to 

adopt motor vehicle emission standards and in-use performance standards 

which it finds to be necessary, cost-effective, and technologically 

feasible; 

WHEREAS, section 43018 of the Health and Safety Code directs the Board to 

achieve the maximum degree of emissions reductions possible from vehicular 

and other mobile sources in order to accomplish the attainment of state 

standards at the earliest possible date; 

WHEREAS, sections 39515 and 39516 of the Health and Safety Code provide that 

the Board may delegate any duty to the Executive Officer which the Board 

deems appropriate and that any power, duty, purpose, function, or 

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Resolution 94-67. 

jurisdiction which the Board may lawfully delegate shall be conclusively 

presumed to have been delegated to the Executive Officer unless the Board 

has expressly reserved such authority onto itself; 

WHEREAS, in July 1990,_the Board adopted and the Office of Administrative 

Law subsequently approved regulations regarding "Malfunction and Diagnostic 

System Requirements—1994 and Subsequent Model-Year Passenger Cars, LightDuty Trucks, and Medium-Duty Vehicles and Engines," (OBD II), which are 

codified at Title 13, CCR, section 1968.1, and which set forth requirements 

for monitoring catalyst efficiency, engine misfire, evaporative system 

integrity, secondary air injection, and chlorofluorocarbon (CFC) 

containment; for improving current monitoring of the fuel system, oxygen 

sensor, EGR system, and other emission-related components of the on-board 

diagnostic system; and for standardizing fault codes, diagnostic repair 

equipment, the vehicle connector used for attaching the repair equipment to 

the vehicle, and the protocol for downloading repair information in order to 

improve the effectiveness of emission control system repairs; 

Whereas, the Board adopted amendments to the OBD II regulations in 1991 and 

1993, and the amendments were approved by the Office of Administrative Law; 

WHEREAS, the staff has now proposed adoption of additional amendments to 

Title 13, CCR, section 1968.1, that, among other things, would provide 

manufacturers with additional guidance and/or flexibility in implementing 

and complying with the malfunction and diagnostic requirements of the 

regulations, including catalyst monitoring, misfire detection, tamper 

resistance, and applicability of the regulations to vehicles and engines 

that use diesel and alternate fuels', and would require manufacturers to 

develop monitoring strategies capable of detecting evaporative system leaks 

as small as the equivalent of a 0.020 inch diameter orifice. 

WHEREAS, the staff has further proposed that Title 13, CCR, section 1968.1 

be amended to provide the Executive Officer with authority to certify 1996-

2000 model year vehicles required to comply with the malfunction and 

diagnostic requirements of the section, but do not fully meet the minimum 

requirements in one or more areas, provided that the manufacturers of such 

vehicles in some cases pay a fine for such nonconformance pursuant to 

section 43016 of the California Health and Safety Code; 

WHEREAS, the staff has further proposed amendments to Title 13, CCR, 

sections 2030 and 2031 and the incorporated "California Certification and 

Installation Procedures for Alternative Fuel Retrofit systems for Motor 

Vehicles Certified for 1994 and Subsequent Model Years" to allow alternative 

fuel retrofit system manufacturers to disable specific on-board diagnostic 

monitoring strategies through the 1998 model year; 

WHEREAS, the California Environmental Quality Act and Board regulations 

require that no project which may have significant adverse environmental 

impacts may be adopted as originally proposed if feasible alternatives or 

mitigation measures are available to reduce or eliminate such impacts; 

WHEREAS, pursuant to section 43013(e) of the Health and Safety Code, the 

Board has considered the effects of the proposed amendments to the 

regulations on the economy of the state; 

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'v Resolution 94-67 -3-

WHEREAS, a public hearing and other administrative proceedings have been 

held in accordance with the provisions of Chapter 3.5 (commencing with 

Section 11340), Part 1, Division 3, Title 2 of the Government Code; 

WHEREAS, the Board finds that: 

To date, more than 35 engine families have been 

certified as meeting the OBD II requirements for the 

applicable model years; 

The proposed amendments to Title 13, CCR, section 1968..1 

should help manufacturers continue to be able to certify 

systems in future model years by clarifying requirements 

and by making minor adjustments to the regulation based 

on technical and practical experience gained to date, 

which should ease the burdens manufacturers face in 

developing OBD II systems that comply with these 

regulations; 

Significant numbers of vehicles continue to operate with 

deteriorated catalytic converters and that catalyst 

performance is crucial to maintaining vehicle emissions 

in compliance with the applicable standards; 

accordingly, it continues to be necessary to monitor 

catalyst performance; however, such monitoring can be 

done by evaluating malfunction criteria based on 

tailpipe emission levels; 

In-use surveillance programs indicate that evaporative 

system leaks as small as 0.020 inches in diameter occur 

on a significant number of in-use vehicles causing 

excess evaporative emissions, and, therefore, 

evaporative monitoring systems that can detect leaks of 

this size, as well as other malfunctions, should 

significantly reduce in-use evaporative emissions from 

vehicles; 

The monitoring of misfire over the full engine operating 

range is necessary because misfire contributes 

substantially to excess emissions and can cause catalyst 

overheating and failure; 

On diesel fueled vehicles, the loss of compression or 

other malfunctions that prevent combustion in one or 

more cylinders and fuel system malfunctions cause excess 

emissions; monitoring systems that detect such 

malfunctions should significantly reduce such emissions 

from diesel fueled vehicles; 

Manufacturers of alternative fuel vehicles and 

alternative fuel retrofit systems require additional 

leadtime to investigate the effects of alternate fuels 

on component performance and durability before full 

implementation of reliable OBD II systems on these 

vehicles can take place; 

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Resolution 94-67 - -4-

The proposed amendments should maximize the long-term 

effectiveness of the OBD II regulations by restructuring 

and enhancing current monitoring requirements based on 

the latest improvements in monitoring technologies; 

The proposed amendments would enable manufacturers that 

have been unable to develop a fully complying OBD II 

system, despite good faith efforts, to certify such 

systems conditionally, through the 2000 model year, upon 

payment of a penalty in some cases; 

The proposed amendments to Title 13, CCR, section 1968.1 

are necessary, cost-effective, and technologically 

feasible to carry out the purposes of the California 

Clean Air Act; and 

The proposed amendments to Title 13, CCR, section 

1968.1, do not affect the Board's earlier findings that 

the full implementation of the regulation will result in 

emission reductions that will help attain and maintain 

national and air quality standards for ozone, carbon 

monoxide and nitrogen dioxide; 

WHEREAS, the Board has determined, in accordance with the California 

Environmental Quality Act and Board regulations, that the proposed 

amendments to Title 13, CCR, section 1968.1, that provide that manufacturers 

may elect to phase-in the monitoring of misfire detection over the full 

range of operating conditions over a four year period and that 

manufacturers may be permitted to certify non-fully compliant OBD II 

systems, may have some short-term adverse environmental impacts in relation 

to the regulations presently in effect; however, overriding considerations 

exist for adoption of the proposed amendments: 

Title 13, CCR, section 1968.1(b)(3.3) presently provides 

that for 1997 and later model year vehicles, misfire 

shall be monitored continuously and under all positive 

torque engine speeds and conditions; however, staff has 

determined, and the Board finds, that some engine and 

driveline characteristics, especially as they apply to 

engines .with 10 or 12 cylinders, still preclude reliable 

misfire monitoring over the full range of operating 

conditions; 

No equally effective alternative methods for misfire 

monitoring have been identified that would be costeffective and technologically feasible for 

implementation by the 1997 model year. 

Strict enforcement of the existing regulations could 

result in several engines not being able to be certified 

and available for sale in California; accordingly, 

amendments have been proposed to permit manufacturers to 

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Resolution 94-67 -5-

phase-in the full-range misfire requirement over four 

years, beginning with the 1997 model year; 

The proposed amendments to Title 13, CCR, section 

1968.l(m) would, enable manufacturers that have been 

unable to develop fully complying OBD II systems, 

despite good faith efforts, to certify such systems 

conditionally, through the 2000 model year; 

Theoretically, allowing vehicles to be certifiedduring 

the phase-in period even though they cannot be monitored 

over the full range of operating conditions could 

prevent the proper and immediate repair of emission 

control systems of such vehicles and could result in a 

possible increase in emissions; 

However, such vehicles, even with the potential 

monitoring system deficiencies that have been 

identified, will be significantly more effective in 

reducing in-use vehicle emissions than malfunction and 

diagnostic systems that comply with pre-OBD II system 

requirements; 

The certification qf such vehicles would minimize 

economic hardship for vehicle manufacturers, 

distributors of such vehicles within California, and 

would minimize any resulting impact on vehicle 

availability and costs for consumers; 

WHEREAS, the Board has determined, in accordance with the California 

Environmental Quality Act and Board regulations, that the proposed 

amendments to Title 13, CCR, sections 2230-2231 will not have significant 

adverse environmental impacts; 

r 

NOW, THEREFORE, BE IT RESOLVED that the Board hereby approves for adoption, 

with modification, the amendments to sections 1968.1 and 2230-2231, Title 

13, California Code of Regulations and the documents incorporated therein, 

which were made available for public comment in Mail-Out 94-38 and are set 

forth in Attachment A. The modifications to the language of Attachment A 

are set forth in Attachment B. 

BE IT FURTHER RESOLVED that the Board directs the Executive Officer to adopt 

Section 1968.1, Title 13, California Code of Regulations, after making the 

modified regulatory language and additional supporting documents and 

information available for public comment for a period of 15 days, provided 

that the Executive Officer shall consider such written comments regarding 

the modification and additional supporting documents and information as may 

be submitted during this period, shall make modifications as may be 

appropriate in light of the comments received, and shall present the 

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Resolution "94-67 -6- _ ' 

* — 

regulations to the Board for further consideration if he determines that 

this is warranted; 

BE IT FURTHER RESOLVED that the Board hereby determines that pursuant to 

section 209(b) of the Clean Air Act the regulations adopted herein will not 

cause California motor vehicle emission standards, in the aggregate, to be 

less protective of public health and welfare than applicable federal 

standards, and will not cause the California requirements to be inconsistent 

with section 202(a) of the Clean Air Act; 

BE IT FURTHER RESOLVED that the Executive Officer shall, upon adoption, 

forward the amended subsections to Title 13, CCR, section 1968.1, to the 

Administrator of the Environmental Protection Agency with a request for a 

waiver of federal preemption pursuant to section -209(b) of the Clean Air 

Act; 

BE IT FURTHER RESOLVED that the Board directs the staff to continue to 

closely monitor vehicle manufacturers in complying with the requirements of 

section 1968.1, Title 13, CCR, and to report to the Board in 1996 if further 

amendments to the regulations are necessary for future model year vehicles. 

I hereby certify that the above 

is a true and correct copy of 

Resolution 94-67 as adopted by ' 

the Air Resources Board. 

9& ;afesw 

Pat Hutchens, Board Secretary 

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Modifications to Section 1968.1, Title, 13, California Code of Regulations 

These are amendments to section 1968.1, Title 13, CCR. Amendments adopted by the Board 

on December 8, 1994 are s"hown in underline to indicate additions and strikeout to indicate 

deletions. Amendments noticed for comment between January 19 and February 3, 1995, are 

indicated by double underline for additions and italics with strikeout to indicate deletions. 

'Z> 
1968.1 Malfunction and Diagnostic System Requirements-1994 and Subsequent Model-Year 

Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and Engines 

(a) GENERAL REQUIREMENTS 

(1.0) All 1994 and subsequent model-year passenger cars, light-duty trucks, and 

medium-duty vehicles shall be equipped with a malfunction indicator light (MIL) 

located on the instrument panel that will automatically inform the vehicle operator in 

the event of a malfunction of any powertrain components which can affect emissions 

and which provide input to, or receive output from, the on-board computer(s) or of the 

malfunction ofthe on-board computer(s) itself. The MIL shall not be used for any 

other purpose. 

(1.1) The MIL shall be of sufficient illumination and location to be readily visible under all 

lighting conditions. The MIL shall illuminate in the engine-run key position before 

_ engine cranking to indicate that the MIL is functional and shall, when illuminated, 

' display the phrase "Check Engine" or "Service Engine Soon". The word "Powertrain" 

may be substituted for "Engine" in the previous phrases. Alternatively, the 

International Standards Organization (ISO) engine symbol mav be substituted for the 

word "Engine." 

(1.2) All 1994 and subsequent model-year passenger cars, light-duty trucks, and 

medium-duty vehicles required to have MIL pursuant to (1.0) above shall also be 

equipped with an on-board diagnostic system capable of identifying the likely area of 

the malfunction by means of fault codes stored in computer memory. These vehicles , 

shall be equipped with a standardized electrical connector to provide access to the 

stored fault codes. Specific performance requirements are listed below. A glossary of 

terms is contained in subsection (n)1 at the end of this section. 

(1.3) Any reference to vehicles in this regulation shall also include medium-duty vehicles 

with engines certified on an engine dynamometer. 

{44)—Manufacturers of diesel engines utilizing computer-based electronic powertrain control 

systems shall submit a plan for complying with these requirements- to the Executive 

Officer for approval at least two years prior to certification. The plan shall be 

approved based on monitoring all powertrain components which can affect emissions 

and for v/hich reliable monitoring techniques are available at costs comparable to 

other engines meeting these requirements, and on meeting all othor applicable 

requirements (e.g., storing freeze frame conditions, meeting standardization 

requirements, etc.). 

1

 Unless otherwise noted, all section references are contained within this subsection of 

Title 13, CCR. 

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(1.S4) For Low Emission Vehicles (LEV), the Executive Officer shall revise the emission 

threshold for a malfunction on any check if the most reliable monitoring method 

developed requires a higher threshold to prevent significant errors of commission in 

detecting a malfunction. 

(1 .§5) For every case in which a malfunction is to be noted when an emission threshold is 

exceeded (e.g., emissions in excess of 1.5 times the standard), the manufacturer may 

perform only a functional check (defined in section (n)(16.0)) of a specific component 

or system if deterioration or failure of such would not cause the vehicle's emissions to 

exceed the emission threshold. 

(1.76) After the 1998 model year, for Non-LEVs, fulfillment of federal On-Board Diagnostic 

(OBD) requirements shall be deemed to be an acceptable option for the manufacturer 

for the purpose of meeting these requirements. 

(1.87) For 1994 and 1995 model years only, illumination ofthe malfunction indicator light 

upon detection of a malfunction shall be optional for catalyst, misfire, and complete 

evaporative system monitoring. MIL illumination for such vehicles shall be optional for 

other monitoring requirements, subject to Executive Officer approval, on the basis of 

use of a new monitoring strategy which is significantly different than that used 

previously by the manufacturer and/or which entails a high degree of sophistication in 

its application. Irrespective of the preceding the MIL shall illuminate on these vehicles 

in accordance with section 1968.1 for lack of function (see section (n)(16.0)) for 

electronic components/systems otherwise approved for not illuminating the MIL. 

Furthermore, setting fault codes for all malfunctions shall continue to conform with 

requirements of section 1968.1. For components/systems not requiring illumination of 

the MIL, manufacturers shall provide a plan for approval by the Executive Officer for 

reporting on the correct performance of the monitoring systems in customer use at 6 

month intervals beginning from the start of production each year for at least the first 

three years after production. Approval of the plan shall be based on obtaining a 

statistically valid sample size, assuring that adequate resources are available to 

investigate the potential problems, and assuring that a wide variety of vehicles, 

operating modes, and mileage accumulation will be included in the evaluation. Should 

incorrect performance of the diagnostic system be determined by the Executive Officer 

on the basis of these reports or through other means, manufacturers shall recall the 

vehicles for correction ofthe OBD II system in accordance with Article 2.2, Title 13 

CCR, or they shall submit an altemate plan for remedying the problem for approval by 

the Executive Officer on the basis of achieving comparable capture rates and 

timeliness as an official recall plan. 

(1.98) Manufacturers may employ altemate statistical MIL illumination and fault code storage 

protocols to those specified in these requirements, subject to Executive Officer 

approval based on comparable timeliness in detecting a malfunction and evaluating 

system performance. For strategies requiring on averaqe between three and six 

driving cycles for MIL illumination, the manufacturer shall provide data and/or an 

engineering evaluation which adequately demonstrate that the monitoring svstem is 

equally effective and timely in detecting component deterioration. Strategies requiring 

on average more than six driving cycles for MIL illumination shall not be accepted. 

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(1.9) Regarding diagnostic svstem monitoring conditions and MIL illumination requirements, 

manufacturers are generally required to define appropriate operating conditions for 

monitoring, subject to the limitation that the monitoring conditions shall be 

encountered at least once during the first engine start portion of the applicable 

• Federal Test Procedure (FTP) test. Upon detection of a malfunction, the MIL is to be 

illuminated and a fault code stored no later than the end of the next driving cycle 

during which monitoring occurs provided the malfunction is again detected. Until the 

1997 model year, diagnostic strategies that illuminate the MIL on the basis of 

completing a trip (trip is defined in section (n)(16.0) of these requirements) shall be 

accepted. When a trip criterion is employed, upon detection of a malfunction, the 

diagnostic svstem shall store a fault code and the MIL shall be illuminated no later 

than the end of the next trio if the malfunction is again present. 

(2.0) Manufacturers mav request Executive Officer approval to disable a diagnostic system 

designed to meet the requirements of section (b) at ambient engine starting 

temperatures below twenty degrees Fahrenheit, and at elevations above eight 

thousand feet above sea level provided the manufacturer submits data and/or an 

engineering evaluation which adeguately demonstrate that monitoring would be 

unreliable when such conditions exist. Notwithstanding, diagnostic system 

disablement mav be reguested at other ambient engine starting temperatures if the 

manufacturer adeguately demonstrates with data and/or an engineering evaluation 

that misdiagnosis would occur due to the impact of such ambient temperatures on the 

performance of the component itself (e.g., component freezing). 

(2.1) Manufacturers mav disable monitoring systems that can be affected by running out of 

fuel (e.g.. misfire detection) when the fuel level is low, provided disablement will not 

occur when the fuel level is above 15 percent of the nominal capacity of the fuel tank. 

(2.2) For vehicles designed to accommodate the installation of Power Take-Off (PTO) units 

(defined in section (n)(19.0)). disablement of affected monitoring systems is permitted 

provided disablement occurs onlv while the PTO unit is active, and provided the OBD 

II readiness code (specified in section (e)) is cleared by the on-board computer (i.e.. 

all bits shall be set to "test not complete") while the PTO unit is activated. The code 

may be restored to its state prior to PTO activation upon. PTO de-activation, upon 

activation of tho PTO unit. 

(b) MONITORING REQUIREMENTS 

(1.0) CATALYST MONITORING 

(1.1) Requirement: 

(1.1.1) LEVs: The diagnostic system shall individually monitor the front catalyst or 

catalysts (i.o., any catalyot(s) which receive engine out untreated exhaust gas), 

except that front catalysts may be monitored in combination with the next catalyst 

downstream if it can be demonstrated that a malfunction will be indicated when 

the front catalyst is alcno malfunctioning (see "(b) (1.2.1)). Catalysts arranged in 

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parallel with tho same inlet and outlet in a single exhaust pipe shall be 

considered as one catalyst. A separate catalyst incorporated in series into the 

same containor as a front catalyst shall be considered a downstream catalyst. 

The diaqnostic'svstem shall monitor the catalvst svstem for proper performance. 

(1.1.2) If the front catalyst is a small volume catalyst (see (b)(1.2.2)), the diagnostic 

system shall also monitor the next catalyst downstream of the small volume 

catalyst either independently of, or (if the conditions in section (1.1.1) are met) in 

combination with, the small volume catalyst. 

(1.1.3) Manufacturers may submit other monitoring strategies, subject to Executive 

Officer approval, based on equal timeliness and reliability in detecting a catalyst 

malfunction as these requirements. 

(1.1.4) Non-LEVs: The diagnostic system shall monitor the oatalyst system for proper 

performance. 

(1.1.2) Manufacturers are not required to implement these catalvst monitoring 

requirements on diesel vehicles and engines. Further, manufacturers of sparkignited lean-burn vehicles and engines may request that the Executive Officer 

exempt such applications from these catalvst monitoring requirements if it can be 

demonstrated that a reliable monitoring technology is nqt available. The 

Executive Officer shall approve such a request upon determining that all 

reasonable monitoring technologies have been considered to the extent possible. 

(1.2) Malfunction Criteria: 

(1.2.1) Low Emission Vehicles (see section (n)(14.0)): Each monitored catalyst, or 

combination of catalysts, shall be considered malfunctioning when average 

Federal Test Procedure (FTP) total hydrocarbon (HC) conversion efficiency falls 

between 50 to 60 percent. The efficiency determination shall be based on an 

FTP test wherein a malfunction is noted when the cumulative total HC emissions 

measured at the outlet ofthe monitored catalyst(s) is more than 40 to 50 percent 

of the cumulative total engine out omissions measured at the inlet of the 

Gatalyst(s). In addition, if a front catalyst is monitored in combination with a 

downstream oatalyst, the front oatalyst shall be considered malfunctioning when 

its efficiency has deteriorated between 40 to 50 peroent from its 4000 mile 

average FTP total HC efficiency. The catalvst svstem shall be considered 

malfunctioning when its conversion capability decreases to the point that either of 

the following occurs: 1) Hydrocarbon (HC) emissions exceed the applicable 

emission threshold2 specified in section (b)(1.2.2) below, or 2) the averaqe 

Federal Test Procedure (FTP) Non-Methane Hydrocarbon (NMHC) conversion 

2

 When related to emission standards, the malfunction criteria shall be based on the 

emission standards to which the vehicle is certified. For low emission vehicle applications, 

hydrocarbon emissions shall be multiplied bv the certification reactivity adjustment factor for 

the vehicle. 

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efficiency of the monitored portion of the catalvst svstem falls below 50 percentRegarding the second criterion, the efficiency determination shall be based on an 

FTP test wherein a malfunction is noted when the cumulative NMHC emissions 

measured at the outlet of the monitored catalyst(s) are more than 50 percent of 

the cumulative enoine-out emissions measured at the inlet of the catalyst(s). 

(1.2.2) TLEV applications shall employ an emission threshold malfunction criterion of 2.0 

times the applicable FTP HC standard plus the emissions from a test run with a 

representative 4000 mile catalvst system (125 hours of operation for medium-dutv 

vehicles with enqines certified on an engine dynamometer). The emission 

threshold criterion for LEV applications shall be 2.5 times the applicable FTP HC 

standard plus the emission level with a representative 4000 mile catalyst system. 

Notwithstanding, beginning with the 1998 model vear, manufacturers shall phase 

in an emission threshold of 1.5 times the applicable FTP HC standard for all 

categories of low emission vehicles, which shall not include the emission level 

with a 4000 mile catalvst system. The phase in percentages (based on the 

manufacturer's projected sales volume for low emission vehicle applications) shall 

equal or exceed 40 30 percent in the 1998 model vear, -70 60 percent in the 1999 

model vear, with 100 percent implementation for the 2000 model year. ULEV 

applications shall comply with the 1.5 times the standard emission threshold, and 

shall be included in the phase-in percentages specified above: however, prior to 

the 1998 model year, the Executive Officer shall revise the emission threshold for 

such vehicles if the manufacturer submits data and/or an engineering evaluation 

which adequately demonstrate that substantial vehicle body and/or catalvst 

system modifications would be necessary for this threshold to be met. 

(1.2.2) For LEVs, each small volume catalyst (i.e., those designed with a conversion 

efficiency too low to be practically monitored for 50 to 60 percent average FTP 

total HC efficiency) monitored independently shall be considered malfunctioning 

when its averdge FTP conversion efficiency has deteriorated by between 40 to 50 

peroent from its 4000 mile conversion efficiency. 

(1.2.3) Non-Low Emission Vehicles: The catalyst system shall be considered 

malfunctioning when its conversion capability decreases to the point that HC 

emissions increase by more than 1.5 times the standard over an FTP test from a 

test run with a representative 4000 mile catalyst system. 

(1.2.4) For 1994 and 1995 model year vehicles and enqines LEVs and Non LEVs. as an 

option to monitoring the catalyst during FTP driving conditions, manufacturers 

may monitor the front catalyst independently of, or in combination with, the next 

catalyst downstream. Each monitored catalyst or catalyst combination shall be 

considered malfunctioning when total HC conversion efficiency falls below 60 

percent while in normal closed loop operation. As a guideline, the catalyst(s) 

should not be considered malfunctioning when its efficiency is greater than 80 

percent. The efficiency determination shall be based on a steady state test 

wherein a malfunction is noted when the total HC emission concentration 

measured at the outlet of the monitored catalyst(s) is more than 20 to 40 percent 

of the cumulative total engine-out emissions measured at the inlet of the 

.. " /ST" 
catalyst(s). Alternatively, if correlation with FTP emissions can be demonstrated, 

manufacturers may use. the malfunction criteria specified in (b)(1.2.1) or 

(b)(1.2.3). 1994 and 1995 model year vehicles certified to this option shall 

incorporate FTP based monitoring no later than the 1997 model year (vehicles 

initially complying with section 1968.1 in the 1996 model year shall utilize an FTP 

based catalyst monitoring system). 

(1.3) Monitoring Conditions: 

(1.3.1) A catalyst monitoring check shall occur at least once per trip excopt for vehicles 

utilizing steady stato monitoring, which shall comply with section (1.3.2). "Trip" ic 

defined in section (n) (5.0). This trip definition applies throughout section 1968.1. 

The manufacturer shall define appropriate operating conditions during which 

monitoring shall occur, subject to the limitation that the monitoring conditions shall 

be encountered at least once during the first engine start portion of the applicable 

FTP test. However, vehicles utilizing steady state monitoring (as permitted by 

section (1.2.3) above), may alternatively comply with the monitoring conditions 

specified in section (1.3.2). The monitoring svstem shall operate at least once 

per driving cycle during which the manufacturer-defined monitoring conditions are 

met. 

(1.3.2) If steady state efficiency is being monitored (see section (b) (1.2.4)), the 

manufacturer shall choose a non-closed throttle, reasonably steady speed 

condition for monitoring the catalyst with the constraints that the check shall (i) 

occur between 20 mph and 50 mph, or within an engine rpm and torque range 

determined by the manufacturer to be representative of medium-duty vehicle 

Operating conditions between 20 and 50 mph steady speed conditions with a load 

equivalent to 50 percent of the maximum load carrying capacity, (ii) take no more 

than a 20 second interval to determine both that the vehicle is operating in a 

proper window to perform the check and to actually perform the check, and (iii) 

be conducted at the earliest such condition encountered after the beginning of 

closed-loop operation for each driving cycle. Performance of the check may be 

delayed after engine startup until stabilized coolant temperature is achieved 

and/or a suitable cumulative time interval of non-closed throttle vehicle operation 

has elapsed to ensure the catalyst is warmed-up for properiy performing the 

monitoring check. The specified cumulative time interval shall begin from the first 

non-closed throttle operation either after achieving a stabilized coolant 

temperature or after engine starting and shall not exceed 180 seconds. These 

monitoring constraints and conditions may be altered, subject to Executive Officer 

Approval. Such approval shall be granted if the manufacturer submits data and 

an engineering evaluation justifying the need for the exception and demonstrates 

that the requested alteration would yield improved catalyst monitoring. 

"Reasonably steady" speed interval in this instance means a 20 second period 

where all accelerations and decelerations are of an average magnitude equivalent 

to 0.5 mph/second or less over any two second interval during this period. The 

If-
P.18 

manufacturer may abort the check if the engine operating conditions change 

during the check so that the vehicle exceeds the speed or 

acceleration/deceleration tolerances before the end of the checking interval. The 

manufacturer may base performance ofthe catalyst check upon engine RPM and 

load conditions equivalent to the above monitoring conditions. If a manufacturer 

develops a means of monitoring catalyst efficiency which cannot utilize a steady 

state monitoring period (e.g., examining time vs. temperature during catalyst 

warmup), it may present a monitoring proposal to the Executive Officer for 

approval based on equivalent accuracy and timeliness as the steady state 

monitoring protocol in detecting a malfunctioning catalyst. 

(1.4) MIL Illumination and Fault Code Storage: 

(1.4.1) Except as noted below, upon detection of a catalyst malfunction, the diagnostic 

system shall store a fault oodo and the MIL shall be illuminated no later than the 

end of the next trip if the malfunction is again present, upon detection of a 

catalyst malfunction, the MIL shall illuminate and a fault code stored no later than 

the end of the next driving cvcle during which monitoring occurs provided the 

malfunction is again present. 

(1.4.2) For steady state catalyst efficiency checks, upon detection of catalyst efficiency 

below 60 percent, the diagnostic system may perform up to two successive 

monitoring checks prior to informing the vehicle operator of a malfunction. These 

monitoring checks need not occur on the same driving cycle, but shall be 

performed as soon as proper monitoring conditions occur. If catalyst efficiency 

remains below 60 percent for the three sequential checks, a fault code shall be 

stored and the MIL shall then be activated. / 

(1.4.3) The diagnostic system shall temporarily disable catalyst monitoring when a 

malfunction exists which could affect the proper evaluation of catalyst efficiency. 

(1.4.4) The monitoring method for the catalyst(s) shall be capable of detecting when a 

catalyst trouble code has been cleared (except diagnostic system self-clearing), 

• but the catalyst has not been replaced (e.g., catalyst overtemperature approaches 

may not be acceptable). 

(2.0) HEATED CATALYST MONITORING 

(2.1) Requirement: 

(2.1.1) The diagnostic system shall monitor.all heated catalyst systems for proper 

heating. 

(2.1.2) In addition to the non heatod catalyst requirements in section (b) (1), the HC 

conversion efficiency of all hooted catalysts shall each be monitored. 

Manufacturers may monitor heated catalysts in combination with another catalyst 

if it can bo demonstrated that a malfunction will be indicated when the heatod 

n 
P. 19 

catalyst is malfunctioning. Otherwise, the heated catalyst shall be monitored 

independently. If a heated catalyst is a small volume front oatalyst, the diagnostic 

system shall alco monitor the noxt catalyst downstream either independently of, 

or (if the conditions-above are met) in combination with, the small volume heated 

catalyst.- The efficiency of heated catalysts shall be monitored in conjunction with 

the reguirements of section (b)(1). 

(2.2) Malfunction Criteria: 

(2.2.1) Pre-Start Heated Catalyst Systems: The system shall be considered 

malfunctioning when the designated pre-start catalyst temperature is not attained 

before engine starting. 

(2.2.24) After-Start Heated Catalyst Systems The catalvst heating system shall be 

considered malfunctioning when the catalyst does not reach its designated 

heating temperature within a requisite time period after engine starting; The 

time period is-to be determined by the manufacturer subject to the requirement 

that the system shall detect a heating system malfunction causing emissions 

from a vehicle equipped with the heated catalyst system to exceed 1.5 times 

any of the applicable FTP standards. 

(2.2.32) Manufacturers using other heating or monitoring strategies may submit an 

alternate plan for approval by the Executive Officer to monitor heated catalyst 

systems based on comparable reliability and timeliness to these requirements in 

detecting a catalyst heating malfunction. 

(2.2.4) Except as noted in section (b) (1.2.4), the diagnostic system shall use the 

malfunction criteria specified in section (b)(1.2.1) or coction (b) (1.2.2), whichever 

is applicable, when monitoring the conversion efficiency of a heated oatalyst. 

(2.3) Monitoring Conditions: 

(2.3.1) Manufacturers shall define appropriate operating conditions for monitoring of the 

catalvst heating svstem. subject to the limitation that the monitoring conditions 

shall be encountered at least once during the first engine start portion of the 

applicable FTP test. The monitoring svstem shall operate at least once per 

driving cvcle during which the manufacturer-defined monitoring conditions are 

met. Pre-Start Heated Catalyst Systems: The diagnostic svstem shall monitor the 

heating system for proper operation once per trip. Manufacturers may disable the 

monitoring system for one engine 6tart if during the previous driving cycle the 

vehicle traveled less than the equivalent ofthe first one mile of FTP driving. 

(2.3.2) After-Start Heated Catalyst Systems: The diagnostic system shall monitor the 

heating system for proper operation once per trip. Manufacturers may disable the 

monitoring system for one ongine start if during the previous driving cycle the 

vehicle traveled less than the equivalent of the first one mile of FTP driving. 

•/*• ' 
(2.3.3) Except as noted in section (b) (1.2.4), the diagnostic system shall monitor the 

conversion efficiency of all heated catalysts at least once per trip. 

(2.4) MIL Illumination and'Fault Code Storage: 

(2.4.1) Upon detection of a catalyst heating malfunction, the diagnostic system shall 

store a fault code and the MIL shall be illuminated no later than the end of the 

next trip if the malfunction is-aqain present the MIL shall illuminate and a fault 

code stored no later than the end of the next driving cvcle during which 

monitoring occurs provided the malfunction is again present. • 

(2.4.2) For heated catalyst efficiency malfunctions, the MIL shall be illuminated, and a 

fault code stored according to section (b) (1.4). 

(3.0) MISFIRE MONITORING 

(3.1) Requirement: The diagnostic system shall monitor engine misfire and shall identify the 

specific cylinder experiencing misfire. Manufacturers mav reguest Executive Officer 

. approval to store a qeneral misfire fault code instead of a cvlinder specific code under 

certain operating conditions provided the manufacturer submits data and/or an 

. engineering evaluation which adequately demonstrate that the misfiring cvlinder cannot 

be reliably identified when such conditions occur. If more than one cylinder is 

misfiring, a separate code shall indicate that multiple cylinders are misfiring (specifying 

the individual misfiring cylinders under this condition is optional, however, identifying 

only one misfiring cylinder shall not occur when a multiple misfire code is stored). 

(3.2) Malfunction Criteria: The manufacturer shall specify in the documentation provided for 

certification (see subsection (g) and (h) infra.) a percentage of misfires out of the total 

number of firing events necessary for determining a malfunction for each of the 

conditions listed below. 

(A) The percent misfire evaluated in 200 revolution increments for each engine speed 

and load condition which would result in catalyst damage. Subject to Executive 

Officer approval, a longer interval (up to 1000 revolutions) may be employed 

provided the manufacturer submits data and/or an engineering evaluation which 

adeguately demonstrate that catalvst damage would not occur due to 

unacceptably high catalvst temperatures before the interval has elapsed. The 

manufacturer shall submit in the certification documentation catalyst temperature 

data versus percent misfire over the full range of engine speed and load 

conditions. The data shall be obtained from a representative cross section of a 

manufacturer's engine offerings from small to large displacements. Up to three 

such engine evaluations shall be documented per manufacturer, though a 

manufacturer may submit more data if desired. An engineering evaluation shall 

be provided for establishing malfunction criteria for the remainder of engine 

families in the manufacturer's product line. The Executive Officer shall waive the 

evaluation requirement each year if, in the judgment of the Executive Officer, 

technological changes do not affect the previously determined malfunction 

criteria; 

9 

/?'..•• • 
P.21 

(B) The percent misfire evaluated in 1000 revolution increments which would cause 

emissions from a durability demonstration vehicle to exceed 1.5 times any ofthe 

applicable FTP standards if the degree of misfire were present from the beginning 

of the test. If tho level cf misfire determined under this requirement is significantly 

lower for an LEV as opposed to a Non LEV-with a similar engine design, the 

manufacturer may request approval from the Executive Officer to use a higher 

percentage of misfire as the malfunction criteria for the LEV, not to exceed the 

level of the Non LEV. For the purpose of establishing the percent misfire, the 

manufacturer shall conduct the demonstration test(s) with the misfire events 

occurring at equally spaced complete engine cycle intervals, across randomly 

selected cylinders throughout each 1000 revolution increment. However, the 

percent misfire established shall be applicable for any misfire condition (e.g. 

random, continuous, equally spaced, etc.) for the purpose of identifying a 

malfunction. This criterion ek&U may be used for all vehicles with engines 

containing the same number of cylinders as the demonstration vehicle. The 

number of misfires in 1000 revolution increments which was determined for the 

durability demonstration vehicle malfunction criterion may be used to establish the 

corresponding percent misfire malfunction criteria for engines with other numbers 

of cylinders. The malfunction criteria for a manufacturer's product line shall be 

updated when a new durability demonstration vehicle is tested which indicates 

more stringent criteria are necessary than previously established to remain within 

the above emission limit; 

(C) The degree of misfire evaluated in 1000 revolution increments which would cause 

a durability demonstration vehicle to fail an Inspection and Maintenance program 

tailpipe emission test. This criterion shall apply to vehicles with the same number 

of cylinders as the demonstration vehicle. The number of misfires in 1000 

revolution increments which was determined for the durability demonstration 

vehicle malfunction criterion may be used to establish the corresponding percent 

misfire malfunction criteria for engines with other numbers of cylinders. The 

malfunction criteria for a manufacturer's product line shall be updated when a 

new durability demonstration vehicle is tested which indicates more stringent 

criteria are necessary than previously established to ensure passing an 

Inspection and Maintenance test, or when the Inspection and Maintenance test is 

revised. 

(3.3) Monitoring Conditions: For 1997 and later model year vehicles, misfire shall be 

monitored continuously and under-all positive torque engine speeds and conditions.-

(3.3.1) For pre-1997 modol year vehicles, Pre-1997 Model Year Vehicles: misfire shall 

be monitored continuously during, at a minimum, positive torque operating 

conditions within the range of engine speed and load condition combinations 

encountered during an FTP test; nonetheless, subject to Executive Officer 

approval, manufacturers may employ higher misfire percentage malfunction 

criteria disable misfire monitoring under specific conditions within the range of 

operating conditions encountered during an FTP test if the manufacturer provides 

data and/or an engineering evaluation which caa adeguately demonstrate that the 

detection of lower levels of misfire monitoring is not would not be reliable feasible 

10 
for the vehicle model in question when such conditions are encountered without 

making fundamental engine or control unit design modifications. If the 

manufacturer can so demonstrate that even the detection of a higher misfire 

percentages is'not feasible under specific FTP operating conditions, the 

manufacturer may request Executive Officer approval to disable the monitoring 

svstem when such conditions are encountered. Further, with Executive Officer 

approval, the manufacturer may disable misfire, monitoring when misfire cannot 

be distinguished from other effects when using the best available monitoring 

technology. The manufacturer shall present data and an engineering evaluation 

to the Executive Officer to justify the proposed action. 

(3.3.2) 1997 and Later Model Year Vehicles: Manufacturers shall phase in expanded 

misfire monitoring conditions beginning with the 1997 model year. The phase in 

percentages (based on the manufacturer's projected sales volume for all vehicles 

and engines) shall equal or exceed 50 percent in the 1997 model vear, 75 

percent in the 1998 model vear, 90 percent in the 1999 model year, with 100 

percent implementation for the 2000 model year. Small volume manufacturers 

shall not be reguired to meet the phase-in percentages: however, 100 percent 

implementation of these monitoring conditions shall be reguired beginning with 

the 2000 model year. On vehicles meeting these phase-in percentages, except 

as provided for in section (3.3.3) below, monitoring for misfire shall be continuous 

and under all positive torgue engine speeds and load conditions. Vehicles not 

meeting the monitoring conditions of this section shall meet the monitoring 

conditions specified in section (b)(3.3.1) above. 

(3.3.3) As an exception to monitoring misfire during all positive torque operating 

conditions, manufacturers mav disable misfire monitoring in the engine operating 

region bound by the positive torque line (i.e.. engine'load with the transmission in 

neutral), and the two following engine operating points: an engine speed of 3000 

rpm with the engine load at the positive torgue line, and the redline engine speed 

(defined in section (n)(18.0)) with the engine's manifold vacuum at four inches of 

mercury lower than that at the positive torgue line. Below is a diagram of the 

permitted misfire detection disablement region with respect to the reguirements of 

this section. Further, with Executive Officer approval, the manufacturer may 

disable misfire monitoring when misfire cannot be distinguished from other effects 

(e.g.. rough roads, transmission shifts, etc.) when using the best available 

monitoring technology. The manufacturer shall present data and/or an 

engineering evaluation to the Executive Officer to justify the proposed actionExecutive Officer approval shall be based on the extent to which monitoring is 

expected to be disabled in relation to the capabilities of the best available 

monitoring technologies as applied to other engines. 

11 

2-7 
P.23 

o 

_ J 

CD 

C 

"o 

c 

UJ 

Positive Torque Load - 4 inches Hg 

Disablement Region 

Postive Torque 

idle 2000 3000 . 4000 

Engine Speed 

5000 redline 

(3.4) MIL Illumination and Fault Code Storage: 

(3.4.1) Except as provided below, upon detection of the level of misfire specified in 

subsection (3.2) (A), the MIL shall blink once per second during actual misfire 

conditions and remain continuously illuminated otherwise. In vehicles which 

provide fuel shutoff and default fuel control to prevent overfueling during misfire 

conditions, the MIL need not blink and .may instead illuminate continuously upon 

detection of misfire provided that the fuel shutoff and default control shall be 

activated as soon as misfire is detected. Fuel shutoff and default fuel control may 

be deactivated only to permit fueling outside of the misfire range. 

(3.4.2) Upon detection of the misfire levels specified in subsection (3.2) (B) or (C), the 

MIL shall be illuminated and a fault code stored no later than the end of the next 

driving cycle if misfire is again detected. If misfire is not detected during the 

second driving cycle, the MIL shall be illuminated and a fault code stored no later 

than the next driving cvcle in which misfire is detected, unless driving conditions 

similar to those under which misfire was originally detected have been 

encountered (see section (3.4.3)) without an indication of misfire, in which case 

the initial temporary code and stored conditions may be erased. Furthermore, if 

similar driving conditions are not encountered during 80 driving cycles tripe 

subsequent to the initial detection of a malfunction, the initial temporary code and 

stored conditions may be erased. 

(3.4.3) Upon detection of misfire, manufacturers shall store the engine speed, load, and 

warm-up status (i.e., cold or warmed-up) under which the first misfire event was 

detected. A trip or driving cycle shall be considered to have similar conditions if 

the stored engine speed conditions are encountered within 375 rpm, load 

12 

-PX 
conditions within 10 percent, and the same warm-up status is present. With 

Executive Officer approval, other strategies for determining if similar conditions 

have been encountered may be employed. Approval shall be based on 

comparable timeliness and reliability in detecting similar conditions. 

(3.5) MISFIRE MONITORING FOR DIESELS 

(3.5.1) Reguirement: Beginning with the 1998 model year, the diagnostic svstem on a 

diesel engine shall be capable of detecting the lack of combustion in one or more 

cylinders. The diagnostic system shall also identify the specific cvlinder for which 

combustion cannot be detected. If the lack of combustion is present in more than 

one cvlinder, a separate code shall indicate that multiple cylinders are 

malfunctioning (specifying the individual malfunctioning cylinders under this 

condition is optional; however, identifying one malfunctioning cvlinder shall not 

occur when a multiple cylinder code is stored). 

(3.5.2) Malfunction Criteria: A cylinder shall be considered malfunctioning when 

combustion cannot be detected. 

(3.5.3) Monitoring Conditions: Manufacturers shall define appropriate operating 

conditions for monitoring, subject to the limitation that the monitoring conditions 

shall be encountered at least once during the first engine start portion of the 

applicable FTP test. -The monitoring svstem shall operate at least once per 

driving cycle during which the manufacturer-defined monitoring conditions are 

met. 

(3.5.4) MIL Illumination and Fault Code Storage: The MIL shall illuminate and a fault 

code shall be stored no later than the end of the next driving cycle during which 

monitoring occurs provided the malfunction is again present. 

(4.0) EVAPORATIVE SYSTEM MONITORING 

(4.1) Requirement: 

(4.1.1) The diagnostic system shall verify air flow from the complete evaporative system. 

In addition, the diagnostic system shall also monitor the evaporative system for 

the loss of HC vapor into the atmosphere by performing a pressure or vacuum 

check of the complete evaporative system. 

(4.1.2) Manufacturers may temporarily disable the evaporative purge system to perform 

a check. 

(4.1.3) Manufacturers may request Executive Officer approval to abort an evaporative 

system check under specific conditions (e.g., when the fuel tank level is over 85 

percent of nominal tank capacity) if it oan be data and/or an engineering 

evaluation are provided which adequately demonstrated- that a reliable check 

cannot be made when these conditions exist. 

13 

^3 
P.25 

(4.1.4) Subject to Executive Officer approval, other monitoring strategies may be used 

provided the manufacturer provides a description of the strategy and supporting 

data showing equivalent monitoring reliability and timeliness in detecting an 

evaporative system malfunction or leak. 

(4.1.5) Implementation of this requirement is mandatory only for 1996 and later model 

year vehicles designed to comply with the requirements of Title 13, California 

Code of Regulations, Section 1976, "Standards and Test Procedures for Motor 

Vehicle Fuel Evaporative Emissions," for 1995 and subsequent model year 

vehicles. 

(4.2) Malfunction Criteria: 

(4.2.1) An evaporative system shall be considered malfunctioning when no air flow from 

the system can be detected, or when a system leak is detected that is greater 

than or equal in magnitude to a leak caused by a 0.040 inch diameter orifice in 

any portion of the evaporative system excluding the tubing and connections 

between the purge valve and the intake manifold. 

(4.2.2) Beginning with the 4993 2000 model vear. manufacturers shall phase-in 

diagnostic strategies to detect svstem leaks greater than or equal in magnitude to 

a leak caused bv a 0.020 inch diameter orifice. The phase-in percentages (based 

on the manufacturer's projected sales volume for all vehicles) shall egual or 

exceed 50 percent for the 4-993 2000 model year. 75 percent for the 4900 2001 

model vear, and 100 percent implementation for the 2000 2002 model yearSmall volume manufacturers shall not be subject to the phase-in requirements: 

however, 100 percent implementation shall be required ior 2000 2002 model 

vear. 

(4.2.3) On vehicles with fuel tank capacity greater than 25 gallons, the Executive Officer 

shall revise the size of the orifice if the most reliable monitoring method available 

cannot reliably detect a system leak of this the magnitudes indicated above. 

(4.3) Monitoring Conditions: The monitoring system shall monitor the evaporative system at 

least once por trip. Manufacturers shall define appropriate operating conditions for 

monitoring, subject to the limitation that the monitoring conditions shall be encountered 

at least once during the first engine start portion of the applicable FTP test. The 

monitoring svstem shall operate at least once per driving cvcle during which the 

manufacturer-defined monitoring conditions are met. However, monitoring conditions 

mav be further limited with respect to detecting leaks eguivalent to a 0.020 inch 

diameter orifice, subject to Executive Officer approval, on the basis that the monitoring 

conditions will be reasonably-occurring in-use. and provided that a check for leaks 

equal or greater in magnitude than a 0.040 inch orifice will continue to be conducted at 

least once per driving cvcle as indicated above. Subject to Executive Officer approval, 

if performance of the check causes vehicles to exceed applicable emission standards 

when using the best available technology, manufacturers may perform evaporative 

system monitoring during a steady-speed condition, as defined in section (b) (1.3.2), 

between 20 and 50 mph. 

14 

. . • • - . - . ^A : ' • ' ' • • 
(4.4) MIL Illumination and Fault Code Storage: 

(4.4.1) Upon detection of an evaporative system malfunction or a malfunction that 

prevents completion of an evaporative system check, the MIL shall illuminate and 

a fault code shall be stored no later than the end of the next driving cycle during 

which monitoring occurs provided the malfunction is again present, the diagnostic 

system shall store a fault code and the MIL shall illuminate no later than the end 

of the next trip if the malfunction is again detected. 

(4.4.2) If the diagnostic system is capable of discerning that a system leak is being 

caused by a missing or improperly secured fuel cap, the manufacturer may notify 

the vehicle operator through the use of an indicator light other than the MIL. The. 

manufacturer is not required to store a fault code in this case. The indicator light 

shall conform to the requirements outlined in section (a) (1.1) for location and 

illumination. As another option, the manufacturer may extinguish the MIL, 

provided no other malfunctions have been detected, and may erase the fault code 

corresponding to the problem once the on-board diagnostic system has verified 

that the fuel cap specifically has been securely fastened. Other equivalent 

strategies shall be considered by the Executive Officer. 

(5.0) SECONDARY AIR SYSTEM MONITORING 

(5.1) Requirement: Any vehicle equipped with any form of secondary air delivery system 

shall have the diagnostic system monitor the proper functioning of (ij. the secondary air 

delivery system and (ii) any air switching valve. 

(5.2) Malfunction Criteria: 

(5.2.1) The diagnostic system shall indicate secondary air delivery system malfunction 

when the flow rate falls below the manufacturer's specified low flow limit such that 

a vehicle would exceed 1.5 times any ofthe applicable FTP emission standards. 

(5.2.2) Manufacturers adeguately demonstrating that deterioration of the flow distribution 

system is unlikely may request Executive Officer approval to perform only a 

functional check of the system. As part of this demonstration, manufacturers 

shall demonstrate that the materials used for the secondary air svstem (e.g., air 

hoses, and tubing) are inherently resistant to corrosion or other deterioration, to 

such a case, If a functional check is approved, the diagnostic system shall 

indicate a malfunction when some degree of secondary airflow is not detectable 

in the exhaust system during a check. 

(5.3) Monitoring Conditions: The monitoring ofthe secondary air delivery system and the air 

switching valve shall occur once per trip.- Manufacturers shall define appropriate 

operating conditions for monitoring of the secondary air system, subject to the limitation 

that the monitoring conditions shall be encountered at least once during the first engine 

start portion of the applicable FTP test. The monitoring svstem shall operate at least 

once per driving cycle during which the manufacturer-defined monitoring conditions are 

met. 

: ' 15 

c3_> 
P.27 

(5.4) MIL Illumination and Fault Code Storage: The diagnostic system shall store a fault 

code and the MIL shall illuminate no later than the end of the next trip if the 

malfunction is again dotocted next driving cycle during which monitoring occurs 

provided the malfunetion is again present. 

(6.0) AIR CONDITIONING SYSTEM REFRIGERANT MONITORING 

(6.1) Requirement: 

(6.1.1) The diagnostic system shall monitor air conditioning systems for loss of 

refrigerants which could harm the stratospheric ozone layer or are reactive in 

forming atmospheric ozone. Any sensor used for such monitoring shall itself be 

monitored for proper circuit continuity and proper range of operation. A provision 

for ensuring that a leak has been corrected before extinguishing the MIL shall be 

provided. 

(6.1.2) Manufacturers of a model vehicle which will phase out the use of 

chlorofluorocarbons in its' air conditioning systems by the 1996 model-year or 

which will use federally-approved refrigerants with substantially less atmospheric 

ozone depleting potential than CFC-12 need not comply with this requirement for 

that model. 

(6.2) Malfunction Criteria: Manufacturers shall provide a monitoring strategy for approval by 

the Executive Officer for monitoring a refrigerant leak. The approval shall be based on 

timeliness and reliability in detecting a leak. 

(6.3) Monitoring Conditions: The diagnostic system shall monitor tho air conditioning system 

at least once per trip. Manufacturers shall define appropriate operating conditions for 

monitoring, subject to the limitation that the monitoring conditions shall be encountered 

at least once during the first engine start portion of the applicable FTP test. The 

monitoring svstem shall operate at least once per driving cvcle during which the 

manufacturer-defined monitoring conditions are met 

(6.4) MIL Illumination and Fault Code Storage: The diagnostic system shall store a fault 

code and the MIL shall illuminate no later than the end of the next trip if the 

malfunction is again present driving cvcle during which monitoring occurs provided the 

malfunction is again present. The diagnostic system shall not clear a fault code and 

the MIL shall not turn off unless the leak has been corrected. 

(7.0) FUEL SYSTEM MONITORING 

(7.1) Requirement: The diagnostic system shall monitor the fuel delivery system for its 

ability to provide compliance with emission standards. For diesel vehicles and 

engines, the manufacturer shall monitor the performance of all electronic fuel svstem 

components to the extent feasible with respect to the malfunction criteria specified in 

section (7.2) below. 

16 

AU 
P.28 

(7.2) Malfunction Criteria: The manufacturer shall establish malfunction criteria to monitor 

the fuel delivery system such that a vehicle's emissions would not exceed 1.5 times 

any of the applicable FTP.standards before a fault is detected. If the vehicle is 

equipped with fuel trim circuitry, the manufacturer shall include as one of the 

malfunction criteria the condition where the trim circuitry has used up all of the trim 

adjustment allowed within the manufacturer's selected limit(s). Manufacturers may 

compensate the criteria limit(s) appropriately for changes in altitude or for temporary 

introduction of large amounts of purge vapor or for other similar identifiable operating 

conditions when they occur. 

(7.3) Monitoring Conditions: The fuel system shall be monitored continuously for the 

presence of a malfunction. 

(7.4) MIL Illumination and Fault Code Storage: 

(7.4.1) For fuel systems with short-term trim only capability, the diagnostic system shall 

store a fault code after the fuel system has attained the criteria limit for a 

manufacturer-defined time interval sufficient to determine a malfunction. If the 

malfunction criteria limit and time interval are exceeded, the MIL shall be 

illuminated and a fault code stored no later than the end of the next driving cycle 

in which the criteria and interval are again exceeded, unless driving conditions 

similar to those under v/hich the problem was originally detected have been 

encountered (see section (7.4.3)) without such an exceedance, in which case the 

initial temporary code and stored conditions may be erased. Furthermore, if 

similar driving conditions are not encountered during 80 driving cycles trips 

subsequent to the initial detection of a malfunction, the initial temporary code and 

stored conditions may be erased. 

(7.4.2) For fuel systems with long-term fuel trim capability, upon attaining a long-term 

based malfunction criteria limit independent of, or in combination with, the 

short-term trim system status, the MIL shall be illuminated and a fault code stored 

no later than the end of the next trip driving cvcle if the malfunction is again 

detected. If the malfunction is not detected during the second driving cycle, the 

MIL shall be illuminated and a fault code stored no later than the next driving 

cvcle in which the malfunction is again detected, unless driving conditions similar 

to those under which the problem was originally detected have been encountered 

(see subsection (7.4.3)) without an indication of a malfunction, in which case the 

initial temporary code and stored conditions may be erased. Furthermore, if 

similar driving conditions are not encountered during 80 driving cycles trips 

subsequent to the initial detection of a malfunction, the initial temporary code and 

stored conditions may be erased. 

(7.4.3) Upon detection of a fuel system malfunction, manufacturers shall store the engine 

speed, load and warm-up status (i.e., cold or warmed-up) under which the 

malfunction was detected. A trip or driving cycle shall be considered to have 

similar conditions if the stored engine speed is encountered within 375 rpm, load 

conditions within 10 percent, and the same warm-up status is present. With 

Executive Officer approval, other strategies, for determining if similar conditions 

17 

' 01 - . 
have been encountered may be employed. Approval shall be based on 

comparable timeliness and reliability in detecting similar conditions. 

(8.0) OXYGEN SENSOR MONITORING 

(8.1) Requirement: 

(8.1.1) the diagnostic system shall monitor the output voltage, response rate, and any 

other parameter which can affect emissions, of all primary (fuel control) oxygen 

(lambda) sensors for malfunction. It shall also monitor all secondary oxygen 

sensors (fuel trim control or use as a monitoring device) for proper output voltage 

and/or response rate. Response rate is the time required for the oxygen sensor 

to switch from lean-to-rich once it is exposed to a richer than stoichiometric 

exhaust gas or vice versa (measuring oxygen sensor switching frequency may 

not be an adequate indicator of oxygen sensor response rate, particularly at low 

speeds). 

(8.1.2) Either the lean-to-rich or both the lean-to-rich and rich- to-lean response rates 

shall be checked. Response rate checks shall evaluate the portions of the 

sensor's dynamic signal that are most affected by sensor malfunctions such as 

aging or poisoning. 

Manufacturers may observe the voltage envelope of the sensor when cycled at a 

frequency of 1.5 Hertz or greater, as determined by the manufacturer, to evaluate 

a slow response rate sensor (i.e. a slow sensor cannot achieve maximum and/or 

minimum voltage as will a good sensor given a properly chosen switching 

frequency and fuel step change for the check). With Executive Officer approval, 

manufacturers may use other voltage requirements/fuel-air switching frequencies 

or monitoring strategies based on a determination of accurate and timely 

evaluation of the sensor. 

(8.1.3) For sensors with different characteristics, the manufacturer shall submit data and 

an engineering evaluation to the Executive Officer for approval based on showing 

equivalent evaluation of the sensor. 

(8.1.4) For vehicles equipped with heated oxygen sensors, the heater circuit shall be 

monitored for proper current and voltage drop (note: a continuity check of oxygen 

sensors is not required). Other heater circuit monitoring strategies would require 

approval by the Executive Officer based on equally reliable and timely indication 

of malfunction as current or voltage-based monitoring. 

(8.2) Malfunction Criteria: 

(8.2.1) An oxygen sensor shall be considered malfunctioning when the voltage, response 

rate, or other criteria are exceeded and causes emissions from a vehicle 

equipped with the sensor(s) to exceed 1.5 times any of the applicable FTP 

standards, or when the criteria of sensors for use as a diagnostic system 

monitoring device (e.g., for catalyst efficiency monitoring) are exceeded. 

18 

' ar -' . • • - - -
(8.2.2) For heated oxygen sensors, the heater circuit shall be considered malfunctioning 

when the current or voltage drop in the circuit is no longer within the 

manufacturer's specified limits for proper normal operation (i.e., within the criteria 

reguired to be met by the component vendor for heater circuit performance at 

high mileage). Subject to Executive Officer approval, other monitoring strategy 

malfunction criteria for detection of heater circuit malfunctions may be used 

provided the manufacturer submits data and/or an engineering evaluation 

adeguately showing monitoring reliability and timeliness to be equivalent to the 

stated criteria in this paragraph. 

(8.3) Monitoring Conditions: 

(8.3.1) For primary oxygen sensor(s) used for fuel control, the response rate and output 

voltage shall be monitored for malfunction before the end of the first idle period 

after the vehicle has commenced closed-loop operation, if the necessary checking 

condition for acceptable oxygen sensor(s) performance has been encountered. 

The performance of the sensor can only be judged acceptable by one or more of 

the following means: within any 20 second reasonably steady speed condition as 

defined in (b) (1.3.2), within any deceleration of 3 seconds or more, or during the 

first idle period of at least 20 seconds after closed loop operation begins (i.e., not 

during an acceleration condition); not withstanding, unacceptable performance 

can be determined at any time. Other monitoring conditions may be used 

provided the manufacturer provides a monitoring strategy and supporting data 

showing equivalent monitoring reliability and timeliness in detecting a 

malfunctioning sensor compared to the above monitoring conditions and the 

Executive Officer approves. 

(8.3.2) For secondary oxygen sensors used for catalyst monitoring and/or fuel system 

trim, the manufacturer shall define appropriate operating conditions for response 

rate and/or output voltage malfunction monitoring shall be monitored for 

malfunction, subject to the limitation that the monitoring conditions shall be 

encountered at least once during the first engine start portion of the applicable 

FTP test. The monitoring svstem shall operate at least once per driving cvcle 

during which the manufacturer-defined monitoring conditions are met per trip. 

(8.3.3) For heated oxygen sensors, the manufacturer shall define appropriate operating 

conditions for malfunction monitoring of the heater circuit shall be monitored for 

malfunction, subject to the limitation that the monitoring conditions shall be 

encountered at least once during the first engine start portion of the applicable 

FTP test. The monitoring system shall operate at least once per driving cvcle 

during which the manufacturer-defined monitoring conditions are met pef-trip. 

(8.4) MIL Illumination and Fault Code Storage: Upon detection of any oxygen sensor 

malfunction, the diagnostic system shall store a fault code and the MIL shall illuminate 

no later than the end of the next trip if the malfunction is again present driving cvcle 

during which monitoring occurs provided the malfunction is again present. 

19 

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P.31 

(8.5) Other (non-lambda) Oxygen Sensors: 

(8.5.1) For vehicles equipped with universal exhaust gas oxygen sensors (i.e. sensors 

which provide an output proportional to exhaust gas oxygen concentration), the 

manufacturer shall define appropriate operating conditions for the diagnostic 

system shall provido to perform a response rate check (the time required to 

respond to a specific change in fuel/air ratio), subject to the limitation that the 

monitoring conditions shall be encountered at least once during the first engine 

start portion of the applicable FTP test. The monitoring svstem shall operate at 

least once per driving cvcle during which the manufacturer-defined monitoring 

conditions are met, per trip and an The diagnostic svstem shall also perform an 

out-of-range check for which monitoring shall be continuous. For malfunctions, 

MIL illumination and fault code storage shall be as in (8.4). 

(8.5.2) If a manufacturer utilizes other types of oxygen sensors, the manufacturer shall 

submit a monitoring plan to the Executive Officer for approval based on 

equivalent monitoring with conventional sensors. 

(9.0) EXHAUST GAS RECIRCULATION (EGR) SYSTEM MONITORING 

j(9.1) Requirement: 

(9.1.1) The diagnostic system shall monitor the EGR system on vehicles so-equipped for 

low and high flow rate malfunctions. 

(9.1.2) Manufacturers may request Executive Officer approval to temporarily disable the 

EGR system check under specific conditions if it can be provided the 

manufacturer submits data and/or an engineering evaluation which adeguately 

demonstrated- that a reliable check cannot be made when these conditions exist. 

(9.2) Malfunction Criteria: The EGR system shall be considered malfunctioning when one or 

both ofthe following occurs: (1) any component ofthe system fails to perform within 

manufacturer specifications, or (2) the EGR flow rate exceeds the manufacturer's 

specified low or high flow limits such that a vehicle would exceed 1.5 times any of the 

applicable FTP emission standards. 

(9.3) Monitoring Conditions: Tho diagnostic system Manufacturers shall define appropriate 

operating conditions for monitoring the EGR svstem, subject to the limitation that the 

monitoring conditions shall be encountered at least once during the first engine start 

portion of the applicable FTP test monitor the EGR svstem at least onco por trip. The 

monitoring svstem shall operate at least once per driving cvcle during which the 

manufacturer-defined monitoring conditions are met. 

(9.4) MIL Illumination and Fault Code Storage: The diagnostic system shall store a fault 

code and the MIL shall illuminate no later than the end of the next driving cvcle during 

which monitoring occurs provided trip-if- the malfunction is again present. 

20 

-3d. 
(10.0) COMPREHENSIVE COMPONENT MONITORING 

(10.1) Reguirement: The diagnostic svstem shall monitor for malfunction any electronic 

powertrain component/system not otherwise described above which either provides 

input to (directly or indirectly), or receives commands from the on-board computer, 

and which: (1) can affect emissions during any reasonable in-use driving condition, or 

(2) is used as part of the diagnostic strategy for anv other monitored svstem or 

component. 

(10.1.1) Input Components: 

{A)—The diagnostic system shall monitor for malfunction any electronic powertrain 

component/system which can affect omissionc not otherwise described above and 

which provides input directly or indirectly to the on-board computer. 

(S^A) The monitoring system shall have the capability of detecting, at a minimum, lack 

of circuit continuity and out of range values to ensure proper operation of the 

input device. The determination of out of range values shall include logic 

evaluation of available information to determine if a component is operating within 

its normal range (e.g.. a low throttle position sensor voltage would not be 

reasonable at a high engine speed with a high mass airflow sensor readino).(er37T 

indicating a malfunction in the case of high fuel tank pressure when the coolant 

temperature is low; an accelerometer output indicating continuous rough road 

conditions, etc.). 

{€4(B) Input components may include, but are not limited to, the vehicle speed sensor, 

crank angle sensor, knock sensor, throttle position sensor, coolant temperature 

sensor, cam position sensor, fuel composition sensor (e.g. methanol flexible fuel 

vehicles), transmission electronic components such as sensors, modules, and 

solenoids which provide signals to the powertrain control system (see section (b) 

(10.5)). 

(D)_C1 The coolant temperature sensor shall be monitored for achieving a stabilized 

minimum temperature level which is needed to achieve closed-loop operation (or 

for diesel applications, the minimum temperature needed for warmed-up fuel 

control to begin) within a manufacturer-specified time interval after starting the 

engine. The time interval shall be a function of starting engine coolant 

temperature and/or a function of intake air temperature. Manufacturers shall 

provide data to support specified times. The Executive Officer shall allow 

disablement of this check under extremely low ambient temperature conditions 

provided a manufacturer submits data and/or an engineering evaluation which 

adeguately demonstrated non-attainment of a stabilized minimum temperature. 

(10.1.2) Output Components: 

(A) The diagnostic system shall monitor output components for proper functional 

response to computer commands, for proper functional response to each computer 

command, any powertrain output component/system receiving commands from the 

21 

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P.33 

computer either directly or indirectly which, can affect omiscionc and which ic not 

otherwise monitored as a component/system in the above monitoring requirements. 

(B) Components for which functional monitoring is not feasible shall be monitored, at a 

minimum, for proper circuit continuity and out of range values, if applicable. 

(C) Output components may include, but are not limited to, the automatic idle speed 

motor, emission-related electronic only transmission controls, heated fuel preparation 

systems, the wait-to-start lamp on diesel applications, and a warmup catalyst 

bypass valve (see section (b) (10.5)). 

(10.2) Malfunction Criteria: 

(10.2.1) Input Components: Input components/systems shall be considered 

malfunctioning when, at a minimum, lack of circuit continuity or 

manufacturer-specified out-of-range values occur. Additionally, the coolant 

temperature sensor shall be considered malfunctioning if it does not achieve a 

stabilized minimum temperature necessary for closed-loop operation within a 

manufacturer specified time interval after starting the engine. 

(10.2.2) Output Components: Output components/systems shall be considered 

malfunctioning when a proper functional response to eaeh computer commands 

does not occur. Should a functional check for malfunction not be feasible, then 

an output component/system shall be considered malfunctioning when, at a 

minimum, lack of circuit continuity or manufacturer-specified out-of-range values 

occur. 

(10.3) Monitoring Conditions: Components/systems in this subsection sholl be monitored 

continuously. 

(10.3.1) Input Components: Input components shall be monitored continuously for proper 

range of values and circuit continuity. For rationality monitoring (where 

applicable), manufacturers shall define appropriate operating conditions during 

which monitoring shall occur, subject to the limitation that the monitoring 

conditions shall be encountered at least once during the first engine start portion 

of the applicable FTP test. Rationality monitoring shall occur at least once per 

driving' cvcle during which the manufacturer-defined monitoring conditions are 

met. 

(10.3.2) Output Components: Monitoring for circuit continuity and proper range of values 

(if applicable) shall be conducted continuously. For functional monitoring, 

manufacturers shall define appropriate operating conditions during which 

monitoring shall occur, subject to the limitation that the monitoring conditions 

shall be encountered at least once during the first engine start portion of the 

applicable FTP test. However, functional monitoring mav be conducted during 

non-FTP driving conditions, subject to Executive Officer approval, if the 

manufacturer provides data and/or an engineering evaluation which adeguately 

demonstrate that the component does not normally function, or monitoring is 

22 

'- ". • . . • X L • ~ . - - '. 
P.34 

otherwise not feasible, during applicable FTP test driving conditions. Functional 

monitoring shall occur at least once per driving cvcle during which the 

manufacturer-defined monitoring conditions are met. 

(10.4) MIL Illumination and Fault Code Storage: 

(10.4.1) Upon detecting a malfunction, the diagnostic system shall-store a fault code an4 

tho MIL shall illuminate) no later than the end of the next driving cycle during 

which monitoring occurs provided trip if the malfunction is again detected. 

(10.4.2) In conjunction with storing a fault code, manufacturers shall illuminate the MIL 

for malfunctions of components/systems for which either of the following occurs: 

1) When malfunctioning, the component or svstem could cause vehicle 

emissions to increase by 15 percent or more ofthe FTP standard, or 2) The 

component/system is used as part of the diagnostic strategy for any other 

monitored system or component. 

(10.5) Component Determination: The manufacturer shall determine whether a powertrain 

input or output component not otherwise covered can affect emissions. If the 

Executive Officer reasonably believes that a manufacturer has incorrectly .determined 

that a component cannot affect emissions, the Executive Officer shall require the 

manufacturer to provide emission data showing that such a component, when faulty 

and installed in a suitable test vehicle, does not have an emission effect. Emission 

data mav be reguested for any reasonable driving condition. 

(c) ADDITIONAL MIL ILLUMINATION AND FAULT CODE STORAGE PROTOCOL 

(1.0) MIL ILLUMINATION For all emission-related components/systems, upon final 

determination of malfunction, the MIL shall remain continuously illuminated (except that 

it shall blink as indicated previously for misfire detection). If any malfunctions are 

identified in addition to misfire, the misfire condition shall take precedence, and the MIL 

shall blink accordingly. The diagnostic system shall store a fault code for MIL 

illumination whenever the MIL is illuminated. The diagnostic system shall illuminate the 

MIL and shall store a code whenever the engine control powertrain enters a default or 

"limp home" mode of operation. The diagnostic system shall illuminate the MIL and 

shall store a code whenever the engine control system fails tp enter closed-loop 

operation (if employed) within a manufacturer specified minimum time interval. 

(2.0) EXTINGUISHING THE MIL 

(2.1) Misfire and Fuel System Malfunctions: For misfire or fuel system malfunctions, the MIL 

may be extinguished if the fault does not recur when monitored during three subsequent 

sequential driving cycles in which conditions are similar to those under which the 

malfunction was first determined (see sections (b) (3.4.3) and (b)(7.4.3)). 

(2.2) All Other Malfunctions: Except as noted in section (b) (6.4), for all other faults, the MIL 

may be extinguished after three subsequent sequential driving cycles during which the 

monitoring svstem responsible for illuminating the MIL functions without detecting the 

23 

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P.35 

malfunction trips in which the malfunction has not recurred and if no other malfunction 

has been identified that would independently illuminate the MIL according to the 

requirements outlined above. 

(3.0) ERASING A FAULT CODE The diagnostic system may erase a fault code if the same 

fault is not re-registered in at least 40 engine warm-up cycles, and the MIL is not 

•illuminated for that fault code. 

(d) TAMPERING PROTECTION Computer-coded engine operating parameters shall not be 

changeable without the use of specialized tools and procedures (e.g. soldered or potted 

computer components or sealed (or soldered) computer enclosures). Subject to 

Executive Officer approval, manufacturers may exempt from this requirement those 

product lines which are unlikely to require protection. Criteria to be evaluated in making 

an exemption include, but are not limited to, current availability of performance chips, 

high performance capability of the vehicle, and sales volume. Manufacturers using 

reprogrammable computer code systems (e.g., EEPROM) shall employ proven methods 

to deter unauthorized reprogramming which mav include copyrightable executable 

routines or other methods. Beginning with the 1999 model vear, manufacturers shall 

include enhanced tamper protection strategies including data encryption using methods 

to secure the encryption algorithm, and write protect features reguiring electronic access 

to an off-site computer maintained by the manufacturer. Eguivalent methods shall also 

be considered bv the Executive Officer. Anv reprogrammable computer code system 

(e.g. EEPROM) shall include proven write-proteot features which may include 

copyrightable executable routines or other methods. 

(e) READINESS/FUNCTION CODE The on-board computer shall store a code upon first 

completing If a full diagnostic check (i.e., the minimum number of checks necessary for 

MIL illumination) of all monitored components and systems (except as noted below) has 

not been completed since the computer memory was last cleared (e.g., through the use 

of a scan tool or battery disconnect).. the manufacturer shall store a code indicating the 

need for additional mixed citv and highway driving to complete the check. The code 

shall be stored in the format specified by SAE J1979 or SAE J1939, whichever applies. 

Both documents are incorporated bv reference in sections (k)(2.0) and (k)(5.0). The 

diagnostic system check for comprehensive component monitoring and continuous 

monitoring of misfire and fuel system faults shall be considered complete for purposes 

of determining the readiness indication if malfunctions are not detected in these areas 

by the time all other diagnostic system checks are complete. If monitoring is 

temporarily disabled under conditions which may lead to false codes for any system, 

that check shall not be considered in determining diagnostic system readiness. For 

evaporative svstem monitoring, the readiness indication shall be set when a full 

diagnostic check has been completed with respect to the 0.040 inch orifice malfunction 

criteria if the monitoring conditions are constrained with respect to detection a 0.020 

inch leak (see sections (b)(4.2.2) and (4.3). The diagnostic svstem shall alco include a 

code or acknowledge message indicating that the diagnostic system itself io functioning 

properly. 

24 
(f) STORED ENGINE CONDITIONS Upon detection of the first malfunction of any 

component or system, "freeze frame" engine conditions present at the time shall be 

stored in computer memory. Should a subsequent fuel system or misfire malfunction 

occur, any previously stored freeze frame conditions shall be replaced by the fuel 

system or misfire conditions (whichever occurs first). Stored engine conditions shall 

include, but are not limited to, calculated load value, engine RPM, fuel trim value(s) [if 

available), fuel pressure (if available), vehicle speed (if available), coolant temperature, 

intake manifold pressure (if available), closed- or open-loop operation (if available), and 

the fault code which caused the data to be stored. The manufacturer shall choose the 

most appropriate set of conditions facilitating effective repairs for freeze frame storage. 

Only one frame of data is required. Manufacturers may at their discretion choose to 

store additional frames provided that at least the required frame can be read by a 

generic scan tool meeting SAE specifications established in SAE Recommended 

Practices on "OBD II Scan Tool" (J1978), March 1092 June. 1994. and "E/E Diagnostic 

Test Modes" (J 1979), December 1991 June, 1994, which are incorporated by reference 

herein. If approval is granted to use the SAE J1939 communication protocol according 

to section (k)(5.0), the data shall be accessible using a scan tool meeting the J1939 

specifications. If the fault code causing the conditions to be stored is erased in 

. accordance with section (c) (3.0), the stored engine conditions may be cleared as well. 

(g) DURABILITY DEMONSTRATION VEHICLE MONITORING SYSTEM 

DEMONSTRATION REQUIREMENTS 

(1.0) REQUIREMENT Each year a manufacturer shall provide emission test data obtained 

from a certification durability vehicle for one engine family certification durability vehicle 

that has not been used previously for purposes of this section. If a manufacturer does 

not have a certification durability vehicle available which is suitable for #ws 

domonstratien the engine family designated for testing, Tthe Executive Officer shall 

permit a manufacturer to satisfy this reguirement with waive this requirement if a 

manufacturer does not have a certification durability vehiclo available which is suitable 

for this demonstration in a given year, provided a manufacturer submits other data from 

a representative high mileage vehicle or vehicles (or a representative high 

operating-hour engine or engines) acceptable to the Executive Officer to demonstrate 

that malfunction criteria are based on emission performance. The Air Resources Board 

(ARB) shall determine the demonstration vehicle engine family to be demonstrated. 

Each manufacturer shall notify the Executive Officer prior to running a California 

durability vehicle in order to allow possible selection as the demonstration vehicle for a 

given model year unless a vehicle has previously been chosen for the given model yeaF 

applying for certification of the engine families planned for a particular model vear in 

order to allow selection of the engine family to be demonstrated. Demonstration tests 

shall be conducted on the certification durability vehicle or engine at the end of the 

required mileage or operating-hour accumulation. For non-LEVs, until a NOx standard 

. applicable for more than 50,000 miles is established in California, the federal 50,000 to 

100,000 mile NOx standard shall be used for demonstration purposes. 

(1.1) Flexible fuel vehicles shall perform each demonstration test using 85 percent methanol 

and 15 per.cent gasoline, and gasoline only. For vehicles capable of operating on other 

fuel combinations, the manufacturer shall submit a plan for performing demonstration 

25 

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P.37 

testing for approval by the Executive Officer on the basis of providing accurate and 

timely evaluation of the monitored systems. 

(2.0) APPLICABILITY! The manufacturer shall perform single-fault testing based on the 

applicable FTP test cycle with the following components/systems at their malfunction 

criteria limits as determined by the manufacturer: 

(2.1) Oxygen Sensors. The manufacturer shall conduct the following demonstration tests: 

The first test involves testing all primary and secondary (if equipped) oxygen sensors 

used for fuel control simultaneously possessing normal output voltage but response rate 

deteriorated to the malfunction criteria limit (secondary oxygen sensors for which 

response rate is not monitored shall be with normal response characteristics). The 

second test shall include testing with all primary and secondary (if equipped) oxygen 

sensors used for fuel control simultaneously possessing output voltage at the 

malfunction criteria limit. Manufacturers shall also conduct a malfunction criteria 

demonstration test for any other-oxygen sensor parameter that can cause vehicle 

emissions to exceed 1.5 times the applicable standards (e.g., shift in air/fuel ratio at 

which oxygen sensor switches). When performing additional test(s), all primary and 

secondary (if equipped) oxygen sensors used for fuel control shall be operating at the 

malfunction criteria limit for the applicable parameter only. All other primary and 

secondary oxygen sensor parameters shall be with normal characteristics. The 

Executive Officer may approve other demonstration protocols if the manufacturer can 

adeguately show comparable assurance that the malfunction criteria are chosen based 

on meeting emission requirements. 

(2.2) EGR System: The manufacturer shall conduct only one flow rate demonstration test at 

the low flow limit. 

(2.3) Fuel Metering System: 

(2.3.1) For vehicles with short-term or long-term fuel trim circuitry, the manufacturer 

shall conduct one demonstration test at the border of the rich limit and one 

demonstration test at the border of the lean limit established by the manufacturer 

for emission compliance. 

(2.3.2) For other systems, the manufacturer shall conduct a demonstration test at the 

criteria limit(s). 

(2.3.3) For purposes of the demonstration, the fault(s) induced may result in a uniform 

distribution of fuel and air among the cylinders. Non-uniform distribution of fuel 

and air used to induce a fault shall not cause an indication of misfire. The 

manufacturer shall describe the fault(s) induced in the fuel system causing it to 

operate at the criteria limit(s) for the demonstration test (e.g., restricted or 

increased flow fuel injectors, an altered output signal airflow meter, etc.). 

Computer modifications to cause the fuel system to operate at the adaptive limit 

for malfunction shall not be allowed for the demonstration tests. 

26 

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P.38 

(2.4) Misfire: The manufacturer shall conduct one FTP demonstration test at the criteria limit 

specified in (b)(3.2)(B) for malfunction and a second .demonstration test showing that 

the vehicle is capable of passing a California Inspection/Maintenance test when 

operating at the misfire criteria limit. This demonstration is not required for diesel 

applications. 

(2.5) Secondary Air System: The manufacturer shall conduct a flow rate demonstration test 

at the low flow limit, unless only a functional check is permitted according to section 

.DM5.2.2). 

(2.6) Catalyst Efficiency: 

(2.6.1) Non-Low Emission Vehicles: The manufacturer shall conduct a baseline FTP 

test with a representative 4000 mile catalyst system followed by one FTP 

demonstration test using a catalyst system deteriorated to' its malfunction limit. If 

a manufacturer is employing a steady state catalyst efficiency check in 

accordance with section (b) (1.2.4), demonstration ofthe catalyst monitoring 

system is not required. 

(2.6.2) Low Emission Vehicles: The manufacturer shall conduct a catalyst efficiency 

demonstration using a catalyst system deteriorated to within the malfunction 

criteria. If,two substrates are integrated into the same container, only the 

upstream substrate shall be deteriorated for the demonstration. 

(2.7) Heated Catalyst Systems: For heated Gatalyst systems that use an aftor start heating 

strategy, t The manufacturer shall conduct a demonstration test where.vthe designated 

heating temperature is reached at the time limit for malfunction after engine starting. 

(2.8) Manufacturers may electronically simulate deteriorated components, but may not make 

any vehicle control unit modifications when performing demonstration tests. All 

equipment necessary to duplicate the demonstration test must be made available to the 

ARB upon request. 

(3.0) PRECONDITIONING The manufacturer shall use the first engine start portion of one 

applicable FTP cycle for preconditioning before each of the above emission tests. If a 

manufacturer saft-prdvides data and/or an engineering evaluation which adeguately 

demonstrate that additional preconditioning is necessary to stabilize the emission 

control system, the Executive Officer shall allow an additional identical preconditioning 

cycle, or a Federal Highway Fuel Economy Driving Cycle, following a ten-minute (or 20 

minutes for medium duty engines certified on an engine dynamometer) hot soak after 

the initial preconditioning cycle. The manufacturer shall not reguire the demonstration 

vehicle to be cold soaked prior to conducting preconditioning cycles in order for the 

monitoring svstem demonstration to be successful. A cold start shall not bo roquirod 

prior to conducting preconditioning cyclos. 

27 

37 
E3H-

(4.0) EVALUATION PROTOCOL 

(4.1) With the exception of short-term trim only vehicles, tThe manufacturer shall set the 

system or componenf for which detection is to be demonstrated at the criteria limit(s) 

from the beginning of and throughout the prior to conducting the applicable 

preconditioning cycle(s) and FTP te6t. (For misfire demonstration, misfire shall be set 

at its criteria limit as specified pursuant to section (b)(3.2)(B)). If a second 

preconditioning cvcle is permitted in accordance with section (3.0) above, the 

manufacturer may adjust the demonstrated svstem or component before conducting the 

second preconditioning cvcle: however, the demonstrated svstem or component shall 

not be replaced, modified or adjusted after preconditioning has taken place. 

(4.2) For short-term trim only vehicles, the fuel system shall operate at the criteria limit from 

the beginning of closed-loop operation for the manufacturer-defined time interval for 

determining malfunction (and normally otherwise) for both the applicable preconditioning 

and FTP test cycles. After preconditioning, the vehicle shall be operated over the first 

. engine start portion of the applicable FTP test to allow for the initial detection of the 

malfunction. This driving cvcle mav be omitted from the evaluation protocol if it is 

unnecessary. If reguired bv the demonstrated monitoring strategy, a cold soak mav be 

performed prior to conducting this driving cycle. 

(4.3) For misfire demonstration, misfire shall be set at its criteria limit as specified pursuant to 

section (b) (3.2) (B) throughout the applicable preconditioning cycle and FTP test. The 

vehicle shall then be operated over a full applicable FTP test. 

(4.4) For all demonstrations, the MIL shall be illuminated before the hot start portion of the 

fulLFTP test in accordance with requirements of subsection (b): 

(4.4.1) If the MIL does not illuminate when the systems or components are set at their 

limit(s), the criteria limit or the OBD system is not acceptable. 

(4.4.2) Except for catalyst efficiency demonstration, if the MIL illuminates and emissions 

do not exceed 1.5 times any of the applicable FTP emission standards, no 

further demonstration shall be required. 

(4.4.3) Except for catalyst efficiency demonstration, if the MIL illuminates and emissions 

exceed 1.5 times any ofthe applicable FTP emission standards, the vehicle shall 

be retested with the component's malfunction criteria limit value reset such that 

vehicle emissions are reduced by no more than 30 percent. Limit value at a 

minimum includes, in the case of oxygen sensors, response rate and voltage; for 

EGR systems, EGR flow rate; for secondary air systems, air flow rate; for 

short-term fuel trim- only systems, time interval at the fuel system range of 

authority limit; for long-term fuel trim systems, shift in the base fuel calibration; 

for heated catalyst systems, the time limit between engine starting and attaining 

the designated heating temperature (if an after-start heating strategy is used); 

and for misfire, percent misfire. For the OBD system to be approved, the vehicle 

must then meet the above emission levels when tested with the faulty 

28 

'•.'.••-•.. " \ • - 3> r _ • ; .-.."- . 
components. The MIL shall not illuminate during this demonstration. 

(4.4.4) For Non-LEV catalyst efficiency demonstration, if HC emissions do not increase 

by more than"1.5 times the standard from the baseline FTP test and the MIL is 

illuminated, no further demonstration shall be required. However, if HC 

emissions increase by more than 1.5 times the standard from the baseline FTP 

test and the MIL is illuminated, the vehicle shall be retested with the average 

FTP HC conversion capability of the catalyst system increased by no more than 

10 percent (i.e., 10 percent more engine out hydrocarbons are converted). For 

the OBD system to be approved, the vehicle must then meet the above emission 

levels when re-tested. The MIL shall not illuminate during this demonstration. 

(4.4.5) For Low Emission Vehicle catalyst efficiency demonstration, if HC emissions do 

not exceed the applicable emission threshold specified in section (b)(1.2.2) and 

the MIL is illuminated, no further demonstration shall be required. However, if 

HC emissions exceed the threshold and the MIL is illuminated, the vehicle shall 

be retested with average FTP HC conversion capability of the catalvst svstem 

increased bv no more than 5 percent (i.e.. 5 percent more engine out 

hydrocarbons are converted). For the OBD II svstem to be approved, the 

vehicle must then meet the above emission levels when re-tested. The MIL shall 

not illuminate during this demonstration, if catalyst efficiency is within the 

malfunction criteria range ovor the FTP test and the MIL is illuminated, no further 

demonstration is required. If catalyst efficiency falls outside of the malfunction 

criteria range, the catalyst's efficiency shall be adjusted, or the oatalyst shall be 

replaced with another deteriorated catalyst, and the system re-tested. If catalyst 

efficiency is within the malfunction criteria range over the FTP test and the MIL 

is not illuminated, the oatalyst may be deteriorated further but not bolow the 

lower limit of tho malfunction criteria range, and the system retested. lf the 

catalyst's efficiency is below the lower limit of the malfunction criteria range and 

the MIL is not illuminated, the OBD system is not acceptable. 

(4.5) If an OBD system is determined unacceptable by the above criteria, the manufacturer 

may re-calibrate and re-test the system on the same QDV vehicle. Any affected 

monitoring systems demonstrated prior to the re-calibration shall be re-verified. 

(h) CERTIFICATION DOCUMENTATION! The manufacturer shall submit the following 

documentation for each engine family at the time of certification. With Executive Officer 

approval, one or more of the documentation reguirements specified in this section mav 

be waived or altered if the information reguired would be redundant or unnecessarily 

burdensome to generate: 

(1) A written description of the functional operation of the diagnostic system to be 

included in Section 8 of manufacturers' certification applications. 

29 

-2*1 
P.41 

(2) A table providing the following information for each monitored component or system 

(either computer-sensed or -controlled) of the emission control system: 

i. corresponding fault code 

ii. monitoring method or procedure for malfunction detection 

iii. primary malfunction detection parameter and its type of output signal 

iv. fault criteria limits used to evaluate output signal of primary parameter 

v. other monitored secondary parameters and conditions (in engineering units) 

necessary for malfunction detection 

vi. monitoring time length and frequency of checks ^ 

vii. criteria for storing fault code 

viii. criteria for illuminating malfunction indicator light 

ix. criteria used for determining out of range values and input component rationality 

checks 

(3) A logic flowchart describing the general method of detecting malfunctions for each 

monitored emission-related component or system. To the extent possible, 

abbreviations in Society of Automotive Engineers' (SAE) J1930 "Electrical/Electronic 

Systems Diagnostic Terms, Definitions, Abbreviations, and Acronyms", September, 

4994-June, 1993. shall be used. J1930 is incorporated by reference herein. The 

information required in the chart under (2) above may instead be included in this 

flow chart, provided all of the information required in (2) is included. 

(4) A listing and block diagram of the input parameters used to calculate or determine 

calculated load values and the input parameters used to calculate or determine fuel 

trim values. 

(5) A scale drawing of the MIL and the fuel cap indicator light, if present, which 

specifies location in the instrument panel, wording, color, and intensity. 

(6) Emission test data specified in subsection (g). 

(7) Data supporting the selected degree of misfire which can be tolerated without 

damaging the catalyst. 

(8) Data supporting the limit for the time between engine starting and attaining the 

designated heating temperature for after-start heated catalyst systems. 

(9) For Low Emission Vehicles, data supporting the criteria used by the diagnostic 

system for establishing a 50 to 60 percent catalyst total HC efficiency level, or a 40 

to 50 percent deterioration level to indicate a malfunction when catalvst deterioration 

causes emissions to exceed the applicable threshold specified in section (b)(1.2.2). 

(10) For Non-Low Emission Vehicles, data supporting the criteria used to indicate a 

malfunction when catalyst deterioration leads to a 1.5 times the standard increase in 

HC emissions. If a steady state catalyst efficiency check is employed in accordance 

with section (b)(1.2.4), data supporting the criteria used by the diagnostic system for 

establishing a 60 to 80 percent catalyst efficiency level shall be provided instead. 

30 

^ _ 
P.42 

(11) Data supporting the criteria used to detect evaporative purge system leaks. 

(12) A description of the modified or deteriorated components used for the fault 

simulation to drive tho fuel system to the criteria limit(s) for demonstrating fuel 

svstem compliance with the requirements of with respect to the demonstration tests 

specified in subsection (g). 

(13) A listing of all electronic powertrain input and output signals. 

(134) Any other information determined by the Executive Officer to be necessary to 

demonstrate compliance with the requirements of this section. 

(i) IN-USE RECALL TESTING PROTOCOL The manufacturer shall adhere to the following 

procedures for vehicles subject to in-use recall testing required by the ARB: 

(1) If the MIL illuminates during a test cycle or during a preconditioning cycle, the fault 

causing the illumination may be identified and repaired following published procedures 

readily available to the public including the independent service sector. 

(2) The test may be rerun, and the results from the repaired vehicle may be used for 

emission reporting purposes. 

(3) If a vehicle contains a part which is operating outside of design specifications with no 

MIL illumination, the part shall not be replaced prior to emission testing unless it is 

determined that the part has been tampered with or abused in such a way that the 

diagnostic svstem cannot reasonably be expected to detect the resulting malfunction.. 

(4) Failure of a vehicle, or vehicles on average, to meet applicable emission standards 

with no illumination of the MIL shall not by itself be grounds for requiring the OBD 

system to be recalled for recalibration or repair since the OBD system cannot predict 

precisely when vehicles exceed emission standards. 

(5) A decision to recall the OBD system for recalibration or repair will depend on factors 

including, but not limited to, level of emissions above applicable standards, presence 

of identifiable faulty or deteriorated components which affect emissions with no MIL 

illumination, and systematic erroneous activation ofthe MIL.. With respect to 

erroneous activation of the MIL, the manufacturer may reguest Executive Officer 

approval to take action apart from a formal recall (e.g., extended warranty or a service 

campaign) to correct the performance of the diagnostic strategy on in-use vehicles. In 

considering a manufacturer's reguest. the Executive Officer shall consider the 

estimated freguencv of false MIL activation in-use, and the expected effectiveness in 

relation to a formal recall of the manufacturer's proposed corrective action in capturing 

vehicles in the field. For 1994 and 1995 model years only, on-board diagnostic 

system recall shall not be considered for excessive emissions without MIL illumination 

(if required) and fault code storage until emissions exceed 2.0 times any of the 

applicable standards in those instances where the malfunction criterion is based on 

exceeding 1.5 times any ofthe applicable standards. This higher emission threshold 

. 31 

H( 
for recall shall extend up to the 1998 model year for TLEV applications (except for 

catalvst monitoring, for which the threshold shall extend to the 2000 model vear), and 

to the 2000 model vear for all applicable monitoring reguirements on LEV and ULEV 

applications. 

(6) Regarding catalvst svstem monitoring, unmonitored catalysts shall be normally aged. 

(j) CONFIRMATORY TESTING The ARB may perform confirmatory testing of 

manufacturers' diagnostic systems for compliance With requirements of this section in 

accordance with malfunction criteria submitted in the manufacturer's approved certification 

documentation. The ARB or its designee may install appropriately deteriorated or 

malfunctioning components in an otherwise properly functioning test vehicle of an engine 

family represented by the demonstration test vehicle(s) (or simulate a deteriorated or 

malfunctioning component response) in order to test the fuel system, misfire detection 

system, oxygen sensor, secondary air system, catalyst efficiency monitoring system, 

heated catalyst system, and EGR system malfunction criteria for compliance with the 

applicable emission constraints in this section. Confirmatory testing to verify that 

malfunction criteria are set for compliance with emission requirements of this section shall 

be limited to vehicles in engine families derived from the demonstration vehicle(s).. 

Diagnostic systems of a representative sample of vehicles which uniformly fail to meet the 

requirements of this section may be recalled for correction. 

(k) STANDARDIZATION Standardized access to emission-related fault codes, 

emission-related powertrain test information (i.e., parameter values) as outlined in 

subsection (I), emission related diagnostic procedures, and stored freeze frame data shall 

be incorporated based on the industry specifications referenced in this regulation. 

(1.0) Either SAE Recommended Practice J1850, "Class B Data Communication Network 

Interface", August, 1901 May, 1994. or ISO 9141_2 GARB, "Road vehicles -

Diagnostic Systems - CARB Requirements for Interchange of Digital Information," 

February, 1994, which are incorporated by reference, shall be used as the on-board to 

off-board network communications protocol. All SAE J1979 emission related 

messages sent to the J1978 scan tool over a J1850 data link shall use the Cyclic 

. Redundancy Check and the three byte header, and shall not use inter-byte separation 

or checksums. 

(2.0) J1978 & J1979 Standardization of the message content (including test modes and 

test messages) as well as standardization of the downloading protocol for fault codes, 

parameter values and their units, and freeze frame data are set forth in SAE 

Recommended Practices on "OBD II Scan Tool" (J1978), March. 1992 June, 1994, 

and "E/E Diagnostic Test Modes" (J1979), December. 1991 June 1994. which have 

been incorporated by reference. Fault codes, parameter values, and freeze frame 

data shall be capable of being downloaded to a generic scan tool meeting these SAE 

specifications. 

(2.1) 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 J1978 generic scan tool 

32 
and commonly available, non-microprocessor based tools. In addition to these 

procedures, manufacturers may publish repair procedures referencing the use of 

manufacturer specific or enhanced equipment. 

(2.2) The J1978 scan tool shall be capable of notifying the user when one or more of the 

required monitoring systems are not included as part of the OBD system. 

(3.0) J2012 Part C Uniform fault codes based on SAE specifications shall be employed. 

SAE "Recommended Format and Messages for Diagnostic Trouble Codes" (J2012), 

March January, 1992 1994, is incorporated by reference. 

(4.0) J1962 A standard data link connector in a standard location in each vehicle based on 

SAE specifications shall be incorporated. The location of the connector shall be easily 

identified by a technician entering the vehicle from the driver's side. Any pins in the 

standard connector that provide any electrical power shall be properly fused to protect 

the integrity and usefulness of the diagnostic connector for diagnostic purposes. The 

SAE Recommended Practice "Diagnostic Connector" (J1962), June, 1992, is 

incorporated by reference. 

(5.0) With Executive Officer approval, medium-dutv vehicles mav alternatively employ the 

communication protocols established in SAE Recommended Practice J1939 to satisfy 

the standardization reguirements specified in sections (k)(1) through (k)(4) above. 

The Executive Officer's decision shall be based on the effectiveness of the SAE J1939 

protocol in satisfying the diagnostic information reguirements of Section 1968.1 in 

comparison with the above referenced documents. 

(I) SIGNAL ACCESS 

(1.0) The following signals in addition to the required freeze frame information shall be 

made available on demand through the serial port on the standardized data link 

connector: calculated load value, diagnostic trouble codes, engine coolant 

temperature, fuel control system status (open loop, closed loop, other; if eouipped 

with closed loop fuel control), fuel trim (if equipped), fuel pressure (if available), 

ignition timing advance (if eouipped), intake air temperature (if equipped), manifold air 

pressure (if equipped), air flow rate from mass air flow meter (if equipped), engine 

RPM, throttle position sensor output value (if equipped), secondary air status 

(upstream, downstream, or atmosphere; if equipped), and vehicle speed (if equipped). 

The signals shall be provided in standard units based on the SAE specifications 

incorporated by reference in this regulation, and actual signals shall be clearly 

identified separately from default value or limp home signals. 

(2.0) The manufacturer shall publish in factory service manuals a normal range for the 

calculated load value and mass air flow rate (if available) at idle, and at 2500 RPM 

(no load, in neutral or park). If 2500 RPM is outside of the operating range of the 

engine, the corresponding data may be omitted. If the total fuel command trim is 

made up by more than one source (e.g. short-term trim and long-term trim), all fuel 

trim signals shall be available. The signals shall be provided in standard units based 

on the incorporated SAE specifications, and actual signals shall be clearly identified 

-33 

4 3 _ .' • " - • . . • 
separately from default value or limp home signals. Diesel vehicles shall be exempt 

from this reguirement. 

(3.0) Oxygen sensor data that will allow diagnosis of malfunctioning oxygen sensors shall 

be provided through serial data port on the standardized data link. In addition, 

beginning with the 1996 model vear (with full compliance reguired bv the 1997 model 

year), for all monitored components and systems, except misfire detection, fuel 

svstem monitoring, and comprehensive component monitoring), results of the most 

recent test performed by the vehicle, and the limits to which the system is compared 

(except for continuously monitored systems/components) shall be available through 

the serial data port on the standardized data link connector. For the monitored 

components and systems excepted above, a pass/fail indication for the most recent 

test results shall be available through the data link . Such data shall be transmitted in 

accordance with SAE J1979 (or SAE J1939, whichever applies). Alternative methods 

shall be approved by the Executive Officer if, in the judgment of the Executive Officer, 

they provide for equivalent off-board evaluation. 

(m),IMPLEMENTATION SCHEDULE 

(1.0) These OBD II requirements, except evaporative purge system monitoring (soo section 

(b) (4.1.5)) unless otherwise specified, shall be implemented beginning with the 1994 

model year. 

(2.0) The Executive Officer'shall grant an extension for compliance with the requirements of 

these subsections with respect to a specific vehicle model or engine family if the 

vehicle model or engine family meets previously applicable on-board diagnostic 

system requirements and a manufacturer demonstrates that it cannot modify a present 

electronic control system by the 1994 model-year because major design system 

changes not consistent with the manufacturer's projected changeover schedule would 

be needed to comply with provisions of these subsections. 

(2.1) The manufacturer which has received an extension from the Executive Officer shall 

comply with these regulations when modification of the electronic system occurs in 

accordance with the manufacturer's projected changeover schedule or in the 1996 

model year, whichever first occurs. 

(2.2) Any manufacturer requesting an extension shall, no later than October 15, 1991, 

submit to the Executive Officer an application specifying the period for which the 

extension is required. 

(3.0) Small volume manufacturers as defined in (n) (13.0) shall meet these requirements by 

the 1996 model year. 

(4.0) Manufacturers may at their discretion implement a portion of these regulations prior to 

the required implementation date provided that the system complies with previously 

applicable on-board diagnostic system requirements. 

34 

44-
(5.0) - Vehicles certified to run on alternate fuels, and dDiesel vehiclesT shall meet these 

requirements by the 1996 model year. Manufacturers may request a delay in the 

implementation of these requirements for diesel vehicles until 1997, subject to 

Executive Officer approval, if it is adeguately demonstrated that the delay will allow for 

the development of significantly more effective monitoring systems. 

(5.1) Vehicles and engines certified to run on alternate fuels shall meet these reguirements 

bv the 1996 model year. However, manufacturers may reguest the Executive Officer 

to waive specific monitoring reguirements for which monitoring may not be reliable 

with respect to the use of alternate fuels until the 1999 model year. 

(5.2) Medium-dutv vehicles with engines certified on an engine dynamometer mav comply 

with these requirements on an engine model vear certification basis rather than on a 

vehicle model basis. 

(6.0) The Executive Officer may waive one or more of the requirements of these 

subsections with respect to a specific vehicle or engine family for which production 

commences prior to April 1, 1994, and which is not otherwise exempted from 

compliance in accordance with sections (2.0) and (2.1) above. In granting a waiver, 

the Executive Officer shall consider the following factors: the extent to which these 

requirements are satisfied overall on the vehicle applications in question, the extent to 

which the resultant diagnostic system design will be more effective than systems 

developed according to section 1968, Title 13, and a demonstrated good-faith effort to 

meet these requirements in full by evaluating and considering the best available 

monitoring technology. 

(6.1) For 1995 and 1996 model year vehicles for which production is to commence 

subsequent to March 31, 1994, and which are not exempted from compliance in 

accordance with sections (2.0) and (2.1) above, the Executive Officer, upon receipt of 

an application from the manufacturer, may certify the vehicles in question even though 

said vehicles may not comply with one or more of the requirements of these 

subsections. Such certification is contingent upon the manufacturer meeting the 

criteria set forth in section (6.0) above. Manufacturers of non-complying systems shall 

be subject to fines pursuant to section 43016 of the California Health and Safety Code 

for each deficiency identified, after the second, in a vehicle model. For the third 

deficiency and every deficiency thereafter identified in a vehicle model, the fines shall 

be in the amount of $50 per deficiency per. vehicle for non-compliance with any of the 

monitoring requirements specified in subsections (b)(1) through (b)(9), and $25 per 

deficiency per vehicle for non-compliance with any other requirement of section 

1968.1. In determining the identified order of deficiencies, deficiencies of subsections 

(b)(1) through (b)(9) shall be identified first. Total fines per vehicle under this section 

shall not exceed $500 per vehicle and shall be payable to the State Treasurer for 

deposit in the Air Pollution Control Fund. Engine families in receipt of a waiver 

granted under section (6.0) above shall be exempt from these fines. Further, small 

volume manufacturers choosing to comply with these requirements in the 1995 model 

year shall also be exempt from these fines. For 1996 model vear vehicles and 

engines onlv. failure to properly monitor multiple electronic transmission components 

shall be considered a single monitoring svstem deficiency. 

35 

IT 
P.47 

(6.2) Beginning with the 1997 model vear and through the 2000 model, the certification 

provisions set forth in section (m)(6.1) above shall continue to apply subject to the 

following limitations: 1) The specified fines shall apply to the second and 

subsequently identified deficiencies, with the exception that fines shall apply to all 

monitoring svstem deficiencies wherein a required monitoring strategy is completely 

absent from the OBD svstem, and 2) Manufacturers may not carry over monitoring 

svstem deficiencies to future model vears unless it can be demonstrated that vehicle 

hardware modifications would be necessary to correct the deficiency, in which case 

the deficiency mav be carried over for one model vear. 

(n) GLOSSARY For purposes of this section: 

(1.0) "Malfunction" means the inability of an emission-related component or system to 

remain within design specifications. Further, malfunction refers to the deterioration of 

any of the above components or systems to a degree that would likely cause the 

emissions of an average certification durability vehicle with the deteriorated 

components or systems present at the beginning of the applicable certification 

emission test to exceed by more than 1.5 times any ofthe emission standards (both 

with respect to the certification and useful life standards), unless otherwise specified, 

applicable pursuant to Subchapter 1 (commencing with Section 1900), Chapter 3 of 

Title 13. 

(2.0) "Secondary air" refers to air introduced into the exhaust system by means of a pump 

or aspirator valve or other means that is intended to aid in the oxidation of HC and 

CO contained in the exhaust gas stream. 

(3.0) "Engine misfire" means lack of combustion in the cylinder due to absence of spark, 

poor fuel metering, poor compression, or any other cause. 

(4.0) Oxygen sensor "response rate" refers to the delay (measured in milliseconds) 

between a switch of the sensor from lean to rich or vice versa in response to a 

change in fuel/air ratio above and below stoichiometric. 

(5.0) A "trip" means vehicle operation (following an engine-off period) of duration and 

driving mode such that all components and systems are monitored at least once by 

the diagnostic system except catalyst efficiency or evaporative system monitoring 

when a steady-speed check is used, subject to the limitation that the 

manufacturer-defined trip monitoring conditions shall all be encountered at least once 

during the first engine start portion of the applicable FTP cycle. 

(6.0) A "warm-up cycle" means sufficient vehicle operation such that the coolant 

temperature has risen by at least 40 degrees Fahrenheit from engine starting and 

reaches a minimum temperature of 160 degrees Fahrenheit. 

(7.0) A "driving cycle" consists of engine startup, vehicle operation beyond the beginning of 

closed loop operation, and engine shutoff. 

36 
(8.0) "Continuous monitoring" means sampling at a rate no less than two samples per 

second. If for engine control purposes, a computer input component is sampled less 

freguently. the value of the component mav instead be evaluated each time sampling 

occurs. 

(9.0) "Fuel trim" refers to feedback adjustments to the base fuel schedule. Short-term fuel 

trim refers to dynamic or instantaneous adjustments. Long-term fuel trim refers to 

much more gradual adjustments to the fuel calibration schedule than short-term trim 

adjustments. These long term adjustments compensate for vehicle differences and 

gradual changes that occur over time. 

(10.0) "Base Fuel Schedule" refers to the fuel calibration schedule programmed into the 

Powertrain Control Module or PROM when manufactured or when updated by some 

off-board source, prior to any learned on-board correction. 

(11.0) "Calculated load value" refers to an indication of the current airflow divided by peak 

airflow, where peak airflow is corrected for altitude, if available. This definition 

provides a unitless number that is not engine specific, and provides the service 

technician with an indication of the percent engine capacity that is being used (with 

wide open throttle as 100%). 

Current Airflow Atm Pressure (@ sea level) 

CLV= • X 

Peak airflow (@ sea level) Barometric pressure 

For diesel applications, the calculated load value shall be determined by the ratio of 

current output torgue to maximum output torgue at current engine speed. 

(12.0) "Medium-duty vehicle" is defined in Title 13, Section 1900 (b)(9). 

(13.0) "Small volume manufacturer" shall mean any vehicle manufacturer with sales less 

than or equal to 3000 new light-duty vehicles and medium-duty vehicles per model 

year based on the average number of vehicles sold by the manufacturer each model 

year from 1989 to 1991. For manufacturers certifying for the first time in California, 

model year sales shall be based on projected California sales. 

(14.0) "Low Emission Vehicle" refers to a vehicle certified in California as a Transitional Low 

Emission Vehicle (TLEV), a Low Emission Vehicle (LEV), or an Ultra Low Emission 

Vehicle (ULEV). These vehicle categories are further defined in Title 13, sections 

1956.8 and 1960.1. 

(15.0) "Diesel engines", for the purposes of these regulations, includes diesel derived refers 

tp_engines and those using a compression ignition thermodynamic cycle. 

(16.0) "Functional check" for an output component means verification of proper response to 

a computer command. For an input component, functional check means verification 

of the input signal being in the range of normal operation, including evaluation of the 

signal's rationality in comparison to all available information. 

37 • -

HI : - • -
P.49 

(17.0) "Federal Test Procedure" (FTP) cycle or test refers to, for passenger vehicles, 

light-duty trucks, and medium-duty vehicles certified on a chassis dynamometer,, the 

driving schedule in Code of Federal Regulations (CFR) 40, Appendix 1, Part 86, 

section (a) entitled, "EPA Urban Dynamometer Driving Schedule for Light- Duty 

Vehicles and Light-Duty Trucks." For medium-duty engines certified on an engine 

dynamometer, FTP cycle or test refers to the engine dynamometer schedule in CFR 

40, Appendix 1, Part 86, section (f)(1), entitled, "EPA Engine Dynamometer Schedule 

for Heavy-Duty Otto-Cycle Engines," or section (f)(2), entitled, "EPA Engine 

Dynamometer Schedule for Heavy-Duty Diesel Engines." 

(18.0) "Redline engine speed" means the manufacturer recommended maximum engine 

speed as normally displayed on instrument panel tachometers, or the engine speed at 

which fuel shutoff occurs. 

(19.0) "Power Take-Off unit" refers to an engine driven output provision for the purposes of 

powering auxiliary eguipment (e.g., a dump-truck bed, aerial bucket, or tow-truck 

winch). 

Note: Authority cited: Sections 39600, 39601, 43013 and 43018, Health and Safety Code. 

Reference: Sections 39002, 39003, 43013, 43100, 43101, 43102, 43104, 43105 and 43204, 

Health and Safety Code. 

38 

ijZ 
• _ 

STATE -OF CALIFORNIAPETE WILSON, Governor 

AIR RESOURCES BOARD 

2020 L STREET 

P.O. BOX 2815 

SACRAMENTO, CA 95812 

STATEMENT RE MAILING 

NOTICE OF AVAILABILITY OF MODIFIED TEXT 

On April 3, 1995 ., the Air Resources Board mailed the 

attached NOTICE OF AVAILABILITY OF MODIFIED TEXT to those persons specified 

in section 44, subsections (a)(1) through (4) Title 1, CCR, as required by 

section 44, Title 1, CCR. In addition, the notice was available to the 

public from April 3, 1995 through April 18, 1995 at the 

Public Information Office of the Air Resources Board, 2020 L Street, First 

Floor, Sacramento, California. 

Date: April 26, 1995 

Artrrf.tfH. Edwards 

Regulations Coordinator 

Attachment 

<fi 
P.51 

._._ MAIL OUT #95-12 . 

State of California 

• AIR RESOURCES BOARD 

Notice of Public Availability of Modified Text 

and Supporting Documents and Information 

PUBLIC HEARING TO CONSIDER AMENDMENTS TO REGULATIONS 

REGARDING ON-BOARD DIAGNOSTIC SYSTEM REQUIREMENTS 

FOR 1994 AND LATER PASSENGER CARS, LIGHT-DUTY TRUCKS, 

AND MEDIUM-DUTY VEHICLES AND ENGINES 

Public Hearing Date: December 8, 1994 

First Public Availability Date: January 19, 1995 

Deadline for Public Comment: February 3, 1995 

Second Public Availability Date: April 3, 1995 

Deadline for Public Comment: April 18, 1995 

At a public hearing held December 8, 1994, the Air Resources Board (the 

"Board") considered amendments to sections 1968.1 and 2030-2031, Title 13, 

California Code of Regulations ("CCR"). The proposed amendments would improve 

the overall effectiveness of the OBD II requirements while addressing 

implementation concerns expressed by manufacturers. The proposed regulatory 

action is described in detail in the Staff Report, released October 21, 1994. 

At the hearing, the Board approved amendments to sections 1968.1 and 

2030-2031, Title 13, CCR, and the documents incorporated therein with 

modifications to the originally proposed regulatory language. Those 

modifications were noticed in the Notice of Availability of Modified Text, 

issued on January 19, 1995, which were available for public comment through 

February 3, 1995. 

In addition to the documents that were identified in the Staff Report, 

the staff has added to the rulemaking record the following Society of 

Automotive Engineer (SAE) documents that staff relied upon, in developing these 

regulations: 

Draft SAE Recommended Practice J1939, "Serial Control and Communications 

Vehicle Network", January 1994. (The document's title and the date of 

the draft were inadvertently omitted from section (k)(5.0) of the 

regulation. Section (k)(5.0) has been modified to correctly reflect the 

title and date, and is attached hereto. The modifications reflecting the 

added language are indicated by double underline.) 

International Standards Organization (ISO) 9141-2, "Road vehicles -

Diagnostic Systems - CARB Requirements for Interchange of Digital 

Information", February 1994. (Reference of this document was 

inadvertently omitted from the Board Hearing Notice). 

SAE 940975, "Road Tests of a Misfire Detection System", William B. 

Ribbens and Jaehong Park, 1994 

SAE 920236, "Miniature Maanetostrictive Misfire Sensor", Robert D. 

Klauber etal , 1992 

SAE 890486, "Cylinder by Cylinder Engine Pressure and Pressure Torque 

Waveform Determinations. Utilizing Speed Fluctuations", Stephen J. Citron, 

John E. 0'Higgins, and Lillian Y. Chen, 1989. 

'•-•'. . r o • 
P.52 

The ARB is also adding to the rulemaking record the following comments 

and information (much of which has been identified as confidential) that 

have been submitted to the ARB by motor vehicle manufacturers and other 

interested parties and that the ARB staff relied upon in adopting amendments 

to the OBD II regulations: 

Data provided by Chrysler Corporation on May 9, 1994, regarding misfire 

detection test results. 

Data provided by General Motors on May 11, 1992, and August 31, 1994, 

regarding evaporative system monitoring requirements. 

Data provided by Ford Motor Company regarding misfire detection and 

catalyst monitoring, received July, 1994. 

Mazda application for 1995 model year certification. 

Mitsubishi application for 1995 model year certification. 

The text of section 1968.1 (k), Title 13, California Code of 

Regulations, with the proposed amendment to complete the reference to SAE 

J1939, is attached. The other materials referenced are available for public 

inspection at the the Mobile Source Division Offices at 9528 Telstar, El 

Monte, California. However, for information that has been designated as 

confidential, the ARB will follow the disclosure policies set forth in Title 

17, CCR, section 91000 et seq. Inquiries should be made to the attention of 

Mr. Allen Lyons, (818) 575-6833. 

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

directed the Executive Officer to adopt the amendments to sections 1968.1 

and 2030-20 and the documents incorporated by reference there, as approved, 

after making the modified regulatory language and additional supporting 

documents and information (excluding confidential information) available to 

the public for comment for a period of at least 15 days, 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 he determines that this is warranted. 

Written comments must be submitted to the Board Secretary, Air 

Resources Board, P.O. Box 2815, Sacramento, California 95812, no later than 

April 18, 1995, for consideration by the Executive Officer prior to final 

action. Only comments relating to the modifications or supporting documents 

and information described in this notice, will be considered by the 

Executive Officer. 

Sincerely, 

K. D. Drachand, Chief 

Mobile Source Division 

Attachment 

fl