• '). 

State of California 

AIR RESOURCES BOARD 

STAFF REPORT: INITIAL STATEMENT OF REASONS FOR RULEMAKING. 

Technical Status and Proposed Revisions to Malfunction and Diagnostic System Requirements 

for 1994 and Subsequent Model-Year Passenger Cars, Light-Duty Trucks, and Medium-Duty 

Vehicles and Engines (OBD II) 

Date of Release: October , 1994 

Scheduled for Consideration: December 8, 1994 

Agenda Item No.: L-_-_j 

This report has been reviewed by the staff of the California Air Resources Board 

and approved for publication. Approval does not signify that the contents necessarily 

reflect the views and policies of the Air Resources Board. nor does mention of trade 

names or commercial products constitute endorsement or recommendation for use. 

State of California 

r\.IR RESOURCES BOARD 

Staff Report: Initial Statement of Reasons for Proposed Rulerriaking 1 

PUBLIC HEARING TO CONSIDER TECHNICAL STATUS AND PROPOSED 

REVISIONS TO MALFUNCTION AND DIAGNOSTIC SYSTEM REQUIREMENTS FOR 

1994 AND SUBSEQUENT MODEL-YEAR PASSENGER CARS, LIGHT-DUTY TRUCKS, 

AND MEDIUM-DUTY VEHICLES AND ENGINES (OBD II) 

I. INTRODUCTION 

Date of Release: October , 1994 

Scheduled f{)r Consideration: December 8, 1994 

Agen,da Item No.: L-_-_] 

The Air Resources Board (ARB or Board) originally adopted Section 1968.1 of Title 

13, California Code of Regulations on September 14, 1989. This section contains the 

malfunction and diagnostic system requirements known as On-Board Diagnostics II or OBD 

II. The regulation requires manufacturers to implement comprehensive monitoring systems on 

vehicles to detect and aid in the diagnosis of malfunctions within vehicle emission and 

emission-related components and systems. OBD II systems are being phased-in beginning 

with 1994 model year vehicles sold in California. With minor exceptions, the regulation 

requires that by the 1996 model year, all vehicles subject to the regulation shall be equipped 

with OBD II systems. 

When th.e OBD II requirements were adopted. the Board recognized the technology 

forcing nature of some aspects of the regulation. The Board, therefore, directed the staff to 

follow manufacturers' progress towards meeting the OBD II requirements, and to report back 

to the Board with proposed amendments should they be deemed necessary to ensure that the 

requirements would be effective and feasible within the required timeframe. In response to 

this direction. the staff has already presented one update to the Board. in September of 1991. 

Since the hearing in 1991, the staff has continued to carefully follow manufacturers· 

progress in developing OBD Jl monitoring technologies, and believes that manufacturers have 

largely been able to design diagnostic strategies that satisfy the requirements. However, some 

The discussion that follows is intended to satisfy th;:> requirements of Government Code 

Section 11343.2 which requires a non-controlling, "plain-english" summary of the regulations 

be made available to the public. 

1. 
concern continues to be expressed regarding specific monitoring requirements that will apply 

to future model Y"'::tr vehicles. Modifications to the OBD II requirements are being proposed 

to address these concerns. The ARB staff had originally .intended to return to the Board 

within two years of the 1991 hearing to address any further OBD II concerns; bowever, it is 

onl.y recently that sufficient information has been available upon which to base proposed . 

modifications (although a hearing was held in I 993 at the request of one manufacturer to 

address potential compliance concerns in the 1994 and 1995 model years). 

Additionally, the staff is proposing modifications based on the experience gained as 

O~D II systems have been brought to production. These modifications either address minor 

OBD II implementation concerns or clarify requirements that are sometimes misunderstood. 

II. BACKGROUND INFORJ\1ATION 

Purpose of OBD Svstems 

OBD systems detect the occurrence of malfunctions within vehicle powertrains that 

cause increases in emissions. As a result, the time between the occurrence of such problems 

and necessary repairs is shortened, yielding lifetime in-use emission reductions from motor 

vehicles. OBD systems also generate diagnostic information to direct service technicians to 

the specific area of detected malfunctions, or to otherwise inform the technician regarding the 

performance of the vehicle. 

How OBD Svstems Work 

Today's vehicles utilize on-board computers to carry out many powertrain management 

functions, such as fuel metering, evaporative purge system control, and automatic transmission 

operation. The computers obtain the information necessary to carry-out these tasks, such as 

engine speed and the amount of air entering the engine, from an ~ay of sensors installed on 

the vehicle. In addition to using sensor information for control purposes, the same 

information can be evaluated by the computer to determine if components and systems are 

working properly. Most emission control systems and components can be monitored in this 

way without the need for any additional hardware on vehicles. For a very few other cases, 

such as the evaporative control system, an additional sensor is necessary to provide key 

information to the computer regarding the performance of the system. 

When an abnormality is detected, the vehicle operator is notified through the· 

illumination of a malfunction indicator light on the instrument panel. The computer also 

stores a code in its memory identifying the ·malfunctioning component and the nature of the 

problem. Service technicians· download these standardized codes with a microprocessor-based 

diagnostic "scan tool.:' 

") 

.... 

• 
OBD II Requirements 

OBD II systems will replace systems designed to meet California's oriainal OBD e , 

requirements, kno\v11 as OBD I. OBD I required monitoring of fuel delivery, the exhaust aas . . e 

recirculatiOn (EGR) valve, and emission-related components that provide input information to 

the on-board computer. Under OBD II, the monitoring requirements have been expanded to 

cover virtually every emission control system and electronic component that can affect 

emissions when malfunctioning. Included are important monitoring strategies that were not 

considered feasible when the OBD I requirements were fommlated (for example, monitoring 

of catalyst efficiency, engine misfire, and evaporative system leaks). 

For the systems and components that significantly impact emissions when 

malfunctioning, the OBD II regulation requires that manufacturers correlate system 

performance with emission increases. Generally, the OBD. II system must be able to 

determine when system performance has deteriorated to the point that emissions will be in 

excess of 1.5 times the vehicle's applicable standards. Systems and cpmponents that 

measurably impact emissions when malfunctionjng, but not to the extent that this emission 

threshold will be exceeded, must be monitored fat function by the OBD II system (but not 

necessarily for degree of performance). Some in industry have stated that it is inappropriate 

for the MIL to be illuminated for a malfunction that has not, by itself, caused vehicle 

emissions to exceed the applicable standards; however, monitoring requirements for all 

powertrain systems that can affect emissions are necessary in order to prevent high emission 

levels (without an indication of a malfunction) caused by a combination of several otherwise 

minor emission related proble~s. At one time during the formulation of the OBD II 

requirements, the ARB staff considered requiring manufacturers to evaluate the emission 

impact of the array of possible combinations of emission-related problems that can ·occur on 

vehicles, and to illuminate the MIL when combinations resulting in high emissions occurred. 

However. manufacturers strongly preferred single fault monitoring for measurable increases in 

emissions, even if the increase is small, in order to reduce the amount of development testing 

required, and to guard against recalls associated with not foreseeing every possible highemission malfunction combination. This is the approach that has been adopted. 

The OBD II regulation also includes specific requirements for stored fault codes and 

other dia£mostic information. Fault codes are standardized throughout the indus.trv based on - - . Society of Automotive Engineers' specifications, and will be available to service technicians 

through a standardized communication link incorporated into each ~ehicle. Standardization of 

the communication protocol will lead to the availability of diagnostic tools that will Work for 

every OBD'II-equipped vehicle make and model (separate tools are no longer necessary to 

obtain diagnostic information from each make of vehicle). Besides fau1t codes, the OBD II 

system will pro~'ide information regarding the vehicle ope:-ating conditions that existed at the 

time a malfunction was detected. This will enable service technicians to recreate the 

conditions in order to better diagnose problems and to verify repairs, particularly those which 

may be intermittent. Continuously updated engi,ne parameter data will also be available to 

further help technicians efficiently se~vice emission-related problems . 

... 

.). 
OBD II and Inspection and Maintenance Pro~rrams 

The utility of OBD II systems is in concept the same as an Inspection and 

Maintenance (liM) program (i.e., the idenrification and repair of malfunctioning vehicles). 

However, even with Oilifomia' s liM program (Smog Check), OBD systems are necessary to 

more fully realize the potential air quality benefits from reducing in-use vehicle emissions. 

Further, OBD systems can be used to create a more effective, efficient, and less expensive 

liM program. · 

OBD II systems will detect emission-related malfunctions as they occur, thereby 

reducing emissions from malfunctions that occur months to potentially years before the next 

scheduled liM inspection. Many emission-related malfunctions are unnoticeable to the vehicle 

operator without an indication from the OBD system. Manufacturers implementing OBD II 

systems for the 1994 model year have indicated to the ARB staff that OJ?D II systems have 

proven very effective in detecting vehicles that were built with defects that otherwise would 

have gone undetected. Such vehicles would have been operated for & least two years prior to 

going through an liM test, but instead were fixed under ¥.rarranty. 

OBD II systems will also be able to detect malfunctions that would not otherwise be 

found even with a loaded-mode tailpipe emission test. Such tests are ·conducted with the 

vehicle warmed-up. Therefore, the performance of critical-cold-start emission reduction 

devices (e.g., electrically heated catalysts, oxygen sensors, secondary air systems, and others) 

can not be fully evaluated in current liM programs, but are monitored by the OBD II system, 

Further, for practical reasons, liM tests generally use a generic pass/fail emission threshold for 

flagging high emitting vehicles. With OBD II, the moriitoring systems are tailored to the 

design of the vehicle and the emission standards to which the vehicle is certified. As a result, 

malfunctions will be detected at much lower tailpipe emission levels with OBD II compared 

to, for example, the liM 240 loaded mode emission test. These advantages are especially 

important for vehicles designed to meet California's Transitional Low Emission Vehicle 

(TLEV), Low Emission Vehicle (LEV), or Ultra Low Emission Vehicle (ULEV) emission 

standards. which achieve progressively more stringent emission levels primarily through 

reductions in cold-start emissions. · 

OBD II Re~rulatorv Historv 

The OBD II requirements were first adopted by the Board on September 1 ~. _1989. 

The Board's resolution (n_umber 89-77) directed the staff to report back to the Board in two 

year's time regarding the progress. of manufacturers towards complying with the requirements 

of the regulation which would be phased-in beginning with the 1994 model year. 

On· September 12, 1991, the staff presented the upd2.te requested by the Board. The 

Board found that most manufacturers had identified monitoring technologies capable of 

satisfying the requirements; however, work stiii !lad to be done to ensure that the monitoring 

systems developed would function reliably in customers· har1ds. In addition to providing an 

4. 
f• 

update. the staff proposed a number of regulatory modifications based on knowledge gained 

since the regulation was first adopted. These modifications were made to address concerns 

expressed by manufacturers, to promote consistency with federal OBD requirements, and to 

improve the effectiveness of the requirements in light of monitoring technology advances 

made by the industry. 

Among the most significant changes to the regulation that were adopted was the 

proposal. to separate catalyst monitoring requirements for vehicles meeting California's LowEmission Vehicle program emission standards, and non-low-emission vehicles meeting less 

stringent emission standards (i.e., vehicles meeting California's equivalent to the federal Tier I 

standards). The requirements for California non-low-emission vehicles were designed to be 

consistent with the federal monitoring requirements for the essentially identical Tier I 

vehicles. However, the staff felt that separate requirements were necessary for low-emission 

vehicle applications to better fulfill the goal of identifying malfunct~ons with respect to 

marginal exceedances of the emission standards. A more detailed discussion of the LEV 

catalyst monitoring requirements is included later in this report. Another significant 

modificatioi'} was the inclusion of an evaporative system leak detection monitoring strategy. 

With the change, OBD II systems will be. able to ensure the integrity of the full evaporative 

system whereas previously, only proper function of the evaporative purge components would 

have been monitored. Additional leadtime for the incorporation of both of these monitoring 

strategies was included in the ad1

opted amendments. 

The 1994 model year marked the first year of the phase-in for OBD II implementation. 

As manufacturers scheduled to produce OBD II-equipped vehicles for the 1994 model year 

finalized their system designs, Ford Motor Company (Ford) revealed that two of its 

monitoring strategies could not be made to meetthe minimum requirements of the. regulation 

in time for production. As a result, Ford petitioned the Board to seek relief from these 

requirements based on its demonstrated good-faith effort to implement fully compliant OBD II 

systems in the 1994 model year when, by the nature of the phase-in provisions, it could have 

delayed the introduction of these systems to the 1995 or 1996 model years. The Executive 

Officer granted Ford's petition and the Board adopted modifications to the regulation to 

permit limited relief from specific monitoring requirements on a case-by-case basis. 

Subsequent to the hearim.?.. a number of other manufacturers have used the orovisions to ~ -. . ~ 

obtain an exemption. usually for minor monitoring system deficiencies. 

Overall to date. the ARB staff has approved the OBD II system designs for ~ore than 

3 5 engine families developed by 14 manufacturers. Four of the engine families are certified 

to the TLEV emission standards.· · 

5. 
III. TECHNICAL STATUS AND PROPOSED MONITORING SYSTEM 

AMENDMENTS 

CATALYST MONITORING 

I. 

As indicated earlier, at the 1991 OBD II Board Hearing, the Board adopted 

amendments that put into place separate monitoring requirements for low-emission vehicle 

applications, and non-low-emission vehicles. For non-low-emission vehicles, the requirement 

is based on the performance of the catalyst system overall. A malfunction is to be indicated 

when the catalyst system has deteriorated to the point that vehicle emissions increase by more 

than 1.5 times the vehicle's applicable standard over the emission level when near new (i.e., 

at 4000 miles). This requirement has been accepted by. the industry and, accordingly, the staff 

proposes no amendments. However, some manufacturers have expressed concern with respect 

to the OBD II requirements for monitoring catalysts on low-emission vehicles. 

Bachrround 

To meet California's stringent Low-Emission Vehicle standards, manufacturers will use 

a variety of sophisticated emission control strategies and advanced catalyst systems. While 

considerable attention is being focused on reducing engine-out emissions to the lowest 

possible levels, manufacturers will rely on electronic fuel controls operating in conjunction 

..\,·ith newly-developed catalysts to further reduce hydrocarbon (HC), carbon monoxide (CO), 

and nitrogen oxide (NOx) emissions to regulated levels. Emis~ion control systems on 

virtually all new California vehicles include three-way catalysts. These catalysts consist of 

ceramic or metal honeycomb structures (commonly referred to as "substrates"), coated with 

precious metals such as platinum, rhodium, or palladium. These precious metals ke dispersed 

within an alumina washcoat containing ceria, and the substrates are mounted in a stainless 

steel container in the vehicle exhaust system. Three-way catalysts are so-designated because 

they are capable of simultaneously oxidizing HC and CO emissions into water and carbon 

dioxide (C02), and of reducing NOx emissions (by reacting with CO and hydrogen) into 

elemental nitrogen, C02, and water. 

This three-way conversion activity only takes place efficiently, hov:ever, when the fuel 

system operates at a single air-fuel ratio, called stoichiometric (where there is just the required 

amount of air to completely burn all of the fuel in the engine). To achieve and maintain 

stoichiometric fuel delivery, manufacturers have incorporated closed-loop fuel contro-l systems 

that utilize an exhaust gas oxygen sensor downstream of the engine to provide feedback on 

the status of the air/fuel ratio being achieved. All closed-loop fuel control systems actively 

cycle the air-fuel ratio slightly above and below the stoic;hiometric point to maximize 

·three-way catalyst conversion efficiency. -The precious metals are used to temporarily retain 

the HC, CO, and NOx molecules in the catalyst while the ceri.a in the \vashcoat is used to 

store and release oxygen which is needed to con:plete the reactions. Oxygen is stored in the 

catalyst during· the lean portion of the fuel system's cycling (i.e .. when the air/fuel ratio is 

slightly higher than stoichiometric) and is released during the rich excursion. \Vithout ceria. 

6. 
there would be insufficient oxygen at the active sites of the catalyst to achieve the most 

efficient performance. . 

As emission conversion efficiency of catalysts containing ceria deteriorates, generally 

the ·oxygen storage capacity is also diminished. Accordingly, oxygen storage can be used as 

an indicator of catalyst performance, discriminating between catalysts with sufficient and 

insufficient oxygen storage capability. By utilizing the information from the upstream oxygen 

sensor and a second sensor located downstream of the catalyst (or catalysts), the oxygen 

storage can be measured by comparing the oxygen sensor signals. In addition to being used 

for catalyst monitoring, the rear sensor can be used to monitor and correct for front oxygen 

sensor aging as needed to maintain the stoichiometric air-fuel mixture at high mileage. With 

a properly functioning catalyst, the rear oxygen sensor signal will be fairly steady since the 

fluctuating oxygen concentration (due to the fuel system cycling about stoichiometric) at the 

inlet of the catalyst is damped by the storage and release of oxygen in the catalyst (see Figure 

I). \Vhen a catalyst is deteriorated, such damping is reduced, causing the frequency and 

peak-to-peak voltage of the rear oxygen sensor signal to approximate the signal from the 

oxygen sensor before the catalyst because the catalyst is no longer capable of storing and 

releasing oxygen. 

Q) 

Cl 

ro 

0 -

> 

.... 

0 

Vl 

t: 

Q) 

en 

t: 

QJ 

Cl 

>-

X 

0 

QJ 

Cl 

ro 

0 -

> 

.... 

0 

Vl 

t: 

QJ 

(/) 

-

c: 

Cl 

>-

X 

0 

~ 

I • I . 

• • 

. '. . i• ' I• • 

I • • "''·.,· 

I ./ I i 

\ r-· 

v 

FIGURE 1 

Properly Functioning Catalyst 

Deteriorated Catalyst 

Before Catalyst 

J(' 

.... --.... rA---· .. _ rx .. --..... f ' • O ' I 

. . . . . ... : .. -· .. - -: .. . .. ·. ... .. .. -· .. : ·. . \ . : ·. . . . ' . . ' 

\ ·; : \ ./ . ·I : ._, 

\ -. :J,.. \ )'.... •, 1--: \ l 

v · 0 'v v 

Af1er Ca1alys; 

7 
Current Reauirement 

. Currently, ihe OBD II regulation requires manufacturers to monitor the front catalyst 

on low-emission vehicles for deterioration in HC conversion efficiency. A malfunction is to 

be indicated when the efficiency of the front catalyst falls to between 50 and 60 percent based 

on the Federal Test Procedure (FTP) driving cycle. The regulation defines a front catalyst as 

the first "substrate" which receives untreated engine-out exhaust gas. A common catalyst 

system configuration places two or more substrates into a single container, but each substrate 

is considered a separate catalyst for purposes of the regulation (as illustrated in Figure 2). 

Manufacturers generally plan to use a series of catalysts in the exhaust system to meet the 

Low-Emission Vehicle standards (all certified TLEV's to date use multiple catalyst 

substrates). 

FIGURE 2 

Typical Catalyst Configuration 

Catalyst substrate #1 

(front catalyst) 

/ 

-Engine 

Catalvst containers 

The catalyst monitoring requirements currently adopted for low-emission vehicles 

were designed to provide for the detection of catalyst system deterioration on vehicles with 

multiple catalysts by the time vehicle emissions marginally exceed the applicable HC 

standard. For a typical engine-out (i.e., untreated) exhaust gas level of 2.0 grams per mile 

\g/mi). an overall caralyst system efficiency of about 92~o is needed to meet the TLE\' HC 

standard at 100.000 miles vvhile an efficienc\ of 88% would cause an increase in emissions to 

i .5 times the standard (generally. the pomt ~t \~·hich the 080-fi malfunction light is required 

to illuminate). Such a drop in efficiency \\·auld be difficult to detect using the correlation 

8. 
between oxygen storage and hydrocarbon efficiency with respect to the whole catalyst system. 

However. through monitoring of the front catalyst only. the timely detection of deterioration 

can be achieved. 

This approach per:mits reliable detection of small but crucial decreases in overall 

catalyst system effi.ciency for low-emission vehicles by monitoring the front catalvst for a 

relatively large loss in conversion efficiency. In multiple catalyst exhaust config~rations, 

downstream catalysts tend to increase in efficiency as more hydrocarbons pass through the 

deteriorated front catalyst and, therefore, minimize the increase in tailpipe emissions resulting 

from the deterioration. The strategy presumes that unmonitored downstream catalysts are 

normally aged, which is reasonable considering that front catalysts are most susceptible to · 

deterioration. 2 Therefore, a monitoring strategy that looks for a significant loss of the front 

catalyst conversion efficiency would be able to reliably detect a smaller loss in overall catalyst 

system performance as early as possible (it should be noted that even if dO\'mStream catalysts 

were deteriorated as well, front catalyst substrates alone are usually more than 90% efficient, 

so that replacement of just the front catalyst would restore most of the overall system 

conversion capability. In addition, front catalysts are often housed with a second do·wnstream 

substrate, so that the replacement of a deteriorated front catalyst could include the second 

catalyst as part of a replacement assembly). The staff estimated that a 50-60 percent 

conversion efficiency of the front catalyst would generally ~esult in tailpipe emissions of less 

than 2 times the HC emission standard; however, the actual emission level does depend on the 

configuration of the catalyst system as well as catalyst volume and composition. 

Some manufacturers, however, have expressed concern over what they feel is a weak 

correlation between oxygen storage and catalyst HC conversion efficiency for front catalysts 

located close to the engine. They contend that sintering of the precious metals in the catalyst 

due to excessive temperatures can lead to decreased oxygen storage apparently without a 

significant decrease in HC conversion efficiency, th.us increasing the chance for illumination 

of the malfunction indicator light when the HC conversion efficiency is stii( high. However, 

recent improvements in catalyst washcoat techno}ogy including recently developed high 

temperature resistant palladium-only catalysts appear to h2ve improved the correlation 

between HC conversion efficiency and oxygen storage, p2.tticularly in the 75% to 95% 

efficiency range. 3 

Another concern that has been expressed regardin~ the catalyst monitoring 

2 Front catalysts reach higher operating temperatures L1an dov:nstream catalysts due to 

being closest to the engine's exhaust manifold and becaus~ of the heat generated in the 

oxidation of a high percentage of the engine out pollutants. 

3 Palladium-only catalysts \Vith high temper~ture resis:.:mt washcoats ha\·e been presented 

in Society of Automotive Engineers (SAE) papers by .--\lli~d Signal Inc. (S.-\E 930386) and 

Ford/EnglehardlJohnson Matthey (SAE 94!058). 

9. 
,, 

' 

requirements for low-emission vehicles is that front catalysts may be too small to have enou!!h . - oxygen storage for reliable monitoring, even when the catalyst is new. Some manufacturers 

have stated that catalvsts need to be at least 0.4 to 0.7 liters in volume in order for catalvst ' . . monitoring to be reliable. 

However. despite these concerns, manufacturers have certified vehicles meeting the 

catalyst monitoring requirements· for low-emission vehicles. The monitored catalysts use 

platinum/rhodium formulations with conventional washcoat technology. One such application 

uses front catalysts that are only 0.25 liters in volume. Nonetheless, the staff is proposing 

catalyst monitoring requirement amendments that should address the above stated concerns 

while providing for uniform and timely detection of catalyst system malfunctions. 

Prooosed Monitorin£ Reauirement Amendments 

The staff proposes to remove the requirement for the independent evaluation of front 

catalyst efficiency, and to instead require a catalyst system monitoring requirement in which 

the malfunction criteria will be based on tailpipe emission levels (similar in concept to the 

monitoring requirements for non-low-emission vehicles). The staff believes that catalyst 

monitoring techniques have matured to the point that a system-based approach can be adopted 

for low-emission vehicles without having to specify a tailpipe malfunction criteria that in 

some instances would be many times the vehicle's emission standards. A system-based 

requirement satisfies manufacturers' requests for more flexibility in catalyst system 

monitoring, and would better ensure that malfunctions will be appropriately detected in all 

catalyst configurations (i.e., the effectiveness of the requirements would no longer depend 

significantly on the ·design of the catalyst system). Specifically, the staffs proposal would 

require the manufacturer to monitor the catalyst system such that a malfunction is determined 

before tailpipe HC emissions exceed 1.5 times the applicable standard. 

To satisfy the proposed requirement, manufacturers would. determine an appropriate 

portion of overall catalyst system volume to be monitored and,. from the measured efficiency 

of that portion, infer the overall catalyst system efficiency to determine if the emission 

threshold has been exceeded. 4 Therefore, manufacturers could maintain a front catalyst 

monitoring strategy if desired, but would have the flexibility to monitor a dovvnstream cau!lyst 

4 The staffs proposal also requires the OBD II system to indicate a malfunction when the 

NMHC conversion efficiency of the monitored portion of the catalyst system falls below 50 

percent. The staff believes that in the vast majority of cases, compliance with the emission 

threshold malfunction criteria ,.,-j]] require illumination of the malfunction indicator light at a 

significantly higher efficiency; however, the incJusion of this requirement is considered 

important as a backstop to ensure that a reasonable portion of the catalyst system will be 

mon.itored. 

10. 
in combination with the front catalyst, or to monitor the entire volume of the catalyst system.5 

The proposed changes to the regulation would also eliminate the potential undesirable 

situation where a manufacturer. can meet the TLEV emission standard with a single catalyst 

substrate, and by the provisions in the current OBD II regulation would not be required to 

indicate a m~lfunction until the HC conversion efficiency of the single catalyst dropped to a 

50-60% level. With a typical engine-out raw HC emission level of 2.0 g/mi, a vehicle 

certified to the TLEV standards (0.125 g/mi HC) with a single catalyst substrate would not 

indicate a malfunction until emissions increased to -0.8 g/mi, about 6.5 times the emission 

standard. The staff did not envision several years ago that TLEV standards could be met 

reliably with a single substrate catalyst but manufacturers have revealed several models for 

which such a catalyst system is planned. With the amendments proposed, the OBD II system 

on all vehicles, regardless of catalyst system design, would be required to illuminate the 

malfunction indicator light at a consistent tailpipe emission level. 

Feasibilitv of the Proposed Amendments 

As part of its investigation into tl_le feasibility of the proposed requirement, the staff 

has conducted limited testing on a 1990 Buick LeSabre equipped with a 3.8 liter, V -6 engine 

that has been modified to be a prototype ULEV. This vehicle achieves a baseline NonMethane Hydrocarbon (NMHC) emission value of 0.035 g/mi (the ULEV standard is 0.040 

g/mi Non-Methane Organic Gas). 6 The Buick.is configured with a 0.45 liter electrically 

heated catalyst (EHC) combined with a non-heated light-off substrate as a front catalyst, 

followed downstream by two 1.4 liter catalysts in a single container (see Figure 3). 

Preliminary test results show that the EHC/light-off combination achieves an average FTP 

total HC aonversion efficiency of approximately 92 percent. Testing was then conducted with 

the 0.45 liter EHC/light-off catalyst combination removed and replaced with a 0.2 liter 

conventional catalyst to simulate a loss of conversion efficiency across the monitored front 

catalyst. HC conversion efficiency across the 0.2 liter catalyst ·was measured at approximately 

80 percent, resulting in a tailpipe emission level of 0.060 g/mi NMHC. Thus, even with a 

relatively large (approximately 12 percent) drop in front catalyst efficiency over the front 

catalyst. tailpipe emissions did not exceed 1.5 times the HC standard. This indicates that if 

< Using the oxygen storage method for catalyst monitoring, it still a_ppears that compliance 

with these proposed requirements would be very difficult if the entire catalyst system is 

evaluated; however, some manufacturers are examining on-board HC concentration sensor 

concepts in place of using oxygen sensor information. If this technology develops 

sufficiently, the sensor could -be most .effective when placed downstream of. the enti!e catal;'st 

svstem. 

"To simplify testing. emissions were meas1.4red in ter;.;s of 1\JMHC even though the LcmEmission Vehicle standards are based on ~on-\1ethane 0:-pnic Gas (~\10G) Hcme,·er. for 

gasoline 'ehicles. ~\fHC and "\:::-dOG emissions are near::. identical. 

II. 
' ' 

the volume of the front catalyst is sized properly, a sufficiently large decrease in its 

conversion efficiency can be used as the basis for identifying a fault before tailpipe emissions 

would exceed. the I .5 times the standard emission threshold. 7 It should be noted that 

pwduction ULEV's are likely- to be certified with emission levels below 0.03 g/mi NMHC in 

order to provide an adequate in-use margin with respect to the emission standard. With 

·optimized production catalyst systems, a greater loss in HC efficiency would probably be 

tolerable before emissions would exceed 1.5 times the standard. 

FIGURE 3 

1990 Buick LeSabre 

EHC/Light-off Underfloor 

Combination dual _substrate 

0.45 Liters 1.4 L1ter 

1 1 . per substrate 

"'--,, , ...... / ,.......---· 

1(Jr, I "'---...-..___>, n ___..--. rl - . '·-- :.. ;. - ~ '-, L:l . [=:J ~E=J c:::::::J ---~~._)·J: / I /I ....... .---- . ·. · ._/ / 91.8%HC ' . . Efficiency 

Underfloor 

dual substrate 

1.4 Liter 

per substrate 

0.035 NMHC 

Tailpipe 

Emissions 

0.060 NMHC 

The staffs testing illustrates that by appropriating the right amount of catalyst volume 

in the front. monitored catalyst, manufacturers can identify a fault when its conversion 

efficiency drops significantly (e.g., in the 90% to 75% region, where catalyst monitoring is 

sufficiently reliable) yet tailpipe emissions are still relati\·ely low. As the graph provided by 

Ford shows (figure 4), new washcoats exhibit an improved relationship between oxygen 

storage and HC conversion efficiency, resulting in significantly more reliable catalyst -

monitoring. In the range from 75% to 95% HC conversion efficiency, the correlation 

between oxygen storage and conversion efficiency is fairJy linear, resulting in a reliable 

.separation between a good catalyst and a ba_d one .. By using this relationship, manufacturers 

- The overall catalyst system conversion efliciency dropped by only 1.2 percem \from 

97.9 percem to 96.7 percent) even th'rough the front catalyst active surface area was reduced 

by over 50 percent. 

12. 
. 0.9 

0 

i= 0.8 

I u 0.7 

._ 

F i :, e 4 

FTP CATALYST MONITOR CAPABILITY FOR 76 Cu.ln. PURd CATALYST· 

• CURRENT WASHCOAT TECHNOLOGY A ADVANCED WASHCOAT TECHNOLOGY 

NWC 

32hr. @ 12

0.6 Bhr.@ 1300C 16hr

>< 

w 

0 z 0.5 32hr.@ 1200 c 

.w 

(!) 

0.4 32hr.@ 1200C 

0 

._ 

II) 0.3 

z 

w 

Cl 

S< 0.2 

0 

100K 

0.1 

0 

I I I _I ,------ I I 

0 10 20 30 40 50 60 70 80 

'THRESHOLDSASSUME2GRAMSHCFEEDGAS FTP - % HC EFFICIENCY 

• NWC =NO WASH COAT, NO PRECIOUS METAL, BARE SUBSTRATE 'THERMALLY AGED, HRS. @ TEMP. 
' I 

can size the front catalyst such that a monitorable decrease in efficiency results in the desired 

tailpipe emission threshold. 

Impact o~ Amendments on Catalvst Svstem Desig:n 

In optimizing catalyst systems to meet the previous OBD-IJ regulatory requirements 

and the Low Emission Vehicle standards, manufacturers generally are adopting configurations 

that utilize single or muhiple catalysts in a close-coupled location. In some cases, the total 

volume of these catalysts could be either too small or too large to reliably monitor for an 

increase of 1.5 times the HC emission standard at the tailpipe. If the front catalyst is too 

small, a malfunction could be indicated before tailpipe emissions reach the proposed 

threshold. If the volume of the front monitored catalyst is too large, a malfunction might not 

be indicated until tailpipe emissions have exceeded the proposed threshold. 

For instance, in several cases manufacturers are planning to place.a single substrate 

catalyst in the front catalyst position. By placing an oxygen sensor downstream of the 

catalyst and monitoring it alone, as discussed previously, manufacturers can infer an overall 

system effici~ncy without directly measuring the efficiency of the dov.;nstream catalyst(s). In 

most cases, no modifications to this configuration should be necessary to meet the proposed 

change to the regulation. However, if the front catalyst is too small or too large (i.e., a 

malfunction would be indicated too early or too late, respectively)., manufacturers can alter 

catalyst size by shifting yolume from the front to rear catalysts or vice-versa. Other options 

that manufacturers can use to achieve a configuration that is capable of being monitored to the 

proposed emission threshold without affecting catalyst configuration include alterations of the 

washcoat formulation, substrate cell density, amount of precious metals in the catalyst, or 

other variables. 

In systems where the front catalyst container contains multiple substrates which in total 

represent a volume which is too large to monitor in accord with the proposed regulatory 

requirement, one possible option to manufacturers (in addition to those previously mentioned) 

is to place an oxygen sensor in the container between the catalyst substrates to reduce the 

amount of monitored catalyst volume. The relative sizes of the individual catalysts in the 

front container could be modified without affecting the O\·erall container size. This option 

\>..·ould allow catalyst systems to be adapted to meet the proposed regulatory requirement 

without requiring major redesign of the underbody of the \·ehicle in many cases. One 

manufacturer is currently pursuing this option and repons that it looks very promising v.:hile 

another manufacturer has already begun implementation of plans for a future model year that 

will include an oxygen sensor mounted between an EHC1ight-off catalyst combination and a 

dov.:nstream catalyst that are in the. same container. · 

An example of a catalyst container with t\vo subst::nes and a rear oxygen sensor 

mounted in the middle of the catalyst container is shO\'-TI· below in Figure 5A. If the volume 

of the front catalyst is too large to reliably monitor to the proposed threshold. catalyst volume 

can be redistributed (fig:ure 58). Converselv. front catahst volume can be increased in a ..... .,. ' . 

14. 
similar manner, if it is too small for reliable monitoring. 

FIGURE SA 

_____ / 

FIGURE SB 

/ / 

OOO! .---,~ 

~ L_____j 

In view of the above considerations, and to minimize potentially costly vehicle 

alterations in implementing the proposed requirement, staff is proposing to phase-in 

compliance of the new catalyst monitoring requirement. The proposed phase-in schedule 

would require compliance for 40 percent of a manufacturer's projected low-emission vehicle 

sales in model year 1998, 70 percent compliance in model year 1999, and full compliance in 

model year 2000. This should allow manufacturers to schedule any catalyst system changes 

in conjunction with their internal design changes and minimize the amount of redesign 

needed. 

In the interim, all vehicles certified to the TLEV standard would be required to 

indicate a malfunction when emissions exceeded 2.0 times the TLFV Hf' standard plus the 

4000 mile emission level. All vehicles certified to the LE\' standard would be required to 

indicate a malfunction at a slightly lower threshold, specifically, 2.5 times the LEV HC 

standard plus the 4000 mile emission level. These higher interim malfunction criteria should 

enahle manufacturers to implement a monitoring strategy which allows them to monitor most 

or all of the total catalyst volume Teliably until systems configured to meet the proposed 

requirement can be designed . 

. With the improvements in washcoat and catalyst technolog:- and the numher 0f onti0n~ 

that manufacturers ha' e to meet the ne\\ regulation (i.e .. ::Jiustin~ CJ.tal: st \ ~'lumes. ceil 

density, washcoat formulations. precious metal concemr;:.::~,ns. locJ.ting an oxygen sensor ir. 

the catalyst container. etc.). the changes to the regulation 5huuld provide a means for all 

15. 
manufacturers to comply within the allotted timeframe. However, as with previous sections 

of this regulation, staff will continue to monitor industry's progress towards compliance with 

these requirements and plans to revisit the issue in 1996 to determine if any mid-course 

co.rrections are needed. 

EVAPORATIVE SYSTEM LEAK DETECTION 

BackQround 

As exhaust emissions are controlled to the maximum extent feasible for California 

vehicles, evaporative HC emissions become a greater ~elative ·contributor to the ozone problem 

than exhaust emissions. Compared to a ULEV, for example, which must emit no more than 

0.040 g/mi of exhaust HC, evaporative emissions from vehicles meeting the high temperature 

evaporative emission standards could be as much as 0.077 g/mi (assumihg 2. grams per test 

HC emissions and using a 26 mile-per-day .average trip length). In addition, 0.05 g/mi 

running loss emissions (evaporative emissions generated during vehicle operation) are 

permitted. Clearly, since· they could exceed exhaust emissions, the strict control of 

evaporative emissions in-use is very important to attainment of the National Ambient Air 

Quality or state health-based standards in many areas of California. 

Fortunately, the control of evaporative emissions is not as difficult, perhaps, as exhaust 

emissions, since the control hardware is comparatively simple. Further, vehicle manufacturers 

have been upgrading materials and minimizing leak sources to ensure that these systems 

perform reliably for many years. Unlike exhaust emission controls, however, where small 

amounts of system or component deterioration can be corrected through adaptive learning 

strategies in order to maintain the needed low-emission levels, even a very small leak in an 

evaporative system can lead to a gross-emitting vehicle. Data from General Motors, for 

example, shows that during a high temperature evaporative emission test, an evaporative 

system leak equivalent to a 0.020 inch diameter orifice or larger can yield about 35 grams per 

test (figure 6). Data from other manufacturers is similar. 8 This is equivalent on average to 

about 1.35 g/mi HC, or over 30 times the allowable exhaust HC emissions for a ULEV. 

Realizing the importance of leak-free evaporative control systems, the OBD-11 regulation 

currently requires monitoring for leaks equivalent in magnitude to an orifice as small as 0.040 

inches in diameter. When the Board adopted this requirement in 1991, a 0.040 inch leak 

appeared to be the smallest leak which could be reliably detected on a routine basis. Even 

achieving this level of leak detection has not been easy, but industry has developed-both 

pressure and vacuum systems which now apperu: capable of reliably meeting the current 

requirement. These systems will begin phase-in with the 1996 model year . 

. Despite this progress, the staff believes it is still necessary to strive to detect leaks as 

small as 0 020 inL:hcs in diameter it! ensure that e\apvrati\ e emissions are ..::ontrolled tv ihe 

' Recem additional data are discussed later in th1s secuon. 

16. 
6 

24 DIURNAL EMISSIONS VS ·LEAK 

45 65-1 05-65F, 1990 BUICK REGAL 

40 

35 

+ 

30 

'1 

E 25 0 

L 

C> 

() 20 I 

15 

10 

+ 

____ L_ __ 

0.000 0.020 0.040 0.060 

Fuol Cap OrlffCo look Slzo (lnchos) 

0 · High data points + Low data points 
,·.: 1' .. 

needed level. The obvious benefit of such a requirement would be the early detection of 

leaks that are of a magnitude equal or greater than a 0.020 inch orifice but less than a 0.040 

inch leak. The industry has questioned the existence of such leaks on in-use vehicles; 

however, tests conducted by the ARB indicate that leaks smaller than a 0.040 inch orifice ate 

like,ly present in a significant number of vehicles on the road. · r 

The staff has been monitoring the results of leak deteetion testing being performed bn 

in-use surveillance cars at the ARB laboratory over the last several years. At this time, 

almost 2,000 vehicles have been che~ked for evaporative system leaks. In an effort to 

determine whether there are significant numbers of vehicles in the California fleet with leaks 

in the evaporative system ranging in size equivalent to a 0.020 to 0.040 inch orifice, the staff 

analyzed pressure decay data from a number of in-use surveillance projects. Vehicles in the 

surveillance program ranged from the 1970 model year (when evaporative canister systems 

. were first required on California vehicles) to the 1989 model year. The ARB surveillance 

program vehicles were leak checked generally before noon (during the cooler hours of the 

day) and within 10 to 30 minutes of arrival at the ARB laboratory, th,ereby limiting the range 

of fuel tank temperatures for the test sample. Vehicle evaporative systems were pressurized to 

14 inches of \\'ater and monitored for the loss of pressure" over a two-minute period to 

determine if a leak was present. The staff has analyzed the data to correlate the pressure 

drop, if any, to evaporative system leak size. The pressure drop to leak size relationship was 

determined based on ARB test data from four vehicles (VW Jetta, Buick LeSabre, Toyota 

Celica, and a Ford F150 truck) whose tank sizes nominally range from_14 to 18 gallons. 

Each of these vehicles was tested over a range of leak sizes (0 to 0.052 inches), fuel 

temperatures, and fuel Reid Vapor Pressure (RVP) values to simulate the range of conditions 

under which the in-use surveillance vehicles may have been tested. The pressure drops 

corresponding to 0.020 and 0.040 inch leaks are listed in Table 1 for the range of fuel RVP 

and temperature conditions. 

In determining the criteria for categorizing leaks on the in-use surveillance vehicles, 

the staff chose near worst case values based on the test vehicle data. Specifically, in 

determining the upper limit for a 0.020 inch leak, the staff chose the lowest two minute · 

pressure yielded when such a leak was installed (11 inches of water), although in several 

cases, the pressure was 12 or more inches of water. 9 In a similar manner, the staff chose the 

criteria for a leak greater than 0.020 inches, but less than 0.040 inches, to be 8 inches of 

water. Because the criteria were based on the limits of the test data generated using multiple 

vehicles under greatly varying fuel tank conditions, the staff believes they provide for a very 

conservative estimate of the number of small"leaks occurring in in-use vehicles. Using these 

criteria, the staff counted ·151 vehicles with leaks between 0.020 and 0.040 inches among a 

total of 1,936 vehicles (7.8 percent). 

9 The criteria were rounded to the nearest in'ch, which is the format in which the in-use 

surveillance data was recorded. 

18. 
Table 1 

Vehicle Initial Fuel RVP (psi) 2 min Press. 2 min Press. 2 min Press. 

Temp (F) for No Leak for 0.020 in for 0.040 in 

(in H20)"· leak (in H20) leak (in 

H20) 

'9I VW Jetta. 77 9.0 I3.8 I0.5 3.1 

I I 8 9.0 I2.6 I2.8 5.9 

8I 7.8 I 3. I 10.6 2.8 

102 7.8 13.0 I 1.2 4.7 

'90 Buick Le 76 9.0 I4.0 I2.0 5.0 

Sabre 78 7.8 I3.7 12.0 5.3 

95 7.8 I3.3 12.3. 5.5 

'90 Toyota 73 9.0 14.0 I 1.2 2.5 • Celica 76 7.8 I3.7 10.9 2.1 

126 7.8 14.9 11.7 3.5 

'94 Ford 80 9.0 14.0 I 1. I 4.3 

F150 115 9.0 14.0 I2.1 7.6 

76 7.8 14.0 11.5 4.2 

120 7.8 12.1 I 1.5 5.6 

Some industry representatives who have already reviewed a portion of the data 

presented have expressed concern that significant fuel cooling may have occurred on the inuse surveillance vehicles during the two minute pressure test, potentially causing a system 

with no leak to appear as a leaking system (falling fuel temperature would reduce the vapor 

generation and system pressure). In response to this concern, the staff recorded the drop in 

fuel temperature on the four test vehicles over the two minute period. Two test cases in 

particular illustrate industry's point: the Jetta was tested at 118 degrees Fahrenheit and the 

Ford at 120 degrees. In both cases, the fuel temperature dropped by approxima\ely 2.5 

degrees over the two minute no-leak test, and nearly a 2 inch drop in pressure was seen in the 

case of the Ford ( 1.4 inches for the Jetta). 10 However, despite such cooling, neither pressure 

value fell below the staffs upper criterion of 11 inches of water (a 3 inch drop in pressure) 

that was used in determining if a leak was present. Theref<;>re, the staff does not believe that 

10 These high fuel temperat~res were generated using a heat blanket v.:hich was removed 

prior to conducting the pressure. tests. Ambient temperatures were in the mid-70s for both 

tests< making the difference between fuel and arvbient temperatures betv.:een approximately 40 

to 45 degrees Fahren.1eit. In-use. the difference between the two temperatures is usually 

much less. in \\·hich case less fuel cooling would be expected. 

19. 
a significant number of vehicle5 we,..~ miscounted for this reason. Further, to the extent that 

cooling could have affected the pressure drop numbers causing vehicles without leaks to 

appear as if a leak existed. it is likely that on some vehicles with a leak between the sizes of a 

0.020 to 0.040 inch orifice, the leak would have appeared to be larger for the same reason 

and, therefore, would not have been counted (thereby cancelling any error .. in determining the 

incidence of leaks in this category). 

In the most recent portion of the surveillance testing program covering 43 7 1980 and 

newer vehicles, with the majority of vehicles newer than 1985 (or less than 10 years old), the 

survey results were a little better than the overall results, as would be expected. Vehicles 

with leaks equivalent to between 0.020 to 0.040 inches still comprised 3. 7 percent of the 

sample (16 vehicles). For leaks greater than a 0.040 inch or:ifice, 23 vehicles (5.3 percent) 

were identified. As these vehicles age further, these percentages will undoubtedly increase. 

Given the relatively older, high mileage proportion of vehicles in California, evaporativ.e 

system leaks are likely to occur on a significant portion of vehicles. 

There are· several factors which can affect evaporative system integrity such ·as 

improper or incomplete vehicle repairs after collisions im·olving evaporative system 

components, removal of engines or other powertrain components for rebuilding (which can 

require at least partial· disassembly of evaporative system components), use of deteriorated 

v.Tecking yard components on older vehicles, and manufacturing problems. Regarding the 

latter, recent news articles have been published describing the recall of late model Chrysler 

and General. Motors trucks for fuel tank leak problems that occurred as a result of improper 

vehicle construction. 11 In one instance, cracked fuel tank gaskets were found that reportedly 

were the result of overtightened fuel pump assemblies, and in the other, it was found that 

leakage could 'result from improper fuel filler neck construction. In addition, vehicle 

manufacturers are planning on installing an evaporative system service port to allow access 

for checking the evaporative system for leaks without otherwise disturbing the system. I:! The 

port consists of a valve similar to those used in automotive tires which can also leak after 

many years of service. Although a tethered cap would be included with the valve, it may not 

always be reinstalled after service, which would permit dirt to accumulate and may eventually 

cause the valve to stick or otherwise not seat completely. In addition, the service port would 

have 2 or 3 vapor lines connected to it. which each pose an additional integrity concern. 

Therefore, while such a port would be useful, it is also another potential source of small leaks 

which would contribute to the need to monitor for them . 

. 

11 Wall Street·Joumal, August 25, 1994. and Automotive News, January 31, 1994 

1

" The service port would facilitate access. in checking the evaporative system for leaks in 

an Inspection/Maintenance program, or for pressurizing the system· for the purpose of 

diagnosing the location of a leak. Presently. sop1e evaporative systems are very difficult to 

access and breaking into an e\;aporative system might induce faults by disturbing aged 

components or through failure to reconnect some of the lines. 

20. 

., 

I 
It is likely that smal_l leaks grovi into larger leaks in situations where vapo~ lines age 

and start cracking, or when components are mishandled or eventually fatigue due to cycling, 

weathering, or other aging effects. While complete breakage of fittings or disconnection of 

vapor lines could result in leaks greater in size than a 0.040 inch orifice, gradual deterioration 

in evaporative system components seems plausible. Leaks in the service port could start small 

as well. 

Given the estimated percentage of vehicles' with small leaks, there is little choice but to 

pursue detection of. leaks at least as small as a 0.020 inch orifice. To illustrate the magnitude 

of the problem in terms of fleet average HC emissions, if the 2003 fleet average requirement 

of 0.062 g/mi HC is adjusted for allowable evaporative emissions, fleet average HC emissions 

could (as indicated earlier) be as high as 0.189 g/mi. If, as the staffs data suggest, 7.8 

percent of the vehicles contained an evaporative leak between 0.020 to 0.040 inches, the fleet 

average would rise to 0.288 g/mi, over a 50 percent increase (see Figure 7). 

FIGURE 7 

The Effect of High Evaporative Emissions on the 

MY 2003 California Light-Duty Vehicle Fleet 

- 0.3 

~ Ul 

c 

0 

u; 

Ul 

E 

w 

(!) 

0 

~ 

z 

O.CE 

Exhaust 

Only 

Exhausr ... 

Evap 

Ex,..,aus: 

wi? 8% small leaks 

The staff has very recentiy received data suggesting :hat evaporative emission increases 

due to small system leaks could be significantly less'thc.n L~.e 35 grams per test previously 

reported by manufacturers. Apparently, with a new eV2.porc.tive system design, the majori!)' 

of fuel vapor generated can be captured under most conditions in the charcoal canister even if 

a leak is present in, for example, the fuel tank or the fuel f:Iler neck. The data suggest that 

the resulting evaporative emission increases could be as low as 3 grams per test. 'While this is 

an encouraging improvement, it is not at all clear that all f1.::ure vehicles w!ll perfonn 

similarly. From the data presented to the staff, it appea:-s 1::2.t the emission impact of a leak 

depends greatly on subtle evaporative system desi,gn variati::':1S. Further. e\·en at 3 ·grams per 

21. 
test. based on 26 miles per. day (on average) of vehicle operation, emissions from a vehicle 

would increase by the equivalent of approximately 0.115 grams per mile, which is almost 

three times the ULEV emission standards. Therefore, relative to future emission standards. 

the emission benefit of ha:ving such leaks detected and repaired is still significant. 

Proposed Amendment 

The staff proposes to phase-in the requirement to detect leaks as small as a 0.020 inch 

orifice. The phase-in would begin with the 1998 model year. Fifty percent of manufacturers' 

projected sales would need to comply with the requirement. This would increase to 75 

percent for the 1999 model year, with 100 percent implementation required with the 2000 

model vear. 

The amendments would permit a manufacturer to more narrowly specify the 

monitoring conditions when checking for a 0.020 inch leak provided that the monitoring 

system will function with reasonable frequency in-use (e.g., a few times a week), and 

provided the diagnostic system will check for 0.040 inch leaks routinely. This would permit 

manufacturers, should it be necessary, to better address in-use variability concerns associated 

with detecting smaller leaks that could, for example, lead to tpe false detection of evaporative 

system malfunctions. 

Feasibilitv of the Reauirement 

In order to satisfy the current _requirement to detect leaks equivalent to or greater than 

a 0.040 inch orifice, manufacturers are implementing strategies to either create a vacuum or 

pressure condition v.1thin the evaporative system. Once the condition is created, the 

evaporative system is sealed by closing the purge valve and the fresh air vent. If a significant 

change in pressure occurs during a subsequent short period of time (generally 15 to 30 

seconds), it is assumed that a leak is present. If the pressure or vacuum is essentially 

maintained in the system, the diagnostic system concludes that the system is leak-free. 

Based on recent data obtained by the staff, detecti~g leaks as small as a 0.020 inch 

orifice appears feasible. At this time. the capability of pressure based systems to detect small 

leaks appears to be greater than that of vacuum-based systems; however, data generated by the 

ARB staff indicate that capability adequate to satisfy the requirement should also ex~st for the 

vacuum-based systems. · 

The staffs testing was conducted on the four test vehicles previously identified. The 

fuel tank volumes for each vehicle are 18 gallons for the Buick LeSabre and the Ford F150 

truck. 14 £allons for the Volkswa£en Jetta, and 16 gallons for the Tovota Celica. Testing was · ' - - - . - conducted generally during vehicle cruise conditions (approximately 40-50 miles per hour on 

a city street). with some of the tests conducted at idle. Tne fuel tanks were 60 percent filled 

\\·ith California Phase-II gasoline with an RVP of 7.0 psi. Tests were conducted for a no-leak 

22. 
condition, a 0.020 inch orifice leak, and a 0.040 inch orifice I~ak. The testing sequence 

included sealing of the evaporative system under the normal operating conditions and 

recording the rise in pressure in the system d1:1e to vapor generation from the fuel for each of 

the leak scenarios. The evaporative system was then evacuated to about 7 inches of water and 

sealed (except for the imp! ante~ leaks). The rise in pressure in the system was then recorded 

at I 0 second intervals up to 80 seconds. These tests were conducted five times for each 

condition. Plots were then prepared showing the net leak rate due to the presence of a leak 

by adjusting the leak rate observed during the vacuum test for the.pressure build up noted 

when the evaporative system was sealed, but not evacuated. The results for the Buick 

LeSabre are shown in Figure 8. Plots for the other test vehicles are included in Appendix B. 

From the figures, it appears that adequate separation between the no leak case and the 

0.020 inch orifice does exist. It is recognized that additional variability may be present with a 

large number of.production vehicles. In examining criteria used by some manufacturers in 

determining the presence of a 0.040 inch orifice leak, it was learned that detecting a rise in 

pressure within a 15 second interval was a typical criterion. .Looking ,at the results of testing 

conducted by the ARB, it appears that achieving a similar change in pressure for the l5 

second period for a 0.040 inch leak cbuld be seen after about 60 seconds for a 0.020 inch 

leak, as might be projected since the area of a 0.040 inch diameter leak is four times the area 

of a 0.020 inch diameter leak. Therefore, by lengthening the monitoring period, sufficient 

separation appears obtainable. Figure 9 illustrates tflis point for the Buick. Normal 

distributions were constructed ba.Sed on the averages and standard deviations calculated for the 

test data with respect to specific time intervals. 

Consistent with "the indications from vehicle manufacturers, the staffs assessment 

based on the testing is that the check will be most reliable in~use under conditions oflow 

vapor generation. Such conditions should be encountered often. Phase II fuel with a 7.0 psi 

R VP will be sold exclusively in California beginning with the 1996 model year, .and fuel 

temperatures lower than 80 degrees Fahrenheit would be encountered routinely d·uring all but 

the hottest months of the year (even during the summer, such temperatures would generally "be 

encountered during morning or evening vehicle operation). Therefore, manufacturers are 

expected to be able to implement monitoring strategies that will operate reliably in-use with 

adequate frequency. The staffs proposal allows manufacturers to appropriately restrict 

monitorim2. conditions. even if the check is not alwavs run during an FTP test (the upper ~ . 

ambient temperature limit for the FTP is 86 degrees Fahrenheit). If in-use a vehicle is filled 

with a hi£her RVP fuel. or if for other reasons vapor generation is higher than expected, OBD 

II system~ should not be subject to falsely detecting a malfunction because the first stage of 

the monitoring strategy will provide a direct indication of the magnitude of vapor generation~ 

Should it be unacceptably high, the check could simply be disabled until appropriate 

conditions are encountered. 

23. 
8.0 

7.0 

6.0 

5.0 

0 

N \ :r: 

s 

E 4.0 

::J 

::J 

u 

C1J 

> 3.0 

2.0 

1.0 

0.0 

Figure 8 

Buick LeSabre - Phase II - 60-% Fill - Fuel Temp 64-88 F 

·-----·-

_---o 

. --· --- ,_ -- ----- =----=-

. > • -- ---- ' ->- ,, '-,_ --·---------------. - --. - "' -------- . . 'L'>"-._ --...__ •• '-- '---... . '·,......._: '\\ '<::::-,,_ ......... 

---· 

0 

---------6-- ___ 

\'\' .,_ ', - ,__ - -- ---

. ,_ . ------, . 

1-

10 20 

. -...::'' "+ 

"'"" 

. ·+ . --- . -----1 

30 40 

Time (s) 

--0 

50 60 70 80 

-•-

--

-&

-•

-·-1 

-+

--

- 

-r.i

Data taken during vehicle cruis
• 9uick LeSabre 

>-

-

"' c:: 

Ill 

c 

>- i(l 

Figure 9 

Fuel Temp Range 64-88 F 

10 seconds 

.. 

Phase II Gas 

0 V 00 ~ ~ N V ~ ~ ~ V V 00 ~ ~ ~ 

0 0 N N M M ~ V ~ ~ 

>-

'iii -

c:: 

Ill 

c 

>-

:.c == 

ttl 

.0 

0 

... 

C... I 

0 

>-. 

'iii -

c:: 

Ill 

c 

> 

-

:.c 

ttl 

.0 

0 

tl: 

v 

0 

Vacuum bleedup (inches H20) 

30 Seconds 

I 

N V 

N 

00 

N 

' . . . 

Vacuum Bleedup (inches H20) 

60 Seconds 

. - -- -- - -- -- - --~-----------~'-----

o <:r ro N 

0 0 ~ 

~ N <:r ro ~ ~ <:r ~ ~ ~ ~ ~ 

. N N M M "'" "'" ~ ~ 

Vacuum Bleedup (inches H20) 

60% Fuel Fill 

----no Leak 

0.020 in leak 

0.040 in leak 

----no Leak 

0.020 in leak 

0.040 in leak 

----no Leak 

0.020 in leak 

0.040 in leak 
Other Considerations 

' ' 

From the manufacturers' perspective there are additional issues to consider. First, they 

po!nt out that in-use field experience even with systems capable of detecting a 0.040 inch leak 

will not begin to accrue until after the 1996 model year. Until it is known how reliable these 

systems will be, they believe further constraining the check may be premature. In addition, 

just finding a leak does not mean that it will be easy to diagnose and repair. Manufacturers 

.have developed a new leak detection device which should be capable of finding small leaks, 

but its success in the hands of service technicians is not well kno~. Further, if a leak 

equivalent in size to a 0.020 inch orifice is the result of a combination of even smaller leaks, 

the diagnosis would be even more difficult, they maintain. However, the service industry has 

successfully located much smaller leaks in air conditioning systems for decades, so that 

detection of leaks in evaporative systems should not prove insurmountable. 

While manufacturers' concerns are understood, the staff has concluded that pursuit of 

detecting smaller leaks is necessary in view of the potential air quality effects of settling for 

Jess. Since detection of a smaller leak is envisioned to be done primarily by lengthening th"e 

. monitoring period, perhaps further constraining the checking conditions, and correcting for 

vapor generation, there should be no increase in hardware cost to accomplish the goal. There 

is also time between now and beginning implementation of the proposed 0.020 inch leak 

detection requirement in 1998 to review the industry's progress: Should it appear that 

manufacturers would have to make significant hardware changes to meet the amended 

requirement, the staff could provide for a revised phase-in of the requirement. Any needed 

alterations could be considered by the Board in a 1996 review of progress in meeting OBD II 

requirements. 

MISFIRE DETECTION 

Since adoption of the OBD II regulation in 1989, the ARB has been seeking misfire 

monitoring capability which extends throughout the full engine operating speed and load 

range. At the 1991 Board review of progress in meeting the OBD II reql.:liremerits, it was 

determined that technology had not progressed sufficiently to ensure that full-range 

monitoring capability could be achieved in the 1994-1996 OBD II phase-in time frame. 

Accordingly, the goal was moved to the 1997 model year. and industry agreed to redouble 

their internal efforts and include evaluation of a number of independent sources of misfire 

detection capability before the next Board review of the OBD II requirements. 

For models introduced before the 1997 model year. the current regulation requires 

misfire monitoring over the engine operating range encountered during an FTP test. The 

OBD II malfunction light is to illuminate when the level of misfire is. high ·enough to lead to 

catalyst damage, cause emissions to exceed the applicable emission standards by a factor of 

1.5. or to result in failure of an Inspection/Maintenance . program test. In addition, the . 

malfunction li£ht is to flash when misfire is occurrin2. at a rate which could lead to catalvst ~ - . damage. and remain steadily illuminated otherwise once the misfire rate exceeds the 

26. 
applicable thresholds. 

The ARB staff has continued to seek full engine operating range monitoring capability 

for a number of reasons. Engine misfire does not necessarily occur at all engine speeds and 

loads: sometimes misfire occurs only at high engine speeds and loads: light load part throttle 

operation. idle, or other isolated operating conditions. Moreover, under high speed and load 

conditions, for example, even small amounts of misfire can very quickly lead to catalyst 

overheating and failure. Misfire may also occur during the cold start and warm-up period, 

which could contribute substantially to excess emissions, but then may subside during warm 

engine.operation. Even high engine speed operation under light load conditions needs to be 

monitored since some vehicles may encounter these conditions in mountainous terrain durin£ 

alternating periods of engine braking and acceleration, or in congested traffic conditions 

(when owners of manual transmission vehicles are prone to minimize shifting and let the 

engine speed climb to high levels during frequent stop and go intervals). Since it is not 

possible to predict. the likely misfire characteristics of older vehicles, it is important to cover 

as much of the full range of engine operation as possible in monitoring for misfire. From a 

re·gulatory implementation standpoint, the staff would also like to avoid making judgment 

calls on the appropriate monitoring range capability for e\·ery engine certified in California, as 

each ·engine will have different characteristics which can affect the misfire monitoring range. 

If all engines must generally meet the full range monitoring requirement, then· certification 

acceptance is simplified, and there would be little potential for inequities in judging the 

acceptabpity of each manufacturer's misfire detection capability 13• 

Since the last Board review, the misfire monitoring capability of the automobile 

manufacturers has steadily improved, and the capabilities of independent parties ih this arena 

have also improved. Manufacturers have generally increased their computer processing speed, 

improved their misfire detection algorithms in numerous areas including incorporation of 

adaptive learning compensation for irregularities in manufacture of the ignition signal pick-up 

wheels, relocated the pick-up sensor to optimum locations to minimize signal noise, improved 

base-engine roughness through improved fuel targeting, and other enhancements. 

At this time it appears that industry will be capable of certifying 50 percent of their 

projected sales volumes to almost all of the full speed and load eng:irie operating range by the 

1997 model year. Only a very small portion of the full er,gine operating range would need to 

be excluded from the full-range monitoring requirement. This is a very light load operating 

condition occurring above 3000 RPM where driving \Vou!G be relatively rare. The engine 

speeq and load region over which misfire monitoring would be required is shov.n in Figure 

10. Ford Motor Company has indicated notable success in its misfire detection capability. 

13There is still· some ~llowa;ce in the regulatory propos.1!. howe\·er. for engines with 

fundamental desi!:Ul limitations which hinder reliable misfi~e detection to fore~o monitoring in ~ - a very narrow operating range. ' 

27. 
., 

I 

Working with Motorola on a high data rate system which incorporates pattern recognition 

techniques, it appears that very high speed misfire monitoring is possible. The only drawback 

to the system appears to be some limitation in identifying the misfiring cylinder at high 

engine speeds, but this limitation is offset by the otherwise excellent reported capability of the 

sys~em. Another significant benefit is that the cost of this adc;ied capability is expected to be 

surprisingly low. · 

"C 

Cl) 

0 

...J 

(I) 

c 

·c;, 

c 

w 

idle 2000 

Fig\.Jre 10 

Postive Torque Load - 4 inches Hg ~ 

. . 

3000 

Engine Speed 

At this time it appears that some engine and driveline characteristics still preclude 

reliable misfire monitoring over the full range of operating conditions; in particular, engines 

with 1 0 or I 2 cylinders may yet pose a challenge for meeting the misfire monitoring 

requirements. Because these engines require further evaluation, staff is proposing to phase-in 

the full-range misfire monitoring requirement beginning in I 997 at 50 percent of a 

manufacturer's projected sales volume, 75 percent in I 998, 90 percent in I 999, and full 

compliance in :2000 (small volume manufacturers would comply in 2000). In addition to 

manufacturers' efforts, staff is aware that Technical Advances, Inc. in conjunction with SSI 

Technologies, Inc, Professor Citron at Purdue University, Professor Ribbens at the University 

of Michigan, Kavlico, ;\nalytical Methods, ABB Industrial Systems, and others are working to 

solve the misfire detection problems of the remaining difficult engines. 

With the current proposal, then, time remains for industry to continue to improve 

misfire monitoring capability for the more difficult to control engines. Staff will again 

evaluate progress at a review hearing in 1996 to determine if changes would be needed to the 

re!.wlation for 1998 and later model year vehicles. 

28. 
OBD II IMPLEMENTATION ON DIESELS 

In 1991. the Board adopted amendments to the regulation making the OBD II 

requirements applicable to diesel engines begi_nning with the 1996 model year. Recognizing 

tha~ some OBD II n!quir~ments would .not apply, or could not be met on diesel applications, 

the regulation currently requires manufacturers of diesel engines to submit an OBD II 

monitoring plan for ARB review. After a number of discussions with manufacturers since the 

time diesels were included in the OBD II regulation, the staff believes enough has been 

learned to more specifically detail the minimum monitoring requirements for diesel 

applications. 

Generally, diesels are not equipped with evaporative systems, secondary air, or 

oxygen sensors. These monitoring requirements would, therefore, not apply. Regarding 

catalyst monitoring, the ARB staff has not yet identified a technology that can be put into 

production to detect diesel catalyst deterioration. Because diesel vehicles operate lean of 

stoichiometric, the principle of oxygen storage as discussed earlier for vehicles using thre.eway catalysts could not be used_. Catalyst monitoring is not proposed 'for diesels on this basis. 

However, with respect to misfire monitoring the ARB staff believes that a fo,rm of 

misfire detection on diesels is feasible and would be useful in reducing in-use emissions, 

especially at high mileages (i.e., beyond I 00,000 miles). It is recognized that diesel engines 

are not likely to develop intermittent misfire problems as are spark ignited engines; however, 

malfunctions can occur that prevent combustion in one or more cylinders. If compression is 

lost, the air/fuel mixture would pass through the cylinder unburh~d, and a large portion of the 

mixture would also pass through the catalyst (if equipped) into the atmosphere. The staffs 

proposal is to require the detection of the complete loss of combustion in one or more 

cylinders. The proposal would allow the misfire detection strategy to be active only during 

certain operating conditions (e.g., during idle), and monitoring would be required only once 

per driving cycle. Implementation of this requirement is proposed to begin with the 1998 

model year. Manufacturers of spark-ignited engines have been able to implement misfire 

detection systems based on engine speed fluctuations that are capable of detecting one to two 

percent engine misfire over a wide range of operating conditions. Compared with the 

requirements for spark ignited engines, the diesel manufacturers should be able to implement 

moniwring strategies to detect complete cylinder misfire under specific operating conditions 

using similar techniques by the 1998 model year. 

Regarding fuel system monitoring, diesel engines do not employ the type of closedloop fuel control systems found on vehicles with three way catalysts (i.e., feedback 

information on exhaust composition with the use of an oxygen sensor), although some diesel 

control system designs are capable of providing feedback regarding fuel injector performance. 

Therefore, the staff has proposed an amendment to clarify that diesel fuel system monitoring 

is required to the extent possible to detect fuel system mc.Jfunctions that would cause t~e 

vehicle or enoine to exceed 1.5 times anv of its emission standards: hov.;ever. manufacturers e ~ . . . 

\\·auld not be responsible for detecting malfunctibns for which the system is incapable of 

29. 
providing necessary feedback (e.g., a ·fuel injector with a broken tip). 

Consistent with the requirements for spark-ignited engines, manufacturers of diesels 

would also be required to implement OBD II monitoring strategies for EGR system 

pe~:formance and for any electroni"c components that· can affect emissions when malfunctioninQ 

(e.g .. intake air heating, electronic transmission components, wait-to-start iamp, etc.). -

1996-2000 MODEL YEAR COMPLIANCE 

Compliance with the OBD II regulation requires the implementation of a large 

number of monitoring s~rategies. Manufacturers are required to design and work with new 

monitoring concepts for components and systems that up until now, have not been monitored 

. on-board. The staff recognizes that manufacturers face a heavy workload in bringing such 

strategies to production across their prodpct lines in a manner that will ensure that OBD II 

systems are effective and reliable in-use. 

. . The Board has recognized the difficuhy of initially implementing OBD II systems on 

vehicles. In July, 1993, the Board adopted an amendment to the regulation that provides for 

limited relief from specific requirements if, despite a good-faith effort, full OBD II 

compliance with the requiremenls could not be obtained. For 1994 and 1994 1/2 models, the 

regulation permits the certification of OBD II equipped vehicles even if one or more 

monitoring strategies do not meet the minimum requirements of the regulation. For 1995 

models, the number of allowed monitoring deficiencies is limited to two per engine family. If 

a manufacturer has more than two deficiencies on a particular engine family, the vehicle could 

still be certified, but fines would be applied to the third and subsequently identified 

deficiency. The amount of the fines is 50 -dollars per vehicle per deficiency for a major 

monitoring system deficiency (e.g., catalyst monitoring, misfire monitoring, evaporative 

system leak detection, and others), and 25 dollars for deficiencies associated with monitoring 

systems for other electronic components. 

The adoption of this provision has proven to be Yaluable, since despite best efforts, 

most manufacturers have needed to certify vehicles with deficiencies when problems arose 

which were unanticipated and which could not- be immediately resolved. It is also clear, 

especially for. 1995 model year vehicles, that manufacrure:-s have generally taken every 

reasonable step to avoid having to request use of the deficiency· provision due to the risk of 

being subject to fines for subsequent unanticipated problems. 

Given the newness and complexity of designing OBD II systems, it is likely that 

deficiencies will continue to occur as manufacturers will implement OBD II across their full 

product lines in 1996. Accordingly, tbe staff is recommending carry-over of the allowance 

for .two deficiencies per engine family for the 1996 mode! year. With respect to electronic 

transrnissions. it is possible that a particular problem (such as the inability to incorporate a 

communication link between the transmission and emrine control units due to a late chanQe in I - -

the type of transmission to be used) could prevent monitoring of several. or even all 

30. 
transmission-components subject to monitoring under the Comprehensive Component 

Monitoring requirements. To address this, the staff further proposes (for the 1996 model vear 

only) to count multiple transmission component monitoring problems as a single deficienc~'. 

Staff is convinced that manufacturers will use permitted deficiencies sparingly since most · 

1996 engine families are not expected to require variances based on preliminary reviews of 

most manufacturers' planned systems. Although some manufacturers may need to utilize one 

of the deficiencies for some models in 1996, few are even suggesting that the sec~nd allowed 

deficiency will be required since they are saving it for an unexpected shortfall. 

- Concerning post-1996 models, the changes being proposed for this hearing would 

continue to require innovation by manufacturers in the area of catalyst monitoring, misfire 

detection, evaporative system leak detection, and issues associated with introducing more lowemission vehicles in this timeframe. Although most of the other monitors will have been 

developed for th~ 1994 to 1996 model year vehicles, 1997 and later vehicles may encounter 

potential deficiencies in trying to meet the proposed changes to the regulation. In discussing 

the proposed changes for some of the major monitoring requirements,with manufacturers, it 

appeared many were willing to try hard to meet_ the new proposed requirements. In return, 

they asked for continuing latitude in case they fall short in meeting some of the requirements 

and requested that the ARB consider some additional latitude with regard to in-use recall 

liability until they can gain more real world experience v.ith some of the new requirements. 

The staff considers industry's request to be reasonable, and is, therefore, proposing 

that one deficiency be permitted for each engine family for 1997 through 2000 model year 

vehicles, although unlike previous deficiencies, complete lack of a monitor would not be 

permitted without incurring a fine. This latter requirement is important with respect to the 

ARB's plans to begin evaluating the potential of using a check of the OBD II system in place 

of the current Inspection and Maintenance testing methods. The staff also proposes that 

deficiencies occurring in the 1997 and later model years could not be carried over to the 

following model year unless it can be demonstrated that correction of the deficiency would 

require hardware modifications that could not be accomplished due to lead-tiil!e 9r similar 

issues. Further, the staff proposes that in no case could a deficiency be carried over more 

than one year without a fine. This would preclude a manufacturer from using the proposed 

latitude to avoid development of a fully complying monil·oring system for an extended period. 

Regarding in-us_e compliance, the staff is proposi::g that for TLEVs. manufacturers 

\v·ould not be subject to compliance. actions until emissior.s exceed 2.0 times the applicable 

standards through the 1998 model year for those monitors which must be designed to mee1 a 

1.5 times-the e~ission standard threshold. LEVs and UL.EVs would have the same allowance 

apply through model year 2000. Further, because the cat2.lyst monitoring requirements would 

continue to evolve in the 1998-2000 model year timefrarr:~ even for TLEVs, if the staff 

proposa1 is approved by the Board, the 2.0 times the emission standard threshold in-use \Vould 

apply to catalyst monitoring for all low-emission vehicles through model year 2000. 

31. 
Given the stated wtllingness of some manufacturers to continue to strive to meet the 

ultin1ate .objectives of OBD II which are now in sight, the staff considers the allowable 

deficiency provisions coupled with intermediate in-use compliance latitude to be an optimum 

balance for promoting the best innovation and development from industry while ensuring that 

the resulting OBD II systems are as reliable and complete as possible. 

OTHER PROPOSED MODIFICATIONS 

In addition to the proposed modifications to the OBD 11 requirements that have 

already been discussed, the staff is proposing a number of more minor modifications. As 

manufacturers have begun to place OBD II systems into production, the staff has found that 

manufacturers have misunderstood or have been uncertain of the intent of some requirements. 

The proposed modifications would clarify the regulation in this respect, and would make 

adju~tments to the requirements when necessary based on the staffs experience in reviewing 

OBD II system designs. The more notable modifications are presented below. A full listing 

of yroposed amendments can be 'found in Appendix A. ' 

!\-tiL Illumination and Fault Code Storaee Protocol: 

Section (a)(l.9): The addition of this section is proposed to slightly modify the 

requirements for the OBD 11 MIL illumination and fault code storage protocol. Currently, 

illumination of the MIL is generally not required unless a malfunction is detected during two 

sequential trips. A trip is defined in part as a period of driving during which all components 

and systems are monitored at least once by the OBD II system. Therefore, if a specific 

monitoring strategy detects a malfunction in two sequential driving cycles, MIL illumination 

is not required unless all other (even non-related) monitoring strategies have operated during 

both of the driving cycles. The staff proposes to modify the protocol such that MIL 

_illumination would be required if a malfunction is detected in two sequential driving cycles 

. r~gardless of whether or not other monitoring systems have functioned. However. 

manufacturers would still be permitted to verify the proper function of components critical to 

a particular monitoring strategy before the monitoring system operates or before the results 

are validated. To allow for any OBD II system softv.·are changes necessary to incorporate 

the revised protocol, its implementation is not required Uiltil the 1997 model year. Other 

sections modified to incorporate the proposed change: (b)(l.3.1).·(1.4.1), (2.3), (2.4), 

(3.4.2). (3.4.3), (3.8). (3.9), (4.3), (4.4.1), (5.3), (5.4). (6.3). (6.4), (7.4.1 ), (7.4.2). 

(7.4.3), (8.3.2), (8.3.3), (8.4), (8.5.1), (9.3), (9 . .4), (10.3.1), (10.3.2), (10.4), (c){2.2). 

Misfire Monitorine Cvlinder Identification: 

Section (b)(:1: 1): Currently, the regulation requ1re~ the specific Identification of the 

misfiring cylinder during all operating conditions under \\ h1ch mistire detection ~ystem~ are 

active. However, in \vorking towards meeting ,the expanded monitoring conditions for 

misfire detection that are to begin with the 1997 model yeJ.r. some manufacturers have founcl 

that specific cylinder identification can be unreliable at h:gher engine speeds. The staff 

32. 

.. 
proposes an amendment that would permit manufacturers to request Executive Officer 

approval to disable algorithms employed to identify the misfiring cylinder under certain 

operating conditions if it can be demonstr~ted that the algorithm would not operate reliably 

when such conditions exist. This amendment would not affect the operating conditions uncler 

wh.ich misfire is to be detected. If misfire is detected under a condition where the specific 

cylinder cannot be reliably identified, the OBD II system would be required to store a 

general misfire fault code. 

Tamper Resistance: 

Section (d): The staff has proposed regulatory language to make more specific the 

requirements for making OBD II vehicle calibrations resistant to tampering. On vehicles that 

LJ)e Electronically Erasable Programmable Read Only Memory (EEPROM). which prov1de 

the capability for a vehicle to be reprogrammed electronically through its communication 

link~ the staff's proposal would require manufacturers to utilize reprogramming strategies that 

require access to a centralized computer maintained by the m'anufactu,rer as well as the use of 

full data encryption (scrambling of the software code). Equivalent strategies would also be 

acceptable. The staff is concerned that an incentive to tamper with OBD II system 

calibrations could exist should California implement an Inspection and Maintenance test 

based on the use of OBD II systems, especially considering the high cost repair limits that 

are likely to be part of the program. The success of this liM concept depends gr~atly on the 

extent to" which OBD II system information is reliable. Implementation of these more 

sophisticated proposed measures would not be required until the 1999 model year in order to 

provide manufacturers with adequate leadtime to make necessary vehicle and reprogra(nming 

equipment modifications. 

Apart from the Inspection/Maintenance program concerns, the staff believes that 

effective security measures are necessary to ensure the integrity of OBD II systems and 

engine control calibrations on vehicles using EEPROMs. With this type of computer chip. 

vehicles can be recalibrated without physically modifying or replacing any on-board 

computer components in an attempt to enhance vehicle performance. Without tamper 

resistance measures, vehicles could be modified with commonly available computer 

equipment. Although information regarding the location of key engine parameters within the 

'eh1cles programming would be necessary to successful!) lamper with the 'ehJcle. such 

Information, once learned by a few, could spread over coznputer bulletin boards and 

networks, for example. which are being used to a greater .:xtent within the service industry. 

With the staff's proposed amendments, individuals would face a much more difficult task in 

trying to "reverse engineer" the reprogramming protocol. Further, if the basic protocol is 

learned, the requirement to access a centralized computer would complicate the task of 

reprogramming on a wide scale basis, and would allow tk manufacturer to ·mo~itor 

reprogramming acti \'i ty. 

It should be noted that the aftermarket p~rts indus::-y ha~ expressed concern over tile 

dllti-tdlllpering prLwi~Jon~ which l1ave been present in ::1e l.lBD II reguiC!tJOJl ~!nee Jt \\d~ 

::n. 
adopted by the Board in 1989. and the proposed changes to make these provisions more 

specific has heightened its concern. In the past, the aftermarket industry has relied on 

decoding manufacturers' software to enable irto integrate replacement or specialty equipment 

into vehicles. The requirements of OBD II substantially complicate their design task in that 

aftermarket parts must be compatible with OBD II systems to prevent inadvertent malfunction 

indications. With additional security provisions, the aftermarket is concerned that 

successfully integrating its products into vehicles equipped with O:SD II will be very difficult 

to accomplish. 

However, it should be noted that some vehicle manufacturers will likely implement 

tougher security measures than currently required without the proposed modifications (in 

which case, the OBD II tamper resistance requirements would primarily only ensure that 

manufacturers remain consistent in implementing adequate security measures). This action 

would be taken primarily in response to recent indications from the United States 

Environmental Protection Agency regarding requirements for greater information availability 

to the aftermarket and service industries which would include the car>ability to install vehicle 

software calibrations. Manufacturers will want to implement additional security measure.s to 

ensure that only authorized reprogramming occurs. In some cases, vehicle manufacturers 

already have computer designs which are very difficult to access. Realistically, it appears 

that the aftermarket parts industry will need to work with vehicle manufacturers to gain . 

assistance in developing calibrations necessary for its products in a business relationship, 

even in the absence of more specific security measures in OBD II. The ARB staff has 

spoken with the vehicle manufacturers about this issue, and it appears that the aftermarket 

industry is viewed as a valuable asset in marketing certain kinds of vehicles, so that working 

with them should eventually occur. Unfortunately, at the present time. vehicle manufacturers 

are busy developing their full product lines to meet the OBD II requirements in the 1996 

model year, so that sufficient dialog has not yet taken place among both parties. 

The purpose of the security measures specified in OBD II. is to ensure that tampering 

will not reasonably occur with respect to Inspection and :-..1aintenance programs and vehicle 

performance. Insofar as legitimate aftermarket products manufacturers are concerned, it 

appears they will need to form business relationships with the vehicle manufacturers· 

regardless of the security meas[Ires being proposed for OBD II. The staff will monitor the 

cJevelopments in this area and determine if additional m~.sures to accommodate legitimare 

aftermarket parts manufacturers interests would be appropriate during the !996 OBD II 

review hearing. 

Alternate Fuel Vehicles: 

Section (m)(5.l ): Vehicles designed to operate on· alternate fuels are currenqy 

required to comply with the OBD II requirements beginr.ing. with the 1996 model year. 

However, manufacturers have stated that due to the worb)ad associated with complying full; 

with the OBD II requirements on conventional t·elliclcs 1·:~ the 1996 model year. coupled \\'IIIl 

·rhc low volumes projectecl for dltcmate fuel \'chicks. 088 II de,elopment and testing with 

34. 

•, 
respect to these vehicles cannot be completed in time for 1996 mode·] year implementation. 

1\ 1an ufacturers have stated that more time is needed to eval·uate the edects of a] ternate fueh 

on component performance to ensure that OBD II diagnostic str~tegies will be reliable. in-us~ . 

. -\s a result, manufacturers h.aw considered pulling back plans to sell alternate fuel velm:lt:·'> 

111 l.Y'::l6 and possibly )llbsequent model years. 

Recognizing manufacturers' concerns, the staff proposes to delay full OBD 11 

implementation until the 1999 model year for alternate fuel vehicles. Between the 1996 and 

l998 model years, manufacturers would· be required to jmplement diagnostic strategies to the 

extent feasible, but would not be required to include monitoring strategies for which the 

effects of alternate fuels are of concern. Specifically, manufacturers would be required to 

implement circuit continuity and functional checks at a minimum as well as unaffected major 

system monitors such as fuel system monitoring. or monitoring of the EGR valve, but could 

request Executive Officer approval to delay, for example. oxygen sensor response rate 

monitoring, or catalyst efficiency checks until the 1999 model year. 

Similarly, the staff proposes an amendment to California's certification procedures for 

alternate fuel retrofit vehicles. The proposal would provide retrofit system manufacturers 

some leniency until the 1999 model year with respect to maintaining full operation of OBD II 

monitoring strategies developed for use with gasoline. For example~ a retrofit system 

manufacturer would be permitted to request Executive Officer approval to disable the vehicle 

manufacturer's oxygen sensor response rate check, but would be-required to maintain other 

oxygen sensor output voltage checks that would not be affected by the use of an alternate 

fuel. The proposed modifications to the procedures are included in Appendix D. 

\"I. IMPACT ON COSTS. THE ENVIRONMENT, AND BUSINESS AND 

ECONOMY OF THE STATE 

The proposed modifications to the OBD II regulation do not necessitate the u~e of 

addi-tional monitoring hardware. The changes revise and clarify already adopted 

requirements and do not expand the scope of the regulation. To this extent, the staff does 

not expect an incremental cost per vehicle to result from ::1ese proposed modifications. 

1\lanuiacturers may need to make some design modificatwns to meet. for example, the 

revised catalyst and evaporative system monitoring requirements: however, the staff estimates 

that the overall OBD II development burden will decrease with the proposed amendments in 

comparison to the current requirements. A more detailed discussion with respect to the costs 

associated with th_e more significant proposed amendments is provided below. 

Reoardino catalvst monitorino in manv instances, the revised malfunction criteria will b ;:::. - .:::0' "' 

not require any suhstantive vehicle design changes. with t'le exception of software changes to 

ensure that the emJSSJon thresholds will be met in-use. Hc,wever, manufacturers have 

Jnci!Glled that 011 '.uJne Jllockh. cat<-dvst nwclifict'tion'> sue:· ;ls the incorporation of an o:--yge11 

~5. 
sensor between catalyst substrates in the same container will be necessary. There will be 

some additional cost associated with confirming the durability of this revised catalyst design. 

although when spread over the large numbers of cataiysts expected in the future, the 

incremental cost woul9 be negligible. In. a few cases, catalysts will need to be relocated in 

tl1e. exhaust system to be optimized for monitoring. In order to reduce tooling and 

development costs, the staff's proposal for catalyst monitoring includes an interim emission 

threshold that will prevent the need for any such modifications untp the 1998 model year at 

the earliest, and po~sibly until as late as the 2000 model year. Manufacturers, therefore, will 

have the opportunity to make necessary changes concurrently with other vehicle 

modifications. In other instances, the proposed modifications provide substantial regulatory 

relief. Some manufacturers have indicated that the current front catalyst monitoring 

requirements for low-emission vehicles cannot be practically implemented on certain !996 or 

1997 model year applications without significant product design changes or the last minute 

development of a new monitoring technology. With .the proposed modifications, such 

changes would no longer be necessary for near-term OBD II compliance. 

For misfire monitoring, the proposed revisions for the .1997 and later model years 

ease the burden of OBD II compliance compared to the current requirements. Manufacturers 

would be permitted to phase-in expanded monitoring conditions in place of full 1997 niodel 

year compliance. Further, the regulation would define a small positive torque engine speed 

and load range where misfire detection is not required.· Both aspects of the staffs proposal 

would reduce the resources necessary for OBD II misfire detection compliance. Regarding 

misfire monitoring for diesels, the requirements for these vehicles are less difficult overall t.o 

satisfy than those already in place for spark-ignited engines. Therefore, the staff expects the 

cost of compliance with ~espect to diesels to be less th~n that for spark-ignited engines. 

Regarding evaporative system monitoring, as discussed previously, it appears that 

manufacturers will be able to incorporate a method to detect leaks equivalent to a 0.020 inch 

orifice through software modifications. These modifications should not have a significant 

impact in terms of cost per· vehicle 

The last proposed modification that could significantly impact the cost of OBD II 

compliance is the incorporation of provisions for OBD II certification with deficiencies 

beginning with the 1996 model year and extending through the 2000 model year. These 

provisions permit the certification of OBD II systems even though one.or more monitoring 

system deficiencies have been identified. Fines of 25 to 50 dollars per deficiency p.er vehicle 

would apply to the third. and subsequent deficiency identiried in a 1996 model year engine 

family, and to the second and subsequent deficiency for 1997 through 2000 model year 

vehicles. Despite the proposed fines, use of the provision will result in a net cost savings,to 

the manufacturer in that the regulation does not currently allow certification of vehicles with 

monitoring system deficiencies after the 1995 model year. The cost to the manufacturer and 

affected California businesses of having to remove developed product from the California 

marketplace would almost certainly far exceed c\ny fine that may apply. 

36. 
The Environment 

Many of the proposed modifications to the OBD li regulation are intended to clarifv 

the monitoring requirements and to make minor regulatory adjustments based on the recent 

experience obtained in certifying OBD II compliant vehicles. As. a result, these changes 

should simplify the task of understanding and implementing the OBD II requirements, and 

are not expected to significantly affect the performance qf OBD II systems in-use or have any 

adverse impact on the environment. More significant amendments are proposed for catalyst 

monitoring, misfire monitoring, and evaporative system leak detection. While in some 

instances the requirements would be relaxed slightly in the near term, the staff believes 

overall that the modifications proposed will provide for greater emission reductions from 

California's OBD II program. 

For catalyst monitoring on low-emission vehicle applications, it is difficult to compare 

the impact on emissions resulting from the proposed system-based requirements relative to 

the current front catalyst monitoring requirements. As stated previously, the tailpipe 

emission level of a vehicle when the front catalyst has deteriorated td the malfunction criteria 

depends significantly on the design of the catalyst system as a whole. In some instances it is 

clear that a front catalyst monitoring strategy would illuminate the MIL before the proposed 

interim system-based malfunction criteria would be exceeded; however, in other instances 

(particularly when only one catalyst substrate is located in the exhaust stream), such a 

monitoring strategy could illuminate the MIL at a HC emission level many times the interim 

criteria. Once the phase-in of the 1.5 times the standard emission threshold is complete, 

catalyst monitoring systems should in all cases be equally or more effective in achieving 

emis~ion reductions in-use than systems developed to meet the current requirements. 

Regarding the OBD II misfire monitoring requirements,· the staff has proposed 

additional leadtime for meeting the expanded misfire monitoring conditions through the use 

of a 4 year phase-in, and has defined a small region of positi:ve torque operation wherein 

misfire detection disablement would be permitted. As such, a significant percentage of 

vehicles in the 1997 to 2000 model year time-frame would have misfire detection systems 

that are operational over a significantly smaller portion of the engine operating range in 

comparison to the current requirements for the I 997 and later model years. However, in 

;ullov:mg the progress of manufacturers towards meeting the current requirements. the staff 

Dclieve<, it IS likely that a number of manufacturers will r.ot be able to meet the current 

requirements on all engine families. Consequently. shouid the staffs proposal not be 

adopted. many vehicle manufacturers would not receive certification for some engin.e families 

after the 1996 model year. It is the staff's determination that the exclusion of vehicles from 

the California market would have an adverse economic ir:1pact on California businesses 

(including dealerships, automotive suppliers, and service centers) that would be 

proportionately greater than any resulting' negative irhpact on the environment. The reduced 

availability of vehicles would also likely translate into higher consumer costs for new vehicle 

rurdlases. As such. the staff believes that overriding economic considerations exist that on 

balance outweigh the potential increase in emiss'ions resu~:ing from the phase-in of the 

. 37. 
misfire detection requirements. 

For alternate fuel vehicles, the staffs proposal would allow manufacturers to delay 

the implementation of some monitoring strategies until the 1999 model year. The staff 

believes that any negative impact on emissions would be minor since manufacturers' 

projected sales volume for aiternate fuel vehicles are very low. Further, manufacturers 

indicate that their alternate fuel engine families will generally be desigl)ed to meet LowEmission Yehicle.standards (the only currently certified ULEV model operates on 

compressed natural gas). It is expected, therefore, that fleet average emissions from 

alternate fuel vehicles will be lower than the fleet average emissions of gasoline powered 

vehiCles in the 1996 through I 998 timeframe. Accordingly, any negative emission impact 

would be somewhat mitigated, since both vehicle manufacturers and retrofit system 

manufacturers are likely to pull back alternate. fuel vehicle plans should full OBD II 

compliance continue to be required with the 199n model year. 

Regarding t.he provision for the certification of OBD II systems through the 2000 

model year with system deficiencies, it is likely that any negative impact on emissions would 

be small from the certification of such systems. This is because the number of permitted 

defic,iencies is limited, and basic monitoring capabilities must be implemented for every 

monitoring req.uirement after the·l996 model year, even though the monitor may fall short of 

the complete regulatory requirement. In addition, manufacturers would avoid use of the 

deficiency provisions to guard against unanticipated problems which would require their use 

in order to avoid a fine situation. These points are discussed in greater detail in section III 

of this report. As with the proposed misfire monitoring amendments, in the absence of such 

provisions, the possibility of vehicles being excluded from the California market would be 

significantly greater, resulting in an overriding negative impact on the economy' of 

California. 

Fi nail y, with respect to the evaporative system monitoring requirem~nt amendments. 

as previously discussed, the enhanced requirement should result in a significant reduction in 

evaporative emissions to the extent that small leaks occur in-use with new evaporative system 

designs. Based on available information, the staff believes the emission benefits from these 

reN'isions should more than compensate for any negative. impact on the environment 

associated with the staff's proposals fm misfire monitoring, alternate fuel vehicles, and 1996 

through 2000 model year compliance. 

Business and Economv of the State of California 

The modifications proposed by the staff should not, in general, have any significant 

impact on the economy of California, or employment or business within the state. The OBD 

II requirements are directed at manufacturers of new motor vehicles, nearly all of which are 

located outside of the state. As discussed above, the proposed modifications should ensure 

that m~nufacturers will be able to keep current product plans intact throughout the early 

years of OBD ·11 Implementation in California. This wili prevent any disruption WJtllJn the: 

38. 
California businesses associated with the automotive indu~try. 

However. the requirements may have a significant adverse impact on businesses 

which design and produce aftermarket components and systems for light- and medium-duty 

vehicles. As mentioned previously, the potential exists for increased development and 

proauction costs associated with having to certify that aftermarket parts will not adversely 

affect the performance of original equipment OBD II monitoring strategies. Nevertheless, 

the proposed amendments should not adversely affect ability of California businesses to 

compete with businesses outside the state in that all aftermarket parts producers must obtain 

certification in order to sell their products for use on California vehicles. 

Conclusion 

After several years of development and discussion. OBD II system~ h;we become a 

reality in California. Monitoring systein concepts have gone from the draw1ng board 1nto 

production on more than 35 engine families already, with many more to follow. The 

regulatory amendments proposed by the staff would help in the proce~s of reviev.·if!g and 

certifying manufacturers' systems by clarifying requirements, and by making minor 

adjustments to the regulation based on the valuable experience gained to date. Further. the 

staff's proposal would maximize the long-term effectiveness of the OBD II program by 

restructuring and enhancing current monitoring requirements based on the latest 

improvements in monitoring technologies. However, at the same time, amendments are 

proposed that would ease the burden manufacturers face in implementing OBD II systems by 

addressing a number of technical and practical concerns. Many of the amendments proposed 

are the result of a high level of cooperation between the staff and the industry in general. 

The staff plans to continue to follow manufacturers' progress towards meeting the OBD I1 

requirements, and will be ready to address any issues that arise in this process. 

39. 

<) 
'• 
APPENDIX A 

Listin~ of Proposed Re!!ulatorv Amendments in "Plain Ene:lish" 

Section (a)( 1.1 ): In response to questions from manufacturers, a modification is 

proposed to clarify that use of the International Standards Organization (ISO) engine symbol 

is acceptable in place of the word "engine" or "powertrain" for purposes of the Malfunction 

Indicator Light (MIL). The staff believes use of the symbol will provide for equal 

effectiveness in alerting vehicle operators of malfunction occurrences. 

Section (a)(l.2): For purposes of clarity, an additional sentence is proposed to state 

that. unless otherwise noted, all section references are c'ontained within the OBD II 

regulation. 

Section (a)( 1.4): Consistent with the modifications proposed for diesel applications, 

this section would be deleted. 

Section (a)(l.8): The ARB staff has had· several discussions with manufacturers 

regarding the use of alternate statistical MIL illumination criteria. The staff has determined 

that more specific approval criteria are necessary to ensure that alternate protocols will be 

comparably effective in indicating malfunctions in timely manner. Specifically, language is 

proposed that would require manufacturers to demonstrate the effectiveness of the alternate 

protocol relative to criteria specified in the regulation (i.e., illumination of the MIL if a 

malfunction is detected in two sequential driving cycles). Further, the staff's proposal would 

make clear that the ARB would not accept as comparably timely a protocol that required 

more than six driving cycles on average to detect a specific component or system failure 

mode. 

Section (a)( 1. 9): An amendment is proposed that would modify the protocol for 

illuminating the malfunction indicator light and storing fault codes when malfunctions are 

detected. The amendment would remove the unnecessa;-:. restriction that all monitoring 

strategies must operate before a detected malfunction is :ndicated to the vehicle operator. 

Section (a)(2.0): Vehicle operation at very low :;::nperatures or high elevations can 

potentially cause a temporary effect on the performance of a system or component. 

Mahufacturers have indicated that monitoring system dis::blement is necessary under. such 

conditions to prevent falsely detecting such components 2.5 broken. The staff has proposed 

the addition of this section to clarify the expected ambient temperature and altitude limits for 

the operation of OBD II mon~toring strategies. Upon demonstrating the need, manufacturers 

may request Executive Officer approval to disable monitoring systems ai ambient engine 

startin~ conditions below 20 degrees Fahrenheit,· and at 2.ltitudes above ·sooo feet above sea · - - ' 

level. In special circumstances, a manufacturer may re~·.:est approval to disable monitoring 

systems at starting temperatures above 20 degrees. 

A-I 
. ' 

.. 

Section (a)(2.1 ): The staff proposes to allow monitoring system disablement when the 

vehicle's fuel tank level is low (below 15 percent of the nominal capacity) in order to avoid 

the false detection of engine misfire or other malfunctions should the vehicle run out of fuel. 

Section (a)(2.2): Manufactu_rers often design medium-duty applications to 

accommodate Power Take-Off (PTO) units. These units harness the engine's power to drive 

auxiliary devices such as a dump truck bed, a snow plow blade, or an aerial bucket. The staff 

proposes to permit OBD II monitoring system disablement while such devices are active to 

avoid the false detection of malfunctions. When a PTO unit is activated, the proposed section 

would require the OBD II system to clear the system readiness code in order to avoid vehicle 

tampering. Section (n)(19.0) contains a proposed definition for Power Take-Off Unit. 

Section (b)( 1 ): The staff proposes to modify the catalyst monitoring requirements for 

low-emission vehicle applications. Under the proposal, catalyst monitoring would be based on 

tailpipe emissions instead of front catalyst hydrocarbon conversion efficiency. The regulation 

would require the OBD II system to indicate a catalyst system malfunction when degraded 

catalyst system performance causes emissions to exceed 1.5 times the hydrocarbon standard 

for the vehicle. Higher emission malfunction criteria that wou1d be phased-out by the 2000 

model year are proposed to address immediate implementation concerns. 

Section (b)(2. 1.2): An amendment is proposed to make the monitoring requirements 

for heated catalysts consistent with the requirements specified in section (b )(1) for 

conventional catalysts. · 

Section (b )(2.2.1 ): An amendment is proposed to delete separate catalyst heating 

monitoring requirements for pre-start and after-start heating strategies. After further 

reviewing catalyst heating technologies, the staff believes a single criteria (failure to obtain 

designated temperature within a specific time period after engine starting such that emissions 

would exceed 1.5 times the standard) is applicable to both designs, making separate criteria 

unnecessary. Sections (b )(2.3 .2) and (g)(2. 7) have also been modified under the staffs 

proposal to reflect this amendment. · 

Section (b)(3): The staff proposes to provide additional leadtime to manufacturers to 

meet expanded monitoring conditi.ons for the detection of engine misfire. Further, the staffs 

proposal defines a high engine speed, light engine load vehicle operating region wh~rein 

misfire monitoring may be disabled. 

Section (b )(3 .1 ): Manufacturers have expressed co_ncerns that misfire detection 

systems may not be ca;Pable qf reliably identifying misfiring cylinders when. the misfire occurs 

at high engine speeds. An amendment is proposed that would allow manufacturers to ·request 

approval to disable cylinder identification strategies under such conditions as long as a general 

misfire fault code is stored should misfire be detected. 

A-2 
Section (b)(3.2)(A): Currently, misfire at levels high enough to cause catalyst damage 

must be detected using 200 revolution intervals. An amendment is proposed to extend this 

interval to up to 1000 revolutions if the manufacturer can demonstrate that catalvst damaQe 

v.:ould not occur before t~e additional evaluation tirne has elapsed. The amend~ent would 

pro.vide manufacturers with greater flexibility in detecting such misfire problems. 

Section (b)(3.2)(B): This section contains a provision for the use of a misfire 

detection threshold on low-emission vehicles that is hi2her than the level of misfire that would . . - cause emissions to exceed 1.5 times the standard. The intent of the provision is to provide 

manufacturers with some relief from the misfire detection requirements should significant 

reliability conc~ms exist with respect to these vehicles. The staff proposes to delete this 

provision. Adequate flexibility regarding for the use of higher malfunction thresholds on lowemission vehicles is provided in section (a)(1.4) making a specific provision with respect to 

misfire monitoring unnecessary .. 

Section (b)(3.4.2): Language is proposed to clarify the MIL illumination protocol • when engine misfire is detected. The amendment would make clear the section's intent that a 

malfunction js to be indicated if misfire is detected on sequential driving cycles regardless of 

the conditions under which it is detected, or if misfire is detected twice sequentially under 

similar operating conditions even if the occurrence of the operating conditions is separated by 

one or more driving cycles. 

Section (b)(3.5): Misfire monitoring requirements are proposed for diesel vehicles and 

engines. Manufacturers of diesel applications would be required to implement monitoring 

systems capable of detecting the lack of combustion in one or more cylinders beginning with 

the 1998 model year. 

Section (b)( 4.1.3): The staff proposes a modification to make clear that evaporative 

system leak monitoring may be disabled, subject to Executive Officer approval, at fuel levels 

greater than 85 percent of the nominal tank capacity. Manufacturers have stated that 

misdiagnosis of the evaporative system can occur at very high fuel levels. 

Section (b)( 4.2.2): The staff proposes to require manufacturers to phase-in evaporative 

system monitoring strategies capable of detecting system leaks equal or greater in magnitude 

to a 0.020 inch diameter orifice. The phase-in would extend from the 1998 model year to the 

2000 model year. 

Section (b )(5.2.2): An amendment is proposed to clarify the criteria that will be used 

by the Executive Officer to determine if a secondary air system will be sufficiently resistant 

to deterioration to qualify for a func!ional check. Manufacturers requesting an Executive 

Officer determination have sometimes misunderstood the extent to which the durability of the 

secondary air system must be demonstrated. 

A-3 
·Section (b)(7.1): An amendment is proposed to clarify the fuel system monitoring 

requirements for diesel vehicles and engines. Manufacturers would not be responsible for 

detecting fuel system failures for which insufficient information would be available to the 

diagnostic system. 

Section (b)(7.4.2): Language is proposed to clarify the MIL illumination protocol 

\\'hen a fuel system malfunction is detected. The amendment would make clear the sections 

intent that a malfunction is to be indicated if a fuel system ·malfunction is detected on 

sequential driving cycles regardless· of the conditions under which it is detected, or if a 

malfunction is detected twice sequentially under similar operating conditions even if the 

occurrence of the operating c~nditions is separated by one or more driving cycles. 

.. 

• 

Section (b)(8.2.2): The staff proposes a modification to clarify the malfunction 

criteria for oxygen sensor heaters. Some man.ufacturers have presented oxygen sensor heater 

monitoring strategies that essentially verify only proper circuit continuity of the heater, and 

do not adequately verify its proper performance. Language is also proposed to clarify that 

data and/or an engineering evaluation must be submitted when a request for Executive 

Officer approval is made .. Amendments are proposed to the following sections to similarly 

clarify the type of information that is required to support a request for Executive Officer 

approval: (b)(9.1.2), (b)(lO.l.l)(C), (g)(3.0), 

Section (b)(lO.l): An amendment is proposed to make clear that any component used 

as part of the diagnostic strategy for any other monitored system or component must itself be 

inonitored for proper function. Some manufactut:ers have initially neglected to incorporate 

monitoring strategies for such components. Manufacturers can be exempted from having to 

illuminate the MIL when such a component is detected as malfunctioning, provided the OBD 

II system would no longer use information provided by the component as criteria for 

temporary monitoring system disablement. 

Section (b)(lO.l. l)(A): A new example is proposed to clarify the requirements for 

input component rationality checking. 

. Section (b)(lO.l.l)(C): This section requires manufacturers to monitor coolant 

temperature sensors for performance with respect to indi(:ating the stabilized temperature 

necessary for closed-loop operation within a specified time period after engine starting. 

However, diesel vehicles generally do not employ cl~sed-loop fuel control. The staff 

proposes an amendment for diesel applications that would tie coolant temperature sensor 

performance with the beginning of warmed-up fuel control instead. Additionally, the staff 

proposes that permitted warm-up times for all vehicles should be a function of Starting 

•coolant temperature and/or intake air temperature to ensure that specified maximum warm-up 

times reasonably correlate with expected times. In reviewing manufacturers' OBD II system 

designs, the staff has found that manufacturers tend to focus on \vorst case operating 

conditions, making the monitoring strategies ov'erly conservative under normal conditions. 

By correlating the maximum time with ambient temperaure information. monitoring system 

A-4 
effectiveness would be improved. 

Section (b)(l 0.1.2)(C):. It is proposed to add the wait-to-start lamp on diesel 

applications as an example of output components that may need to be monitored under the 

Comprehensive Component Monitoring requirements. The modification clarifies that the lamp 

is an output component for which monitoring must be considered. 

Section (b)( I 0.2.1 ): The staff proposes to delete regulatory text that is redundant with 

language.in section (b)(IO.l.l)(C). 

Section (b)(l0.3): A modification is proposed to clarify the monitoring conditions for 

computer input and output components consistent with the original intent of the requirements. 

The modification would make clear that input components are to be monitored continuously 

with respect to out of range values, and one<: per trip at. a minimum for rationality checking. 

Output components are to be monitored at least once per trip for proper function, and 

continuously with respect to circuit continuity or out of range values if such monitoring is - ' - included. 

Section (b )(1 0.5): A modification is proposed to make clear that the determination of 

a component's impact on emissions is not limited to formal test procedures such as the FTP 

cycle or the Highway Fuel Economy Test,(HWFET). Manufacturers have incorrectly 

determined that a component does not have to be monitored if an emission impact is not 

noticeabl~ during an FTP test, regardless of the potential impact on emissions during other 

driving conditions such as freeway driving or hard.accelerations. 

Section (d): The staff proposes an amendment that would require enhanced tamper 

resistance measures for vehicles using Electronically Eraseable Programmable Read Only 

Memory (EEPROM) devices, which allow for _electronic reprogramming of vehicle on-board 

computers. The measures could include the use of data scrambling and required access to ·offsite computers when installing new programming. 

Section (e): Modifications are proposed to clarify the readiness/function code 

requirements. The proposed language would indicate that the readiness code is to be stored 

according to the protocol established in SAE 11979 or S:\.E 11939, whichever applies. Some 

manufacturers have misunderstood how the readiness/function code is to be implemented. 

Further, for evaporative system monitoring readiness, the proposed language would make 

clear that readiness should be indicated when a full diagnostic check with respect to-the 0.040 

inch orifice malfunction criteria has been ~ompleted if more constrained monitoring conditions 

are re~uired with respect to detecting 0.020 _inch leaks. This modification would ensure 

timely setting of the readiness code in-use. 

Section (g)(l.O): The requirements for selecting OBD II demonstration vehicles have 

been clarified to bener reflect the intent of the section. Some manufacturers have not 

• 

understood that any OBD II equipped engine family can be selected by the ARB for 

A-5 
demonstration. The provisions for using an alternate high mileage vehicles instead of a 

certification Durability Demonstration Vehicle have also been misunderswod. 

Section (g)(2.4): A modification is proposed to exclude diesel applications from the 

requirements to demonstrate misfire detection capability. Diesel applications have separate 

misfire detection requirements and the demonstration test specified would not .be applicable. 

Sections (g)(2.Q.2), (g)(4.4.5), (h)(9): Modifications are proposed to make the 

·~ . 

. demonstration test protocol for catalyst monitoring on low-emission vehicles consistent with 

the proposed modifications 'to the monitoring requirements. 

Section (g)(3.0): Language is proposed to make clear that a cold start is not to be 

required for demonstration test preconditioning cycles. A required cold start for 

preconditioning would unnecessarily complicate the demonstration test procedure. 

Section (g)( 4.0): Amendments to this section are proposed tQ clarify the testing 

sequence for demonstration evaluations to better reflect the ARB's intent. 

Section (h): A modification is proposed to grant the Executive Officer the authority to 

waive or modify any of the requirements for certification documentation if it is determined 

that generation of the information would be redundant or excessively burdensome to the 

manufacturer. This amendment would prevent manufacturers from having to provide 

winecessary information. 

Section (h)(12): The staff proposes to require a description of deteriorated components 

used for all required OBD II demonstration tests in order to verify that the components are 

·appropriate for OBD II demonstration and to aid in OBD II confirmation testing. 

Section (h)(l3): The addition of this section is proposed to require manufacturers to 

submit a listing of all powertrain computer input and output components in the certification 

application. This information is necessary for the staff to verify that all components subject 

to the regulation are monitored. 

Section (i)(3): An amendment is proposed to make clear that manufacturers will not 

be held responsible during in-use recall testing for undetected malfunctions caused by 

tampering or abuse when it is clear that the diagnostic system could not reasonably be 

expected to detect such failures. · 

Section (i)(5): When it is determined that an OBD II system design is subject to 

systematic false activation of the MIL, the staff proposes to allow manufacturers to request 

Executive Officer approval to take corrective action other than a formal recall if the 

manufacturer demonstrates that alternative action would, ce equally effective in capturing and 

correcting vehicles in the field. 

A-6 
Section (i)(6): The catalyst monitoring requirements permit monitoring of a portion 

of the catalyst system to infer total system performance. The addition of this section is 

proposed to clarify that unmonitored catalysts are to be normally aged during in-use testing 

in order to limit manufacturers' liability in instances where abnormal deterioration or damage 

of _such catalysts has occurred. 

Sections (f), (h)(3), (k)(l.O), (k)(2.0), (k)(3.0). (k)(4.0): The staff proposes to update 

the referenced industry standards to the most recent published versions. The industry has 

incorporated a number of modifications to the referenced documents since they were 

referenced in 1991. · 

Section (k)( 1.0): The staff proposes to limit restrictions on the use of inter-byte 

separation and checksums to only the messages specified in SAE J 1979 in order to provide 

additional flexibility in transmitting other emission- and non-emission related messages. The 

staff does not believe that the added flexibility will have i'tllY significant impact on diagnostic 

tool designs. 

Section (k)(5.0): Manufacturers of medium-duty vehicles and engines h:.we requested 

approval to use the heavy-duty vehicle communication protocol specified in SAE J 193.9 as an 

alternative to the referenced SAE and ISO protocols. Medium-duty vehicles are often 

serviced at establishments specializing in maintaining heavy-duty vehicles, and 'Often require 

the use of different diagnostic tools than used for passenger cars and light-duty trucks.· 

Inclusion of the 11939 protocol as an option for these vehicles is likely to promote better 

standardization of heavy/medium-duty diagnostic equipment which could more adequately 

satisfy the goals of the standardization requirements tha~ would forcing manufacturers to 

implement a "light-duty" communication protocol solely for emission diagnostics. While the 

staff believes the request is reasonable, the SAE J 1939 document is currently in draft form 

and has not been thoroughly evaluated by the ARB staff. Therefore, the staff proposes to 

make use of the protocol optional only with Executive Ofticer approval in order to provide 

the ARB with the opportunity to ensure that it~ use will satisfy OBD II goals and benetit the 

vehicle service industry. 

Sect1on (1)(2.0): This secllon requ1res manufacturers to publish certain engine 

operating parameter:, in factory ~ervH.:e manuah. The p<::-ameters are specific to spark 

1gnited engines. Thereiore, a modJficauon 1s proposed :o make clear that the section does 

not apply to diesels. Further. modifications are proposed to make the information 

requirements compatible with engines that have a low JT.aximum engine speed and engines 

that do not use mass air flow sensors. 

. . Section (l)n.OJ: The stafi proposes a modification to provide an addition_al year's 

leadtime to incorporate meam to provide some of the in~·ormation required.under the-section 

f'l·1anufacturer'> have requested additional leadtime to faci~Itate necessary software 

moditications. Modnlcations are also proposed to clarir":- the scope of required information. 

Industry representatives have requested this clarHication. 

A-7 
Section (m)(5.1): The staff proposes to provide manufacturers with additional 

leadtime to address concerns regarding OBD II implementation on alternate fuel vehicles. 

The proposal would allow manufacturers, up until the 1999 model year, to request exemption 

from certain monitoring requirements for these vehicles if the use of alternate fuels could 

affect the reliability of the monitoring strategy. A similar provision is proposed for 

California's certification procedures for retrofit alternate fuel vehicles. 

Section (m)(5.2): An amendment is proposed to clarify that medium-duty engines 

certified on an engine dynamometer may comply with the OBD II regulation on an engine 

model year basis instead of a vehicle model year basis. consistent with provisions for 

emissions certification. 

Section (m)(6.1), (6.2): Amendments are proposed that would provide for the 

certification of OBD II systems with identified monitoring systems shortcomings through the 

2000 model year. Forlhe 1996 model ye~r, manufacturers would be permitted to certify 

engine families with up to two monitoring system deficiencies withctut penalty, but would be 

required to pay fines for the third deficiency and every additional deficiency. For the 1997 . 

model year through the 2000 model year, only one deficiency would be permitted per engine 

family before fines would be imposed. The staffs proposal would not allow the carry over 

of deficiencies after the 1997 model year, except that carry over for one year is permitted if . 

hardware chang.es are needed to tix the deficiency. Also. after the 1996 model year, tines 

would be imposed for all monitoring system deficiencies wherein a component or system is 

left completely unmonitored. · 

Section (n)(l.O): When the determination of a malfunction is based on vehicle 

emissions with respect to the applicable standards, both the certification and useful life 

standards apply (e.g., on a vehicle with less than 50,000 miles, a malfunction is to be 

indicated with respect to the 50,000 mile standards, whereas at higher mileages, a 

malfunction would be judged with respect to the I 00.000 or 120.000 mile standards). An 

amendment to this section is proposed to clarify the definition of a malfunction in this 

respect. 

Section (n)(8.0): A modification is proposed to modify the definition of .. continuous 

monitoring·· with respect to computer input components that are sampled for engine control 

purposes at relatively low rates. The amendment makes clear that manufacturers do not need 

to increase the sampling rate of a component solely for the purposes of monitoring. 

Section (n)(ll.O): A separate definition for "calculated load value" is proposed for 

diesel applications. The current definition is not easily c.pplicable to diesels. 

·Section (n)( 15.0): The staff proposes to modify the definition for diesel c:ngines to 

Jncluck only engine::, u::,ing a compression ignition thermodynamic cycle. and not spark 

1glllted diesel-derived engines. The latter more closely :-.:semble conventional spark ignited , 

engines than compression ignition engines with respect to the emission control system design. 

A-8 
Section (n)( 18.0): For the purposes of the mistire detection requiremems, the staff 

proposes a definition for ··redline engine speed .. that is based on manufacturer's InaxiJllum 

recommended engine speed or the engine speed at which fuel cutoff occurs. Manufacturers 

have r.equested that the regulation be clarified to reflect this. 

A-9 
'• 
"APPENDIX B 

Evaporative System Leak Detection Plots 

u. 

.CD 

a) 

I 

orr--. 

c. 

E 

Q) 

1-

Q) 

:::l 

u. 

Q) 

u 

rc 

..... 

0 

> 

0 

1-

~ 

rc 

..!!: 

0 

,-

• 

c 

c::: 

N 

..:.: 

rc 

..!!: 

0 

,-

-..: 

Cll 

"0 

M "<:t LD 

~ ..:.: ~ rc rc rc ..!!: ..!!: ..!!: 

0 0 0 c c c 

• 

=· ... • • 

'f 

/r 

n .. I, 

I 

I\ 

h 

I ~ .... • : /t .I I r I 

) I ! i ,. I .ct .• 

ii I I 

\i I \ 

I I I l I I I 

I I c.: ... I 

,f 

=·· 

... • 

I 

!! • I 

C) 

:§ 

.- N M .... LD .- N M "<:t 

' ' ' c c c = c c c c c 

N N N N N "<:t "<:t "<:t "<:t 

0 0 0 0 0 0 0 0 0 

0 0 0 0 0 0 0 0 0 

~ • • 

• I.:-. 

T /• 

i 

i \1 /\I \! I /J l • <:: ' ) i/' y /)'' II I 

t .. ; 

I . II J ','r 

• 'P ;>.:. 

! I 

/~ I 

I / 

• < >. 

J !~ ; 

I 

I 

e::: 

0 

.... ,.., 

• I 

I ;/ 

• <:ic 

(OZH U!) wnnoeA 

' 

• +i:l'. 

/ 

0 

N 

I 

• / 

' / 

~.1 'J: I ' ,' , I 

/ 

:'; ... 

t -!-= 

0 0 

0 

C) 

:§ 

LD 

' 

c 

"<:t 

0 

0 

'-' 

! 

0 

Qj 

0 

r-.. 

0 

CD 

0 

LD 

-Ul 

0 Cll "<:t E 

i= 

0 

M 

0 

N 

0 

0 
u.. 

'I""" 

en I ,.... 

,.... 

c. 

E 

Q) 

1-

Q) 

u. = 

("0 

--

Q) 

"""") 

;: 

> 

,_. 

' 

.>I! 

10 

~ 

0 

c 

N M «:t ' ' .>I! .>I! .>I! 

10 10 10 

~ ~ ~ 

0 0 0 c c c 

i 

I I 

¢ ' J, i I r I I 

0 

CD 

~ 

:E 

L!) 

' 

.>I! 

10 

~ 

0 

c 

... 

I 

,_. 

' 

c 

N 

0 

0 

I 

t 

0 

L!) 

N 

c 

N 

~ 

0 

I 

I 

• 

I 

M «:t ' 

c c 

N N 

0 0 

0 0 

c 

I 

I 

/ I; 

• c-' ' I 

//1 

c 

C"'": 

(OZH U!) wnnoe/\ 

CD 

g 

L!) 

c 

N 

~ 

0 

I 

"" I 

,_. 

c 

'<t 

0 

0 

I 

I 

+ 

0 

N 

I 

I 

N M 

' 

c c 

'<t '<t 

0 0 

0 0 

0 

«:t 

c 

'<t 

0 

0 

i 

• 

0 

0 

0 

CD 

0 

1.0 

0 

M 

0 

N 

0 

~ 

:E 

L!) 

c 

'<t 

0 

0 

~ 

~ 

0 

u; 

CD 

E 

i= 
0 

N 

:r: 

c: 

8.0 

7·.0 

6.0 

5.0 

E 4.0 

::J 

::J 

u 

10 

> :1.0 

2.0 

1.0 

0.0 

Ford F 150 - Phase II - 60% Fill - Fuel Temp 71-88 F 

I 

l,, .. ·; 

'\ 

0 10 

'•. "· 

'·' • I 

• 

' li,_ 

20 

... 

_ -__-_ 

·- . 

- Ill 

. 

--: c " ' -

-·>-____ 6 . 

-- ··. ->L_= "C::) • 

' '-:--U--

30 

","'....,, 

•... 

. .._____ 

----------

',_ I, • 

' .... _ 

·,,, "---,,._ 

·I····-·· -------1 

40 

Time (s) 

50 

·, 1-

I 

60 70 

--.... 

:::.·::-:iJ 

80 

---

----

-·--·

---

---

-.--- 

APPENDIX C 

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

Note: These are amendments to section 1968.1, Title 13, CCR. The proposed amendments 

are shown in underline to indicate additions to the sections and strikeout to indicate 

deletions. 

1968.1 Malfunction and Diagnostic System Requirements--1994 and Subsequent Model-Year 

Passenger Cars, Light-Duty Tr~cks, 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 of the 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 en·gine-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 may be substituted for the 

word "Engine." 

(1.2). 

(1.3) 

(1 4) 

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 m·eans 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 Stltlsection (n), at the end of this section._ 

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

with engines certified on an engine dynamometer. 

Manu7acturerc of diesel engine: uti!i7ing ccmpu::~ based e!::tren:c p8WefH;..~ 

systems shall submit a plan for complying vlith tt-.:ce requirements to the Executive 

Officer for approval at least two years prior to ce:-:ification The plan shall be 

approved based on monitoring all powertrain co~ponents which can affect emissions 

and for which reliable monitoring techniques are :vailable at costs comparable to 

other engines meeting these requirements, and en meeting all other applicable 

requirements (e.g., storing freeze frame· conditio:--s, m_eeting standardization 

requirements, etc.). 

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

Title 13, CCR. 

C-1 
(1.~ 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 :e§J 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 tlie vehicle's emissions to 

exceed ~he emission threshold. 

(1.7§) 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.&Z) For 1994 and 1995 model years only, illumination of the malfunction indicator light 

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

evaporative system monitoring. MIL illumination for such vel'licles shall be optional for 

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

use of a new monitoring strategy which is sigQificantly 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 confonn 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 perfonnance of the monitoring systems in customer use at 6 

month inter:vals 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 detennined by the Executive Officer 

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

vehicles for correction of the OBD II system in· accordance with Article 2.2. Title 13 

CCR, or they shall submit an alternate 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 .BID Manufacturers may employ alternate statistical MIL illumination and fault code storage 

protocols to those specified i~ these requirements, subject to Executive Officer 

approval based on comparable timeliness in detecting a malfunction and evaluating 

system performance. For strategies requirina on average between three and six 

drivina cycles for MIL illumination. the manufacturer shall provide data and/or an 

engineerina evaluation which adequately demonstrate that the monitorina system is 

equally effective and timely in detectinq'component deterioration. Strateaies requiring 

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

C·2 
f.1.:.m Regarding diagnostic system monitoring conditions and MIL illumination reauirements. 

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 

diaanostic 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 again present. 

(2 0) Manufacturers may request Executive Officer aporoval to disable a diaanostic system 

desianed to meet the requirements of section (b) at ambient engine sta'rting 

temperatures below twenty degrees Fahrenheit. and at elevations above eight 

thousand feet above sea level provided the manufacturer subr;nits data and/or an 

engineering evaluation whi.ch adequately demonstrate that monitoring would be 

unreliable when such conditions exist. Notwithstanding, diagnostic system 

disablement may be requested at other ambient engine starting temperatures if the 

manufacturer adequately 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). 

{£J.l Manufacturers may 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. 

{£21 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 only while the PTO unit is active, and provided the OBD 

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

activation of the PTO unit. 

(b) MONITORING R=OUiREMENTS 

(1 0) CATALYST MONITORING 

(1.1) Requirement: 

(11.1) LE'is: The diagnostic systern shall individua~'y monitor the front catalyst or 

catalysts (i.e., any catalyst(s) 'Nhich receive :ngine out unfreated exhaust gas), 

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

dovmstream if it can be demonstrated that a :-:~alfunction will be indicated ~~;·hen 

tha fron: catal;,'st is alone malfunctioi1ing (so: (b) (1.2.1 )).· Catalysts arranged in 

parallel .,.,.;th the same inlet and outlet in a s;:-:;le exhaust pipe shall be 

consider:d as one catalyst ,t., separate cata'::-st in?orporated in series into the 

C-3 
same container as a front catalyst shall be considered a downstream catalyst. 

The diagnostic system shall monitor the catalyst system 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 

_Qombination with, the small VQiume catalyst. 

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

Officer appre'Jal, 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 catalyst system for proper 

pertormance. 

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

requirements on diesel vehicles and engines. 

(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) tot~l hydracarnan (HC) con'Jersion efficiency falls 

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

FTP test 'A'herein a malfunction is. noted when the cumulative total HC emissions 

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

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

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

downstream catalyst, the front catalyst shall be considered malfunctianing when 

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

average FTP total HC efficiency. The catalyst system 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 threshold specified in section (b)(1.2.2) below. or 2) the average Federal 

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

of the monitored oortion of tho catalyst system falls below 50 oorcent. Reaardino 

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 engine-out emissions measured at the inlet of the catalyst(sf 

(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 catalyst system (125 hours of operation for medium-duty· 

vehicles with engines certified on an engine dvnamometer). The emission 

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

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

Notwithstanding. beginning with the 1998 model year. manufacturers shall phase 

C·4 
,· 

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 catalyst system. The phase in percentages (based on the 

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

- equal or exceed 40 percent in the 1998 model year/70 percent in the 1999 · 

model year, with.lOO' 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 catalyst 

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

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

efficiency too !ov: to be practically monitoicd for 50 to 60 percent average FTP 

total HC efficiency) monitored independently shall be considered mal~unctioning 

when its average FTP conversion efficiency has deteriorated by between '10 to 50 

percent from its '1000 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 engines 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 <;lownstream. Each monitored catalyst or catalyst combination shall be 

considered malfunctioning when total HC conversion ~fficiency 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 

cata!yst(s). Alternatively, if co;re!ation with FTP emissions can be demonstrated 

manufacturers may use the malfunction crite:ia 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) /l, catalyst monitoring check shall occur at la:st once per· trip except for vehicles 

utilizing steady state monitoring, which shall :omply V·o'ith section (1.3.2). "Trip" IS 

defined in section (n) (5.0). This trip definiti21 applies throughout section 1968 1. 

The manufacturer shall define aporooriate oceratino conditions during which 

C·5 
·, 

. 

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 applicaole 

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 monitorina system 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 maximu,m 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 perfprm 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 properly 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 

manufacturer may abort the check if the engine operating conditions change 

during the check so thatthe vehicle exceeds the speed or 

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

manufacturei may base perfoimance of the 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 detecrion o7 a ;atalyst malfunction, the diagnostic 

system shall store a fault code and the MIL ::.all be illuminated no later than the 

end of the next trip if the malfunction is aga::- present. upon detection of a 

C-6 
catalyst malfunction: the MIL shall illuminate and a fault code ·stored no later than 

the end of the next driving cycle 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 o~cur. If catalyst efficiency 

remains below so· 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 ove~emperature 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 heated catalyst require_ments in section (b) (1 ), the HC 

conversion efficiency of all heated catalysts shall each be monitored. 

Manufacturers may monitor heated catalysts in combination with another catalyst 

if it can be demonstrated that a malfunction 'Nill be indicated 'Nhen the heated 

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

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

system shall also monitor the next catalyst downstream either independently of, 

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

ca_ta!ys~. The efficiency of heated cataivsts shail be monitored in conjunction with 

the reauirements of section (b)(1 ). 

(i2) Malfunction Criteria: 

(2.2.1) 

(2.2.2-jj 

Pre Start Heated Catalyst Systems: The system shall be considered 

malfunctioning when the designated pre start catalyst temperature is not attained 

before :ngine starting. 

/\~or Start Heated Catalyst Systems The catalyst heating system shall be 

considered malfunctioning when the catalyst does not reach its designated 

heating temperature within a requi~ite time period after engine starting. The 

time ;Jeriod is to be determined by the manufacturer subject to the requirement 

C-7 
that the system shall detect a heating system malfunction causi[lg emissions 

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

any of the applicable FTP standards. 

(2.2.~~ . Manufacturers uslng 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 section (b) (1.2.2), 'tYhichever 

is applicable, when monitoring the conversion efficiency ef a heated catalyst. 

(2.3) Monitoring Conditions: 

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

catalyst heating system. subject to the limitation that the monitoring conditions 

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

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

driving cycle during which the manufacturer-defined monitoring conditions are 

met. _Pre 5tart Heated Catalyst Systems: The diagnostic system shall monitor 

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

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

vehicle traveled less than the equi,,•alent of the first one mile of FTP driving. 

(2.3.2) After 5tart 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 engine start if during the previo~:~s driving cycle the 

vehicle traveled lees 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 

ccnv:rcion efficienc)' of all heated catalysts at least once per trip. 

(24) M!L Illumination and Fault Code Storage: 

~2 -1 1; Upon detection .of a catalyst heating malfunction, the diagnostic system shall 

stcr: a fault code and the MIL ehal! be illuminated no later than the end of the 

next_~:ip if the malfunction is again present the MIL shall illuminate and a fault 

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

monitoring occurs provided the malfunction is again present. 

(2.4.2) Fer r.eatf::dcatalyst efficiency malfunctions, the MIL shall be illuminated, and a 

fault :ode stored according to section (b) (1.4). 

(3 0) MISFIRE MONITORING 

(3 1) Requirement: The diagnostic system shc!fl monitor engine misfire and shall identify the 

specific cyiinder experiencing misfire. Manufacturers may request Executive Officer 

C-8 
approval to store a general misfire·fault code instead of a cylinder specific code under 

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

engineering_evaluation which adequately demonstrate that the misfiring cylinder 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 

adequatelv demonstrate that catalyst damage would not occur due to 

unacceptably high catalyst 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 t~ree 

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; 

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

emissions from a durability demonstration vehicle to exceed 1.5 times any of the 

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

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

lov.'er fer an LEV as opposed to a Non LEV wi!h a similar engine design .. the 

iiianuf:cturer may request approvol from the Executive Officer to use a higher 

parcer.:aga of misfire as the malfunction criteria for the LEV, not to exceed the 

level e7 the Non LEV. For the purpose of establishing the percent misfire, the 

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

occurring at equally spaced complete engine cycle intervals, across randomly 

selected cylineers 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 shall be used for all vehicles with engines containing 

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

misfires in 1 000 revolution incremer¥s which was determined for the durability 

demonstration vehicle malfunction criterion may be used to establish the 

C-9 
corresponding percent misfire malfunction criteria for engines with other numbers 

of cylinders. The m~lfunction 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 1 000 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 nec~ssary 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 positP.te torque engine speeds and conditions. 

(3.3.1) For pre 1997 model year vehicle.s, 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 Ga-R adequately demonstrate that the 

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

for the vehicle model in questioh 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 

percentaaes is not feasible under soecific FTP operatina conditions. the 

manufacturer may request Executive Officer approval to disable the monitoring 

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

approval, the manufacturer may disable misfire monitoring when misfire cannot 

be distinguished from other effects v.,rhen 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 monitorina conditions beainnina with the 1997 model vear. The phase in 

percentages (based on the manufacturer's projected sales volume for a·ll vehicles 

and enaines) shall equal or exceed.SO oercent in the 1997 model year. 75 

percent in the 1 998 model year. 90 oercent in the 1999 model year. with 100 

percent implementation for the 2000 model year. Small volume manufacturers 

C·10 
shall not be required to meet the phase-in percentaaes: however. 100 percent 

implementation of these monitoring conditions shall be required beginning with 

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

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

and under all positive torque 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 may 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 enaine speed of 3000 

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

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

mercury lower than that at the positive· toraue line. Below is a diaaram of the 

permitted misfire detection disablement reaion with respect to the reauirements of 

this section. Further, with Executive 0fficer aoproval, 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 

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

enaineerina evaluation to the Executive Officer to justify the proposed action. 

Executive Officer approval shall be based on the extent to which monitoring is 

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

monitoring technologies as applied to other enaines. · 

'0 

·1'0 

0 

_; 

Q) 

c 

Vl 

c 

w 

idle 2000 

Postive Torque Load - 4 inches Hg 

~I 

3000 4000 5000 Redline 

Engine Speed 

c. 1 1 
(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 aaain 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 cycle in which misfire is detected, unless driving conditions 

similar to those under which misfire was originally detect~d 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 ~ 

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 

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) Requirement: Beainninq with the 1998 model year. the diaanostic system on a 

diesel engine shall be caoabie of detectina the lack of combustion in one or more 

cylinders. The diaanostic system shall also identify the specific cylinder for which 

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

one cylinder, 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 multiole 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 aopropriate operating 

conditions for monitoring subject to the limitation that the monitoring conditions 

C· 12 
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 cycle during which the manufacturer-defined monitorina conditior:Js are 

met. 

. . 

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

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

monitoring occurs provided the malfunction is aaain 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 disable or 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 can be data and/or an 

engineering evaluation are provided which adequately demonstratee. that a 

. reliable check cannot be made when these conditions exist. 

(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 th·e intake manifold. · · 

(4.2.2) Beginning with the 1998 model year. manufacturers shall phase-in diaanostic 

strateaies to detect system leaks areater thar. or eaual in maanitude to a leak 

C-13 
caused by a 0.020 inch diameter orifice. The phase-in percentages (based on 

the manufacturer's projected sales volume for all vehicles) shall equal or exceed 

50 percent for the11998 model year, 75 percent for the 1999 model year. and 100 

percent implementation for the 2000 model year.· Small-Volume manufacturers 

·shall not be subject to the phase-in requirements; however. 100 percent 

implementation shall be required for 2000 model year. 

(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 tffi& the magnitudes indicated. above. -

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

least once per trip. Manufacturers shall define aporopriate 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 system shall operate at least once per driving cycle during which the 

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

may be further limited with respect to detecting leaks equivalent to e 0.020 inch 

diameter orifice, subjeet 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 cycle as indicated above. Subject to Executive Officer approval, 

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

when u~ing 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. 

(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 noxt 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 th~ Executive Officer .. 

C-14 
(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 (i) 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 of the applicable FTP emissi.on standards. · 

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

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

functional check of the system. .A.s part of this demonstration, manufacturers 

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

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

such a case, If a functiona~ 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 of the secondaPf 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 system shall operate at least 

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

met. · 

(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 detected next driving cycle during which monitoring occurs 

provided the malfunction is again present. 

(6.0) AIR CONDITIONING SYSTEM REFRIGERANT MONITORING 

(6.1) Requirement: 

(61 .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 

c. 15 
ozone depleting potential than CFC-12 need not comply with this requirement for 

that model. 

(6.?) 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 Condibons: The diagnostic sy~tem shall monitor the 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 system shall operate at least once per driving cycle 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 cycle 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 di_agnostic system shal! monitor the fuel delivery system for its 

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

enaines. the manufacturer shall monitor the performance of all electronic fuel system 

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

section (7 .2) below. I 

(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 fimit(s). Manufacturers may 

:::o;-:,pensate the criteria limit(s) appropriately for changes in altitude or for temporary 

int~~duction of large amounts of purge vapor or for other similar identifiable operating 

co~ditions 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: 

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 fbr 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 

C-16 
in which the criteria and interval are again exceeded, unless driving conditions 

similar to those under which 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~ 

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 t$ driving cycle 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 

cycle in which the malfunction is again detected, unless driving conditiOJlS similar 

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

(see Stlbsection (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 ~ 

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 

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: 

(81.1) 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 monitorall 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 rict:ler 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). 

(~.1.2) Either the lean-to-rich or both the lean-to-rich and rich- to-lean response rates 

shall be checked. Response rate ct1ecks shall evaluate the portions of the 

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

C-17 
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 th.e 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 

freq~~ncy and fuel step change fqr 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 bas~d 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. 

(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 

reauired to be met by the compor:1ent 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 enaineerina evaluation 

adequately 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 fL,Jel control, the response rate and output 

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

after tire 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 

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

during an acceleration condition); not ~ithstanding, 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 enaine start portion of the aoplicable 

FTP test. The monitoring system sh~ll operate at !east once per driving cycle 

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 cycle 

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

during which monitoring occurs provided the malfunction is again present. 

(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 aporopriate operating conditions for the diagnostic 

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

respond to a specific change in fuel/air ratio). subiect to the !imitation that the 

monitoring conditions shall be encountered a: least once durina the first engine 

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

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

conditions are met. per trip and an The diaanostic -system shall also periorm 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 type~ of oxygen sensors, the m·anufacturer shall 

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

equivalent monitoring with conventional sensors. 

C·19 
(9.0) EXHAUST GAS RECIRCULATION (EGR) SYSTEM MONITORING 

(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 san be provided the 

manufacturer submits data and/or an engineering evaluation which adequately 

demonstrateS. 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 of the following occurs: (1) any component of the 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: The diagnostic system Manufacturers shall define appropriate 

ooerating conditions for monitoring the ·EGR 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 monitor the EGR system at least once per trip. The 

monitoring system shall operate at least once per driving cycle 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 cycle during 

which monitoring occurs provided ~ the malfunction is again present. 

(1 0.0) COMPREHENSIVE COMPONENT MONITORING 

(1 0.1) Requirement The diagnostic system shall monitor for malfunction any electronic 

powertrain component/system not otherwise described above which either provides 

inout 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 any other monitored system or 

comoonent. 

(1 0.1.1) Input Components: 

(f:.,) The diagnostic system shall monitor for malfunction any electronic powertrain 

ccmponontlsystem which can affect emissions not otherwise described above and 

wr.ish provides input dir.ect_ly or in9i~ectly to the on board compufer. 

The monitoring system shall have the capability o( detecting, at a minimum, lack 

of circuit continuity and out of rang~ 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 

C-20_ 
its normal range (e.g., a "low throttle position sensor voltage would not be 

reasonable at a high engine speed with a hiah mass airflow sensor reading).~ 

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

temperature is lo•N; an accelerometer output indicating continuous rough road 

conditions, etc.). 

fG1{ID Input components may include, but are not limited to, the vehicle speed sensor, 

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

se.nsor, 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) 

(1 0.5)). 

fQ-j{Q The coolant temperature sensor shall be monitored for achieving a stabilized 

minimum temperature level which is needed to achieve closed-lqop operationJQr 

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 

adequately demonstrat!2_iAg- non-attainment of a stabilized minimum temperature. 

(1 0.1.2) OtJtput 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 componenUsystem ·receiving commands from the 

computer either directly or indirectly which can affect emissions and which is not 

otherv,rise monitored as a component'system in the above monitoring requirements. 

(8) 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 net 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) (1 0.5)). 

(1 0.2) Malfunction Criteria: 

(1 0.2.1) 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 

tompe~ature sensor shall be considered ma!~:.:nctioning if it does not achieve a 

stabilized minimum temperature nebessary f:~ closed loop operation 'Nithin a 

manufa:turer specified time inter.'al after s:c:~ing the engine. 

C-21 
(1 0.2.2) Output Components: Output components/systems shall be considered 

malfunctioning when a proper functional response to ~ computer commands 

does not occur. Should a functional check for malfunction not be feasible, thenan output component/system shall be considered malfunctioning when, at a 

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

occur. 

(1 0.3) Monitoring Conditions: Components/systems in this subsection shall be monitored 

continblously. 

(1 0.3.1) 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 qccur at least once per 

driving cycle during which the manufacturer-defined monitoring conditions are 

met. 

(1 0.3.2) 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 shaH 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 may be conducted during 

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

manufacturer provides data and/or an engineering evaluation which adequately 

demonstrate that the component does not normally function. or monitoring ~ 

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

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

manufacturer-defined monitoring conditions are met. 

(10.4) MIL Illumination and Fault Code Storage: Upon detecting a malfunction, the 

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

the end of the next driving cycle during which monitoring occurs provided ~the 

malfunction is again detected. 

(1 0.5) Component Determination: The manufacturer shall determine whether a pqwertrain 

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 may be requested for any reasonable driving condition. 

C-22 
(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 

iiJumination 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 to 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 mi.sfire or fuel system malfu.nctions, 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 system responsible for illuminating the MIL functions without detecting the 

malfunction trips in which the malfunction has not recurred and 1f 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 protectior.. 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 

reproarammable computer code systems (e.g., EEPROM) shall employ proven methods 

to deter unauthorized reprogramming which may include copyrightable executable 

routines or other methods. Beginning with the 1999 model year. manufacturers shall 

include enhanced tamper protection strategies including data encryption using methods 

to secure the encryption algorithm. and write protect features requirina electronic access 

to an off-site computer maintained by the manufacturer. Equivalent methods shall also 

be considered by the Executive Officer. Any rep:-og~ammable computer code system 

(e.g. EEPROM) shall include proven write protec~ f.catures \lo'hich may include 

copyrightable executable routines or other methods. 

C·23 
(e) READINESS/FUNCTION CODE The en-board computer shall store a code upon first 

completing#' 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~ Ra.s 

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 city 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 by reference in sections (k)(2.0) and (k)(5.0). The 

diagnostic system check for comprehensive component monitoring and continuous 

monitoriCig 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 system monitoring, the readiness indication shall be set when a full 

diagnostic check has been completed with respect to the O.O~Q 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 system shall also include a 

code or acknowledge message indicating that the diagnostic system itself is functioning 

properly. 

(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 condition's shall 

include, but are not limited to, calculated load value, engine RPM, fuel trim value(s) ill 

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 l~ast 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), Maret: : ':'92 June. 1994, and "E/E Diagnostic 

Test Modes" (Ji 979), December 1001 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 

(1.0) REQUIREMENT Each year a manufacturer shall provide emission test data obtained 

from a certification durability vehicle for Ot"Je enaine 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 this 

demonstration. T!he Executive Officer shall permit a manufacturer to satisfy this 

C-24 
requirement with waive this requirement if a manufacturer doec not have a certification 

durability vehicle available which ic 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 Re-sources Board (ARB) shall determine the demonstration 

'<'Chicle 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 h?s previously 

been chosen for the given model year applying for certification of the enqin·e families 

planned for a particular model year 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 demonstra~ion purposes. 

(1.1) Flexible fuel vehicles shall perform each demonstration test usil'lg 85 percent methanol 

and 15 percent gasoline, ahd gasoline only. For vehicles capable of operating on other 

fuel combinations, the manufacturer shall submit a plan for performing demonstration 

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 fo·r 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 

adequately 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. 

C-25 
(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. 

(2.4) Misfire: The manufacturer shall conduct one FTP demonstration test at the criteria limit 

specified in (b)(3.2)(8) for malfunction and a second demonstration test showing that 

the vehicle is capable of passing a California l.flspection/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 

(b)(5.2.2). 

(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 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 of the catalyst monitoring system is not 

required. 

(2.6.2) Low Emission Vehicles: The manufacturer shall conduct a cata·lyst effteiency 

demonstration using a catalyst system deteriorated to ~ the malfunction 

criteria. If two substrates are integrated into the same container, o.nly the 

upstream substrate shall be deteriorated for !he demonstration. 

(2. 7) Heated Catalyst Systems: For heated catalyst sys::ms that use an af:ter start heating 

strategy, t The manufacturer shall conduct a demonstration test where the designated 

heating temperature is reached at the time limit for malfunction after engine starting. 

C·26 
(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 s~all use the first engine start portion of one 

applicable FTP cycle for preconditioning before each of the above emission tests. If a 

manufacturer Ga-A-provides data and/or an engineering evaluation which adequately 

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. A cold start shall not be required prior to conducting 

preconditioning cycles. 

(4.0) EVALUATION PROTOCOL 

(4.1) 'A':"th the exception of short term trim only vehicles, tihe manufacturer shall set-the 

system or compo~ent for which detection is to be demonstrated at the criteria limit(s) 

from the beginning of and thro,ughout the prior to conducting the applicable 

preconditioning cycle{§l and FTP te.st. (For misfire demonstration. misfire shall be set 

at its criteria limit as specified pursuant to section {b)(3.2){8)). If a second 

preconditioning cycle is permitted in accordance with section {3.0) above, the 

manufacturer may adjust the demonstrated system or component before conductina the 

second preconditioning cycle; however, the demonstrated system or component shall · 

not be replaced, modified or adjusted after precof.lditioning has taken place. 

(4.2) Fe:- 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 

de:armining malfunction (and normally otherwise) for both the applicable preconditioning 

and FTP test cycles.· After preconditioning, the vehicle shall be operated over the first 

en:Jine start portion of the applicable FTP test to allow for the initial detection of the 

malfunction. This driving cycle may be omitted from the evaluation protocol if it is 

un:-~ecessarv. If required by the demonstrated monitoring strategy. a cold soak may be 

oe~ormed prior to conducting this driving cycle. 

(4.3) rc~ misfire demonstration, misfire shall be set at its criteria limit as specified pursuant to 

::::ion (b) (3.2) (8) 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 

full FTP test in accordance with requirements of subsection (b): 

(4.~.1) If the MIL does not illuminat~ when the systems or components are set at their 

limit(s), the criteria limit or the 080 system is not acceptable. 

C-27 
(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 of the 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. (jf an after-start heating strategy is used); 

and for misfire, percent misfire. For the 080 system to be approved, the vehicle 

must then meet the above emission levels when tested with the.faulty 

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 

FifP 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 080 systeni 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 catalyst system 

increased by no more than 5 percent (i.e .. 5 percent more engine out 

hydrocarbons are converted). For the 080 II system to be approved. the 

vehicle must then meet the above emission levels when re-tested. The MIL shall 

no{ illuminate during this demonstration. if c::talyst efficiency is within the 

malfunction criteria range over 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 bs adjusted, or the catalyst shall be 

replaced with another deteriorated catalyst, and the system re tested. If catalyst 

efficiency is within the malfunction criteria range over the nP test and the MIL 

is not illuminated, the catalyst may be deteriorated further but not below the 

lower limit ofthe malfunction criteria range, and the syS!tem retested. If the 

catalyst's efficiency is below the lower limit 9: the malfunction criteria range and 

the MIL is not illuminated, the 090 system is not acceptable. 

C-28 
(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 DDV. Any affected monitoring 

systems demonstrated prior to the re-calibration shall be re-verified. 

(h) CERTIFI.CATION 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 r:equirements specified in this section may 

be waived or altered if the information required 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. 

(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 maffunction detectiron 

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, 

~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 parame:ers 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 withDut 

damaging the catalyst 

C·29 
(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 pement catalyst total HC efficiency level, or a 4 0 

to 50 percent deteri.oration level to indicate a malfunction when catalyst deterioration 

causes emissions to exceed the applicable threshold specified in section (b)(1.2.2).· 

(1 0) 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. 

(11) Data supporting the criteria used to detect evaporative purge system leaks. 

(12) A description of the modified or deteriorated component§. used for~ fault 

simulation to dri'.'e the fuel system to the criteria 'limit(s) for•demonstrating fuel 

system compliance with th~ requirements of with respect to the demonstration tests 

specified in stffisection (g). 

@ A listing of all electronic powertrain input and output siqnals. 

(1 J1) 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 

diaanostic system 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. 

C·30 
(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 vihich affect emissions with no MIL 

illumination, and systematic erroneous activation of the MIL. With respect to 

erroneous activation of the MIL, the manufacturer may request 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 diaonostic strategy on in-use vehicles. In 

considerina a manufacturer's request, the Executive Officer shall consider the 

estimated frequency 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~. 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 of the applicable standards. This hiqher·emission threshold 

for recall shall extend up to the 1998 model year for TLEV applications (except for 

catalyst monitoring, for which the threshold shall extend to the 2000 model year), and 

to the 2000 model year for all applicable monitoring requirements on LEV and ULEV 

applications. · 

{§l Regarding catalyst system monitoring, unmonitored catalysts shall be normally aged. 

U) 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 efficienGy monitoring system, 

heated catalyst system, and EGR system malfunction critefia for.co~pliance with the 

applicable emission constraints in this section. Confirmatory testing to verify ~hat 

malfunction criteria are set for complian·ce 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 Stan.dardized access to emission-related fault codes, 

emission-related powertrain test information (i.e., parameter values) as outlined in 

subsection (1), emission related diagnostic procedures, and stored freeze frame ·data shall 

be incorporated based on the industry specifications referenced in ~his regulation. 

(1.0) Either SAE Recommended Practice J1850, "Class B Data Communication Network 

Interface", i\tJgust, 1991 May, 1994, or ISO 9141-2 ~. "Road·vehiclesDiagnostic Systems- CARB Requirements for Interchange of Digital Information," 

February. 1994, which are incorporated by refere:~ce, shall be used as the on-board to 

off-board network communications protocol. All S.-\E J1979 emission related 

messages sent to the J1978 scan tool over a J1250 data link shall use the Cyclic 

C-31 
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 sca'n tool 

and commonly available, non-microprocessor based tools. _In addition to these 

procedures, manufacturers may publish repair procedures referencing the use of . I 

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, m 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 Connect_or'' (J1962), June, 1992; is 

incorporated by reference. 

i§Jll With Executive Officer approval, medium-duty vehicles may alternatively employ the 

communication orotoco!s established in SAE Recommended Practice J1939 to satisfy 

the standardization requirements specified in sections (k)(1) throuah {k)(4) -above. 

The Executive Officer's decision shall be based on the effectiveness of the SAE J1939 

protocol in satisfying the diagnostic information requirements of Section 1968.1- in 

comoarison 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 equipped 

with closed loop fuel control), fuel trim (if equipped), fuel pressure (if available), 

C-32 
ignition timing advance (if equipped), 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 

separately from default value or limp home signals. Diesel vehicles shall be exempt 

from this requirement. 

(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 year (with full comoliance required by the 1997 model 

year), for all monitored components and systems, except misfire detection, fuel 

system monitoring, and comprehensive component monitoring), results of the most 

recent test performed by the vehicle, and the limits to which the syste~ is compared 

(except for continuously monitored systems/components) shall be available thro.ugh 

the serial data port on the standar.dized 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 J1 9.79 (or SAE J1 939, 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 (see section 

(b) ('1 1.5)) unless otherwise soecified, shall be implemented beginning with the 1994 

model year. 

(2 0) The Execut1ve Officer shall grant an extension for complian~e 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 prese11t 

electronic control system by the 1994 model-year because majo_r 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 arf extension from the Executive Officer shall 

comply with these regulations when modification of the electronic system occurs in 

C:33 

• 
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. 

• (5.0) Vehicles certified to run en alternate fuels, and dDiesel vehicles; 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 adequately demonstrated that the delay will allow for 

the development of significantly more effective monitoring systems. . 

.(§Jl Vehicles certified to run on alternate fuels shall meet these requirements by the 1996 

model year. However. manufacturers may request the Executive Officer to waive 

specific monitoring requirements for which monitoring may not be reliable with respect 

to the use of alternate fuels until the 1999 model year 

f§.1l Medium-duty vehicles with engines certified on an engine dynamometer may comply 

with these requirements on an engine model year certification basis rather than on a 

vehicle model basis. ' I 

(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 arid 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 r~ceipt of 

an application from the manufacfurer, 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 continQent 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 

C-34 
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 year vehicles and 

engines only, failure to properly monitor multiple electronic transmission components 

shall be considered a single monitoring system deficiency. 

@.1.1 Beginning with the 1997 model year and throuah 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 

subsequentl'l identified deficiencies, with the exception that fines shall apply to all 

monitoring system deficiencies wherein a required monitoring strategy is completely 

absent from the 080 system, and 2) Manufacturers may not carry over monitoring 

system deficiencies to future model years unless it can be demonstrated that vehicle 

hardware modifications would be necessary to correct the deficiency, in which case 

the deficiency may be carried over for one model year. 

(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 of the emission standards (both 

with resoect to the certificat'ion and useful life standards), unless otherwise specified, 

appli.cable 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. 

C·35 
(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 h;:~s risen by at least 40 degrees Fahrenheit from engine starting and 

reaches a minimum temperature pf 160 degrees Fahrenheit. 

(7.0) A "driving cycle" consists of engine startup, vehicle operation beyond the beginning of 

closed loop operation, and engine shutoff. · · 

(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 

frequently, the value of the component may instead be evaluated each time sampling 

(9.0) 

· occurs. 

"Fuel trim" refers to feedback adjus.tments 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. 

(1 0.0) "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 1 00%). · 

Current Airflow Atm Pressure (@ sea level) 

CLV = X 

Peak airflow (@ sea level) Barometric pressure 

For diesel aoplications, 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 1 ~. 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 veh'!cles 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, 

C·36 
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 Lo~ Er.nission 

Vehicle (ULEV). These vehicle catego_ries are further defined in Titte 13, sections 

1956.8 and 1960.1. 

(15.0) "Diesel engines'\ for the purposes of these regulations, includes diesel derived refers 

i.Q_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 

sign<:ll's rationality in comparison to all available information. 

(17.0) "Federal Test Procedure" (FTP) cycle or test refer:s 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." 

l..1.§Jll "Redline enaine speed" means the manufacturer recommended maximum engine 

speed as normally displayed on instrument panel tachometers, or the engine speed at 

which fuel shutoff occurs . 

.L1ELQl "Power Take-Off unit" refers to an engine driven output provision for the purposes of 

powering auxiliary equipment (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. 

C-37 

APPENDIX D 

Modifications to Sections 203.0, 2031, and the incorporated certification proc"edures, 

"California Certification and Installation Procedures for Alternative Fuel Retrofit Systems for 

Motor Vehicles Certified for 1994 and Subsequent Model X ears. 

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

and strikeout to indicate deletions. 
. ,, 
Amend Title 13, California Code of Regulations, Sect-ions 2030 and 2031, to 

read as follows: 

Article 5. Approval of Systems Designed to Convert Motor Vehicles to Use 

Fuels Other Than the Original Certification Fuel 

2030. liquefied Petroleum Gas or Natural Gas Retrofit Systems. 

(a) Applicable Standards and Test Procedures. 

The.standards and test procedures for approval of systems designed to 

convert 1993 and earlier model year motor vehicles to use liquefied 

petroleum gas or natural gas fuels are contained in "California Exhaust 

Emission Standards and Test Procedures for Systems Designed to Convert 

Motor Vehicles Certified for 1993 and Earlier Model Years to Use Liquefied 

Petroleum Gas or Natural Gas Fuels" adopted by the State Board on April 16, 

1975, as amended March 11, 1993. The standards and test procedures for 

approvai of systems designed to convert 1994 and subsequ~nt model year 

motor vehicl~s to use liquefied petroleum gas or natural gas fuels are 

contained in "California Certification and Installation Procedures for 

Alternative Fuel Retrofit Sysfems for Motor Vehicles Cert~fied for 1994 and 

Subsequent Model Years," adopted by the State Board March 11, 1993, ll_ 

amended At the option of the retrofit system manufacturer, 

the standards and test procedures for approval of systems designed to 

convert 1994 and subsequent model year vehicles to use liquefied petroleum 

gas or natural gas fuels may be used for approval of systems designed to 

convert 1993 and earlier model year motor vehicles to use liquefied 

petroleum gas or natural gas fuels in lieu of the "California Exhaust 

Emission Standards and Test Procedures for Systems Designed to Convert 

Motor Vehicles Certified for 1993 and Earlier Model Years to Use liquefied 

Petroleum Gas or Natural Gas Fuels." 

{b) Implementation Phase-In Schedule. 

Notwithstanding subsection (a), a retrofit system manufacturer may 

apply "California Exhaust Emission Standards and Test Procedures for 

Systems Designed to Convert Motor Vehicles Certified for 1993 and Earlier 

Model Years to Use Liquefied Petroleum Gas or Natural Gas Fuels" to certify 

retrofit systems for 199~ and 1995 model-year vehicles in accordance with 

the follcwing implementation phase-in schedule. Each manufacturer may 

certify a maximum of 85 percent of its total 1994 model-year engine family 

retrofit systems and 45 percent of its total 1995 model-year systems 

according to the requirements of these test procedures and "California 

Exhaust Emission Standards and Test Procedures for Systems Designed to 

Convert Motor Vehicles Certified for 1993 and Earlier Model Years to Use 

A 1 coho 1 or A 1 coho 1 /Gaso 1 i ne Fue 1 s", adopted by the State Bo·ard on Apr i 1 28, 

1983, as amended March 11, 1993. The remaining percentage of each manufactu~er's certified 1994 and 1995 model-year engine family retrofit 

systems and all of 1996 and subsequent model-year engine family retrofit 

systems s~all be certified according to."California Certification and 

Installatlon Procedures for Alternative Fuel Retrofit Systems For Motor 
Vehicles Certified For 1994 and Subsequent Model Years." The percentages 

shall be determined from the total number~: retrofit systems certified and 

shall be met prior to the end of the applicable calendar year. "California 

Exhaust Emission Standards and Test Procedures for Systems Designed to 

Convert Motor Vehicles Certified for 1993 and Earlier Model Years to Use 

Liquefied Petroleum Gas or Natural Gas Fuels" shall not Qe applied to 

certify a a retrofit system for installation on a transitional low-emission 

vehicle ("TLEV"), low-emission vehicle ("LEV"), or ultra-low-emission 

vehicle ("ULEV") or to certify a retrofit system designed to convert a 

vehicle to TLEV, LEV, 6r ULEV emission standards (a& defined in Section 

1960.1, Title 13, California.Code of Regulations). 

NOTE: Authority cited: Sections 39515, 39600, 39601 and 43006, Health and 

Safety Code; Sections 27156 and 38395, Vehicle Code. Reference: Sections 

43000, 43004, 43006, 43008.6, 43013 and 43018~ Health and Safety Code; 

Sections 27156, 38391 and 38395, Vehicle Code. 

• 

2031. Alcohol or-Alcohol/Gasoline Fuels Retrofit Systems. 

(a) Appli~able Standards and Test Procedu~es. 

The standards and test procedures for approval of systems designed to 

convert 1993 and earlier model year motor vehicles to use alcohol or 

alcohol/gasoline fuels in lieu of the original certification fuel system 

are contained in "California Exhaust Emission Standards and Test Procedures 

for Systems Designed to Convert Motor Vehicles Certified for 1993 and 

Earlier Model Years to.Use Alcohol or Alcohol/Gasoline Fuels," adopt~d by 

the State Board April 28, 1983, as amended March 11, 1993. The standards 

and test procedures for approval of systems designed to convert 1994 and 

subsequent model year motor vehicles to use alcohol or alcohol/gasoline 

fuels are contained in "California Certification and Installation 

Procedures for Alternative Fuel Retrofit Systems for Motor Vehicles 

Certified for 1994 and Subsequent Model Years," adopted by the _State Board 

March 11, 1993, as amended At the option of the retrofit 

system manufacturer, the standards and test procedures for approval of 

systems designed to convert 1994 and subsequent model year motor vehicles 

to use alcohol or alcohol/gasoline fuels may be used for approval of 

systems ~esigned to convert 1993 and earlier model year motor vehicles to 

use alcohol or alcohol/gasoline fuels in lieu of the "California Exhaust 

Emission Standards and Test Procedures for Systems Designed to Convert 

Motor.Yehicles Certified for 1993 and Earlier Model Years to Use Alcohol or 

Alcohol/Gasoline Fuels." 
{b) Implementation Phase-In Schedule. 

Not~ithstanding subsection (a), a retrofft system manufacturer may 

apply "California Exhaust Emission Standards and Test Procedures for 

Systems Designed to Convert Motor Vehicles Certified for 1993 and Earlier 

Model Years to Use Alcohol or Alcohol/Gasoline Fuels" to certify retrofit 

systems for 1994 and 1995 model-year vehicles in accordance ~ith the follo~ing implementation phase-in schedule. Each manufacturer may certify 

a maximum of 85 percent of its total 1994 model-year engine family retrofit 

systems and 45 percent of its total 1995 model-year systems according to 

the requirements of these test procedures and the "California Exhaust 

Emission Standards and Test Procedures for Systems Designed to Convert 

Motor Vehicles Certified for 1993 and Earlier Model Years to Use Liquefied 

Petroleum Gas or Natural Gas Fuels," adopted by the State Board on April 

16, 19i5, as amended March 11, 1993. The remaining percentage of each 

manufacturer's certified 1994 and 1995 model-year engine family retrofit 

systems and all of 1996 and subsequent model-year engine family retrofit 

systems shall be certified according to "California Certification and 

Installation Pracedures for Alternative Fuel Retrofit Systems For Motor 

Vehicles Certified For 1994 and Subsequent Model Years." ' The percentages 

shall be determined from the total number of retrofit systems certified and 

shall be met prior to the end of'the applicable calendar year. "California 

Exhaust Emission Standards and Test Procedures for Systems Designed to 

Convert Motor Vehicles Certified for 1993 and Earlier Model Years to Use 

Alcohol or Alcohol/Gasoline Fuels" 'shall not be applied to certify .a 

retrofit system for installation on a transitional lo~-emission vehicle 

("TLEV•), lo~-emission vehicle ("LEV"), or ultra-lo~-emission vehicle 

("ULEV") or to certify a retrofit system designed to convert a vehicle to 

TLEV, LEV, or ULEV emission standards (as defined in Section 1960.1, Title 

13, California .code of Regulati~ns). 

' 

NOTE: Authority cited: Sections 39515, 39600, 39601 and 43006, Health and 

Safety Code; Sections 27156 and 38395, Vehicle Code. Reference: Sections 

43000, 43004, 43006, 43008.6, 43013 and 43018, Health and Safety Code; 

Sections 27156, 38391 and 38395, Vehicle Code. 

. ' 

State of California 

AIR RESOURCES BOARD 

• CALIFORNIA CERTIFICATION AND INSTALLATION PROCEDURES 

FOR ALTERNATIVE FUEL RETROFIT SYSTEMS 

FOR MOTOR VEHICLES CERTIFIED FOR 1994 

AND SUBSEQUENT MODEL YEARS 

Note: Proposed changes to the text adopted are indicated by strike-. 

out (deletion) and underline (addition). 

Adopted: March 11, 1993 

Amended: 

1. 

2. 

3. 

TABLE OF CONTENTS 

APPLICABILITY 

DEFINITIONS . 

GENERAL REQUIREMENTS 

(a) Product Specifications 

(b) Emission Control Labels 

(c) Owner's Manuals 

... 

(d) Manufacturer Recordkeeping Requirement 

(e) Installer Recordkeeping Requirement 

4. REQUEST FOR CERTIFICATION 

5. TEST PROCEDURES . 

(a) Description of Vehicle Categories 

· (b) Test Procedures for Vehicles in Category I 

(c) Test Procedures for Vehicles in Category II 

(d) Test Procedures for Vehicles in Category III 

6. APPROVAL . . . . 

(a) Issuance of Executive Orders 

(b) Carry-Over and Carry-Across 

7. INSTALLATION REQUIREMENTS .... 

Page 

1 

2 

2 

2 

3 

4 

4 

5 

5 

6 

6 

6 

8 

9 

11 

11 

11 

11 

8. IN-USE ENFORCEMENT TEST REQUIREMENTS ............. 12 

9. ~ARRANTY REQUIREMENTS . . . . . . 14 

(a) Requirements of Manufacturers 

(b) Extended Warranty Requirements. 

(c) Requirements of Installers •.. 

- i14 

14 

15 

California Certification and Installation Procedures for 

Alternative Fuel Retrofit .Systems for Motor Vehicles Certified for 

1994 and Subsequent Model Years 

1. · APPLI CAB I LI.TY 

(~} "Certification and Installation Procedures for Alternative Fuel 

Retrofit Systems for Motor Vehicles Certified for 1994 and 

Subsequent Model Years" ("these Procedures") apply to alternative 

fuel retrofit systems designed for installation on gasoline- or 

diesel-fueled light-, medium-, and heavy-duty motor vehicles for 

1994 and subsequent model years. Only these Procedures shall be 

used to certify a retrofit system for installation on a . 

transitional low-emission vehicle ("TLEV"), low-emission vehicle 

("LEV"}, or ultra-low-emission vehicle ("ULEV") or to certify a 

retrofit system designed to convert a vehicle•to TLEV, LEV, or ULEV 

emission standards {as defined in Section 1960.1, Title 13, CCR). 

Each manufacturer shall certify a minimum of 15 percent of 1994, 55 

percent of 1995, and 100 percent of 1996 and subsequent model year engine family retrofit systems according to the requirements of 

these Procedures. "California Exhaust Emission Standards and Test 

Procedures for Systems Designed to Convert Motor Vehicles Certified 

for 1993 and Earlier Model Years to Use Liquefied Petroleum Gas or 

Nitural Gas Fuels," (for certifying liquefied petroleum gas or 

natural g~s retrofit systems) and "California Exhaust Emission 

Standards and Test Procedures for Systems Designed to Convert Motor 

Vehicles Certified for 1993 and Earlier Model Years to Use Alcohol 

or Alcohol/Gasoline Fuels" (for certifying alcohol and 

a 1 cohol/gasol i ne retrofit systems) sha 11 be used to certify the 

remaining percentage of 1994 and 1995 model year engine family 

systems and 1993 and prior model year engine family systems, except 

as provided in paragraph 1.(b). 

(b} A retrofit system manufacturer may as an option use these 

Procedures to ·certify alternative fuel retrofit systems des1gned for installation on pre-1994 model year gasoline- or diesel-fueled 

light-, medium-, and heavy-duty motor vehicles, with the following addition: the Executive Officer may order 25,000 mile du~ability 

vehicle testing for alternative fuel retrofit systems designed for 

installation on pre-1994 model year vehicles which include hardware 

or components other than the fue 1 conversion· system as part of the 

overall retrofit system. 

(c) A certification issued pursuant to these Procedures shall have the 

effect of a certification of an alternative fuel retrofit system 

pursuant to Health and Safety Code Section 43006; and shall also 

have the effect of an exemption issued pursuant to Vehicle Code 

Sections 27156 and 38395. 

2. DEFINITIONS 

-1-
"Alternative fuel" refers t~ liquefied petroleum gas, natural gas, alcohol and alcohol/gasoline fuels. 

1 \ 

An "alternative fuel retrofit system" or "retrofit system" is a package of fuel, ignition, emission control, and engine components that are 

modified, removed, or added during the process of modifying a motor 

vehicle to operate on an alternative fue~. 

"Driveability" of a vehicle refers to the smooth delivery of power, as 

demanded by the driver. Typical causes of driveability degradation are 

rough idling, misfiring, surging, hesitation, or insufficient power. Conversion from gasoline to gaseous fuels usually entails a loss of 

volumetric efficiency, resulting in some power loss. Normal power loss 

shall not be considered to be driveability degradation. 

"Installer" refers to a person who installs alternative fuel retrofit 

systems on motor vehicles. 

"Retrofit system manufacturer" or "manufacturer" 'refers to a person who 

manufactures or assembles an alternative fuel retrofit system for sale 

in California and requests or is granted the Executive Order certifying the alternative fuel retrofit system. 

For purposes of these Procedures "useful life" is the duration, 

expressed in miles, of the longest durability period for the new 

vehicle or engi~e-emission standards to which the vehicle or engine was 

·certified. {This is typically 50,000 miles for light-duty vehicles. 

However, as of the 1993 ~odel year, a pha~e-in of new, more stringent, light-duty standards with 100,000 mile useful life requirements will 

begin.} 

3. GENERAL REQUIREMENTS 

(a) Product Specifications: 

In addition to all other standards or requirements imposed, the 

following general requirements shall apply to all alternative fuel 

retrofit systems to be certified for installation on Californiacertified gasoline or diesel-fueled motor vehicles: 

(i} Alternative fuel retrofit systems for gaseous fuels shall be 

equipped with a lockoff valve, actuated by an electrical or 

vacuum signal, preventing delivery of fuel to the carburetor, 

or fuel injection system, while the engine is shut down. 

(ii) The driveability of a vehicle equipped with a retrofit system shall not be degraded in such a way as to encourage consumer 

tampering. To verify that the driveability of a retrofitted 

vehicle is acceptable, the Executive Officer may require that 

an independent laboratory evaluate driveability. The Executive 

Officer's determination that driveability must be evaluated 

shall be based on an engineering evaluation of the retrofit 

system described in the applicatiqn for certification or on 

reports or observations that retrofit systems similar in design 

-2-
to the system for which certification is sought have caused 

driveabilty degradation. The cost of this evaluation shall be 

borne by the applicant. 

(iii) If the vehicle to be retrofitted was certified with an on-board 

diagnostic (080) system pursuant to Section 1968 or 1968.1, 

Title 13, Californi.a Code of Regulations (CCR), the proper function of the on-board diagnostic system sha 11 not ·be 

impaired as a result of the installation and operation of the 

alternative fuel retrofit system. This requirement may necessitate modification of the 080 system to prevent it from 

storing erroneous trouble codes (e.g., storing a code 

signifying faulty operation of the evaporative canister purge valve because the evaporative emission control system has been 

removed). All modifications to 080 components, programming or 

wiring, must be fully specified as parts of the retrofit 

system. If the retrofit system includes modifications to the 

080 system, the applicant must submit an analysis showing that 

these modifications will not adversely affect 080 performance. Notwithstanding, for 1998 and previous model year vehicles, 

retrofit system manufacturers may request Executive Officer 

approval to disable specific on-board diagnostic monitoring strategies for which monitorino may not be reliable with 

respect to the use of alternative fuels (e.g .. oxygen sen~or 

response rate checks). The manufacturer shall submit data 

and/or an engineering evaluation to justify the request. 

(iv) With the exception of idle speed control and throttle position control, no component or calibration of the fuel system that 

could affect emission performance shall be adjustable by the 

system installer or the vehicle's user. 

(b) Emission Control Labels: 

"California Motor Vehicle Emission Control Labe~ Specifications," incorporated by reference in Title 13, CCR, Section 1965, shall 

apply to installations of alternative fuel retrofit systems, with 

the following additions: 

( i ) 

( i i ) 

The retrofit system manufacturer shall provide a supplemental Emission Control Information label, which shall be affixed in a 

permanent manner to each retrofitted vehicle, in a location 

adjacent to the original Emission Control Information Label. 

If the supplemental label cannot be placed adjacent to the 

original label, it shall be placed in a location where it can 

be seen by a person viewing the original label. 

The supplemental label shall clearly state that the vehicle has 

been equipped with an alternative fuel retrofit system designed 

to allow it to operate on a fuel other than gasoline or diesel, 

and shall identify the fuel(s) which the vehicle is'designed to 

use. The label shall sh~w the vehicle model year; the Executive 

Order number certifying the retrofit system; the retrofit system 

manufacturer's name, address, and telephone number; and shall 

state that the retrofitted vehic1e complies with California · 

-3-
•• \ II' 

emission requirements. If the retrofit system has been 

certified as being capable of converting the vehicle into a 

TLEV, LEV, or ULEV, the label shall prominently display the 

title, "Transitional Low-Emission Vehicle," "Low-Emission 

Vehicle,·" or "Ultra-Low-Emission Vehicle," as appropriate. The 

label shall also list any original parts ·that were removed 

during installation of the retrofit system, as well as any changes in tune-up specifications required for the retrofit 

system. In addition, the label shall show the installer's name, 

address, and telephone number; the date on which the retrofit 

system was installed; and the mileage (retrofitted vehicle 

odometer reading) and date at which the retrofit system warranty ~xpires. It is not necessary fQr emission control labels 

installed with retrofit systems to be machine readable. 

(iii) The retrofit system manufacturer shall provide routing diagram for each retrofit system sold. 

routing diagram shall be placed underhood .in a 

at a visible and accessible location and shall 

modifications to the original vacuum system. 

(c) Owner's Manuals: 

a vacuum hose 

The vacuum hose 

permanent manner 

show 

Each retrofit system installed shall include an owner's manual 

containing at least the following information: 

(i) a brief description of the retrofit system, including major 

components and their theory of ope~ation; 

(ii) the correct refueling procedure; I . . 

(iii) ·a··listing of necessary service and service intervals, as well as 

tune-up data, which differ from the service requirements specified by the vehicle's or engine's original manufacturer; 

(iv) the name, address, and phone number of the installer, as well as 

a list of the names, addresses, and phone numbers of the major dealers in California who supply parts for, or service, the 

retrofit system; and 

(v) warranty information. 

(d) Manufacturer Recordkeeping Requirement: 

Manufacturers of retrofit systems shall maintain a record of the 

vehicle identification numbers and California license plate numbers 

of those vehicles on which their product has been installed. As 

part of this record,. manufacturers shall identify the installation 

date and the certification number of those systems installed on 

each vehicle and shall identify the vehicles' owners at the time o.f 

installation, including the•owners' current addresses and phone numbers at the time of installation. The retrofit system manufacturer shall supply a copy of all installation information to 

the Executive Officer upon request. 

-4-
.. 

I '' 

(e) Installer Recordkeeping Requirement: 

Installers of retrofit systems shall maintain a record as specified in paragraph 3(d) and shall provide this information to retrofit 

system manufacturers upon request. 

4. REQUEST FOR CERTIFICATION 

(a) A request for certification of an alternative fuel retrofit system 

may be submitted by an authorized representative of the retrofit ~ystem manufacturer intending to offer the retrofit system for sale 

or installation in the State of California. 

(b) A separate request shall be required for each model year, even 

though the emission standards for certifying new vehicles may be 

the same for consecutive model years. The request shall include 

all test data and other information required pursuant to these 

Procedures, except where other provisions of these Procedures allow 

carry-over or carry-across of test data from an engine family to 

the engine family(ies) 'for which certification is sought. Procedures governing carry-over and carry-across are discussed 

under paragraph 6, "Approval." 

(c) The request for certification shall be submitted in writing, signed ·by an authorized representative of the retrofit system manufacturer, and shall include the following: 

(i) Identification and description of the engine families for which 

the retrofit system to be certified is designed; the emission 

standards applicable to those engine families; and if 

applicable, a statement that the retrofit system is designed [A] to convert conventional vehicles into either TLEVs, LEVs or 

ULEVs, [8] to convert a TLEV into either an LEV or ULEV, or [C] 

to convert an LEV into a ULEV. 

(ii).A complete description of the alternative fuel retrofit system, including details of the carburetor, mixer, regulator, vaporizer, or fuel injection system; the feedback mixture 

control system (if applicable), part number(s), calibration 

data, hose routing, specifications for the fuel tank, and 

pressure regulator; a sample of the emission control label as 

specified in 3.(b); a sample of the warranty statement as 

specifiecl in 9(a) and (b); and all necessary modifications to 

the engine, emission control system, or other parts of the 

vehicle. 

(iii) Procedures for installing and maintaining the retrofit system, including tune-up specifications and discussion of any special tools or techniques required for proper installation, 

maintenance, or operation. 

-5-
( i v) 

' . 

t ~ I • 

An agreement to supply the Air Resources Board, within 45 

calendar days of the Executive Officer's request, with any one 

or more of the vehiclei used for certification testing, or to 

provide Air Resources Board personnel with the equipment to 

inspect and test such vehicles at the applicant's facility, if 

requested by the Executive Officer. 

5. TEST PROCEDURES 

(a) Description ~f Vehicle C~tegories: 

For the purposes of these certification Procedures, the motor 

vehicle fleet is divided into three major categories: 

I. Passenger cars, light-duty trucks, and medium-duty vehicles as 

defihed in "California Exhaust Emission Standards and Test 

Procedures for 1988 and S~bsequent Model Passenger Cars, Light- Duty Trucks, and Medium-Duty Vehicles" (~s incorporated by reference. in Section 1960.1, T.itle 13, CCR), which were 

certified to an exhaust emission standard based on a chassisdynamometer test procedure; 

II. Vehicles with gross vehicle weight ratings less than or equal 

to 14,000 lbs and not originally certified to a chassis 

dynamometer-based exhaust emission standard; and 

III. Vehicles with gross vehicle weight ratings greater than 14,000 

lbs. 

(b) Test Procedures: for Veh i c 1 es in Category I: 

For vehicles in Category I, the emission standards and test 

procedures set forth in the "California Exhaust Emission Standards 

and Test Procedures for 1988 and Subsequent Model Passenger Cars, 

Light-Duty Trucks, and Medium-Duty Vehicles" also apply to the 

certification of alternative fuel retrofit systems, with the 

following exceptions: 

(i) The applicable emission standards shall be at least as 

stringent as the emission standards applicable to the engine families for which the retrofit systems to be certified are 

designed. In addition, vehicles retrofitted to operate on a 

give.n alternative fu"el shall also be subject to any additional 

emission standards applicable to new motor vehicles that are 

designed to operate on the alternative fuel, and that. are of 

the model year and vehicle class for which certification is 

sought. A maximum of one emission-dat~ vehicle per engine family for which certification is sought shall be required. Where durability testing is required, a bench-test vehicle 

may be substituted for,a durability vehicle and may also be 

considered an emission-data vehicle. Prior to the commencement 

of testing, the choice of durability vehicle or bench-test 

vehicle, emission-data vehicle(s) and engine(s) must be 

-6-
. ' 

I I 

-

approved by the Executive Officer as being representative of 

the range of engine families for which certification is sought. 

(ii) For the purpose of applying the provisions of the "California 

Exhaust Emission Standards and Test Procedures for 1988 and 

Subsequent Model Passenger Cars, Light-Duty Trucks, and MediumDuty Vehicles" to certification testing of alternative fuel 

retrofit systems, test vehicles equipped with an alternative 

fuel retrofit system shall be assumed to have zero miles of 

mileage accumulation at the time that the retrofit system is 

installed. Mileage may be subsequently accumulated by driving the vehicle on the road, following a typical suburban route, or 

on a chassis dynamometer using the Automobile Manufacturer's 

Association mileage accumulation cycle (40 C.F.R., Part 86, 

Appendix IV, as adopted January 28, 1977). 

(iii) Vehicle mileage accumulation on a durability vehicle or bench 

aging of retrofit system components shall be conducted to 

determine deterioration factors. Prior to the commencement of 

any emission or bench aging, the applicant's test plan must be 

approved by the Executive Officer. Approval of the test plan shall be contingent upon a demonstration by th€ applicant that 

bench aging produces· deterioration factors at 1 east as great as 

durability vehicle testing. 

(iv) Bench aging conducted in lieu of vehicle mileage accumulation 

shall be conducted for a period of time such that the resulting deterioration bf the retrofit system i~ equivalent to that 

which would occur during durability vehicle mileage accumulation over a mileage equal to the useful life of the 

vehicle. : ! 

(v) Vehicle mileage accumulation on a durability vehicle shall be 

performed in conjunction with emission testing. Before 

beginning vehicle mileage accumulation of the retrofit system, the system shall be installed on the durability vehicle, the 

vehicle shall be driven 4,000 + 100 miles and the vehicle shall 

be tested using the alternative fuel. A dual-fuel retrofit 

system shall be emission tested using each fuel that it is 

capable of operating on. At the conclusion of vehicle mileage accumulation, a second emission test or series of tests shall 

be performed. 

Alternatively, if bench aging is used to determine 

deteri oration factors, then bench aging shall b.e performed in 

conjunction with emission testing of a bench-test vehicle. 

Before beginning bench aging of the retrofit system, it shall 

be installed on the bench-test vehicle, the vehicle shall be 

driven for 4,000 + 100 miles, and the vehicle· shall then be 

emission tested using the alternative fuel. A dual-fuel 

retrofit system shall be emission tested using each fuel that 

it is capable of operating on. After the emission tests are 

completed, the retrofit system shall be removed from the 

vehicle and subjected to bench aging. At the conclusion of 

bench aging, the retrofit syste~ shall be reinstalled on the 

-7-
' . I ' 

0 I I 

(vi) 

·(vii ) 

(v.iii) 

bench-test vehicle, and a second emission test or series of 

tests shall be performed. 

For exhaust emissions of each regulated pollutant measured 

during the ~ehicle mileage accumulati~n or bench-test 

procedure, a deterioration factor shall be calculated by dividing the emission rate obtained during the second emission 

test by that obtained during the first. Jf the resulting quotient ts less than one, the deterioration factor shall be 

assigned ' value ~f one. The deterioration constant for 

·evaporative emissions shall be calculated by subtracting the 

evaporative emissions found during the first emission test from 

those found during the second test. If the resulting difference is less than zero, the deterioration constant shall 

be assigned a value of zero. 

Choices of vehicle models, engines, and transmissions for use 

in emission-data vehicles shall be approved by the Executive 

Officer as being representative of the engine families for 

which certification is sought, prior to the commencement of 

testing. Following installation of the retrofit system, the 

emission-data vehicle shall be driven 4,000 + 100 miles to 

stabilize emission rates. After the specified mileage has been 

accumulated, the emission-data vehicles' exhaust and· 

evaporative emissions, where applicable, shall be tested, ~sing 

the appropriate procedure as set forth in "California Exhaust 

Emission Standards and Test Procedures for 1988 and Subsequent Model Passenger Cars, light-Duty Trucks, and Medium-Duty Vehicles." Dual f~el vehicles shall b~ emission tested using· each fuel that the vehicle is capable of operating on. 

I 

The deteriorated emissions of emission-data vehicles shall be 

calculated using the deterioration factors and constants found 

during vehicle mileage accumulation or bench testing. The 

useful life exhaust emission values are defined as the product of each emission value at 4,000 miles times the corresponding deterioration factor. For evaporative emissions, the 

certification emission value is equal to the sum of the 

emissions measured at, or extrapolated to 4,000 miles, plus the 

deterioration constant. The durability vehicle, bench-test 

vehicle, and all emission-data vehicles shall meet the 

applicable new vehicle useful life emission standards, as well 

as all applicable emission standards for intermediate mileage levels, for the vehicles' model year and fuel type(s). 

{c) Test Pro~edures for Vehicles in Category II: 

For durability, bench-test and emission-data vehicles in Category II, test vehicles shall have accumulated a total mileage greater than 4,000 miles and less than 10,000 miles with the O(iginal fuel 

system, prior to emission tEsting. If the manufacturer chooses to 

use the option as described in l(b) for pre-1994 model year vehicles, then the 10,000 mile limit shall not be applicable. A 

test vehicle's engine and emission control system shall be equipped and calibrated as certified. The vehicle shall then be tested for 

-8-

. 
' ' . . . I I -

exhaust and, if applicable, evaporative emissions using the test 

procedures set forth in the "California Exhaust Emission Standards 

and Test Proced~res for 1988 and Subsequent Model Passenger Cars, 

Light-Duty Trucks, and Medium-Duty Vehicles". The inertia weight setting shall be eq~al to the average of the vehicle's curb weight and _gross vehicle weight rating and road load horsepower based on 

the frontal area of the vehicle without modifications, as 

determined in "California Exhaust Emission Standards and Test 

Procedures for 1988 and Subsequent Model Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles," Section 9.b. The test results 

shall be defined as the baseline emission rates. After the 

baseline emission rates have been measured, the retrofit system shall be installed. 

(i) The procedure outlined in paragraphs S(b)(iii) through S(b)(vi) shall be used with the following modifications: ''useful life" 

shall equal 120,000 miles for vehicles in Category II; the 

durability or bench-test vehicle's emission rates of regulated pollutants measured at 4,000 ! 100 miles pfter the installation 

of the retrofit system shall not exceed 1.10 times the baseline 

rates; the deteriorated exhaust emissions of regulated pollutant~ projected to 120,000 miles shall not exceed 1.3 

times the baseline emissions; and the deteriorated evaporative emissions of regulated pollutants projected to 120,000 miles 

shall not exceed the baseline emissions plus 0.5 grams. 

(ii) When the Executive Officer determines that deterioration 

factors determined in paragraph S(c)(i) may be carried across 

or carried over to other engine families in Category II, the 

representative emission-data vehicles shall be tested as 

specified in paragraph S(b)(vii). Emission rates measured at 

4,000 + 100 miles after installation of the retrofit system shall not exceed 1.10 times the vehicles' baseline rates. 

(d) Test Procedures for Vehicles in Category III: 

Applicants requesting certification for retrofit systems for use in 

Category III vehicles shall submit a test plan utilizing eight mode 

chassis dynamometer testing to verify that the retrofit system will 

not cause excess emissions from engine families for which 

certification is sought. Test vehicles shall have accumulated a 

total mileage greater than 4,000 miles and less than 10,000 miles 

with the original fuel system·prior to emission testing. If the 

manufacturer chooses to use the option as described in l(b) for 

pre-1994 model year vehicles, then the 10,000 mile limit shall not 

be applicable. A test vehicle's engine and emission control system shall be equipped and calibrated as certified. The vehicle shall 

then be tested for exhaust emissions using the eight mode chassis 

dynamometer.test specified in the test plan. The test result shall 

be defined as the baseline emission rate. After the baseline 

emission rate has been measured, the retrofit system shall be 

installed. Emission rates ~hall then be measured at 4,000 ± 100 

miles after installation of the retrofit system using the eight mode chassis dynamometer test specified in the test plan. 

-9-
(i) 

( i i) 

(iii) 

( i v) 

\. I I 9 

' . 

• 1 e o 

Subject to the Executive Officer's approval of the applicant's 

test plarr prior to ~ommencing testing, testing utilizing procedures other than the eight mode chassis dynamometer test 

shall be allowed. 

Emission testing shall be conducted to determine exhaust 

emission rates of carbon monoxide and the sum of non-methane 

hydrocarbons plus nitrogen oxides. Emissions shall not exceed 

1.10 times the baseline rates. 

The p~ocedures outlined in paragraphs S(b)(iii) through S(b)(vi) shall be used with the following modifications: 

"useful life" shall equal 180,000 miles for vehicles in 

Category III; the durability or bench-test vehicle's emission 

rates of CO, and the sum of non-methane hydrocarbons plus NOx 

measured at 4,000 + 100 miles shall not exceed 1.10 times the 

baseline rates; the deteriorated exhaust emissions projected to 

180,000 miles shall not exceed 1.3 times the baseline 

emissions; and, the deteriorated evaporative emissions 

projected to 180,000 miles shall not exceed baseline emissions 

plus 0.5 grams. For the purposes of this section, the 

evaporative baseline emissions shall be estimated by the 

manufacturer based on good engineering principles and judgment. The manufacturer's test plan shall specify the evaporative baseline emissions estimate and describe ~ow this estimate was 

derived. 

The Executive Officer may allow carry~across of durability data 

from certification bench testing of retrofit systems designed ·for vehicles i_n Categor·ies I or II to Category III retrofit 

system applications, if ·the'Executive Officer determines that 

the carry-across durability data will adequately represent the 

durability performance of the retrofit system to be certified. 

(v) Applicants requesting certification for retrofit systems designed to allow Category III vehicles to operate on an 

alternative fuel in addition to diesel fuel shall conduct smoke 

opacity testing on the emission-data vehicle(s) utilizing the 

peak smoke opacity standards and procedures set forth in 

"Heavy-Duty Diesel Vehicle Smoke Opacity Test Procedure," as 

incorporated by reference in Title 13, CCR, Section 2182. 

Smoke opacity testing shall be conduc.ted using each fuel that 

the retrofitted vehicle is designed to operate on. The 

applicable peak smoke opacity standard shall be that·set for 

the model year for which certification is sought. 

(vi) The selection of duty cycle(s) and all other aspects of the 

test procedure shall be subject to approval by the Executive 

Officer, and emission testing shall commence only after the 

Executive Officer has approved the test plan. The Executive 

Order shall be issued following review of the test data and 

determination that they_ meet the criteria specified in the test 

plan .. 

-10-
,J 1 f 4 

, I 1 

6. APPROVAL 

(a) Issuance of Executive Orders: 

If, after reviewing the test data and other information submitted 

by the retrofit system manufacturer, the Executive Officer 

determines that the retrofit system meets the applicable emission 

standards or the criteria of an approved test plan, as applicable, 

an Executive Order shall be issued certifying the retrofit system for sale and installation on vehicles in the engine families 

specified in the applic9tion. The Executive Order shall specify, if applicable, that the retrofit system is certified as [A] converting a conventional motor· vehicle into a TLEV, LEV or ULEV, 

[B] converting a TLEV into a LEV or ULEV, or [C] converting a LEV 

into a ULEV. 

(b) Carry-Over and Carry-Across: 

Carry-over of emission test data from the previous model year to 

the following model year will be allowed, if'the Executive Officer 

determines that the carry-over data wi 11 adequately represent the 

emissions performance of the retrofit system to be certified. 

Carry-across to similar engin·e families will also be allowed. 

Applications for carry-over and carry-across must be accompanied by 

an engineering analysis demonstrating that the emissions and 

durability of the retrofit system and engine family for which 

certification is being sought will be. adequately represented by a 

certified retrofit system/engine family application. Applications for carry-over and carry-across will be evaluated according to the 

the criteria contained in EPA Advisory Circular 17F, which is 

incorporated herein by reference, and paragraph 4.b.4 of the 

"California Exhaust Emission Standards and Test Procedures for 1988 

and Subsequent Model Passenger Cars, light-Duty Trucks, and MediumDuty Vehicles." These include, but are not limited to, similarity of catalyst location and configuration, similarity of fuel metering 

system, similarity of emission control system logic and design, and 

similarity of any other features that may affect the durability of 

the retrofit system's emission performance. · 

7. INSTALLATION REQUIREMENTS 

(a) Prior to releasing a converted vehicle to the consumer, the· 

installer of an alternative fuel retrofit system shall submit the 

converted vehicle to a Bureau of Automotive Repair Referee Smog Check Station for inspection and testing. 

(i) The installer of an alternative fuel retrofit system shall keep 

a copy of the certifiGate of compliance, issued by the Bureau 

of Automotive Repair Referee Smog Check Station, as part of the 

record specified in paragraph 3(e). The certificate of 

compliance shall conta\n, but need not be limited to, the 

following: the vehicle's identification number, the vehicle's 

model year and make, the date of installation, and the 

emissions category to which the retrofitted system is certified 

-11-
\. ' t , 

l I • -. 

(i .. e., conventional vehicle, TLEV, LEV, or ULEV). The original certificate of compliance shall be submitted to the vehicle 

owner upon the vehicle's release. 

(ii) The installer of an alternative fuel retrofit system shall not 

release the converted .vehicle to the consumer without the 

issuance of a certificate .of compliance for the vehicle by a 

Bureau of Automotive Repair Referee Smog Check Station. 

(iii) The installer of an alternative fuel retrofit system shall also 

meet the requirements of paragraph 9(c). 

8. IN-USE ENFORCEMENT TEST REQUIREMENTS 

(a) Manufacturers of alternative fuel retrofit systems shall, upon order by the Executive Officer, perform in-use enforcement emission 

testing of their products. The Executive Officer may order in-use 

enforcement emission testing of not more thag 20 percent of a 

manufacturer's certified retrofit systems/engine family applications per year. If 20 percent constitutes less than one of 

a manufacturer's certified systems, the Executive Officer may order 

in-use enforcement emission testing of not more than one certified 

system/engine family application per year. Manufacturers shall be 

required to perform emission testing of not less than ten vehicles 

per certified retrofit system/engine family application selected by the Executive Officer for.in-use enforcement emission testing. Upon order by the Executive Officer, manufacturers shall perform the applicable emission test~·pursuant to the following: 

(i) No vehicle shall be accepted by the manufacturer as a 

representative vehicle for enforcement testing unless the 

following criteria are met: 

(1) California certified and registered. 

(2) Odometer indication of less than certified useful-life 

mileage and vehicle age within useful-life time period. 

(3) No indication of abus~ (e.g., racing, overloading, misfueling, or other misuse), neglect, improper maintenance or other factors that would have an effect 

on emission performance. · 

(4) No major repair to engine or major repair of vehicle 

resulting from collision. · 

(5) lead content of fuel sample from the vehicle tank meets 

applicable standards. · 

(6) No indication of any problem that might jeopardize the 

safety of laboratory personnel. 

(ii) The manufacturer shall, under ARB supervision, perform diagnosis or restorative maintenance on those vehicles selected 

-12-
.I I f .. 

rJ ~ r I I . 

( i i i ) 

( i v) 

(v) 

(vi) 

. for in-use enforcement testing. The manufacturer or a 

laboratory approved by the Executive Officer shall (1) identify 

part numbers of all essential emission control system 

components; (2) check air filter, all drive belts, all fluid 

levels, radiator cap, all vacuum hoses and electrical wiring related to emission control for integrity; check fuel metering and emission control system components for maladjustments and/or tampering, and record all discrepancies; (3) check 

ignition system w~th oscilloscope and replace any defective 

components; i.e., spark plugs, wires, etc.; (4) check 

compression; (5) check and adjust engine parameters to 

manufacturer's specifications; and (6) perform maintenance if 

the vehicle is within 500 miles of scheduled maintenance 

service. 

For vehicles in Category I, the manufacturer or a laboratory approved by the Executive Officer shall perform the applicable· emission test procedures set forth in the "California Exhaust 

Emission Standards and Test Procedures for 1988 and Subsequent Model Passenger Cars, light-Duty Trucks, and Medium-Duty Vehicles." The applicable emission standards shall be the 

vehicle's useful life standards as well as any intermediate 

emission standards, as stated in the Executive Order. 

For vehicles in Category II, in-use enforcement exhaust and, if 

applicable, evaporative emissions shall be performed using the 

test procedures set forth in the "California Exhaust Emission 

Standards and Test Procedures for 1988 and Subsequent Model 

Passenger Cars, light-Duty Trucks, and Medium-Duty Vehicles". 

The inertia weight setting shall be. equal to the average of 

the vehicle's curb weight and gross vehicle weight rating and 

road load horsepower based on the frontal area of the vehicle 

without modifications, as determined- in "California Exhaust 

Emission Standards and Test Procedures for 1988 and Subsequent Model Passenger Cars, light-Duty Trucks, and Medium-Duty Vehicles," Section 9.b. For vehicles in Category III, in-use 

enforcement exhaust emission tests shaJl be' performed in 

accordance with the test plan approved by the Executive Officer 

prior to certification testing of the engine family applications specified for in-use enforcement testing. 

The applicable exhaust emissipn standards for vehicles in 

Categories II and III shall be the baseline emission rates 

established during certification testing of the engine family applications specified for in-use enforcement testing ·times 

1.3. The applicable evaporative emission standards for 

vehicles in Categories II and III shall be the baseline 

emission rates established during certification testing of the 

engine family applications sp~cified for in-use enforcement 

testing plus 0.5 grams. 

Manufacturers shall comP.lete in-use enforcement testing within 

6 months of the issuancd of the in-use compliance testing drder 

and shall submit all test data to the Executive Officer within 

30 calendar days following completion of testing. 

-13-
,. ' ' . I 

'I ( I '"I 

(vii)" Following review of manufacturer in-use enforcement test data, 

the Executive Officer may conduct confirmatory in-use 

enforcement testing. 

(b) If the results of the in-use vehicle emission tests conducted· 

pursuant to paragraphs 8(a)(i) throug~ 8(a)(vii) indicate that the 

average emissions of the test vehicles for any pollutant exceed the 

applicable emission standards, the entire vehicle population so represent~d shall be deemed to exceed such standards. Upon. order 

by the Executive Officer, the manufacturer shall have 45 days to 

submit an influenced recall plan in accordance with Sections 2111 

through 2121, Title 13,. CCR. If no such recall plan is submitted, 

the Executive Officer may order corrective action including recall 

of the affected vehicles in accordance with Sections 2122 through 2135, Title 13, CCR. For the purpose of these Procedures, the term 

"manufacturer," as referenced in Sections 2111 throug~ 2135, Title 

13, CCR, ·sha 11 mean .. retrofit system manufacturer ... 

9. WARRANTY REQUIREMENTS 

(a) Requirements of Manufacturers: 

The manufacturer of an alternative fuel retrofit system shall 

warrant to the person having the vehicle retrofitted and to; each 

subsequent purchaser of the vehicle that the alternative fuel · retrofit system is designed and manufactured to conform with the 

applicable requirements of these Procedures and is free from 

defects fn materials and workmanship which cause the alternative 

fuel retrofit system to fail to conform with the applicable requirements of these Procedures or cause damage to any part on the 

retrofitted vehicle. This warranty shall be effective for three 

years or 50,000 miles, which~ver first occurs, of customer service, 

and shall cover the full repair or replacement costs including the 

costs of diagnosis, labor, and parts (including any part on the 

retrofitted vehicle that is damaged due to a defect in the 

alternative fuel retrofit system). 

(b) Extended Warranty Requirements: 

Each manufacturer of an alternative fuel retrofit system shall 

identify in its application for certification the warranted parts whose individual replacement cost, at the time of certification, 

exceeds the cost limit defined in paragraph 9(b)(i). Th~ 

replacement cost shall include the cost of the diagnosis, parts, and labor. The costs shall be those of the highest cost 

metropolitan area of California. Each manufacturer shall warrant 

to the person having the vehicle retrofitted.and to each subsequent purchaser pf the vehicle that those parts identified in its 

application for certification as exceeding the cost limit defined 

in paragraph 9(b)(i) are free from defects in materials and 

workmanship which cause th~ alternative fuel retrofit system to 

fail to conform with the requirements of these Procedures or cause 

damage to any part on the retrofitted vehicle, for seven years or 

70,000 miles, whichever first occurs. 

-14-
' f f , .. ' ' > ., . :. 

• • 

(i) The cost limit shall be calculated using the following equation: 

Cost limitn = $300 X (CPin_ 2

/121.9) 

where: 

Cost limit is the cost limit for the year in which the alternativ~ fuel retrofit system is to be certified. 

n is the year in which the alternative fuel retrofit system is 

to be certified. 

CPI is the annual average consumer price index for California 

published by the United States Bureau of Labor Statistics. 

(ii) The cost limit shall be revised annually by the Executive 

Officer. The highest cost metropolitan area in California 

shall be identified by the Executive Officer. 

(iii) Each manufacturer shall submit to the Executive Officer the 

documentation ·used to identify the warranted parts required in 

this subsection. The documentation shall include the estimated 

retail parts costs, labor rates in dollars per hour, and the 

labor hours necessary to replace the parts. 

(c) Requirements of Installers: 

Each installer of an alternative fuel retrofit system shall warrant 

to the person.having the vehicle retrofitted and to each subsequent purchaser of the vehicle that the alternative fuel retrofit system will not fail to conform with the applicable requirements of these 

Procedures due to incorrect installation, and that no part on the 

retrofitted vehicle will be damaged due to incorrect installation. 

Installers of alternative fuel retrofit systems shall install only those systems of a certified configuration and shall agree to 

indemnify the person having the vehicle retrofitted and to each 

subsequent purchaser of the vehicle for the cost of repair of any vehicle upon whi~h a noncertified configuration was installed. In 

addition, the installer shall agree to indemnify the person having the vehicle retrofitted and to each subsequent purchaser of the 

vehicle for any tampering fines that may be imposed as a result of 

improper installation of the alternative fuel retrofit system. The 

warranties and agreements to indemnify shall be effective for three 

years or 50,000 miles, whichever first occurs, of customer service, 

and shall cover the full repair or replacement costs including the 

costs of diagnosis, labor, and parts (including.any part on the 

retrofitted vehic~e that is damaged due to incorrect installation 

of the ~lternative fuel retrofit system). 

-15-
.• } : ~ . 

Before an inst•aller installs an alternative fuel retrofit system, he or she shall have submitted to the ARB a sample of the warranty 

statement to be provided by the installer in accordance with this 

paragraph. 

-16-