Washington Way: Battle Over Heavy Duty OBD Repair Info Continues - Engine Builder Magazine
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Washington Way: Battle Over Heavy Duty OBD Repair Info Continues


In early 2003, the California Air Resources Board (CARB) decided to extend to heavy-duty vehicles the on-board-diagnostics information access rules then applicable only to automobiles and light duty vehicles. These access rules specify the information which the vehicle manufacturers have to make accessible from within the OBD system on their vehicles and from outside the system so that independent service technicians can adequately repair and replace parts and systems monitored by the OBD system.

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Three aftermarket trade associations, the Heavy Vehicle Maintenance Group, the Engine Rebuilders Association and the Automotive Aftermarket Industry Association, recommended that CARB merely adopt the automotive information access rules with such limited changes as were necessary to address different conditions in the heavy duty aftermarket. The CARB staff accepted this recommendation and the original proposed rule merely added heavy-duty vehicles to the existing automotive rule.

As soon as the draft rule was published it ran into heated opposition from the heavy-duty engine and transmission manufacturers. Among their stated reasons for objecting to the rule were:

  1. It was unnecessary: heavy-duty technicians already had access to all the information they need.

  2. The law which authorized information access only applies to light duty vehicles. (An incorrect assertion.)

  3. The heavy-duty aftermarket is so different from the automotive aftermarket that an entirely different rule is necessary.

  4. There are many fewer heavy-duty service technicians, so the manufacturers should not have to bear the expense of providing access, especially by computer.


  • Access to the information will allow technicians to tamper with the emissions systems of the vehicles, thus increasing air pollution. (This argument is so old that it probably qualifies for social security and has been proven untrue on numerous occasions.)

    The CARB staff rejected all of these arguments and proposed a final rule which was adopted by the CARB board last January. However, over the past summer, after extensive lobbying by the manufacturers, some significant changes were made to the rule which weaken its application to heavy duty vehicles.

    In general the rule still requires that all “covered persons” (including service technicians and parts manufacturers and remanufacturers) be able to purchase, at a fair and reasonable price, the information needed to diagnose, service and repair “emissions-related motor vehicle parts” if that information is available to the manufacturer’s franchised dealerships or authorized service networks. This includes diagnostic, service and repair information and procedures, technical service bulletins, troubleshooting guides, wiring diagrams and training materials useful for self-study outside of a manufacturer’s training classroom.


    The manufacturers must also make available to covered persons a general description of each OBD system used on its vehicles. This description must include a general description of the operation of each monitor; a listing of typical OBD diagnostic trouble codes associated with each monitor; a description of the typical enabling condition for each monitor; a listing of each monitor’s sequence, execution frequency and typical duration; a listing of typical malfunction thresholds for each monitor; and identification and scaling information to understand data available through a generic scan tool.

    Some information can be withheld, including specific algorithms, software codes or calibrations beyond what is required to be made available through the generic scan tool (unless the information is available to the manufacturer’s dealers or authorized services network). Trade secret information may also be withheld but the manufacturer must disclose the nature of the information it alleges is a trade secret so that such a determination can be challenged by CARB or a covered person.


    All information must be available on the internet and the rule has specific requirements with which the Web site must comply to assure quick and easy access.

    However, the heavy-duty rule differs substantially from the automotive rule with respect to diagnostic and reprogramming tools. Generally the automotive rule requires that manufacturers make available to covered persons, at a fair and reasonable price, all emissions-related enhanced diagnostic and reprogramming tools available to their franchised dealers. In addition the manufacturers have to supply data stream and bi-directional control information used in those enhanced tools to generic tool manufacturers so that they can incorporate this enhanced information into their generic diagnostic tools. Similarly, reprogramming information has to be provided if it is available to dealers.


    The final version of the heavy-duty rule deletes all of these diagnostic and reprogramming requirements for heavy-duty vehicles. However, the CARB staff insists that this is only a temporary deletion. Under pressure from the manufacturers, the staff had agreed to delay implementation of full OBD requirements for heavy-duty vehicles. Therefore, they agreed to delete these diagnostic and reprogramming requirements until they adopt full OBD requirements for heavy-duty vehicles.
    This should happen in about a year and a half.

    However, we expect continuing strong opposition from the manufacturers on this issue. Moreover, while it is still likely that the rule will eventually require access to enhanced diagnostic and reprogramming tools and information, it is also likely that it will require some training before those enhanced tools (or generic tools using the enhanced information) can be purchased. We have argued that most, if not all, of such training is unnecessary and, if required, should not be used as a means to limit who can get access to these items. The manufacturers, however, have currently convinced the CARB staff that because of the greater complexity of heavy-duty systems and the way systems of different manufacturers are combined in most heavy-duty vehicles, independent service technicians could easily misprogram the vehicles without proper training.


    EPA is working on its own rule, which should be at least as favorable to us as the CARB rule. Unlike the current CARB rule, it is likely to contain the requirement for access to enhanced diagnostic and reprogramming tools and information.

    On September 22, 2004 the Subcommittee on Commerce, Trade and Consumer Protection of the U.S. House of Representatives held a hearing on the Motor Vehicle Owners Right To Repair Act (HR 2735). If passed, this Act would require that vehicle manufacturers disclose to vehicle owners and repair facilities the information necessary to integrate replacement equipment into the vehicle and other information of any kind used to diagnose, service, repair, activate, certify or install any motor vehicle equipment.


    Speaking in support of the bill were representatives of the Automotive Aftermarket Industry Association and the American Automobile Association. The Motor & Equipment Manufacturers Association and the Tire Industry Association also submitted statements of support. Opposing the bill at the hearing were the Alliance of Automobile Manufacturers, the Association of International Automobile Manufacturers and the Automotive Service Association (ASA).

    The major argument of those opposing the bill is that it is unnecessary because of a 2002 agreement between the car manufacturers and ASA to provide to independent repair shops the same information that the manufacturers give their franchised dealers. As a result of such agreement, they say, all necessary information is now available on the manufacturers’ Web sites.


    Speakers supporting the bill noted, however, that while significant information is available it is often difficult or impossible to find and that access to it is too expensive. Moreover, because the agreement between ASA and the manufacturers contains no enforcement mechanism, there is nothing to ensure that the manufacturers are or will continue to supply all the required information.

    No immediate action on the bill was taken because the hearing occurred shortly before the House of Representatives adjourned for the federal elections. However, at least one Congressional leader said that Congress would act unless motor vehicle owners were assured of full access to the information they needed for their vehicles. Full consideration of this bill should occur in the next session of Congress.


    Mike Conlon is legal counsel for the Engine Rebuilders Association (AERA) and the Automotive Parts Rebuilders Association (APRA). He is an attorney with the Washington, DC, firm of Conlon, Frantz, Phelan, Knapp & Piers.
    [email protected]

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