STUD 1786554 - Caterpillar

Truck Engines:
AllAuthorized Caterpillar dealers have expressed concern about their responsibilities in performing maintenance on engines that may have been modified by the owner from their original Environmental Protection Agency (EPA) certified configuration. Modifications to emission controls are considered "tampering" and are prohibited by law if they "render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with" EPA regulations. This prohibition, while originally applicable only to manufacturers and dealers, now applies to "any person."EPA guidance is available on its website (www.epa.gov) to help a dealer evaluate whether its activities run afoul of EPA tampering prohibitions. In general, EPA guidance suggests:
All persons are prohibited from making changes to the hardware or software of a vehicle or engine that would change its emissions characteristics from those of the prototype for which the manufacturer obtained emission certification.
Neither the use of non-original equipment aftermarket parts, nor adjustment of parts in keeping with the manufacturer's maintenance instructions during regular maintenance will be regarded as tampering as long as the dealer has a reasonable basis to know that this will not affect emission control performance.
Dealers and others who perform maintenance are forbidden from actively perpetuating tampering. Thus, they may not replace or repair parts that others have added or modified to render the vehicle/engine non-conforming. Apart from that restriction, they may work on a tampered-with vehicle/engine without other limitation.
A dealer is not required to report tampering to EPA. Nor is a dealer obliged to return an engine to certified configuration. But, a dealer must abstain from repairing or replacing the part of the engine that has been tampered with unless it is to return it to certified configuration.
Nothing in the "Clean Air Act" or "EPA's enforcement guidance" suggest that a dealer must make a record if a customer's refusal to allow the dealer to return an engine to a certified configuration. But a dealer who works on an engine that was tampered with faces a risk that he will be accused of tampering or perpetuating a tampered-with engine configuration. Therefore, it may be in the dealer's interest to make a record concerning work performed on engines that have been tampered with.