The U.S. Environmental Protection Agency (EPA) recently progressed its effort to stymie the aftermarket tuning of vehicles used for racing and competition in a complaint alleging that Gear Box Z violated the Clean Air Act by selling certain types of aftermarket software that modifies the engine control module (ECM), among other practices. EPA’s action is part of its national mobile source enforcement initiative to prevent the manufacturing, sale, and installation of aftermarket tuning and emission control defeat devices, in which EPA has pursued enforcement against both large and small suppliers.

On March 18, 2021, the U.S. District Court of Arizona in United States v. Gear Box Z, Inc. granted EPA’s request for a preliminary injunction against Gear Box Z’s sale of aftermarket tuning software for diesel trucks. Gear Box Z is a high-tech manufacturer specializing in “off-road competition” tuning for various makes and models of diesel trucks. EPA asserts that the Clean Air Act prohibits “road-to-track” conversions (that is, modifications of vehicles certified for road use for the purpose of off-road competition or racing). In February 2021, the Specialty Equipment Market Association (SEMA) filed an amicus brief in support of Gear Box Z, arguing that whether modifications are lawful should depend on whether the vehicle ultimately modified is driven on the road or used exclusively in competition.

In disagreeing with SEMA’s position, EPA asserted that “[t]he [Clean Air Act] is clear that a certified motor vehicle remains a motor vehicle throughout its life even if it is modified for some other use such as competition motorsports or is not used on public roads.” United States v. Gear Box Z, No. 3:20-cv-08003 (D. Ariz.). In other words, according to EPA, motor vehicles originally designed and certified by the manufacturer for use on a street or highway can never be modified (including ECM tuning or the installation of emission defeat devices) for use solely in competition. The District Court, in granting the preliminary injunction, determined that Gear Box Z had failed to present any evidence that its tuning software was being used in competition vehicles and therefore, any interpretation of the EPA’s competition exception would be hypothetical at this point in the litigation.

EPA’s position in Gear Box Z evidences EPA’s continuing skepticism of industry claims that certain ECM tunes are lawful because they are purportedly performed on road-certified vehicles intended for competition. Perhaps more importantly, EPA’s interpretation signals that in the future it may consider any modification of a stock ECM on a vehicle engine certified for road use to be unlawful “tampering” under the Clean Air Act. This might include even those modifications that do not directly defeat a vehicle’s emissions control system.

While the court’s grant of an injunction indicates that it believes EPA is likely to prevail later in the case, it is possible that it could be convinced otherwise as the case proceeds. The next steps in the case will likely be discovery and motions for summary judgment. We will continue to closely monitor and report on developments in EPA’s enforcement initiative against aftermarket tuning and defeat devices.