United States v. Pro Diesel Werks, LLC, et al.

On February 19, 2025, a grand jury indicted Roy Ladell Weaver and his company, Pro Diesel Werks, LLC, with conspiring to impede the lawful functions of the Environmental Protection Agency (EPA) and to violate the Clean Air Act (CAA), and substantive CAA violations (18 U.S.C. § 371; 42 U.S.C. § 7413(c)(2)(C)).

Pro Diesel Werks provided vehicle repair and maintenance and performance enhancement services, including services on diesel engines and vehicle emission systems. The indictment alleges that between 2013 and March 2024, Weaver and the company, along with co-conspirators, disabled the hardware emissions control systems on diesel vehicles of Pro Diesel Werks’ customers (a practice referred to as a “delete” or “deleting”), defeating the systems’ ability to reduce pollutant gases and particulate matter released to the atmosphere. The defendants are also alleged to have tampered with the monitoring device and method required under the CAA, that is they disabled the onboard diagnostic system on vehicles preventing the system software from monitoring the emission control system hardware deletes (a practice referred to as a “tune” or “tuning”).

The defendants charged customers between approximately $2,000 and $4,000 per vehicle to remove and disable the emission control systems on motor vehicles with diesel engines.

The U.S. Environmental Protection Agency Criminal Investigation Division conducted the investigation.