DOJ will no longer pursue criminal charges for diesel ‘deletes’ and ‘tunes’
Federal officials said that they will no longer issue criminal charges for Clean Air Act violations that involve diesel emissions tampering.
On January 21, 2026, the U.S. Department of Justice (DOJ) Environment and Natural Resources Division announced that they will no longer pursue criminal charges for removing or altering emissions control devices in diesel trucks, a practice often referred to as a “tune” or a “delete.”
From the DOJ:
“Today, the Justice Department is exercising its enforcement discretion to no longer pursue criminal charges under the Clean Air Act based on allegations of tampering with onboard diagnostic devices in motor vehicles.“
Officials say that civil penalties could still be issued:
“DOJ is committed to sound enforcement principles, efficient use of government resources, and avoiding over-criminalization of federal environmental law. In partnership with the Environmental Protection Agency (EPA), DOJ will still pursue civil enforcement for these violations when appropriate.“
Today, @TheJusticeDept is exercising its enforcement discretion to no longer pursue criminal charges under the Clean Air Act based on allegations of tampering with onboard diagnostic devices in motor vehicles.
— DOJ Environment and Natural Resources Division (@DOJEnvironment) January 21, 2026
The Trump Administration signaled policy change towards the prosecution of Clean Air Act violations when mechanic Troy Lake Sr. was pardoned by the White House in November 2025.
Lake pleaded guilty to conspiring to violate the Clean Air Act after he and his repair company were accused of disabling the computerized on-board diagnostic (OBD) systems on at least 344 heavy-duty commercial trucks. Lake was sentenced to 12 months and 1 day in prison for the violation, but was released early due to the pardon.
Wyoming Senator Cynthia Lummis introduced a bill called the “The Diesel Truck Liberation Act” in October 2025 after she was inspired by Lake’s story. The bill sought to protect individuals from prosecution for removing or altering emissions control devices in diesel trucks. The bill did not advance out of the Committee on Energy and Natural Resources.