Diesel Truck Liberation Act of 2025

This bill, titled the Diesel Truck Liberation Act of 2025, would dramatically roll back federal authority to require emissions-control devices and onboard diagnostics (OBD) on motor vehicles and engines. It prohibits any federal law, including regulations and executive actions under the Clean Air Act, from requiring installation, certification, or maintenance of these devices. It also bars the Environmental Protection Agency (EPA) from creating or enforcing such requirements under any federal law, provides liability protections for actions involving vehicles that do not include emissions controls, and voids regulations related to installation or removal of these devices. Finally, it directs that criminal penalties or civil findings tied to such prohibited conduct be vacated or expunged. In short, the bill would nullify federal standards that mandate emissions-control technology on diesel trucks and other motor vehicles, and shelter actors from liability related to not using such devices. It signals a broad shift away from federal emissions-control requirements toward a framework where no federal mandate would compel installation or maintenance of these controls.