This bill aims to prohibit the enforcement of all federal laws, including the Clean Air Act , that mandate the installation, certification, or maintenance of emissions control devices and onboard diagnostic systems on motor vehicles and engines. It explicitly prevents federal agencies, such as the Environmental Protection Agency , from promulgating or enforcing any such requirements. The legislation further eliminates all civil and criminal liability for individuals or entities involved in the manufacture, sale, use, or modification of vehicles lacking these emissions control systems. Additionally, it mandates the repeal of all existing federal regulations related to these devices and requires the vacating of past criminal imprisonment penalties and the expungement of records for prior violations.