Defeat device

[1][2][3] The United States Environmental Protection Agency (EPA) has taken numerous enforcement actions against car makers and other companies that have used or installed defeat devices, whether deliberately, or through error or negligence.

Aftermarket parts or software, such as modified exhausts or chip tuning products and services, are considered defeat devices if they inhibit or bypass a vehicle's emissions controls.

[5] Also in 1973, Volkswagen agreed to a settlement with the EPA, in which they admitted no wrongdoing and paid a $120,000 fine, for failing to disclose the existence of two temperature sensing switches that affected emissions function.

Besides the fine, the second largest Clean Air Act penalty to date in 1995, GM had to spend up to $34 million for anti-pollution programs and recall 470,000 Cadillac 4.9 liter Eldorados, Fleetwoods, DeVilles, and Sevilles.

[11][12] In late 2015, the EPA discovered that software used in millions of Volkswagen Group turbocharged direct injection (TDI) diesel engines included features intended to produce misleading results during laboratory emissions testing.

[15] Fiat Chrysler produced over 100,000 model year 2014 through 2016 Ram 1500 and Jeep Grand Cherokee vehicles for sale in the United States with EcoDiesel engines in which the US EPA and the California Air Resources Board alleged had a defeat device.