Cobb has manufactured and sold over 81,000 tuners for gas-powered vehicles to disable emissions controls or alter engine performance. The tuner also sold over 8,400 exhaust pipe upgrades that fall foul of the Clean Air Act.

Cobb Tuning Products, the U.S. Environmental Protection Agency (EPA), and the U.S. Department of Justice have announced a settlement to resolve violations of the Clean Air Act stemming from the sale of aftermarket defeat devices for factory emissions systems.

Defeat devices, which are often sold to enhance engine performance, work by disabling a vehicle's emission controls, causing air pollution. As a result of enforcement efforts, some of the largest manufacturers of defeat devices have agreed to pay penalties and stop the sale of defeat devices.