Detroit Judge Rejects GM-Bosch Motion to Dismiss Lawsuit about Diesel Cheating

General Motors Co. and Robert Bosch GmbH have failed to quash a U.S. lawsuit that claims they used illegal software to evade diesel emission regulations.

A District Court judge in Detroit says the plaintiffs produced enough evidence to allow the class-action case to proceed. The lawsuit was filed in May.

The represents the owners of some 705,000 of GM’s 2011-2015 model Chevrolet Silverado and GMC Sierra fullsize pickup trucks that are equipped with Duramax diesel engines.

The lawsuit claims GM and Bosch developed three software “defeat devices” that illegally switch off emission controls during routine driving conditions. Two of the software programs allow nitrogen oxide emissions to more than double during stop-and-go conditions whenever the air temperature falls below 68°F or rises above 86°F.

A third program permits NOx emissions to quadruple whenever the engine is running at a steady speed for more than a few minutes, regardless of ambient temperature.

The lawsuit contends that Bosch and GM colluded to develop illegal software that deceived customers and left them to face unexpected future repairs and diminished resale values.​​​​​​