DETROIT (AP) - Shares of General Motors fell almost 2 percent Thursday after some truck owners alleged in a lawsuit that the company cheated on government diesel emissions tests.
The lawsuit filed in U.S. District Court in Detroit alleges that GM pickup trucks with Duramax diesel engines have three devices on them that are rigged to allow more pollution on the road than during treadmill tests in the Environmental Protection Agency laboratory.
GM said the allegations are without merit.
The lawsuit filed by the Hagens Berman firm of Seattle alleges the trucks emit two to five times the legal limit for harmful nitrogen oxide. Also named as a defendant is Robert Bosch LLC, which made GM's electronic diesel controls. Bosch said it is cooperating with government investigations into emissions cases and "defending its interests" in lawsuits.
Diesel engines have been under scrutiny worldwide since Volkswagen admitted its diesel cars cheated on tests.
The complaint on behalf of two truck owners against GM alleges that the devices were installed on diesel engines in the Chevrolet Silverado and GMC Sierra heavy-duty pickups. Two of the devices reduce emissions controls when the air temperature is above or below the range in government lab tests. The other reduces the level of emissions controls when the trucks are running continuously for 200-500 seconds. Government tests don't last that long, the lawsuit said.
The law firm estimates there are 705,000 of the diesel pickup trucks on U.S. roads.