SANTA BARBARA, Calif. -- General Motors is the first automaker to feel the backlash from the Volkswagen diesel emissions cheating scandal.
GM has been told by the EPA and the California Air Resources Board that the new diesel-powered versions of the Chevrolet Colorado and GMC Canyon pickups will not be certified until they have been tested on the road as well as in the lab.
The sales launch of the trucks, which is scheduled for the fourth quarter, could be delayed slightly by the additional testing, GM says.
“The EPA and CARB told us they are going to do on-road testing,” Scott Yackley, Chevrolet Trucks assistant chief engineer, said on the sidelines of a media event here for the diesel-powered Colorado.
Last week -- in the wake of VW's violation of diesel emissions rules -- the EPA said it would begin more stringent testing to ensure that vehicles meet emissions in the lab and on the road. It is not clear if the EPA road tests will be done with CARB or separately.
The four-cylinder diesel engine GM slated for the Colorado and Canyon has been used in global markets without some of the emissions equipment required for U.S. sales. That includes the Selective Catalytic Reduction system that periodically sprays urea fluid into the exhaust system.
Yackley said GM engineers have conducted extensive lab and road tests and are confident that the trucks will pass the additional testing.
“Part of our development process is on-road and off-road [laboratory] testing,” he said.
VW, in violation of environmental rules, installed software that switched on the emissions system when certain diesel-powered vehicles were being tested in the lab. On the road, a vehicle's computer switched off the emissions system, causing as much as 40 times the legal limit of nitrogen oxide.