After VW's violation of environmental rules, EPA has taken a more drastic approach to all diesel powered vehicles. 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. 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.