The four-cylinder diesel engine generates 181 horsepower and 369 lb-ft of torque and is paired with a six-speed automatic transmission. Both components help trucks equipped with two-wheel drive to achieve an EPA-estimated 22 mpg in city, 31 mpg on the highway and 25 mpg in combined driving. Models with four-wheel drive are certified for 20 mpg city, 29 mpg highway and 23 mpg combined.

Since discovering, in September, that Volkswagen Group had installed electronic “defeat” devices on roughly a half-million diesel cars and sport-utility vehicles sold in the U.S. since 2008, the EPA is now aggressively testing all new light-duty diesels. The agency has “expressed no issues or concerns following its recent extensive testing and evaluation of the emission-control system” on the Chevrolet and GMC trucks, GM noted.

Pricing for the Duramax diesel option, which goes on sale this fall, is $3,730 more than a comparably equipped truck with a 3.6-liter V-6 gasoline engine; however, it is available only on the more expensive crew-cab models with upscale trim packages.