GM postpones launch of diesel engines for big trucks to 2020 MY

General Motors is postponing the launch of a new inline-six turbodiesel engine in the Chevrolet Silverado 1500 and GMC Sierra 1500 until the 2020 model year.

The EPA's emissions certification process for the engine is taking longer than anticipated, creating a "slight delay," according to a memo GM sent to dealers Tuesday.

The full-size diesel pickups were expected to go on sale for the 2019 model year in early 2019, months after gasoline versions started arriving at dealerships last fall.

GM said 2020 diesel pickup production will begin "soon" but the delay means dealer orders for the models will be canceled and must be resubmitted.

Dealers and customers impacted by the cancellation will be offered a replacement 2020 vehicle, according to the memo. Notification and timing of the replacement orders will be provided later, the company said.

A company spokesman said dealer orders for the 2020 diesel models will open "soon." He declined to comment on how many orders were placed for the 2019 model year.

The U.S. government has taken a stricter stance on emissions certification — particularly diesel engines — since Volkswagen Group's sweeping emissions violations emerged in September 2015. Other automakers, including Fiat Chrysler Automobiles and BMW Group, have also been forced to delay launches because of the prolonged certification process.

The 3.0-liter Duramax engine is GM's first turbodiesel in a light-duty full-size GM pickup since 1997.

In March, GM said the engine — paired with a 10-speed automatic transmission — would achieve segment-leading power of 277 hp and 460 pound-feet of torque.

GM has not released towing capacity, payload and fuel economy ratings for the Duramax diesel model, which will be priced starting at $2,495 over a 5.3-liter V-8 model and $3,890 over a 2.7-liter turbo model.

The new diesel engine is being produced at a GM powertrain plant in Flint, Mich.

According to the memo, the Silverado, like its Sierra sibling, will receive updates such as adaptive cruise control and expanded availability of the 10-speed transmission for the 2020 model year, confirming earlier reports.