General Motors has been forced to cancel orders and delay the new 3.0-liter engine for its full-size and pickup trucks, which were originally scheduled to be available early this year, due to emissions testing for the engine taking longer than anticipated.

reported that a memo sent out to GM dealers on Tuesday announced the delay, which was later confirmed to the publication by a company spokesperson. Here’s more from Automotive News:

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.

Chevrolet spokesperson Monte Doran gave a little about the cause of the delay:

“Yes, we are shifting the 3.0L Diesel from a late 2019MY to a 2020MY as emissions testing is taking longer than expected,” Chevrolet representative Monte Doran told Motor1.com.

“However, we did not attribute to a single entity, as the truth is this is a collaborative effort between GM and several government entities. We will make the 2020MY Duramax available for dealers orders soon, and expect to deliver the first trucks to customers soon after emissions testing is complete.”

The delay is enough to knock GM’s introduction of the diesel full-size pickup offerings out of the 2019 model year, meaning dealers were forced to cancel any existing orders for the pickups, but customers will be offered replacement 2020 model year pickups in the near future, according to AutomotiveNews.

Here’s the a full statement from GM:

GM is currently working with government officials to complete emissions certification of this great new product. Unfortunately, the process is taking longer than anticipated. Therefore, rather than do an abbreviated production for the 2019 Model Year, GM will launch the 3.0L Duramax as a 2020 Model Year with production starting soon.

The decision to introduce the 3.0L Duramax as a 2020 Model Year will necessitate the return and cancellation of existing 2019 Model Year production. Dealers and customers impacted by this action will be offered a replacement 2020 Model Year vehicle. Notification and timing associated with the replacement order will be provided through a subsequent communication.

It was revealed and later that the 3.0-liter diesel makes a claimed 277 horsepower and 460 lb-ft of torque, though payload and towing capacity figures have yet to be announced. Obviously there are no EPA figures just yet, either.

The engine is slated to be priced at the same as the optional 6.2-liter V8 over the 5.3-liter V8, and than the optional 2.7-liter four-cylinder. GM previously announced that the Duramax would be available on of the Silverado, and .