General Motors has told its dealers to stop selling any Chevrolet Cruze cars equipped with 1.4-liter turbo engines on their lots.

The automaker did not provide any information why it issued the order. Automakers typically halt sales of a car if they learn of some safety defect. Sometimes it can be a minor issue that puts the model out of compliance with federal safety regulations.

The stop-sale order is for 2013 and 2014 model year Cruze sedans with the gasoline turbocharged engine, not the diesel version, said Alan Adler, a GM spokesman. It amounts to about a third of the Cruze inventory at Chevrolet dealers.

“No other details to share,” he said.

The Cruze is GM’s best-selling compact car in the U.S. It sold nearly 250,000 last year, making it one of the top-selling vehicles in America.

GM’s decision to halt sales of certain Cruzes comes as its deals with the fallout from recalling 1.6 million vehicles in the past two months to fix an ignition-switch issue linked to at least 12 deaths.

On Friday, GM added 824,000 small cars to its ongoing recall tied to defective ignition switches, bringing the total number of vehicles recalled to nearly 2.5 million.

The company will add vehicles from the 2008-2011 model years to a recall that initially covered cars only through the 2007 model year.

The Chevrolet Cobalt, Chevrolet HHR, Pontiac G5, Pontiac Solstice, Saturn Ion and Saturn Sky are all involved in the recall.

GM says some 5,000 of the faulty switches were used for repairs on 2008-11 model cars. GM says it’s expanding the recall to make sure it finds all the switches. The ignition switches can move out of the “run” position and cause the engine to stall.

Documents filed with the National Highway Traffic Safety Administration indicate GM knew about the problem at least a decade ago but failed to recall the vehicles.

GM Chief Executive Mary Barra is scheduled to testify about the auto-maker’s actions at congressional hearings next week.