General Motors on Tuesday expanded a recall it announced nearly two weeks ago because of a problem with the ignition switch that can shut down the car’s motor and most of its electrical systems.

The recall now affects 1.37 million cars — twice as many as named in the initial recall, GM said in a news release. The cars are made by the GM divisions Pontiac, Saturn and Chevrolet.

There have been 31 head-on collisions in which the suspected problem might be linked to the failure of the airbags to deploy, GM said.

Thirteen people died in those accidents.

GM said it issued the recall to correct a condition with the ignition switch “that may allow the key to unintentionally move or switch to the ‘accessory’ or ‘off’ position, turning off the engine and most of the electrical components on the vehicle.”

The cars included in the recall are the 2005-2007 Chevrolet Cobalt, the Pontiac G5 and Pontiac Pursuit sold in Canada only, 2003-2007 Saturn Ions, 2006-2007 Chevrolet HHRs and 2006-2007 Pontiac Solstice and Saturn Sky models, the company said. All the affected cars were made for the US or Canada.

GM said the ignition could be turned off in the affected cars if the key ring is heavy or if the vehicle goes off road and the car is jarred.

As required by law, GM will notify all affected customers in writing.

Dealers will replace the ignition switch to prevent unintentional or inadvertent key movement.

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