DETROIT — US safety regulators are checking to see if up to 400,000 General Motors cars should be added to two recalls for defective air bags.
The probe covers Chevrolet Cruze and Sonic small cars, the Chevrolet Camaro muscle car, and the Buick Verano small car from the 2012 model year.
The National Highway Traffic Safety Administration said in documents posted on its website Tuesday that GM recalled just over 6,800 of the cars in two recalls in October of last year and January.
The main front driver’s air bags wouldn’t inflate due to a defect in the electrical connections.
In the recalls, GM dealers were to replace the steering wheel air bag coil free of charge to fix the problem.
The cars covered by the two recalls were built from Dec. 16, 2011, to Feb. 1, 2012, and from April 2, 2012, to June 29, 2012, according to the documents.
The agency says GM may not have fully identified the cause of the problem, so it will see if the recall should be expanded.
If the air bags don’t inflate, people could be injured in a crash.
But NHTSA has no reports of crashes or injuries from the problem.
GM is cooperating with the investigation and will answer NHTSA’s questions, said company spokesman Alan Adler. He would not comment on whether GM had fully identified the cause.
‘‘It is a process that is just beginning,’’ he said. ‘‘We recalled vehicles that we believe have an issue.’’
GM said in recall documents filed with NHTSA that if the electrical problem happens, the air bag warning light will come on.