DETROIT (AP) - U.S. safety regulators are checking to see if more General Motors cars should be recalled because the air bags won't inflate. The probe covers about 400,000 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 says GM recalled just over 6,800 of the cars in two recalls last year and in January. The main front air bags wouldn't inflate due to a defect in the electrical connections. The agency says GM may not have fully identified the cause of the problem, so it will see if the recall should be expanded. The agency has no reports of crashes or injuries from the problem.