Two weeks ago, the automaker announced the recall of more than 780,000 Chevrolet Cobalts and Pontiac G5s. GM is now adding 842,000 cars - bringing the total to more than 1.6 million vehicles.
The vehicles being recalled include: Chevrolet Cobalts and Pontiac G5s from the 2005 through 2007 model years; Saturn Ion compacts from 2003 through 2007; and Chevrolet HHR SUVs and Pontiac Solstice and Saturn Sky sports cars from 2006 and 2007. Most of the cars were sold in the U.S., Canada and Mexico.
GM says a faulty ignition switch could shut off the engine and electrical power. The problem is being linked to several fatal crashes.
The company admits it may have been too slow issuing the recall. GM North American President Alan Batey issued a rare apology saying, "We are deeply sorry and we are working to address this issue as quickly as we can."
According to chronology documents GM filed with the National Highway Traffic Safety Administration, the company knew of the problem as early as 2004 and was told of at least one fatal crash in March of 2007.
GM issued service bulletins in 2005 and 2006 telling dealers how to fix the problem with a key insert, and advising them to tell customers not to dangle too many items from their key chains. But the company's records showed that only 474 vehicle owners got the key inserts.
The company thought the service bulletin was sufficient because the car's steering and brakes were operable even after the engines lost power, according to the documents.
By the end of 2007, GM knew of 10 cases in which Cobalts were in front-end crashes where the air bags didn't inflate. In 2005, GM initially approved an engineer's plan to redesign the ignition switch, but the change was "later canceled."
Drivers with these vehicles will be notified. Dealers will replace the ignition switch for free, but GM said it will take some time for the parts to be manufactured and sent to dealers. No time frame was given for making the repairs.
The Associated Press contributed to this report.