(CNN) - The recall now affects 1.37 million vehicles built between 2003 and 2007.
GM says the ignition on the vehicles recalled can accidentally switch out of the "Run" position while the car is being driven. When that happens, the car's engine shuts off, rendering power brakes, power steering and airbags not operational.
Originally, GM said there had been six fatalities among front-seat passengers as a result of this problem. There have been 31 frontal crashes involving vehicles with the problem.
"Ensuring our customers' safety is our first order of business," said GM North America President Alan Batey. "We are deeply sorry and we are working to address this issue as quickly as we can."
GM has been accused of not responding quickly enough to resolve this problem. A Georgia attorney is suing GM on behalf of a woman who died in 2010 while driving a 2005 model year Cobalt. The attorney, Lance Cooper, has also petitioned the National Highway Traffic Safety Administration to fine GM for not acting quickly enough once it knew of the problem.
A GM engineer experienced the problem while test-driving one of the vehicles in 2004 according to deposition transcripts provided to CNNMoney by Cooper. GM's engineers concluded there was a problem with the ignition switch in 2005, the depositions showed.
Under current law, automakers are required to report safety defects to the NHTSA within five days of discovering them. Failure to do so carries a maximum fine of $35 million. Last year, Ford had to pay the maximum fine, at the time, of $17.4 million for failing to promptly recall Ford Escape SUVs with gas pedals that could become stuck. The fine was increased to the maximum in October of 2013. Toyota has also had to pay large fines for failing to promptly report safety issues.
In a chronology of events recently filed with NHTSA, GM indicates that its engineers did not originally think the problem was safety related because steering and brakes, albeit without power assistance, would still work with the engine off. Also, the engine could be restarted after shifting the car to Neutral or Park.
It was also not immediately clear why the airbags did not deploy in many crashes, according to the document.
"The chronology shows that the process employed to examine this phenomenon was not as robust as it should have been," said GM's Batey. "Today's GM is committed to doing business differently and better. We will take an unflinching look at what happened and apply lessons learned here to improve going forward."
GM will notify owners of vehicles involved in the recall to bring their vehicles to a dealer, which will replace the ignition switch at no charge.
In the meantime, GM is advising owners to avoid having anything other than the car keys hanging on their key chain. The added weight of additional objects can make it more likely the key will turn accidentally.