The National Highway Traffic Safety Administration has opened an investigating into the timeliness of General Motors' recall of defective ignition switches which affects approximately 1.4 million vehicles in the U.S.

GM could receive a fine of $35 million if it did not recall the vehicles within five days after determining the switches could cause harm to occupants of affected vehicles.

Federal regulations state that once an automaker is aware of a safety problem it has to inform the NHTSA, within five business days, of its plan for a recall or face a hefty fine.

Affected vehicles include: the 2005-'07 Chevrolet Cobalt, 2006-'07 Chevrolet HHR and Pontiac Solstice, 2003-'07 Saturn Ion, 2007 Pontiac G5, and 2007 Saturn Sky.

The NHTSA has "opened an investigation into the timeliness of General Motors' recall of faulty ignition switches to determine whether GM properly followed the legal processes and requirements for reporting recalls," according to a company statement.

GM revealed on February 10 that it was recalling the affected vehicles, but on Feb. 25 the automaker said it would be doubling the original count to nearly 1.4 million vehicles in the U.S.

"If the key is not in the run position, the airbags may not deploy if the vehicle is involved in a crash, increasing the risk of injury," NHTSA said.

The ignition switch defect has caused at least 13 deaths and resulted in 31 crashes.

"GM reportedly knew about the safety problem for almost a decade," Se. Edward J. Markey said in a post on his website. "Currently Early Warning Reporting System too little, too late, we need to overhaul the Early Warning Reporting system so that NHTSA is not looking at auto defects through a rearview mirror."

GM hired an outside firm to conduct a review of the recall.

"The chronology shows that the process employed to examine this phenomenon was not as robust as it should have been," said GM North America President Alan Batey in a statement this week. "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."

Batey has apologized to consumers for how the company has handled the recall. 

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