General Motors Co recalled 511,528 Chevrolet Camaros on Friday for an ignition switch problem similar to the defect linked to at least 13 deaths in Chevrolet Cobalts and other models, reported Reuters.

GM said it was aware of minor accidents but no fatalities from the Camaro, a sporty two-door car. It said the Camaro switch defect differed from the problem in the Cobalts, but a consumer advocate said GM still should have recalled the Camaros sooner.

GM said a driver's knee could bump the Camaro key fob and move the ignition switch out of the "run" position, causing the engine to shut off.

The earlier recall of Cobalts and other small cars involved an ignition switch in which a bump of the key fob could turn off the engine, disabling power steering and airbags.

That defect, first observed by GM engineers in 2002, was not reported to consumers for years. Chief Executive Mary Barra in recent months overhauled the way GM handles safety recalls.

The Camaro recall bloats the number of GM vehicles summoned back for switch-related problems to more than 3.1 million as Barra prepares to return to Congress next week to give more testimony on the earlier recall.

"It is troubling that GM continues to announce ignition switch-related recalls on late-model vehicles (which) raises questions about how pervasive the problem is and why it is taking so long for GM to act," said Representative Henry Waxman of California, the senior Democrat on the House Energy and Commerce Committee that is investigating GM.

Barra will be joined by Anton Valukas, chairman of GM's outside law firm Jenner & Block, who conducted a months-long investigation that detailed deep flaws in GM's internal decision-making process.

The so-called Valukas report, made public last week, triggered the departures of 15 GM employees, including several high-ranking executives in the legal, engineering and public policy groups.

GM's 3.1 million switch-related recalls are a fraction of the record 16.5 million cars the automaker has recalled this year in 38 actions. That's about as many cars as the entire auto industry expects to sell this year in the United States.

The switch problem in this recall, of Camaros from model years 2010 to 2014, is "not at all related to the Cobalt," GM safety spokesman Alan Adler said in an interview. "The condition here is a switchblade key" in which a key pops out of the key fob when a small button is depressed.

The problem with the Camaro switch "is an external bumping issue," Adler said. He said it involves "an atypical seating situation. If you sit somewhat normally and don't pull your seat way up, you are not going to have this problem."

The Cobalt and Ion had a similar issue involving the location of the switch on the steering column and the tendency of some drivers to bump that switch. Some other key issues also are similar: When the key fob is bumped and the switch is moved out of the run position, the engine can turn off, causing loss of power steering and failure of airbags to deploy in a crash.

GM said it was aware of three crashes causing four minor injuries linked to the issue in Camaro. Adler said air bags did not deploy in those crashes and he did not know details.

GM "should have recalled" the Camaro earlier, said Clarence Ditlow, director of the Center for Auto Safety, a Washington-based watchdog group. "GM said it's not the same problem, but it's a first cousin," Ditlow said.

Adler said GM would send letters to Camaro owners, advising them to visit dealers to get a new key made. Until then, he said GM is advising Camaro owners to "drive the car and be aware" of the problem.

The U.S. National Highway Traffic Safety Administration, which is responsible for overseeing safety defects and recalls, had not yet posted an official Camaro recall notice, but the agency has received and posted several consumer complaints.

NHTSA said Friday afternoon it had not received GM's official recall notice on the Camaro, but "is monitoring the issue closely."

Lawmakers have criticized NHTSA for not acting more swiftly to recall GM small cars with defective switches.

The agency awarded the 2012-2014 Camaro five-star safety ratings, its highest, for safety in front, side and rollover crashes.

Adler said GM discovered the issue in the Camaro as it was testing a wide range of its 2014-2016 models after the widely publicized small-car ignition switch recall.

Jeff Boyer, appointed to the new position of vice president for GM global safety earlier this year in response to the small-car ignition switch recall, said the Camaro recall was a quick action that is "the new norm for product safety at GM," according to the press statement.

GM shares closed at $35.63, up 11 cents.