Mary Barra, the embattled chief executive of General Motors, appeared before Congress on Tuesday replete with apologies but offering few explanations for the car giant’s years-long failure to fix an ignition-switch defect linked to 13 deaths.

With the pictures of victims pinned to the back wall of the committee room, Barra promised to find out why the company had been so slow to issue a recall that now covers 2.6m vehicles, despite first learning about the problems with ignition switches 10 years ago.

Barra, a company veteran who has been portrayed as the face of a “new GM”, leading the company out of bankruptcy into a new era of success, once again apologised to the families of the victims, promised to find out what went wrong and – despite her years at the heart of the business – sought to distance herself personally from the scandal.

Before the crisis hit the company this year, GM was hailed as the success story in Barack Obama's attempts to rescue the American economy from debt-induced disaster. That reputation has taken a serious knock. This year, taking into account defects connected to and separate from the problem with ignition switches that was the focus of Tuesday’s hearing, GM has recalled nearly 7m vehicles – almost as many cars and trucks as it recalled in the US over the last four years combined.

Barra's appearance before the committee represented an attempt to demonstrate its determination to find out what went wrong, but her failure to give any substantive answers irritated members of Congress, who dismissed her comments as “gobbledegook” and "unacceptable”.

Congresswoman Diana DeGette held up a defective switch demonstrating that a car could easily be turned off if jiggled by a heavy keyring or knocked by a knee. She said the fix would have cost 57¢ per car.

"I just want to show how easy it is to turn this key in this switch," said DeGette. The switch was especially a problem for short driver whose knees were more likely to contact the ignition, and for people who had heavy keychains or "mom keychains, like me,” she said.

Barra avoided questions about whether GM would take “responsibility” for the deaths. GM emerged from bankruptcy in 2008 and is technically a new company, and therefore not liable for lawsuits related to deaths before that time. Barra announced that GM had appointed Kenneth Feinberg, a lawyer who specializes in a restitution payments in major disasters, including the terrorist attacks of 9/11 and the BP oil spill, to look at the case.

Memos released by the committee show that GM was aware of issues with the ignition in its Chevrolet Cobalts and other vehicles in 2004. In 2005, an unnamed GM project engineering manager closed an investigation into the issue, saying the "lead time for all solutions is too long", "the tooling cost and piece price are too high" and none of the proposed fixes "represents an acceptable business case".

The ignition switch also affected other systems in the vehicles, including air bags that failed to deploy leading to other injuries and fatalities.

Barra could not explain why GM continued to use the ignition switch after it was determined not to meet GM specifications, and could not explain why, when GM replaced the part, the company did not assign it a new part number. "I want to know that as much as you," Barra told the committee.

Barra pledged that the internal investigation into the scandal would get to the bottom of the issue. She said she had not learned about the issue until 31 January and had moved swiftly to issue a massive recall after the problem was disclosed to her.

“I was not a part of that organization at the time – that's why I'm doing an investigation,” said Barra. "I don't know the people who would have been handling that issue at that point,” she said.

“Why in the world would a company with the stellar reputation of General Motors buy [a substandard part]," asked congressman Joe Barton. “I want to know that as much as you do,” said Barra.

Barra said former US attorney Anton Valukas was just a few weeks into his investigation, but that she was determined to uncover all the facts. Barra said putting cost ahead of safety was “unacceptable”. She said GM had moved from a cost-focused company to a consumer-focused company since it had emerged from bankruptcy. “This is not the way we do business at GM,” she said.

“Today’s GM will do the right thing,” said Barra. “That begins with my sincere apologies to everyone who has been affected by this recall … especially to the families and friends of those who lost their lives or were injured. I am deeply sorry.”

Testifying after Barra, David Friedman, acting administrator of the National Highway Traffic Safety Administration (NHTSA), said GM has now uncovered “critical information” that the regulator did not have and that could have triggered an intervention earlier.



NHTSA staff suggested investigations in 2007 and 2010 but despite 20 consumer complaints and four fatalities the Cobalt was not statistically worrying to the NHTSA, he said.



Friedman said the agency was now investigating whether GM “met its timeliness responsibilities” in telling it about problems with ignition switches. The information given to NHTSA ahead of the recalls was not enough to stand out, said Friedman.



He said he was specifically looking at: when GM identified a link between problems with its ignition kets and its air bags; the decision to change parts in the car and what information was given to NHTSA; and the conversations GM had with suppliers ahead of the recalls.