The New York Times cited people familiar with the inquiry as saying that a settlement likely to surpass the $1.2 billion paid out by Toyota over sudden unintended acceleration could be reached in the next few months.
The report said GM had sought to cooperate with investigators -- in contrast to Toyota which battled prosecutors -- and could earn a "cooperation credit" for its stance on the probe.
The report said former GM employees, including some who were fired last year, could face criminal charges while the company itself was still negotiating exactly what misconduct it would admit to.
The Times said federal prosecutors in New York and the FBI were focusing on whether GM breached laws requiring swift disclosure of vehicle defects and misled regulators about the extent of the problems.
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"We are cooperating fully with all requests," a GM statement said Friday. "We are unable to comment on the status of the investigation, including timing."
GM began recalling 2.6 million Chevrolet Cobalts and other cars with faulty ignitions in February 2014 after it emerged the switches could unexpectedly turn off the engine, disable power steering, power brakes and airbags.
The family of one victim welcomed the prospect of GM being linked to criminal wrongdoing by the Justice Department probe.
"Is it going to be closure? No. But it's going to be a little bit of justice," said Ken Rimer, whose 18-year-old stepdaughter Natasha Weigel died in a 2006 accident.