General Motors knew of problems with its auto ignition switches, blamed for numerous crashes and 12 deaths, as early as 2001, three years before previously thought, fresh data shows.

GM's updated chronology of the problem, sent to the National Highway Traffic and Safety Administration, says a report during pre-production work on the Saturn Ion in 2001 pointed to a problem.

And two years later a service technician experienced the same problem that hundreds of drivers later experienced, a stall while driving related to a heavy key ring moving the ignition position.

That raised questions about why it took the US auto giant until last month to issue a recall and why the NHTSA did not act, despite being aware of complaints that the ignition would turn off while the car was in motion.

This shut-down would also turn off a car's electrical systems, preventing airbags from deploying in the case of an accident.

GM says it knows of a total 31 crashes and 12 deaths tied to the problem. Earlier it had reported 13 deaths, but this week corrected that, saying one had been counted twice.

Last month GM announced the recall of 1.6 million cars sold in North America between 2003 and 2007, including some of its most popular models: the Chevrolet Cobalt and HHR, the Pontiac G5, Pursuit and Solstice, and the Saturn Ion and Sky.

GM said a highway or off road jolt, or a heavy set of keys, could move the ignition into "off" or "accessory" position, leading to a shutdown of the car's electrical systems.

But the company still has not explained clearly why it took so long to act. New GM chief executive Mary Barra, facing her first crisis, has started an internal investigation and promised transparency.

Two committees in the US Congress have said they will launch probes into the issue, and media reports say the Department of Justice is also now investigating.

Meanwhile, analysts say GM is likely to face lawsuits that could lead to potentially hefty damage claims against the company on top of the recall costs.

GM spokesman Greg Martin said Thursday that the company is "fully committed to learning from the past while embracing the highest standards for quality and performance now and in the future."