NHTSA received the GM letter on March 11, and it came as part of the timeline it released to explain the widened recall. The report includes a case of a pre-production Ion where engineers found a problem with the ignition switch's "passlock" system. The engineers diagnosed it as "low detent plunger force," and a design change fixed the issue.
The same report documents a case in 2003 where a service technician was driving an Ion, and the car stalled. The mechanic said: "'[t]he owner had several keys on the key ring,' and stated that '[t]he additional weight of the keys had worn out the ignition switch,'" according to the letter. The worker replaced the vehicle's ignition switch.
GM said that it received customer complaints to its warranty and technical assistance offices around this time of customers not being able to start their vehicles, and some of these included reports of stalling.
For the Ion alone, GM says in the new report that it has found eight frontal crashes of 2003-2007 models where the ignition switch fault may have played a role. Among these accidents, there were four fatalities and six injuries. It also has evidence of three frontal impacts of 2006-2007 Chevrolet HHRs where the switch might have been responsible, and they resulted in three injuries.
This latest letter to NHTSA comes in addition to the 107 questions the automaker has to answer for the regulator by April 7. The company is also facing a hearing before the US House Energy and Commerce Committee, but a date hasn't been set yet. The entire 10-page letter can be viewed as a PDF here. Much of the new information comes on page nine.