"I think this is a serious safety problem ... I'm thinking big recall," Andres wrote in an e-mail to 11 GM colleagues.
Yet it wasn't until Monday that GM recalled the Impalas, Buick LaCrosses and other models with the same switch, almost nine years after Andres' e-mail. Safety regulators received dozens of similar complaints about the cars during that time.
GM said that excess weight on a keychain could cause the ignition switch to move out of the "run" position if the car is jarred, like when it hits a pothole. The engine stalls, and the drivers loses power steering and power brakes.
Under federal law, automakers must notify the National Highway Traffic Safety Administration within five business days of determining a safety defect exists. A maximum $35 million fine is possible if the agency finds an automaker took too long to report a problem.
GM paid a $35 million fine last month for its 11-year delay in reporting defective ignition switches in the Chevrolet Cobalt and other small cars.
Multiple fines are not without precedent. From 2010 through 2012, NHTSA fined Toyota Motor Corp. four times for a total of $66 million due to safety-related violations.
GM wouldn't comment Thursday on the possibility of another fine. NHTSA also wouldn't comment on the Impala case, but said it reviews all recalls to make sure they comply with the notification law and it takes "appropriate action" when it finds problems.
Andres's e-mail alone isn't enough to trigger the five-day rule, because it only suggests the ignitions are unsafe. But it's proof that some GM employees knew about a potential problem for almost a decade. GM has not yet submitted a required timeline to NHTSA that will say when it officially determined the Impala switches were defective.
Andres, who still works for GM in design and engineering, could not be reached for comment. But in her 2005 e-mail, she urged engineers to build a "stronger" switch.
Andres' warning was brushed off by GM engineer Ray DeGiorgio, who replied that he had recently driven a 2006 Impala and "did not experience this condition." He also noted that the Impala had "a completely different column/ignition switch" than the one that was causing problems in GM's small cars.
DeGiorgio is a central figure in the small-car recall saga. GM says he approved using the switches even though they failed to meet company specifications, and then took actions that hid the defect for years.
Andres's e-mail wasn't the only indication of problems. NHTSA's Web site lists more than 100 complaints about stalling for 2006-2009 Impalas alone. Those are complaints GM would have had access to.
In one 2012 complaint, an Impala stalled in the middle of a large intersection. The owner took it to a dealer four times but couldn't get it repaired.
"I'm fearful I will be the one causing a fatal pile-up," the driver wrote.