General Motors Co. got its first internal company report on ignition-switch problems in 2001, during pre-production development of the Saturn Ion, the automaker said in a letter to U.S. regulators.

The ignition-switch defect that led to the recall of 1.6 million cars worldwide was believed fixed and the model went into production, GM said in an amended recall report filed with the National Highway Traffic Safety Administration Wednesday. Then in 2003, service technicians found that an owner with a heavy key ring was experiencing engine stalls while driving.