Fred Meier and James R. Healey

USA TODAY

General Motors now says the first sign of the ignition switch problem that led to its massive recall last month came in 2001 during development of the 2003 Saturn Ion.

GM made the disclosure in an update of its recall chronology filed with federal regulators and posted late Wednesday.

The document is an amendment to the time line that GM filed with the National Highway Traffic Safety Administration last month.

The company says that it only now is reporting the 2001 incident because it only discovered a record of it last month.. After an initial recall, GM looked into other cars that used the same switch and then more than doubled the number of models and cars recalled, including the 2003 Ion, which is the earliest vehicle in the recall.

The earliest report until now was in 2004 during development of the 2005 Cobalt and it is more detailed. In that case, an engineer had the car stall while driving, according to depositions in a now-settled civil lawsuit against GM.

Engineers were able to replicate the problem and proposed solutions, according to GM's filing, but a decision was made not to adopt them, "after consideration of the lead time required, cost and effectiveness."

GM says that the 2001 Ion report found "low detent pressure force" in the switch. The detent is the part of the switch's inner workings that keeps it from rotating from one setting to another unless the driver turns the key.

Low force could allow it to move unintentionally out of the "run" position while underway into the "accessory" position, shutting off the engine and disabling safety systems -- the problem for which GM now has recalled 1.62 million vehicles worldwide, 1,37 million of those in the U.S.

The company said a change was made to the switch in 2001, the matter was closed and the Ion went on sale .

But the search of the records, according to GM's amended time line, also found that a dealer service technician reported an incident of a stall while driving in an Ion in 2003. It said the technician noted the car owner had "several keys on the key ring" and that the "additional weight of the keys had worn out the ignition switch." GM said the tech replaced the switch and again the matter was closed.

The new chronology says that GM knows of four fatalities in 2004 Saturn Ions, which should have had the "design change" switch referred to in the 2001 report.

The chronology says that in February GM searched records for all the vehicles using this switch and the recall of the 2005-07 Chevy Cobalt and 2007 Pontiac G5 then was expanded to include the 2003-07 Saturn Ion, the 2006-07 Chevy HHR, the 2006-07 Pontiac Solstice and the 2007 Saturn Sky.

GM has said that a heavy key ring -- the problem cited in 2003 with the Ion -- will make it more likely for the faulty switches to slip out of "run" and cut off power. It is advising owners of the recalled models to strip everything from their ignition key and use only the key itself while driving.