SECURITY Indicator Flashes and Engine Does Not Start
WARNING: This page is about a different car, the 2003 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
The theft deterrent control module has measured an incorrect transponder value when the ignition key is turned to the ON position. The transponder has not been learned by the theft deterrent control module. This is considered a tamper condition by the theft deterrent control module.