Circuit Description
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora and 2001 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
When an ignition key is inserted into the ignition lock cylinder, the transponder embedded in the head of the key is energized by the exciter coils surrounding the ignition lock cylinder. The energized transponder transmits a signal that contains its unique value, which is received by the theft deterrent control module.
The theft deterrent control module then compares this value to a value stored in memory (learned key code). If the value is correct the theft deterrent control module sends the enable password via the class 2 serial data circuit to the powertrain control module (PCM).