GM Service Manual Online
For 1990-2009 cars only

Important: If the wrong ignition key is used in an attempt to start the vehicle, a diagnostic trouble code (DTC) will be set. The body control module (BCM) will not send a fuel enable or starter enable message to the powertrain control module (PCM) for 3 minutes even if the correct ignition is used.

The Pass-Key II® Theft Deterrent system prevents vehicle theft by disabling the starter motor and fuel system. If the BCM dose not identify the use of the correct ignition key to start the vehicle, the BCM will communicate a message to the PCM which will disable the crank relay and fuel delivery to the engine.

When the BCM identifies the use of the correct ignition key (resistor pellet) to start the vehicle, the BCM will send a fuel enable and starter enable message to the PCM which will allow the vehicle to start.