Conditions for Setting the DTC
WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The BCM detects a short to ground or open on the Passlock sensor power circuit for one second, with the ignition switch in the ACCESSORY, ON, or START position for a short to ground.
The BCM detects a open in the Passlock ground circuit after the ignition is cycled from START to the OFF position.
For a short to power, the BCM must sense battery voltage for at least 1 second after the ignition is cycled from RUN, to START, and back to OFF.