Conditions for Setting the DTC
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The BCM detects a short to ground on the Passlock sensor power circuit for one second, with the ignition switch in the ACCESSORY, ON, or START position.