Conditions For Setting The DTC

WARNING: This page is about a different car, the 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, 2001 Chevrolet Monte Carlo, and 2001 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.

DTC sets when BCM detects an open, short to voltage in trunk ajar switch signal circuit for greater than 2 seconds.
BCM detects a loss of battery voltage, ignition 0 voltage or ground for rear compartment occupant sensor.