Conditions for Setting the DTC

WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.

When the BCM receives a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is shorted to ground.
When the BCM is not receiving a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is open only to the first splice from the BCM or the circuit is shorted to voltage.
There is a loss of the instrument panel fuse block TBC 2B battery supply voltage to the BCM for one second.