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.

When the BCM receives a command to illuminate the low beam or DRL headlamps and the low beam headlamp driver module control circuit is open or shorted to voltage.
When the BCM does not receive a command to illuminate the low beam or DRL headlamps and the low beam headlamp driver module control circuit is shorted to ground.