Conditions for Setting the DTC

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

When the BCM receives a front fog lamp switch OFF command and the front fog lamp relay control circuit is shorted to ground.
When the BCM receives a front fog lamp switch ON command and the front fog lamp relay control circuit is shorted to voltage or open.