Conditions for Setting the DTC

WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.

The BCM detects an open/high resistance in the headlamp switch park lamps ON signal circuit.
The BCM detects a short to ground in the headlamp switch headlamps ON signal circuit.
The BCM detects a short to ground in the headlamp switch headlamps OFF signal circuit.