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.
DTC B255F 02
The BCM detects a short to ground in the accent lamp control circuit terminal 22 X7
DTC B255F 04
The BCM detects a short to voltage or an open/high resistance in the accent lamp control circuit terminal 22 X7