Conditions for Setting the DTC
WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
DTC B2585 01 and B2585 04
The BCM detects a short to voltage or an open/high resistance in the park lamps control circuit terminal 11 X4.
DTC B2585 02
The BCM detects a short to ground in the park lamps control circuit terminal 11 X4.