Conditions for Setting the DTC
WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
B2A87
The BCM receives a switch signal voltage message too high out of the expected range
B2A88
The BCM receives a switch signal voltage message too low out of the expected range
B2A8A
The BCM receives a valid switch signal voltage message for greater than a calibrated time (approximately 90 seconds).