Circuit/System Description

The body control module (BCM) monitors the vehicle system voltage on 2 circuits: BCM B+ circuit terminal X3-3, which is fed through the BCM fuse, and the high resolution B+ circuit terminal X4- 10, which is fed through the RVC fuse. The BCM monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range. The BCM monitors the system voltage over an extended length of time. If the BCM detects the system voltage is outside an expected range for the calibrated length of time, or the two BCM battery sense circuits differ by 2 volts, DTC B1517 will set. The system voltage message is sent to the other modules. The message will default to 12.9 volts if there is a plausibility failure.