Circuit/System Description
WARNING: This page is about a different car, the 2016 GMC Acadia, 2016 Chevrolet Traverse, and 2016 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
The B18 Battery Current Sensor is a 3-wire hall effect current sensor. The body control module (BCM) supplies 5 V and ground to the B18 Battery Current Sensor. The B18 Battery Current Sensor measures the amount of current flowing to or from the battery, and supplies a pulse width modulation (PWM) signal to the BCM.