Circuit/System Description
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.
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.