Theory Of Operation
WARNING: This page is about a different car, the 2014 Dodge Journey. However, it is still accessible from the selected car via links, so may be relevant.
The Intelligent Battery Sensor (IBS) is mounted in-line with the negative Battery Cable. The IBS monitors the Battery state of charge and current draw. The IBS also has a built in thermistor that calculates the Battery temperature. This information is reported through a LIN BUS circuit to the Body Control Module (BCM). The BCM broadcasts the information to the Powertrain Control Module (PCM) over the CAN BUS.