Use a scan tool (Tech 2) to read Body Control Module (BCM) status of inputs and outputs. Use this information to check that the BCM is sending and receiving the proper data. The BCM uses data received from other vehicle systems in order to carry out some functions. Therefore, if the BCM receives the incorrect data from another vehicle system, the BCM may function improperly. Use the scan tool in order to review the data coming from its inputs and vehicle systems that interact with the BCM.

For example, when a door is closed, the scan tool displays the input status of the door ajar switch as on . When the door is open, the scan tool reads ACTIVE.

Use this kind of information when diagnosing a malfunction associated with a particular BCM input, or an input that is shared with another vehicle system.

Use a scan tool to cycle BCM outputs. Refer to the scan tool user's manual for menu navigation instructions.

Use this feature to determine if the BCM is able to activate an output, regardless of BCM inputs. Use a scan tool to select a BCM output and command the BCM to activate the output. The scan tool then displays the status of the selected output. The status information represents only what the BCM has commanded, not what action was actually taken. Check if the BCM is performing each of the selected output functions.