Passlock sensor data is supplied to the body control module (BCM) by CKT 1836.

The passlock sensor data supplied to the BCM is in the form of V-codes or voltage codes. When the proper ignition key is turned in the ignition switch, the correct V-code is supplied to the BCM. The BCM responds by sending a serial data password to the engine controller allowing the engine to run.

If the BCM has not learned a V-code, DTC B3031 will be set. The vehicle will not start.