Key, Transponder: Operation

When the status of the ignition switch transitions to On, the Body Control Module (BCM) communicates through its antenna with the Sentry Key transponder using a Radio Frequency (RF) signal. The BCM then listens for a RF response from the transponder through the same antenna. The Sentry Key transponder chip is within the range of the BCM transceiver antenna ring when it is inserted into the ignition lock cylinder. The BCM determines whether a valid key is present in the ignition lock cylinder based upon the response from the transponder. If a valid key is detected, that fact is communicated by the BCM to the Electric Vehicle Control Unit (EVCU) over the Controller Area Network (CAN) data bus, and the EVCU allows the electric vehicle drive unit to operate. If the EVCU receives an invalid key message from the BCM, or receives no message from the BCM over the CAN data bus, the vehicle will be disabled from operation. The Instrument Panel Cluster (IPC) will also respond to the invalid key message on the CAN data bus by flashing the security indicator On and Off.