Transponder Key - Operation

OPERATION

When the ignition switch is turned to the ON position, the Sentry Key Immobilizer System (SKIS) communicates through its antenna with the Sentry Key transponder using a Radio Frequency (RF) signal. The SKIS then listens for a RF response from the transponder through the same antenna. The Sentry Key transponder chip is within the range of the SKIS transceiver antenna ring when it is inserted into the ignition lock cylinder. The SKIS 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 SKIS to the Body Control Module (BCM) over the Controller Area Network (CAN) data bus, and the PCM allows the engine to continue running. If the PCM receives an invalid key message from the BCM, or receives no message from the SKIS over the CAN data bus, the engine will be disabled after about two seconds of operation. The instrument cluster will also respond to the invalid key message on the CAN data bus by flashing the security indicator ON and OFF.