Transponder Key: Operation

Each Sentry Key has a unique transponder identification code permanently programmed into it by the manufacturer. Likewise, the SKIM has a unique "Secret Key" code programmed into it by the manufacturer as well. When a Sentry Key is programmed into the memory of the SKIM, the SKIM stores the transponder identification code from the Sentry Key, and the Sentry Key learns the "Secret Key" code from the SKIM. Once the Sentry Key learns the "Secret Key" code of the SKIM, it is also permanently programmed into the transponder's memory. Therefore, blank keys for the SKIS must be programmed by the SKIM in addition to being cut to match the mechanical coding of the ignition lock cylinder. Refer to STANDARD PROCEDURE - TRANSPONDER PROGRAMMING .

The Sentry Key's transponder is within the range of the SKIM's transceiver antenna ring when it is inserted into the ignition lock cylinder. When the ignition switch is turned to the ON position, the SKIM communicates with the Sentry Key via a radio frequency (RF) signal. The SKIM determines if a valid key is present based on the information it receives from the Sentry Key. If a valid key is detected, that fact is communicated to the PCM via the PCI bus and the vehicle is allowed to continue running. If an invalid key is received by the PCM or no status at all is communicated, the vehicle will stall after two (2) seconds of running. The LED indicator will be flashing at this point. The Sentry Key's transponder can not be repaired. If it is faulty or damaged, it must be replaced.

Common communication problems:

1. Two transponder keys too close together.
2. Speed Pass too close to transponder key.

Solid indicator that there is a system failure.

1. Loss of PCM communication.
2. Failed antenna circuit.