Voyager V6-3.3L VIN 3 Flex Fuel (2003)
Alarm System Transponder: Description and Operation
Sentry Key Immobilizer Transponder
TRANSPONDER KEY
The Sentry Key Immobilizer System (SKIS) uses a transponder chip that is integral to each ignition key to communicate with the Sentry Key
Immobilizer Module (SKIM). Ignition keys are supplied with the vehicle when it is shipped from the factory The transponder chip is undermolded
within the head of the key. This undermold is hidden beneath an overmolded rubber cap.
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
Electrical, Vehicle Theft Security, Transponder Key, 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 indicator light 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:
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Two transponder keys too close together.
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Speed Pass too close to transponder key.
Solid indicator that there is a system failure.
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Loss of PCM communication.
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Failed antenna circuit.
