PASS-Key

PURPOSE
The Personal Automotive Security System (PASS-Key) is designed to disable vehicle operation if the incorrect key or starting procedure is used.

OPERATION
The PASS-Key decoder module sends a signal to the Powertrain Control Module (PCM), on circuit 229, if the correct key is being used. If the proper signal does not reach the PCM, it will not pulse the fuel injectors "ON" and thus not allow the vehicle to start.

Passkey II Schematic (Typical):

Passkey System Diagram - Typical:

CIRCUIT OPERATION

Resistor sensing contacts are located in the ignition key lock cylinder. These contact the key resistor pellet on the key when it is inserted. When the lock is rotated, battery voltage is applied through a fuse to the PASS-Key decoder module. The pellet resistance is then compared against a fixed resistance in the module.

If the key pellet is the proper resistance, terminal A4 is grounded, energizing the starter enable relay. At the same time, a signal is applied at terminal A3 to enable the Electronic Control Module (ECM). When this signal is received by the Electronic Control Module (ECM), it allows fuel injector pulses to begin.

If the key resister pellet is the wrong value, the PASS-Key decoder module will shut down for 2 to 4 minutes. During this interval there will be no output at terminals A3 or A4.

If the ignition switch is turned on again during this interval, the timer will remain shut down for another 2 to 4 minutes. The PASS-Key decoder module will continue this process even if a key with the correct pellet is used to turn the ignition back on. The timer is restarted by the ignition switch voltage at terminal A2 when the ignition switch is turned to RUN.

Once the timer has completed its 2 to 4 minute cycle with the ignition off, the PASS-Key decoder module and timer are reset. A key having the correct code can then be used to start the engine.

The security indicator is controlled directly by the PASS-Key decoder module. If there is a PASS-Key failure this indicator will be grounded by the PASS-Key decoder module with the ignition in RUN, BULB TEST, or START. When the ignition switch is first placed in RUN, BULB TEST, or START the indicator lights for about 2 seconds as a bulb check.

Special Passkey Ignition Key - With Specific Resistance Coded Pellet:

The special ignition key used for the PASS-Key system includes a special coded resistor pellet.

Contacts In The Lock Cylinder Touch The Key's Pellet:

The special PASS-Key ignition lock cylinder contains a set of contacts that touch the coded resistor pellet in the key. A two wire harness carries this key code signal to the PASS-Key decoder module.