Passkey II Systems

Passkey II Wiring Schematic:

Passkey System Diagram - Typical:

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 the PCM/IGNITION fuse 5 to the PASSkey(R) decoder module terminal A1. The pellet resistance is then compared with the programmed value in the module.

If the key pellet is the proper resistance, terminal A3 is grounded, energizing the starter enable relay. At the same time, a signal is applied at terminal A2 to enable the Electronic Control Module (ECM). When this signal is received by the Powertrain Control Module (ECM), it allows fuel injector pulses to begin.

If the key resister pellet is the wrong value, the PASSkey(R) decoder module will shut down for 2 to 4 minutes. During this interval there will be no output at terminals A3 or A2.

If the ignition switch is turned on again during this interval, the timer will begin again and the PASSKey Decoder Module will remain shut down for another 2 to 4 minutes. The PASSkey(R) 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 A1 when the ignition switch is turned to RUN.

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

When the PASS Key Decoder Module senses battery voltage at terminal A1 (Ignition input) the PASS Key Decoder Module also will ground the SECURITY indicator for approximately 2 seconds as a bulb-check function. Should the key resistance not match the programmed value in the Module, the SECURITY Indicator will remain on. If the Ignition Key circuit is open or shorted, the SECURITY Indicator will not light at all and the vehicle will not crank. In vehicles equipped with UA6 the Theft Deterrent Module also controls the SECURITY Indicator during the arming sequence of the Universal Theft Deterrent System (UTD).

If the PCM loses the Cranking Fuel Enable Signal while the engine is running, the engine will not stall, and PCM Code 58 will be set. If just the Cranking Fuel Enable Circuit fails the engine will restart. However, if a loss of power or ground to the Pass Key Decoder Module caused the Cranking Fuel Enable failure, the engine will not crank when attempting to restart the vehicle.