Personal Automotive Security System (Pass-Key (R) II)

The PASS-Key(R) II system prevents the engine from starting if the proper resistance is not sensed from the ignition key. Only one of the 15 resistance values available works with each PASS-Key(R) II module.

The PASS-Key(R) II module controls the starter enable relay and the Powertrain Control Module PCM fuel enable input. If the PASS-Key(R) II module does not send the proper pulse width modulated (PWM) signal to the PCM fuel enable input, the PCM does not allow fuel to be provided to the engine.

Resistor sensing contacts are located in the Ignition Key Lock Cylinder. These contact the Key Resistor Pellet on the key when it is inserted. Rotating the lock applies ignition voltage to the PASS-Key(R) II module and pellet resistance is read. The pellet resistance, read across terminals B7 and B8, is then compared to the resistance value stored in the PASS-Key(R) II module.

If the Key Resistance Pellet is of the proper resistance, the PASS-Key(R) II module grounds terminal A4, energizing the Starter Enable Relay. At the same time, the module provides the cranking fuel enable signal at terminal A3 to inform the Powertrain Control Module (PCM) to allow fuel to flow.

If the resistance is incorrect, the PASS-Key(R) II module shuts down for approximately three minutes. During this interval, there is no output at A3 or A4 and the SECURITY indicator illuminates. The Ignition Switch input is ignored during this shut down period. For this reason, the timer will run and the SECURITY indicator remains illuminated with Ignition ON or OFF.

Once the timer expires, the next time the Ignition Switch is cycled from OFF to ON, the PASS-Key(R) II module timer is reset. A key having the correct code can then be used to start the engine.