System Components

Ignition Key
The ignition key for vehicles equipped with the PASS-Key II(R) system is an assembly of a typical square ignition key blank and resistor. The ignition key blank and resistor are not serviceable separately. There are 15 different ignition keys, each with a different resistance value. The ignition key also has mechanical cuts similar to non- PASS-Key II(R) ignition keys.

IMPORTANT:
^ When servicing the PASS-Key II(R) system, obtain all ignition keys, if possible, and verify proper values with tool J 35628-A, VATS/PASS Interrogator. Refer to "Duplication of Keys".

Steering Column Lock and Ignition Cylinder
The ignition cylinder in vehicles equipped with the PASS-Key II(R) system contains a set of electrical contacts used to measure the resistor in the ignition key. When servicing the ignition cylinder, be certain to maintain proper wire routing. A two pin connector at the base of the steering column connects the contacts to the vehicle wiring. The connector is also used for diagnostic purposes. The ignition cylinder also performs all functions of ignition cylinders on non-PASS-Key II(R) vehicles. When replacing an ignition cylinder, it will be necessary to make new ignition keys which match the PASS-Key II(R) key code of the theft deterrent module and the mechanical cut of the new ignition cylinder.

IMPORTANT:
^ The wire routing for the contacts inside the steering column is critical.

Theft Deterrent Module
The theft deterrent module contains the logic of the PASS-Key II(R) system. The theft deterrent module has inputs from the ignition circuit and the resistor. The theft deterrent module has outputs to the starter enable circuit, the fuel enable circuit, and the security lamp circuit.

Theft Deterrent Relay
The relay is used to stop the engine from cranking if the correct resistance is not sensed at the ignition key. It prevents the engine from cranking by opening the circuit to the starter solenoid switch.

Powertrain Control Module (PCM)
The PCM reads the fuel enable circuit to determine if fuel injection should be allowed. If the fuel enable PWM signal is not present, the PCM will not allow fuel injection. If the PWM signal is present, the PCM will allow fuel injection and normal engine operation.

The PCM has some diagnostic features associated with the fuel enable input, including diagnostic trouble codes. For details, refer to Computers and Controls. Powertrain Management

Ignition Input
The ignition input is used to turn the theft deterrent module on. When the theft deterrent module is turned on, it will read the resistor and control the outputs accordingly. When the theft deterrent module is turned off the resistor is not read, and the theft deterrent relay and fuel enable output will not allow the engine to start. When the ignition switch is in the "OFF" position, the battery input to the theft deterrent module will draw about 1 milli-amp.

Key Resistor Inputs
The key resistor inputs are used to determine if the correct ignition key is being used to start the vehicle. The key resistor inputs are read only when the theft deterrent module is first turned on. If the key code (resistance value) of the ignition key matches the value stored in the theft deterrent module, the theft deterrent relay and fuel enable output will allow the vehicle to start. If the resistance value of the ignition key does not match the value stored in the theft deterrent module, the relay and fuel enable output will not allow the vehicle to start.

Starter Enable Output
The starter enable circuit controls the theft deterrent relay. When the theft deterrent module sees the proper resistance at the ignition key, it grounds the theft deterrent relay which closes the starter enable circuit. This process allows the engine to be cranked. If the theft deterrent module does not see the proper resistance at the ignition key, it will not ground the theft-deterrent relay.

Fuel Enable Output
The fuel enable circuit is an output from the theft deterrent module and an input to the PCM. When the theft deterrent module sees the proper resistance at the ignition key, it will output a pulse width modulated (PWM) signal to the PCM. If the theft deterrent module does not see the proper resistance at the ignition key, it will not output the PWM signal to the PCM.

Security Indicator Lamp Output
The "SECURITY" lamp circuit is an indicator lamp Output. The lamp output will be grounded during a five second "bulb test" at key on, at any time that the theft deterrent module is preventing the engine from starting, or if the theft deterrent module is not properly programmed.