B2781

CIRCUIT DESCRIPTION
The instrument panel cluster (IPC) supplies a 5 volt signal and a ground circuit for the PASS-Key(R) system. This allows the IPC to detect PASS-Key(R) resistance values. Inserting the PASS-Key(R), with resistor pellet, in the ignition lock cylinder completes the PASS-Key(R) circuit. Contacts in the ignition lock cylinder mate with the pellet contacts. The IPC compares the resistance value of the key pellet to the valid resistance programmed into the IPC. If the proper resistance value is read, the IPC allows the engine to start. If the resistance value is incorrect, a malfunction is present and a DTC will set.

CONDITIONS FOR SETTING THE DTC
^ The IPC determines that one of the 15 valid key pellets was detected and matches the resistance of the one stored in the IPCs memory.
^ The IPC class 2 vehicle security password report message was sent and acknowledged by the PCM.
^ The IPC then determines that one of the 15 valid key pellets was detected, but now the key pellet does not match the resistance of the one stored in the IPCs memory.

ACTION TAKEN WHEN THE DTC SETS
The IPC displays the THEFT SYSTEM PROBLEM, CAR MAY NOT RESTART message on the driver message center.

CONDITIONS FOR CLEARING THE DTC
^ This DTC requires an ignition cycle in order to change from current to history.
^ The IPC detects a valid PASS-Key(R) resistance value on the PASS-Key(R) signal circuit.
^ A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
^ Use a scan tool.

DIAGNOSTIC AIDS
Before attempting to diagnose a wiring problem, try to start the vehicle with every available ignition key for the vehicle. If one key starts the vehicle and another key does not, replace the malfunctioning key with another key of the same code value as the key that starts the vehicle.

TEST DESCRIPTION

Steps 1-4:

Steps 5-14:

The number below refers to the step number on the diagnostic table.
5. This test determines the key resistance code currently stored in the IPC memory.