System Check

A Diagnostic System Check - Theft Deterrent:

CIRCUIT DESCRIPTION
The Passlock system is designed to prevent engine operation if the correct key is not used to start the vehicle. The ignition key turns the lock cylinder, cylinder rotation produces an analog voltage code in the Passlock sensor.

The EVO/Passlock module receives this voltage code and is compared to the last learned voltage code. If the codes match, the EVO/Passlock module sends a class 2 message to the VCM/PCM, enabling the fuel injectors.

DIAGNOSTIC AIDS
You must perform the Diagnostic System Check prior to diagnosing any symptom or any Diagnostic Trouble Code table. Diagnose the DTC's in the order specified in the Passlock System Displaying DTC list. Failure to do so may result in the following conditions:
^ Extended diagnostic time
^ Incorrect diagnosis
^ Incorrect parts replacement

If a EVO/Passlock module, a passlock sensor, or the VCM/PCM have been replaced, perform the learn procedure before following the Diagnostic System Check.

IMPORTANT: On vehicles equipped with diesel engines, if you are instructed in any Theft Deterrent System test to start the vehicle you must always wait for the "Wait to Start" indicator to distinguish prior to cranking the engine. This process could take anywhere from 2 to 17 seconds.