Diagnostic System Check - Passlock

CIRCUIT DESCRIPTION
The theft deterrent system function has been incorporated into the Body Control Module (BCM).The theft deterrent is provided in order to prevent the vehicle operation if the correct key is not used in order to start the vehicle. The ignition key turns the lock cylinder. The cylinder rotation produces an analog voltage code in the Passlock sensor. The voltage code is received by the BCM. The BCM compares the voltage code to the previously learned voltage code. If the codes match, a class 2 message is sent from the BCM to the Powertrain Control Module (PCM)/Vehicle Control Module (VCM). The message enables the fuel injectors.

DIAGNOSTIC AIDS
You must diagnose the Diagnostic Trouble Codes (DTCs) in the order specified in the Passlock(TM) system DTC list. Failure to do so may result in the following conditions:
^ Extended diagnostic time
^ Incorrect diagnosis
^ Incorrect parts replacement

If the BCM, the Passlock sensor, or the PCM/VCM have been replaced, perform the learn procedure before following the diagnostic system check.

Refer to the instrument panel section for additional information on the message center display. Vehicles equipped with a content theft deterrent system use the message center in order to provide an indication similar to that of the vehicle theft deterrent system. Carefully follow the steps within the VTD Diagnostic System Check.

TEST DESCRIPTION

A Diagnostic System Check - Theft Deterrent:

The numbers below refer to the step numbers on the diagnostic table.
1. This test inspects for a malfunction related to the instrument panel cluster (IPC) preventing the SECURITY telltale bulb inspection. If this malfunction is due to an open GAUGES fuse, the SECURITY telltale will not turn ON and the engine will not run.
2. The SECURITY telltale will turn ON and remain ON when the ignition switch is in the RUN position and a Passlock(TM) DTC is currently detected.
3. This test inspects for a tamper condition. The engine will not run while the SECURITY telltale is flashing and the tamper timer is running. Refer to Tamper Timer in Scan Tool Data Definitions Scan Tool Data Definitions for more information. Scan Tool Testing and Procedures
4. This test inspects for a malfunction that prevents communication between the IPC and the BCM. This condition causes the security telltale to remain ON when the ignition switch is turned to the OFF position.
8. This operation of the SECURITY telltale indicates that Passlock(TM) DTCs exist. If the scan tool is operating properly and indicates that no Passlock(TM) DTCs exist, the BCM may be malfunctioning.
9. This condition indicates an open in the Passlock(TM) sensor circuits. If the powertrain parameter VTD Fuel Disable displays ACTIVE during or immediately following cranking, the sensor circuits are also open. This condition is tested in the DTC B2958 diagnostic table. Refer to DTC B2958 Security System Sensor Data Circuit High. B2958