B2947

Circuit Description
The Passlock (TM) system is designed in order to prevent vehicle operation if the correct ignition key is not used in order to start the vehicle. The ignition key allows the lock cylinder to turn. Once the lock cylinder turns, the passlock (TM) sensor (located inside the ignition switch assembly) sends an analog voltage code to the Body control module (BCM). If the BCM receives the correct analog voltage code from the Passlock (TM) sensor, the BCM sends a class 2 serial data password to the powertrain control module (PCM)/vehicle control module (VCM). This action allows the vehicle to start.

Conditions for Setting the DTC
The Passlock (TM) power circuit remains low (shorted to ground) for 1 second when the ignition switch is in the RUN position.

Action Taken When the DTC Sets
- The vehicle does not start if the fault occurs before you start the vehicle. The security telltale will be ON.
- The vehicle will continue to start if the fault occurs after the vehicle is running. The following conditions will exist:
- The vehicle will be in the Fail Enable mode.
- The security telltale will be ON.

Conditions for Clearing the MIL/DTC
- All current DTC (except B3031) clears after an ignition cycle occurs without the fault recurring.
- A history DTC clears after 100 concurrent ignition cycles occur without the fault recurring.
- Use a scan tool in order to clear history and current DTCs.

Diagnostic Aids
- When the ignition switch is turned from the OFF position to the RUN position, the security telltale will turn ON STEADY and then turn OFF after 3 seconds.
- Perform a visual inspection of the wiring.
- Perform a visual inspection of the connectors.
- Refer to Intermittents and Poor Connections for intermittent and poor connections.

Steps 1 - 5:

Step 6:

Steps 7 - 10:

Test Description
The numbers below refer to the step number(s) on the diagnostic table.
2. This test inspect for a short to ground of CKT 812.
3. This step inspects for a short between CKT 812 and CKT 1057.
5. This step isolates the short in CKT 812 between the harness and the Passlock sensor.
8. This step isolates the short in CKT 812 and CKT 1057 between the harness and the Passlock sensor.