B2958

Circuit Description
The Body control module (BCM) will read an analog voltage form the Passlock sensor. Based on an internal reference, the BCM will determine if the measured voltage is in 1 of the following conditions:
- Open
- Shorted to ground
- A valid code
- A tamper code
There are 10 possible valid code combination. The BCM will only recognize the last learned valid code.

Conditions for Setting the DTC
- The ignition switch is ON.
- The BCM signal input is greater than 4.9 volts for 1 second after turning the ignition switch to the CRANK position.

Action Taken When the DTC Sets
- The DTC will set only when the engine is running
- The BCM will be in the fail enable mode allowing the vehicle to start and run.
- The security telltale will be on.

Conditions for Clearing the DTC
- The current DTC will clear once an ignition cycle has occurred without the fault recurring.
- After 100 concurrent ignition cycles occur without the fault recurring, a history DTC clears.
- Using a scan tool.

Diagnostic Aids
- When replacing the Passlock sensor, all of the following components are included as a replacement part and must be replaced:
- The lock
- The sensor
- The filter
- The harness
- Use a scan tool in order to inspect the Passlock data voltage and the Passlock code.
- Perform a visual inspection of the wiring and the connectors.
- Inspect the Passlock sensor harness for an intermittent or a short to battery. Refer to Intermittents and Poor Connections in Overall Vehicle Information / Testing and Inspection.
- You may be directed to this table from the VTD Systems Check without a DTC B2958 being set. If you were directed to this table, follow all of the steps in this diagnostic.
- When directed to this table, DTC B2958 may have a history status.
- When connecting connector C201, make measurements on the harness side of the connector.

Steps 1 - 2:

Steps 3 - 5:

Step 6:

Steps 7 - 11:

Steps 12 - 14:

Steps 15 - 18:

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the Passlock (TM) data terminal has an open condition or a short to battery.
3. This step determines if Passlock (TM) sensor power is available at the Body control module (BCM). If CKT 812 is shorted to ground, DTC B2947 will set in addition to DTC B2958. Troubleshoot DTC B2947 prior to DTC B2958. Diagnosing and repairing DTC B2947 may clear DTC B2958.
4. This step inspects the BCM Passlock ground.
5. This step inspects for an open in any of the Passlock (TM) sensor lines.
8. This step inspects for a short to battery on the Passlock (TM) data line.
9. This step isolates the short to battery between the Passlock~ sensor and CKT 1836.
13. This step inspects for a short to ignition 1.
14. This step inspects for a short between CKT 1836 and CKT 812.
15. This step isolates the short to ignition I between the harness and the Passlock sensor.
17. This step inspects for a short between CKT 812 and CKT 1836.