B3135

DTC B3125, B3130, or B3135

Diagnostic Instructions

* Perform theDiagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptors
DTC B3125 00
- Left Front/Driver Door Only Unlock Circuit

DTC B3130 00
- All Door Unlock Circuit

DTC B3135 00
- All Door Lock Circuit




Diagnostic Fault Information






Circuit/System Description

The body control module (BCM), upon receipt of a lock switch lock signal, will switch the door lock relay control circuit to battery positive voltage. This will energize the LOCK relay. The remaining unlock relays receive voltage from the underhood fuse block, the BCM upon receipt of a unlock signal or driver door unlock signal will switch the appropriate unlock relay to ground. This will energize the appropriate unlock relay unlocking the appropriate doors.


Conditions for Running the DTC

The system voltage must be between 9-16 volts.


Conditions for Setting the DTC

B3125 00

The BCM detects a fault in the driver door unlock control circuit while commanding the LOCK relay.

B3130 00

The BCM detects a fault in the door unlock control circuit while commanding the DOOR UNLOCK relay.

B3135 00

The BCM detects a fault in the door lock control circuit while commanding the DOOR LOCK relay.


Action Taken When the DTC Sets

The power door locks will not operate.


Conditions for Clearing the DTC

* This DTC will change from current to history when the fault is no longer present.
* A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.



Reference Information
Schematic Reference

Door Lock/Indicator Schematics (Door Lock/Indicator Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Power Door Locks Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

Command the driver door and passenger door latches to Lock and Unlock with the scan tool, all doors should Lock and Unlock.


Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the I/P fuse block.
2. Connect a test lamp between the control circuit terminal 56 and ground.
3. Ignition ON, command the Lock Doors ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

4. Connect a test lamp between the control circuit terminal 54 and B+.
5. Command the Driver Door Unlock ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the BCM.

6. Connect a test lamp between the control circuit terminal 58 and B+.
7. Command the Unlock Doors ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the BCM.

8. If all circuits test normal, replace the I/P fuse block.



Repair Instructions

Perform theDiagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Instrument Panel Wiring Harness Junction Block Replacement (Instrument Panel Wiring Harness Junction Block Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming