Chevrolet Trax: DTC B3125, B3130, OR B3135: Driver door only unlock/all doors lock/unlock

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B3125

Driver Door Only Unlock Circuit

DTC B3130

All Doors Unlock Circuit

DTC B3135

All Doors Lock Circuit

For symptom byte information refer to: Symptom Byte List

Diagnostic Fault Information

Circuit/System Description

The body control module (BCM) controls the driver and passenger door latches. When the BCM receives a driver door unlock, passenger door unlock or all door lock command, it will provide voltage to the appropriate door lock circuits and ground to the opposite door lock circuits causing the actuator to perform the lock or unlock function.

Conditions for Running the DTC

When the output is actively being requested by the BCM.

Conditions for Setting the DTC

B3125 02, B3130 02 and B3135 02

• A short to ground or an open/high resistance in the BCM B+ circuit.
• The BCM detects a short to ground on a door latch control circuit.

Action Taken When the DTC Sets

The power door locks will be inoperative

Conditions for Clearing the DTC

• The DTC will be current for as long as the fault is present.
• When the fault is no longer present, the DTC will be a history DTC.
• A history DTC will clear after 50 ignition cycles.

Reference Information

Schematic Reference

• Door Lock/Indicator Schematics (Encore), Door Lock/Indicator Schematics (Trax)
• Body Control System Schematics (Encore) , Body Control System Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Power Door Locks Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify all vehicle doors LOCK and UNLOCK when commanding the All Doors Lock/Unlock with a scan tool.

• If only the driver door LOCK or UNLOCK functions do not work

Refer to Power Door Locks Malfunction.

• If one or more, but not all, passenger door LOCK or UNLOCK functions do not work Refer to Power Door Locks Malfunction.
• If all door LOCK and UNLOCK functions do not work

Refer to Circuit/System Testing

• If the LOCK and UNLOCK function for all doors works

3. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON.
2. Verify a test lamp illuminates between the B+ circuit terminal 4 and ground.

If the test lamp does not illuminate and the circuit fuse is good

1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open

3. Ignition OFF.
4. Test for infinite resistance between the B+ circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

5. Disconnect the harness connector at each of the A23 Door Latch Assemblies.
6. Test for infinite resistance between each control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the appropriate A23 Door Latch Assembly.
• If the test lamp illuminates

3. Ignition OFF, connect the X2 harness connector at the K9 Body Control Module. Disconnect the harness connector at the A23D Door Latch Assembly-Driver, ignition ON.

NOTE:

Leaving the DMM connected between a control circuit and ground for greater than 20 seconds will cause the K9 Body Control Module to interpret the test as a system fault and will cause the voltage on the control circuit to drop to 0 V. If the voltage drops to 0 V, operate the door locks using the door lock switch to restore the voltage for testing.

4. Test for greater than 5 V between the control circuit terminal 2 and ground.

• If 5 V or less

1. Ignition OFF, disconnect the X6 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the control circuit terminal listed below and ground:

• Control circuit terminal 1 X6
• Control circuit terminal 2 X6
• Control circuit terminal 4 X6
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K9 Body Control Module.
• If greater than 5 V

5. Verify that a test lamp does not illuminate between the control circuit terminal 2 and ground

• If the test lamp illuminates

1. Ignition OFF, disconnect the X6 harness connector at the K9 Body Control Module
2. Test for less than 1 V between the control circuit terminal listed below and ground:

• Control circuit terminal 1 X6
• Control circuit terminal 2 X6
• Control circuit terminal 4 X6
• If greater than 1 V, repair the short to voltage on the circuit.
• If less than 1 V, replace the K9 Body Control Module.
• If the test lamp does not illuminate

6. Replace the K9 Body Control Module.

Component Testing

1. Ignition OFF, disconnect the harness connector at the appropriate A23 Door Latch Assembly.
2. Install a 25 A fused jumper wire between one of the control terminals and 12 V. Momentarily install a jumper wire between the other control terminal and ground. Reverse the jumper wires at least two times, the A23 Door Latch Assembly should perform the LOCK and UNLOCK function.

• If the actuator does not perform the LOCK and UNLOCK function

Replace the A23 Door Latch Assembly.

• If the actuator performs the LOCK and UNLOCK function

3. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Front Side Door Latch Replacement
• Rear Side Door Latch Replacement
• Control Module References for BCM replacement, programming and setup

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