Service Information

Volt

DTC B3125, B3130, or B3135

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 B3125 02: Driver Door Only Unlock Circuit Short to Ground

DTC B3125 04: Driver Door Only Unlock Circuit Open

DTC B3130 02: All Doors Unlock Circuit Short to Ground

DTC B3130 04: All Doors Unlock Circuit Open

DTC B3135 02: All Doors Lock Circuit Short to Ground

DTC B3135 04: All Doors Lock Circuit Open

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
BCM B+	B3125 02, B3130 02, B3135 02	B3125 02, B3130 02, B3135 02	--	--
Door Lock Actuator Lock Control 2	B3125 02, B3130 02, B3135 02	B3125 04, B3130 04, B3135 04	1	--
Door Lock Actuator Lock Control	B3125 02, B3130 02, B3135 02	B3125 04, B3130 04, B3135 04	1	--
Door Lock Actuator Unlock Control	B3125 02, B3130 02, B3135 02	B3125 04, B3130 04, B3135 04	1	--
1. All Door Latches Inoperative

Circuit/System Description

The body control module (BCM) controls the door lock, passenger door unlock and driver door unlock circuits. Voltage is applied to the appropriate circuit when the BCM detects a door lock/unlock switch activation or a keyless entry lock or unlock command.

Conditions for Running the DTC

The system voltage is 9-16 V.

Conditions for Setting the DTC

B3125 02, B3130 02, B3135 02

The BCM detects a short to ground on a door latch control circuit.

B3125 04, B3130 04, B3135 04

The BCM detects an open/high resistance on a door latch control circuit

Action Taken When the DTC Sets

All the power door locks will be inoperative.

Conditions for Clearing the DTC

•	This 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

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

Command the door latches to LOCK and UNLOCK with a scan tool. Observe the operation of the door latches, each door should LOCK and UNLOCK when changing between the commanded states.

Circuit/System Testing

Vehicle OFF, disconnect the X2 harness connector at the K9 BCM.
Vehicle in Service Mode, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance

Vehicle OFF, disconnect the X6 harness connector at the K9 BCM.
Disconnect the X1 harness connector at the X50A fuse block-under-bonnet.
Test for infinite resistance between the control circuit listed below and ground:

•	Connector X1, terminal 11 at the X50A fuse block-under-bonnet

•	Connector X1, terminal 12 at the X50A fuse block-under-bonnet

•	Connector X6 terminal 1 at the K9 BCM

•	Connector X6 terminal 4 at the K9 BCM

⇒	If not the specified value, test the appropriate control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate A23 door latch assembly.

Connect the X1 harness connector at the X50A fuse block-under-bonnet.
Test for infinite resistance between the control circuit terminal 2 X6 at the K9 BCM and ground.

⇒	If not the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the X50A fuse block-under-bonnet.

If all circuits test normal, replace the K9 BCM.

Component Testing

Vehicle OFF, disconnect the harness connector at the appropriate A23 door latch assembly.
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 functions.

⇒	If it does not perform as specified, replace the A23 door latch assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Front Side Door Lock Replacement

•	Rear Side Door Lock Replacement

•	Fuse Block Replacement

•	Control Module References for BCM replacement, programming and setup