Power Door Locks Malfunction
Power Door Locks Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) monitors the voltage level of the door lock and door unlock signal circuits. When the central door lock switch is in the open position, the voltage level in the signal circuit will be near 12 volts. When the central door lock switch is pressed to the lock or unlock position, a signal will be sent to the K9 BCM requesting a lock or unlock command.
The BCM, upon receipt of a lock switch lock or unlock signal, will supply battery voltage to the door lock actuator lock or unlock control circuits. Since the opposite side of the lock actuator is connected to ground through the other lock actuator control circuit, the doors will then lock or unlock as commanded.
Reference Information
Schematic Reference
Door Lock/Indicator Schematics (Door Lock/Indicator Schematics)
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 (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Central Door Lock Switch on Center Console parameter while using the central door lock switch. The reading should be Inactive and change to Lock and Unlock when pushing the appropriate switch.
• If the value does not change, refer to Central Door Lock Switch Malfunction.
2. Command the doors to LOCK and UNLOCK by using the central door lock switch, the doors should LOCK and UNLOCK when changing between the commanded states.
• If a door does not LOCK or UNLOCK, refer to Door Lock Malfunction.
• If all doors do not LOCK or UNLOCK, refer to All Door Locks Inoperative.
Circuit/System Testing
Central Door Lock Switch Malfunction
1. Ignition OFF, disconnect the X2 harness connector at the A20 radio/HVAC control.
2. Ignition ON, verify the scan tool Central Door Lock Switch on Center Console parameter is Inactive.
• If the value is Lock, test the signal circuit terminal 12 for a short to ground. If the circuit tests normal, replace the K9 BCM.
• If the value is Unlock, test the signal circuit terminal 13 for a short to ground. If the circuit tests normal, replace the K9 BCM.
3. Install a 3 A fused jumper wire between the signal circuit terminal 12 and ground. Verify the scan tool Central Door Lock Switch on Center Console parameter is Lock.
• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 13 and ground. Verify the scan tool Central Door Lock Switch on Center Console parameter is Unlock.
• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
5. If all circuits test normal, replace the A20 radio/HVAC control.
Door Lock Malfunction
1. Ignition OFF, disconnect the harness connector at the A23 door latch assembly.
2. Connect a test lamp between the control circuit terminals listed below:
* A23D door latch assembly-driver terminal 2 and terminal 3
* A23P door latch assembly-passenger terminal 7 and terminal 8
3. Ignition ON, command the door to LOCK and UNLOCK by using the central door lock switch. The test lamp should briefly illuminate when commanding the LOCK and UNLOCK states.
• If the test lamp is always OFF, test either control circuit for an open/high resistance. If the circuits test normal, replace the K9 BCM.
• If the test lamp is always ON, test either control circuit for a short to voltage. If the circuits test normal, replace the K9 BCM.
4. If all circuits test normal, test or replace the A23 door latch assembly.
All Door Locks Inoperative
1. Ignition OFF, disconnect the X2 harness connector at the K9 BCM.
2. Ignition ON, 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.
3. Ignition OFF, disconnect the X6 harness connector at the K9 BCM.
4. Test for infinite resistance between the control circuit terminals listed below and ground:
* Control terminal 1
* Control terminal 2
* Control terminal 4
• If not the specified value, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate A23 door latch assembly.
5. If all circuits test normal, replace the K9 BCM.
Component Testing
1. Ignition OFF, disconnect the harness connector at the appropriate A23 door latch.
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 door latch should perform the LOCK and UNLOCK functions.
• If it does not perform as specified, replace the A23 door latch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Front Side Door Latch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM and radio/HVAC control replacement, setup and programming