Power Door Locks Malfunction (UE1 without ZQ6)
Power Door Locks Malfunction (RPO UE1 without ZQ6)
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
OnStar or the scan tool can command the body control module (BCM) to unlock the driver door. When this command is given, the BCM grounds and actuates the coil on the Door Unlock relay. Once the relay is actuated, B+ is passed through the switch side of the relay and the door unlock actuator is actuated.
Reference Information
Schematic Reference
Door Lock/Indicator Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
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
Ignition ON, command the driver door lock actuator to UNLOCK with a scan tool. The driver door should perform the UNLOCK command.
Circuit/System Testing
1. Ignition OFF, disconnect the Door Unlock relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
• If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the door unlock relay.
4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the A23D door latch assembly - driver.
6. Test for less than 30 ohm between the ground circuit terminal 2 and ground
• If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the A23D door latch assembly - driver.
8. Connect a 20 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the A23D door latch assembly - driver is activated.
• If the A23D door latch assembly - driver does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the A23D door latch assembly - driver.
9. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
10. Command the A23D door latch assembly - driver to UNLOCK with a scan tool. The test lamp should illuminate while commanding the UNLOCK state.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
11. If all circuits test normal, test or replace the A23D door latch assembly - driver.
Component Testing
Door Lock Actuator
1. Ignition OFF, disconnect the harness connector at the appropriate A23D door latch assembly - driver.
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 A23D door latch assembly - driver should perform the LOCK and UNLOCK functions.
• If it does not perform as specified, replace the A23D door latch assembly - driver.
Relay Test
1. Ignition OFF, disconnect the Door Unlock relay.
2. Test for 60-180 ohm between terminals 85 and 86.
• If not within the specified range, replace the Door Unlock relay.
3. Test for infinite resistance between the following terminals:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If not the specified value, replace the Door Unlock relay.
4. Install a 25 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2.0 ohm between terminals 30 and 87.
• If greater than the specified range, replace the Door Unlock relay.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Front Side Door Lock Replacement (Front Side Door Lock Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming