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
Each door lock switch is wired to the body control module (BCM) through a separate door lock/unlock signal circuit. While these circuits are separated between the BCM and respective door lock switch, they are connected into a single circuit within the BCM. The BCM supplies voltage through the door lock/unlock signal circuits to each door lock switch. When either door lock switch is operated, this supply voltage is pulled to ground, providing the BCM with the required lock or unlock signal. In order for the BCM to distinguish between a lock and unlock signal, the lock switch contains two separate paths for this voltage to flow to the same body ground. When the switch is operated to the unlock position, the supply voltage flows to ground through a 1.5k ohm resistor. When the switch is operated to the lock position, the supply voltage flows to ground through a different part of the switch circuit, which has no resistor. The BCM then interprets the flow of voltage as a lock or unlock request and powers the door lock actuators to the appropriate lock or unlock position.
The BCM powers the reversible door latch assemblies by providing battery positive voltage and ground to the appropriate lock and unlock control circuits of the door latch assemblies. The lock control circuits of the driver and passenger door latch assemblies are all connected together; however, the unlock control circuits are connected in a slightly different way. While the unlock control circuits for the passenger door latch assemblies are connected together, the door latch assembly has a separate unlock control circuit. The system is designed this way so that the keyless entry transmitter may be used to unlock only the driver door. Despite this difference, all lock actuators perform much the same way. When the door latch assemblies are not active, all actuator lock and unlock control circuits are at ground potential within the BCM. Transitioning of the lock actuators to the lock or unlocked position depends upon which control circuits receive voltage and which control circuits receive ground.
Reference Information
Schematic Reference
Door Lock/Indicator Schematics Door Lock/Indicator Schematics
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
1. Ignition ON, observe the scan tool Door Lock Switch parameters while using the driver and passenger door lock switches. The parameter should change from Idle to Lock and Unlock.
• If the value does not change, refer to Door Lock Switch Malfunction.
2. Command the Driver Door Unlock, Lock All Doors and Passenger Door(s) Unlock with a scan tool, all the door latches should perform the LOCK and UNLOCK function.
• If all door latches are inoperative, refer to Door Locks Inoperative.
• If a door does not LOCK or UNLOCK, refer to Door Lock Malfunction
Circuit/System Testing
Door Lock Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate door lock switch.
2. Test for less than 30 ohms between the ground circuit terminal A and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Door Lock Switch parameter is Idle.
• If not the specified value, test the signal circuit terminal C for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3A fused jumper wire between the signal circuit terminal C and ground. Verify the scan tool Door Lock Switch 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 BCM.
5. If all circuits test normal, test or replace the door lock switch.
Door Locks Inoperative
Note: A short to ground on any door latch control circuit or an internal short in any door latch will cause the DOOR LOCK fuse to open and all door latches will become inoperative.
1. Ignition OFF, disconnect the X4 harness connector at the BCM.
2. Test for less than 1 ohm between the ground circuit terminal E12 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect the X4 harness connector and disconnect the X3 harness connector at the BCM.
4. Test for infinite resistance between the control circuit terminals listed below and ground:
* Terminal A1
* Terminal A2
* Terminal A4
* Terminal A5
* Terminal B1
• If not the specified value, test the control circuit for a short to ground.
5. Verify that a test lamp does not illuminate between the control circuit terminals listed below and ground:
* Terminal A1
* Terminal A2
* Terminal A4
* Terminal A5
* Terminal B1
• If a test lamp illuminates, test the control circuit for a short to B+.
6. Install a 15A fused jumper wire between the control terminal A5 and 12V. Momentarily install a jumper wire between the control terminal B1 and ground. Reverse the jumper wires at least two times, the driver door latch should perform the LOCK/ UNLOCK functions.
• If it does not perform as specified, test either control circuit for an open/high resistance. If the circuit tests normal, test or replace the driver door latch.
7. Install a 15A fused jumper wire between the control terminal A5 and 12V. Momentarily install a jumper wire between the control terminal A2 and ground. Reverse the jumper wires at least two times, the passenger door latch should perform the LOCK/ UNLOCK functions.
• If it does not perform as specified, test either control circuit for an open/high resistance. If the circuit tests normal, test or replace the passenger door latch.
8. Install a 15A fused jumper wire between the control terminal A2 and 12V. Momentarily install a jumper wire between the control terminal A4 and ground. Reverse the jumper wires at least two times, the right rear door latch should perform the LOCK/ UNLOCK functions.
• If it does not perform as specified, test either control circuit for an open/high resistance. If the circuit tests normal, test or replace the right rear door latch.
9. Install a 15A fused jumper wire between the control terminal A4 and 12V. Momentarily install a jumper wire between the control terminal A1 and ground. Reverse the jumper wires at least two times, the left rear door latch should perform the LOCK/ UNLOCK functions.
• If it does not perform as specified, test either control circuit for an open/high resistance. If the circuit tests normal, test or replace the left rear door latch.
10. If all circuits test normal, replace the BCM.
Door Lock Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
2. Test for less than 20 ohms between the control circuit terminals listed below and ground:
* Driver door latch terminal 2
* Driver door latch terminal 3
* Left rear door latch terminal 2
* Left rear door latch terminal 2
* Passenger door latch terminal 5
* Passenger door latch terminal 6
* Right rear door latch terminal 5
* Right rear door latch terminal 6
• If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
3. Connect a test lamp between control circuit terminals listed below:
* Driver door latch terminals 2 and 3
* Left rear door latch terminals 2 and 3
* Passenger door latch terminals 5 and 6
* Right rear door latch terminals 5 and 6
4. Ignition ON, command the door latch to LOCK and UNLOCK by using the door lock switch. The test lamp should briefly illuminate while commanding the LOCK and UNLOCK states.
• If the test lamp remains OFF during either of the commands, test either control circuit for a short to ground. If the circuits test normal, replace the BCM.
5. If all circuits test normal, test or replace the door latch.
Component Testing
Door Lock Switch Test
1. Ignition OFF, disconnect the harness connector at the appropriate door lock switch.
2. Test for infinite resistance between the signal terminal C and the ground terminal A with the switch in the open position.
• If not the specified value, replace the door lock switch.
3. Test for less than 2 ohms between the signal terminal C and the ground terminal A with the switch in the lock position.
• If greater than the specified range, replace the door lock switch.
4. Test for 1.4-1.6k ohms between the signal terminal C and the ground terminal A with the switch in the unlock position.
• If greater or less than the specified range, replace the door lock switch.
Door Latch
1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
2. Install a 15A fused jumper wire between one of the control terminals and 12V. 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 door latch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Front Side Door Lock Replacement Front Side Door Lock Replacement
* Rear Side Door Lock Replacement Rear Side Door Lock Replacement
* Door Lock Switch Replacement Service and Repair
* Control Module References Programming and Relearning for BCM replacement, setup, and programming