Power Door Locks Inoperative
Power Door Locks Inoperative
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of the diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) provides battery positive voltage and ground to the appropriate lock and unlock control circuits of the door lock and unlock relays. The lock control circuits of the driver and passenger door latch assemblies share a common relay; however, the unlock control circuits have separate relays. The system is designed this way so that the keyless entry transmitter may be used to unlock only the driver door.
The BCM supplies and monitors a reference voltage to the door lock switch through the door lock switch lock/unlock signal circuit. The door lock switch also receives a constant ground source. If a door lock switch is placed in the lock position or unlock position, the reference voltage is taken directly to ground and the BCM detects 0.0 volts on the signal circuit.
The BCM, upon receipt of a lock switch lock signal, will switch the all lock relay control circuit to battery positive voltage. This will energize the lock relay. The relay will supply voltage to the door lock actuator lock control circuits to one side of the lock actuator. Since the opposing side of the lock actuators are connected to ground through the other lock actuator control circuit and the normally closed contacts of the lock or unlock relay, the doors will then lock appropriately. The remaining unlock relays receive voltage from the I/P fuse block, the BCM upon receipt of a unlock signal or driver door unlock signal will switch the appropriate unlock relay to ground. This will energize the appropriate unlock relay. The relay will supply voltage to the appropriate door unlock control circuits to one side of the appropriate lock actuator. Since the opposing side of the lock actuators are connected to ground through the other lock actuator control circuits and the normally closed contact of the lock relay, the doors will then unlock appropriately.
Reference Information
Schematic Reference
Door Lock/Indicator Schematics (Door Lock/Indicator Diagrams)
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 (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Rear Doors Lock Cmd and Rear Doors Unlock Cmd parameters while using the driver door lock switch. The parameter should change between On and Off when changing between the commanded states.
• If the parameter does not change, Refer to Door Lock Switch Malfunction.
2. Command the door latches to LOCK and UNLOCK by using the driver door lock switch, the doors should LOCK and UNLOCK.
• If a door latch 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 driver door lock switch.
2. Install a 3A fused jumper wire between the signal circuit terminal 1 and ground. Verify the power door locks transitioned to LOCK.
• If the power door locks do not lock, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the BCM.
3. Install a 3A fused jumper wire between the signal circuit terminal 3 and ground. Verify the power door locks transitioned to UNLOCK.
• If the power door locks do not unlock, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the BCM.
4. If all circuits test normal, test or replace the driver door lock switch.
Door Lock Malfunction
1. Ignition OFF, disconnect the X1 harness connector at the I/P fuse block.
2. Test for less than 1 ohm between the ground circuit terminal 57 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal 56 and ground.
4. Ignition ON, command the Lock Rear Doors ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM
5. Connect a test lamp between the control circuit terminal 54 and B+.
6. Command the doors to UNLOCK by using the driver door lock switch. The test lamp should illuminate when 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 BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the BCM
7. Connect a test lamp between the control circuit terminal 58 and B+.
8. Command the doors to UNLOCK by using the driver door lock switch. The test lamp should illuminate when 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 BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the BCM.
9. Ignition OFF, connect the X1 harness connector at the I/P fuse block and disconnect the harness connector at the appropriate door latch.
10. Test for less than 1 ohm between the control circuit terminal and ground of the appropriate door latch listed below:
* Driver door latch control circuit terminal 2
* Driver door latch control circuit terminal 3
* LR door latch control circuit terminal 2
* LR door latch control circuit terminal 3
* RR door latch control circuit terminal 5
* RR door latch control circuit terminal 6
* Passenger door latch control circuit terminal 5
* Passenger door latch control circuit terminal 6
• If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the I/P fuse block.
11. Connect a test lamp between control circuit terminals of the appropriate door latch listed below:
* Driver door latch control circuit terminal 2 and control circuit terminal 3
* LR door latch control circuit terminal 2 and control circuit terminal 3
* RR door latch control circuit terminal 5 and control circuit terminal 6
* Passenger door latch control circuit terminal 5 and control circuit terminal 6
12. Ignition ON, command the door latch to LOCK and UNLOCK by using the driver door lock switch. The test lamp should illuminate when commanding the LOCK and UNLOCK states.
• If the test lamp does not illuminate during each of the commands and the DR/LCK fuse is good, test for a short to ground on both control circuits. If the circuits test normal, replace the I/P fuse block.
13. If all circuits test normal, test or replace the door latch assembly.
Component Testing
Door Lock Switch
1. Ignition OFF, disconnect the harness connector at the driver door lock switch.
2. Test for infinite resistance between the signal terminals 3 and 1 and the ground terminal 2 with the switch in the open position.
• If less than infinite resistance, replace the driver door lock switch.
3. Test for less than 2 ohms between the signal terminal 1 and the ground terminal 2 with the switch in the LOCK position.
• If greater than the specified range, replace the driver door lock switch.
4. Test for less than 2 ohms between the signal terminal 3 and the ground terminal 2 with the switch in the UNLOCK position.
• If greater than the specified range, replace the driver door lock switch.
Door Latch Assembly
1. Ignition OFF, disconnect the harness connector at the door latch.
2. Install a 15-amp fused jumper wire between the lock control terminal and 12 volts. Momentarily install a jumper wire between the unlock control terminal and ground. The appropriate door latch should perform the LOCK/ UNLOCK function.
• If the function does not perform as specified, replace the door latch
3. Reverse the jumper wires; the appropriate door latch should perform the UNLOCK/LOCK function.
• If the function does not perform as specified, replace the door latch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Door Lock Switch Replacement (Service and Repair)
* Front Side Door Latch Replacement (Service and Repair)
* Rear Side Door Latch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming