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 DR/LCK fuse supplies battery positive voltage to the I/P fuse block for the door lock system. The body control module (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 the voltage drop on the signal circuit.
The BCM, upon receipt of a door lock switch lock or unlock signal, will switch the appropriate door lock actuator control circuits to battery positive voltage. The opposing side of the door lock actuators are connected to ground internally within the BCM through the other door lock actuator control circuit and the doors will lock or unlock appropriately.
Diagnostic Aids
Verify the smooth and consistent mechanical operation of each part of the door latch system prior to performing extensive electrical diagnostics
Any door that does not function smoothly or consistently, refer to Door Will Not Open/Close, Door Binding, or Locks, Handles, or Cylinders Do Not Function Door Will Not Open/Close, Door Binding, or Locks, Handles, or Cylinders Do Not Function.
Reference Information
Schematic Reference
Door Lock/Indicator Schematics Door Lock/Indicator Schematics
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Driver Door Lock Sw, Psgr Door Lock Sw, Driver Door Unlock Sw and Psgr Door Unlock Sw parameters while using the driver and passenger door lock switches. The parameters should change between Active and Inactive.
• If the values are always Active or always Inactive, refer to Door Lock Switch Malfunction.
2. Verify the function of the driver and passenger door lock knobs by manually moving the door locks knobs between the LOCK and UNLOCK positions, both door lock knobs should move between the LOCK and UNLOCK positions without binding or require excessive force.
• If a driver or passenger door lock knob does not function or requires excessive force, refer to Door Will Not Open/Close, Door Binding, or Locks, Handles, or Cylinders Do Not Function Door Will Not Open/Close, Door Binding, or Locks, Handles, or Cylinders Do Not Function.
3. Command the driver door and passenger door lock actuators to LOCK and UNLOCK with the scan tool, the doors should LOCK and UNLOCK when changing between commanded states.
• If the driver door does not LOCK or UNLOCK, refer to Driver Door Lock Malfunction.
• If a passenger door does not LOCK or UNLOCK functions, refer to Passenger Door Lock Malfunction.
• If all doors locks are inoperative, refer to All Doors Inoperative.
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 1 ohms between the ground circuit terminal B 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 Sw parameter is Inactive.
• If not the specified value, test the signal circuit terminal D 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 D and ground. Verify the scan tool Door Lock Sw parameter is Active
• 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. Verify the scan tool Door Unlock Sw parameter is Inactive.
• If not the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the BCM.
6. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool Door Unlock Sw parameter is Active.
• 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.
7. If all circuits test normal, test or replace the door lock switch.
Driver Door Lock Malfunction
1. Ignition OFF, verify the harness connector for the driver door latch is firmly seated and secure.
• If not the specified condition, seat and secure the harness connector and perform the Circuit/System Verification.
2. If the harness connector for the driver door latch is firmly seated and secure, refer to Driver Door Lock Circuit Testing.
Driver Door Lock Circuit Testing
1. Ignition OFF, disconnect the harness connector at the driver door latch.
2. Ignition ON, connect a test lamp between the control circuit terminal 3 and control circuit terminal 2.
3. Command the driver door to LOCK and UNLOCK by using the driver door lock switch. The test lamp should briefly illuminate when commanding the LOCK and UNLOCK states.
• If the test lamp does not illuminate during either of the commands and the B+ circuit fuse is open, test either control circuit for a short to ground. If the circuit tests normal, test or replace the driver door lock.
• If the test lamp does not illuminate during either of the commands and the B+ circuit fuse is good, test either control circuit for an open/high resistance. If the circuit tests normal, refer to I/P Fuse Block Test.
4. If all circuits test normal, test or replace the driver door latch.
Passenger Door Lock Malfunction
1. Ignition OFF, verify the harness connector for the appropriate passenger or rear door latch is firmly seated and secure.
• If not the specified condition, seat and secure the harness connector and perform the Circuit/System Verification.
2. If the harness connector for the passenger or rear door latch is firmly seated and secure, refer to Passenger Door Lock Circuit Testing.
Passenger Door Lock Circuit Testing
1. Ignition OFF, disconnect the harness connector at the appropriate passenger or rear door latch.
2. Ignition ON, connect a test lamp between the control circuit terminals listed below:
* Terminal 2 and terminal 3 - left rear door latch
* Terminal 5 and terminal 6 - right rear door latch
* Terminal 5 and terminal 6 - passenger door latch
3. Command the door to LOCK and UNLOCK by using the driver door lock switch. The test lamp should briefly illuminate when commanding the LOCK and UNLOCK states.
• If the test lamp does not illuminate during either of the commands and the B+ circuit fuse is open, test either control circuit for a short to ground. If the circuit tests normal, test or replace the passenger or rear door latch.
• If the test lamp does not illuminate during either of the commands and the B+ circuit fuse is good, test either control circuit for an open/high resistance. If the circuit tests normal, refer to I/P Fuse Block Test.
4. If all circuits test normal, test or replace the passenger or rear door latch.
I/P Fuse Block Test
1. Ignition OFF, disconnect the X1 harness connector at the I/P fuse block.
2. Test for less than 1 ohms between the ground circuit terminal J1 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between control circuit terminal K4 and ground.
4. Ignition ON, command the doors to LOCK with a scan tool. The test lamp should briefly illuminate during the LOCK command.
• 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 control circuit terminal K5 and B+.
6. Command the doors to UNLOCK with a scan tool. The test lamp should briefly illuminate during the UNLOCK command.
• 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 control circuit terminal K6 and B+.
8. Command the driver door to UNLOCK with a scan tool. The test lamp should briefly illuminate during the UNLOCK command.
• 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. If all circuits test normal, replace the I/P fuse block.
Component Testing
Door Lock Switch
1. Ignition OFF, disconnect the harness connector at the appropriate door lock switch.
2. Test for infinite resistance between the signal terminals D and E and the ground terminal B 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 D and the ground terminal B with the switch in the lock position.
• If greater than the specified range, replace the door lock switch.
4. Test for less than 2 ohms between the signal terminal E and the ground terminal B with the switch in the unlock position
• If greater than the specified range, replace the door lock switch.
Door Lock Assembly
1. Ignition OFF, disconnect the harness connector at the appropriate door lock.
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 lock should perform the LOCK and UNLOCK functions.
• If it does not perform as specified, replace the door lock.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Door Lock Switch Replacement (Impala) Service and Repair
* Front Side Door Lock Replacement Front Side Door Lock Replacement
* Rear Side Door Lock Replacement Rear Side Door Lock Replacement
* Accessory Wiring Junction Block Replacement Accessory Wiring Junction Block Replacement
* Control Module References Control Module References for BCM replacement, setup, and programming