Power Door Locks Malfunction (Except Panel Van)
Power Door Locks Malfunction (Except Panel Van)
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 body control module (BCM) for the door lock system. 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, the reference voltage is taken directly to ground and the BCM detects the voltage on the signal circuit. If a door lock switch is placed in the unlock position, the reference voltage is taken to ground through a 1.5k ohm resistor that is internal to the door lock switches and detects approximately 2.9 volts on the signal circuit. This is how the BCM determines what portion of the door lock switch was activated. 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. Vehicles without keyless entry have 2 internal drivers in the BCM to control the door lock actuators. All door lock and all door unlock. Vehicles equipped with keyless entry have 3 internal drivers in the BCM. Driver door unlock, passenger door unlock and all door lock. This is done to isolate the driver door lock actuator so it can be unlocked by itself using the keyless entry transmitter.
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
Programming and Relearning (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Door Lock Switch parameter 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 between the commanded states, refer to Door Lock Switch Malfunction.
2. Command the Driver Door Unlock, Lock All Doors and Passenger Door(s) Unlock with the scan tool, the doors should LOCK and UNLOCK when changing between the commanded states.
• If a door does not LOCK or UNLOCK when changing between the commanded states, refer to Door Lock Malfunction.
• If all door latches are inoperative, refer to Door Latches 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 ohm between the ground circuit terminal E 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 A 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 A 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 Lock Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
2. Connect at test lamp between the control circuit terminal 2 and control circuit terminal 3.
3. Ignition ON, command the door latch to LOCK and UNLOCK by using the driver door lock switch. The test lamp should turn ON when commanding the LOCK and UNLOCK states.
• If the test lamp is always OFF, test either control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the BCM.
• If the test lamp is always ON, test either control circuit for a short to voltage. If the circuits test normal, replace the BCM.
4. If all circuits test normal, test or replace the door latch.
Door Latches 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. Verify that a test lamp does not illuminate between the control circuit terminal B1 and B+.
• If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the driver door latch.
5. Verify that a test lamp does not illuminate between the control circuit terminal A5 and B+.
• If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate door latch.
6. Verify that a test lamp does not illuminate between the control circuit terminal A1 and B+.
• If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate door latch.
7. Verify that a test lamp does not illuminate between the control circuit terminal A2 and B+.
• If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate door latch.
8. Verify that a test lamp does not illuminate between the control circuit terminal A4 and B+.
• If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate door latch.
9. If all circuits test normal, replace the BCM.
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 A and the ground terminal E with the switch in the idle position.
• If less than the specified value, replace the door lock switch.
3. Test for less than 2 ohms between the signal terminal A and the ground terminal E with the switch in the lock position.
• If greater than the specified value, replace the door lock switch.
4. Test for 1.4k-1.6k ohms between the signal terminal A and the ground terminal E with the switch in the unlock position.
• If not within 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/ 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.
* Door Lock Switch Replacement (Service and Repair)
* Front Side Door Lock Replacement (Front Side Door Lock Replacement)
* Rear Door Lock Replacement (Rear Door Lock Replacement)
* Programming and Relearning (Programming and Relearning) for BCM replacement, setup, and programming