Power Door Locks - Inoperative
POWER DOOR LOCKS INOPERATIVEDIAGNOSTIC AIDS
The following may cause erratic door lock operation.
- A high resistance or an open in the ground circuit of the power door lock switch.
- An intermittent or poor connection of the wiring and connectors.
If door lock operation is erratic, thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis and unnecessary parts replacement with the reappearance of the malfunction. If an intermittent malfunction exists.
Rear door lock actuator control circuits are normally grounded by the rear door modules when the locks are not being operated. However, if one of these control circuits is shorted to ground, the RRDR MDL fuse will open and DTCs U1162 and U1163 will be set current when the door locks are operated. All rear door functions will be inoperative. If the control circuits between the rear door modules and rear door lock actuators are found to be intact, it will be necessary to determine which rear door lock actuator has a control circuit internally shorted to ground. This can be done by disconnecting one of the rear door modules, replacing the damaged RRDR MDL fuse, and repeating the instructions in Step 3. When the RRDR MDL fuse does not open while repeating the Step 3 instructions, the door lock actuator that was disconnected is the cause of the malfunction.
TEST DESCRIPTION
Step 1 - 4:
Step 5 - 7:
Step 8 - 13:
Step 14 - 17:
Step 18 - 24:
The numbers below refer to the step numbers on the diagnostic table.
3. This step determines if a rear door lock actuator has a control circuit shorted to ground. This condition could open the RRDR MDL fuse when the rear door lock actuator is actuated and cause DTCs U1162 and U1163 to be simultaneously set current.
4. This step determines if the door modules recognize the lock switch inputs.However, if the lock switch ground circuit has failed, the scan tool could still display switch inputs transitioning to Lock and Unlock as if there were no failure. This is due to the fact that the lock switch can find an alternate path to ground through the switch illumination circuit when the headlamps are turned Off. By turning the headlamps On in this step, the possibility of overlooking an open lock switch ground circuit as the cause of the malfunction is eliminated.
7. This step determines if the unlock control circuit to the door lock actuator may be the cause of the malfunction.If the test lamp is already illuminated before operating the lock switch, test the unlock control circuit for a short to battery positive voltage.
8. This step determines if the lock control circuit to the door lock actuator may be the cause of the malfunction.If the test lamp is already illuminated before operating the lock switch, test the lock control circuit for a short to battery positive voltage.
13. This step eliminates the logic ground circuit of the inoperative door module as the cause of the malfunction.
14. This step will determine which control circuit is shorted to ground. However, if the external hard wire circuits between the rear door modules and rear door lock actuators are found to be intact, it will be necessary to determine which of the rear door lock actuators has a control circuit internally shorted to ground. This can be done by disconnecting one of the rear door modules, replacing the damaged RRDR MDL fuse, and repeating the instructions in Step 3.
17. This step directs you to, either inspect for poor connections at the passenger door module, or, at the driver door switch assembly (DDSA) as a pre-requisite to replacing the passenger door module or driver door switch assembly (DDSA). This is because lock switch signals for the driver door are detected and processed by the driver door switch assembly (DDSA), while lock switch signals for the passenger door are detected and processed by the passenger door module.
21. This step directs you to, either replace the passenger door module or driver door switch assembly (DDSA). This is because lock switch signals for the driver door are detected and processed by the driver door switch assembly (DDSA), while lock switch signals for the passenger door are detected and processed by the passenger door module.