The rear doors of Volkswagen MKV platform vehicles, including the Jetta and Golf, can sometimes experience locking issues. This often manifests as an intermittent problem where the door sometimes locks and sometimes doesn’t. Using a VCDS (Vag-Com Diagnostic System) scan tool can help pinpoint the cause. This article explores a common scenario involving trouble codes related to the rear left door not locking, specifically focusing on diagnostics using VCDS.
Identifying the Problem: VCDS Scan Results
Two 2009 Jetta TDIs presented with the same intermittent rear left door locking issue. In both cases, a VCDS scan revealed identical fault codes within module 62 (Rear Left Door):
Fault Code 00930 – Locking Module for Central Locking; Rear Left (F222)
- 008 – Implausible Signal – Intermittent: This indicates the locking module is receiving a signal that doesn’t make sense, suggesting a potential wiring or connection problem. The intermittent nature suggests a loose connection, damaged wire, or failing actuator within the door.
Fault Code 01554 – Motors for Central Locking; Rear Doors; Lock
- 012 – Electrical Fault in Circuit: This points to a problem with the electrical circuit that controls the locking motor. This could be due to a short circuit, open circuit, or a faulty motor itself. Again, the intermittent nature of the fault in one car suggests a possible loose connection.
Diagnosing the Issue with VCDS
While both cars shared the same fault codes, slight variations in the freeze frame data (mileage, fault frequency) suggest the root cause may differ slightly. Here’s a breakdown of how to use VCDS for further diagnostics:
1. Check Measuring Values: Within module 62 in VCDS, access the “Measuring Values” function. Observe the values related to the door lock actuator while attempting to lock and unlock the door. This can help determine if the actuator is receiving the correct signals and responding appropriately. Look for inconsistencies or values that don’t change as expected.
2. Wiring Harness Inspection: Based on the “Implausible Signal” error, carefully inspect the wiring harness that connects to the door lock module. Look for any signs of damage, such as broken wires, frayed insulation, or corroded connectors. Pay close attention to areas where the harness flexes when the door opens and closes, as these are common points of failure.
3. Actuator Testing: If the wiring harness appears intact, the door lock actuator itself may be faulty. VCDS can sometimes be used to activate the actuator directly through the “Output Tests” function. This allows you to isolate the actuator and determine if it’s functioning correctly.
4. Microswitch Check: The door lock mechanism includes microswitches that signal the door’s locked/unlocked status. A faulty microswitch can also trigger these fault codes. Use VCDS to monitor the microswitch status in Measuring Values while operating the lock manually. This can help identify a faulty switch.
Resolving the Issue
Once the problem is identified, the solution may involve:
- Repairing or replacing damaged wiring in the door harness.
- Replacing the door lock actuator.
- Replacing a faulty microswitch within the door lock mechanism.
- Cleaning and securing all electrical connections within the door.
By using VCDS in conjunction with careful inspection and testing, you can effectively diagnose and resolve the issue of a rear door not locking on a VW MKV platform vehicle. Addressing this problem promptly can prevent security concerns and ensure the proper functioning of your vehicle’s central locking system.
