VW Golf Hybrid Parking Heater System Failure Fix

As someone with moderate car repair experience, I had a similar issue with my 2018 VW Passat Hybrid last winter. The car heater system showed similar symptoms, and the climate control was completely unresponsive when using the parking heater function. After diagnostic testing, the workshop found a defective glow plug in the auxiliary heating system. The temperature sensor readings were also inconsistent, which initially made troubleshooting challenging. The repair involved replacing the faulty glow plug and recalibrating the system. Total cost was 440€ including parts and labor. The blower motor and heater core were also inspected during the repair but were functioning correctly. The fix took about 3 hours, and the heating system has worked flawlessly since then. To provide more specific advice for your case, could you share: Have you noticed any warning lights on the dashboard? What error code is stored in the system memory? Does the regular heating work when the engine is running? When did the problem first appear?

Thanks for the detailed feedback. Just had the 70000km service done last month and all seemed fine then. The regular heating works perfectly when the engine runs, but no warning lights appear on the dash. The error code shows P0093. The issue started about two weeks ago during the first cold days. The coolant leak check at the service showed no issues, and the auxiliary heater was not inspected specifically. The temperature sensor readings appear normal in the diagnostics when the engine is running. Seems the parking heater activation is the only problematic function right now. Wondering if this could be a smaller issue than initially thought.

Thanks for providing those details. Your symptoms match what I experienced almost exactly, especially the working regular heat but failing parking heater function. In my case, despite no warning lights, the P0093 code also pointed to a fuel pressure issue affecting the auxiliary heater system. While my initial repair focused on the glow plug, we later found the actual problem was the fuel metering valve in the auxiliary heater unit. The valve was sticking intermittently, preventing proper fuel flow when the parking heater tried to activate. This explains why the climate control worked fine during normal engine operation. The repair ended up being simpler than first expected, cleaning and recalibrating the metering valve resolved the issue without needing full component replacement. The total cost was only 180€ compared to what could have been a much more expensive fix. Key points from my experience: The heat control system worked normally during engine operation, No coolant leaks were present, Regular service hadnt caught the issue, The fuel metering valve was the root cause I suggest having your workshop specifically check the fuel metering valve in the auxiliary heater assembly before replacing more expensive components.

Thank you all for the insights. After taking the car to the workshop based on your suggestions, they confirmed it was indeed the fuel metering valve causing the parking heater malfunction. The ventilation system and blower motor were thoroughly checked but showed no issues. The repair was straightforward, they cleaned and recalibrated the valve as suggested, plus performed a full system diagnostic test. Total cost came to 160€, which feels reasonable considering the alternative of replacing the entire auxiliary heater unit. The heating system now works perfectly in all modes. Really glad it turned out to be a relatively minor fix. The workshop also noted they would add this specific check to their regular service routine for similar models since these valves apparently need periodic maintenance to prevent sticking. For anyone facing similar issues, requesting a specific check of the fuel metering valve when the parking heater fails could save significant repair costs, especially when the regular heating system still functions normally.