RS3 Auxiliary Heater Failure: Parking Mode Not Working

Having some experience working on Audis, I encountered a similar issue with my 2014 S3 last winter. The heat control system showed similar symptoms, working fine while driving but the auxiliary heating system completely failed. Initially thought it was the ventilation system playing up, but after getting it checked at my regular workshop it turned out to be a defective glow plug in the auxiliary heater. The heating system diagnostics pointed directly to this component. The repair involved: Complete diagnostic scan, Removal of the auxiliary heater unit, Replacement of the glow plug, System reset and testing Total cost came to 440 Euro including parts and labor. The whole process took about 4 hours. For more specific advice about your RS3, could you share: Current mileage, Any warning lights showing, The exact error code displayed, Whether you notice any coolant leaks, If you hear any unusual sounds when trying to activate the parking heater These details would help determine if your issue matches what I experienced or if it might be something different in your auxiliary heating setup.

Thanks for sharing that detailed info about the glow plug repair. My RS3 has 155186 KM and just had its regular service last month. After checking more closely, I can see error code P0597 on the dash. No warning lights other than the auxiliary heater error. The coolant level is normal with no visible leaks around the temperature sensor or heater components. When trying to activate the parking heater, theres a slight clicking sound but nothing else happens. Do you think the repair cost would be similar for this model? The auxiliary heater symptoms sound identical to what you described.

Based on your description and error code P0597, this does sound very similar to what I experienced. The clicking noise without activation is a classic symptom of a faulty glow plug in the auxiliary heater system, just like my case. For the RS3, the repair costs can run slightly higher than what I paid for my S3. The auxiliary heater unit is positioned differently and requires more labor time to access. I ended up paying around 520 Euro for the complete fix on my second occurrence of this issue. A few things I learned from my experience: The car heater working normally while driving but failing in park is a key indicator, Regular coolant changes help prevent premature glow plug failure, Temperature sensor readings should be verified during repair, The blower motor test is essential to rule out other issues The workshop will need to run a full diagnostic to confirm, but with those symptoms and that error code, I would bet on the glow plug being the culprit. The repair typically takes 4-5 hours due to the tight positioning of the heater core in the RS3.

Thanks for the input. Just wanted to follow up, took the car to the workshop today and you were right about the glow plug diagnosis. The climate control system test confirmed the auxiliary heater failure was indeed caused by a faulty glow plug. The final repair cost came to 495 Euro, which was better than I expected given the labor involved. The heating system is now working perfectly again, including the parking heater function. Temperature sensor readings are all normal and the auxiliary heater activates without any clicking or error codes. Really appreciate the detailed advice about this issue. Will definitely keep up with regular maintenance to hopefully prevent another glow plug failure in the future. The whole repair process took about 4.5 hours, just as predicted.