Audi S6 Parking Heater Failure: Owners' Experience Needed

Had a similar auxiliary heater failure on my 2018 Audi S4. The car heater worked normally while driving, but the parking pre-heat function completely stopped responding. After diagnosis, it turned out the auxiliary heating system had multiple issues, a faulty control module and a damaged coolant circulation pump. The fix required: Replacing the auxiliary heater control unit, Installing a new coolant pump specific to the parking heater circuit, Clearing fault codes and recalibrating the system, Pressure testing the entire heating system for coolant leaks This was definitely a serious repair requiring specialized diagnostic equipment. The auxiliary heater is a separate system from the main car heater, which explains why normal heating worked fine while driving. Most standard shops struggle with these units since they need Audi-specific tools to properly diagnose and reset the system. The repair was complex but solved the issue completely. Would strongly recommend having this checked at a shop specializing in VAG vehicles, as incorrect diagnosis could lead to replacing wrong parts. Side note: Make sure the coolant level is correct, low coolant can trigger auxiliary heater shutdown as a safety measure.

Thanks for sharing your experience with the S4 parking heater. Sounds like my S6 has very similar symptoms. Really hoping its not as extensive as your repair. The heater core and ventilation system seem to work fine otherwise, with good airflow from the blower motor and normal temperature control while driving. How much did the full repair end up costing you? Has everything stayed working properly since the fix? Just trying to get a sense of what Im looking at cost-wise before heading to the shop.

After taking the car to a certified shop, my auxiliary heater issue turned out to be much simpler than initially feared. The climate control technician found a defective glow plug in the parking heater system, which was causing the complete shutdown. The total repair came to 440 Euro, including diagnostic time and parts replacement. The auxiliary heater has been working flawlessly for the past 6 months since the fix. The parking pre-heat function now activates normally, and the heating system maintains proper temperature control in all conditions. Much cheaper than I expected, especially compared to a full heater core or control module replacement. If your symptoms are similar, definitely have them check the glow plug first before exploring more complex issues with the heating system. Sometimes the simplest solution turns out to be the right one.

After getting great feedback here, I finally took my S6 to a certified shop last week. Turns out my auxiliary heater problem was caused by a clogged fuel line feeding the heater unit. The ventilation system and blower motor were working perfectly, it was just a fuel supply issue preventing the parking heater from starting. The repair was straightforward, they cleaned out the fuel line, replaced a small filter, and recalibrated the heat control module. Total cost came to 280 Euro including diagnostic time. Much better than I feared after hearing about more extensive repairs others needed. The climate control and auxiliary heater are now working perfectly. Really glad I got input here before going back to my previous questionable mechanic. Sometimes getting a second opinion and finding the right shop makes all the difference.