Audi S5 Parking Heater Failure: Troubleshooting Guide

Had a similar issue with my 2019 Audi S4 last winter. Have some experience working on cars but mostly basic maintenance stuff. The auxiliary heater problem turned out to be a faulty glow plug in my case. The car heater worked fine in normal operation like yours, but the parking heat function failed completely. The ventilation system and blower motor were tested and worked perfectly, which helped narrow down the issue. Took it to a workshop where they diagnosed the problem through specific error code testing. The full repair including diagnosis, parts and labor came to 440 Euro. They had the car for about a day, most of the time was spent on proper diagnosis to rule out other potential causes. To better assist with your specific case, could you share: The exact error code showing up? Does the auxiliary heater make any sounds when trying to activate? Have you noticed any unusual fuel consumption? When did the problem first occur? These details would help determine if your issue is similar to what I experienced or if it might be something else in the heating system.

Thanks for the response. My car has 51548 KM since new and got serviced last month. The error code P1484 appears briefly when trying to activate the parking heater. No sounds whatsoever from the auxiliary unit. The car heater works normally through the climate control panel, but the parking heat feature is completely dead. No changes in fuel consumption noticed. Just checked again and found small traces of coolant under the car, so this might be connected to a coolant leak somewhere in the heating system. Will get it checked properly, but wanted to know if the glow plug replacement fixed similar symptoms permanently in your case?

Thanks for the additional details. My issue was slightly different since I never had any coolant leaks with my S4. The glow plug replacement did fix my parking heater completely and it has been working flawlessly for about 14 months now. However, the coolant leak you mentioned raises concerns about a possible heater core issue rather than just a faulty glow plug. In my repair experience, the temperature sensor and heat control systems typically work fine even with a compromised heater core, which matches your symptoms. The error code P1484 on these models can indicate multiple issues in the auxiliary heater circuit, but combined with a coolant leak, I would suggest getting the heater core checked first. My glow plug repair was straightforward because there were no fluid leaks involved. When the workshop does the inspection, make sure they: 1. Pressure test the entire heating system 2. Check the auxiliary heater housing for cracks 3. Verify all coolant lines are properly sealed Based on your description, this sounds more complex than my glow plug issue. The repair costs might be higher if the heater core needs replacement, possibly ranging from 600 Euro to 1000 Euro depending on what they find.

The coolant leak definitely makes my case different from yours. Makes sense that we might be looking at a heater core problem rather than just a glow plug. Pretty worried about those repair costs mentioned, but better to fix it properly now before winter hits. The error code definitely helps narrow things down. Will schedule an appointment and have them do all those inspection points you suggested. Really hoping its just a loose connection in one of the coolant lines and not a full heater core replacement. Appreciate the detailed response about your experience with the climate control system repair. Even though our issues seem different, its helpful to know what checks the workshop should perform. Will update once I get the diagnosis done and know exactly whats causing the auxiliary heater failure and coolant leak.