Audi TT Cold Start Issues: PTC Heater Warning Signs

I had similar issues with my 2013 Audi TTS last winter. The symptoms match exactly what you describe, cold air problems and rough running during warm-up. After the heating not working properly for a few weeks, I took it to a workshop. They diagnosed a faulty electric auxiliary heater (PTC heater), which was causing the temperature control system to malfunction. The repair included replacing the heating element and updating the control module. Total cost was 350 Euro, but it solved both the heating issues and the rough running completely. Could you share: Current mileage on your TT? Any other warning lights besides check engine? Did you notice if the heat not working issue started suddenly or gradually? What error code is stored? This information would help determine if your issue is identical to what I experienced. The PTC heater failure is relatively common on these models, particularly after 70,000-100,000 km. Getting it fixed sooner rather than later is important as it can affect engine performance and fuel economy.

Last service was at 45000 KM, currently at 48519 KM. The electrical fault started gradually over the past month. Besides the engine light, no other warning indicators are active. The stored error code is P0597. The blower motor still works, but the heating performance has definitely decreased. Really appreciate the detailed information about the PTC heater repair. Since my symptoms match yours so closely, I will have the HVAC system checked professionally. Better to address it now before winter sets in and the heater issue gets worse.

Thanks for providing those details. That error code P0597 is exactly what my TTS showed when I had the heater repair done. At 48519 KM, this is earlier than usual for a PTC heater failure, but not unheard of. My heating element failed around 85000 KM. The gradual onset of the electrical fault matches my experience too. I noticed the cold air issues became more prominent over several weeks before the engine performance started to suffer. The fact that your blower still works but with reduced heating performance is another typical sign of a failing PTC heater. Since having the heating element replaced, my fuel consumption returned to normal and the cold start roughness disappeared completely. One tip, when you take it in, have them check the wiring connections to the heater as well. In my case, they found some minor corrosion on the connectors that they cleaned up during the repair. Based on your mileage, this should likely be covered under the extended warranty if you have one. Worth checking before scheduling the work.

Thanks for all the feedback about the PTC heater issues. I feel much more confident now about the repair needed. The details about checking warranty coverage are especially helpful since my TT is relatively low mileage at 48519 KM. Given the matching error code P0597 and identical symptoms with the heating system, I will schedule a repair appointment this week. The heating element replacement should resolve both the rough running and the cold start problems. Good point about having them inspect the wiring connections too. I will make sure to mention the gradual onset of the heating not working properly and the increased fuel consumption when I bring it in. This should help them confirm if the HVAC system fault is indeed related to the PTC heater as suspected. Really glad to hear the repair fully resolved similar issues in other cases.