Audi TT Climate Control System Complete Failure

As an Audi A5 2018 owner, I encountered nearly identical HVAC sensor issues last season. The climate control system showed similar symptoms, complete failure to engage and stored fault codes. The root cause turned out to be a faulty temperature sensor connection at the evaporator core. The HVAC sensor wiring harness had developed corrosion at the plug, disrupting the climate regulation signals. The sensor diagnostics confirmed intermittent communication failures between the temperature control module and the main climate control unit. This is typically not a severe issue, but requires careful disassembly of the dashboard components to access the connection points. The repair involved cleaning the connector pins and replacing the wiring harness section that had corroded. The temperature sensor itself was functioning correctly. Getting proper climate control function back required recalibration of the system after the repair. Since then, the automatic temperature control has worked flawlessly. For your TT, I suggest having a certified technician perform detailed sensor diagnostics before replacing any major components. The repair complexity lies mainly in accessing the components rather than the actual fix. Attempting DIY repairs risks damaging other dashboard elements during disassembly.

Thanks for sharing that experience with the sensor issue. Really helpful to know it was the wiring harness in your case. My Audi TT is showing the exact same symptoms with the climate regulation system. I was quoted around 400 Euro for diagnostics and potential temperature sensor replacement, but your post makes me think I should specifically ask them to check the wiring harness and connections first. Those HVAC sensor problems can be tricky to diagnose correctly. How has your repair held up since then? Have you had any recurring temperature reading issues or needed additional work done? Just want to ensure I budget appropriately if more repairs might be needed down the line.

Just had to follow up, after taking it to a certified shop based on the sensor diagnostics discussion here, they found and fixed the exact issue with my TT. The climate control problems were traced to a faulty interior temperature sensor, but it wasnt the sensor itself that needed replacement. The repair involved fixing a bad cable connection going to the temperature sensor component. Total cost came to 95 Euro, which was way less than the 400 Euro quote I initially received. The climate control system now works perfectly again, automatic temperature regulation is back to normal and no more stored fault codes. Really glad I asked them to specifically check the wiring and connections first before replacing the entire sensor assembly. This approach to sensor diagnostics saved considerable money and fixed the root cause. No temperature control issues since the repair three weeks ago. Getting the right diagnosis makes all the difference with these climate issues. Sometimes its just a simple connection problem rather than a failed component.

Thanks for the input. Just wanted to close the loop on my Audi TT climate control situation. Took it to a certified shop last week after reading all the advice about checking connections before replacing parts. The technician ran comprehensive sensor diagnostics and found that the temperature sensor wiring had worked loose from the main connector, causing the climate control system to fail. They cleaned the connection points, secured everything properly, and recalibrated the system. Total repair cost was 120 Euro including labor, which felt reasonable. The automatic temperature control now works perfectly again. Such a relief it wasnt a major component failure. Really glad I asked about previous sensor issues here first. Saved me from potentially paying for unnecessary parts replacement. Will definitely keep this shop in mind for future climate control problems, they were thorough with their sensor testing and honest about the simple fix needed. The car runs great now with properly functioning AC. No more error codes or temperature regulation problems since the repair.