Faulty Temp Sensor Wreaks Havoc on Audi A6 Systems

As someone with some experience working on cars, I encountered almost identical issues with my 2005 Audi A4 2.0T. The vehicle temperature sensor diagnostics revealed similar symptoms, particularly with climate control malfunctions and error codes. After initial sensor diagnostics, my mechanic found that the sensor malfunction was actually caused by damaged wiring connections to the temperature sensor, not the sensor itself. The cable insulation had worn out, causing intermittent connection issues. The repair was straightforward, they fixed the wiring harness and plug connection near the sensor. Total cost was 95 Euro, and it resolved all the symptoms: AC functionality returned to normal, washer nozzles stopped freezing, and the mirror heating system started working again. To provide more specific advice for your case, could you share: Which engine variant does your A6 have? Are there any specific error codes stored? Did these issues start gradually or all at once? Have you noticed any other electrical issues? Proper sensor diagnostics are crucial for accurate troubleshooting, as similar symptoms can sometimes point to different root causes. A professional inspection of the wiring might save you from unnecessarily replacing the entire sensor.

Last service was completed at 30200KM and they found no issues back then. My temperature sensor readings have been erratic lately, triggering multiple warning lights. After running sensor diagnostics with my OBD scanner, error code P0073 keeps appearing even after clearing it. The sensor malfunction seems worse in wet conditions. The outside temperature sensor replacement costs around 180 Euro at the local shop, but I want to verify this is actually the root cause before proceeding with repairs. The sensor calibration also seems off, it shows -5 degrees when its clearly much warmer outside. Is this price reasonable for temperature sensor replacement on an A6? Wondering if I should attempt calibrating the existing sensor first before replacing it completely.

I should clarify something about my previous response on the A4 temperature monitoring system. While I initially thought my issue was wiring-related, further diagnosis revealed the outside temperature sensor itself was failing intermittently, similar to your symptoms. The 180 Euro quote you received for temperature sensor replacement is actually reasonable. On my A4, the initial 95 Euro wiring repair didnt fix the problem permanently. I ended up paying 165 Euro for a complete sensor replacement, which finally resolved all issues. The erratic readings and multiple warning lights you describe match the classic signs of sensor malfunction. The P0073 code specifically indicates an ambient air temperature sensor circuit high input, which typically means the sensor itself is faulty. Calibration rarely fixes this type of issue when combined with multiple system failures. Based on my experience, attempting sensor calibration would likely be wasting time. When the temperature monitoring system shows such inconsistent readings (-5 degrees when clearly warmer), its almost always the sensor itself thats failed. The sensitivity to wet conditions also strongly suggests a failed sensor rather than a calibration issue. Consider getting it fixed soon, as a faulty temperature sensor can affect multiple vehicle systems, including engine performance and fuel efficiency.

Thanks for the detailed feedback regarding the sensor issue. After reviewing all responses, I think I'll proceed with the temperature sensor replacement since the symptoms match what others experienced. The 180 Euro price seems fair based on what others paid, and trying calibration first would probably just delay fixing the real problem. The vehicle temperature sensor clearly shows the classic failure signs, erratic readings, multiple system issues, and that persistent P0073 error code that wont clear. Since the sensor malfunction gets worse in wet conditions and the temperature readings are way off, it makes sense to just replace it. Will schedule the repair next week and update the forum once its done. Hopefully the temperature sensor replacement resolves all these connected issues like it did for others. Really appreciate everyone sharing their diagnostic experiences and repair costs, helped confirm I'm making the right call.