Audi A5 Temperature Sensor Issues Disrupt Key Functions

Had the same sensor malfunction symptoms on my 2020 Audi A4. The vehicle temperature gauge showed incorrect readings and multiple systems malfunctioned because they rely on accurate temperature data. A sensor diagnostics scan confirmed the outside temperature sensor was failing. The main issue was a corroded wire harness connection to the sensor, causing intermittent signal problems. The sensor replacement itself was straightforward, but accessing the wiring required removing the front bumper cover. This is actually a common problem that affects various systems: Climate control malfunction, Mirror defrost issues, Incorrect temperature readings, Stored trouble codes The repair involved replacing both the temperature sensor and the associated wiring harness connector. While not a complex repair, proper sensor diagnostics and accessing the component makes it a job best left to experienced technicians who can properly test the system after installation. The replacement parts must be dealer-certified to ensure proper function, as aftermarket sensors can cause continuing issues. This isnt a repair to postpone, as faulty temperature readings can affect multiple vehicle systems.

Thanks for that detailed response. I had almost identical issues with my A5 last winter. The outside temperature sensor was definitely the root cause, seems like these parts have a common failure point. Really interested to hear what you paid for the fix since I went to an independent shop. Also curious if everything has been working properly since the repair? My washer nozzles and mirror heating have been fine, but occasionally the car temperature sensor still shows a brief wrong reading when first starting up.

Glad I could help with the sensor issue. After getting it fixed, every temperature-dependent system has worked flawlessly, no more incorrect readings or malfunctions. The outside temperature sensor repair was completed about 8 months ago and cost 95 Euro for fixing the faulty cable connection. The brief temperature reading issue you mentioned during startup actually sounds unusual, might be worth having the sensor calibration checked, since properly working temperature sensors should show accurate readings from the start. The initial diagnostic pointed to the wire harness connection rather than a complete sensor malfunction, which saved quite a bit on parts costs. My mechanic cleaned and resealed the connector assembly instead of replacing the entire temperature sensor unit. This turned out to be the right call since all systems, AC, mirror heating, and washer nozzles, have worked perfectly since the repair.

Thanks for the input. I finally got this sorted at my local shop last week. The total bill came to 280 Euro for a complete temperature sensor replacement plus labor. Turns out the original sensor was totally shot, not just a wiring issue. The mechanic showed me the corroded unit after removing it. The repair took about 2 hours since they had to remove some trim pieces to access the sensor properly. After sensor replacement and calibration, everything works like new. The AC kicks in properly, mirror heaters function normally, and the washer nozzles no longer freeze up. The temperature monitoring is now spot-on from cold start, no more weird readings. Really glad I went with an independent shop, dealer quoted almost double for the same sensor replacement job. For anyone facing similar symptoms, definitely get it checked sooner rather than later since the faulty readings can affect multiple systems.