RS3 Transmission Warning: Bad Temp Sensor Symptoms

As someone with moderate experience working on Audis, I had a very similar transmission issue with my 2021 S3. The symptoms you describe match exactly what I encountered, rough shifting, warning lights, and emergency mode activation. The gearbox sensor readings were off because the transmission oil level was critically low, causing overheating problems. While initial symptoms suggested a faulty temperature sensor, the real culprit was insufficient oil causing multiple transmission issues. The repair process involved: Complete transmission oil level check, System diagnostic scan, Oil top-up and sensor calibration, Test drive to confirm proper operation Total cost was 365 Euro including parts and labor. The workshop completed everything in about 4 hours. To provide more specific guidance, could you share: Current mileage on your RS3, When was the last transmission service, Any recent work done on the transmission, Specific error codes showing up This information would help determine if your issue is identical to what I experienced or if there might be other factors involved. The transmission repair was straightforward once properly diagnosed, but catching it early is crucial to prevent permanent damage to the gearbox components.

Just had my last service at 167255 KM and can confirm the error codes showing P0711 and P0712. The transmission temperature sensor readings are fluctuating wildly between -40C and 120C. My mechanic checked the transmission oil level which appears normal, ruling out low fluid as the cause. Has anyone actually replaced just the sensor to fix similar symptoms? The part seems relatively inexpensive, but labor costs for accessing the sensor location concern me. Would prefer to confirm this fix worked for others before proceeding.

Based on your error codes P0711/P0712 and the erratic temperature readings, this definitely points to a faulty transmission temperature sensor, exactly what I dealt with on my S3. While my initial issue turned out to be oil-related, I later encountered these same error codes and symptoms. I went ahead with the temperature sensor replacement since the part was fairly cheap at around 85 Euro. The labor took about 3 hours since the transmission pan needed removal to access the sensor location. Total repair cost was around 450 Euro. The automatic transmission responded immediately after the repair: Temperature readings stabilized, Warning lights cleared, Transmission shifted smoothly again, Emergency mode deactivated Since your oil level is good, the transmission sensor is almost certainly the root cause. The wild temperature fluctuations between -40C and 120C are a classic sign of a failed sensor. These erratic readings trigger the transmission control unit to enter emergency mode as a protective measure. Getting the sensor replaced sooner rather than later is important, running in emergency mode for extended periods can cause additional transmission issues due to improper shift timing and clutch engagement.

Thanks for the detailed feedback regarding the sensor replacement. The error codes and symptoms you experienced match my situation exactly. Called around to several shops and got quotes ranging from 390 Euro to 580 Euro for the complete transmission sensor replacement job. Going to schedule the repair next week since the part is in stock and the 3-hour labor estimate seems reasonable. The wild temperature fluctuations and emergency mode are getting worse, so addressing it quickly makes sense to prevent additional transmission damage. Will update once the repair is complete, but feeling more confident now that replacing the gearbox sensor is the right fix given your successful results with nearly identical transmission issues. The fact that your automatic transmission returned to normal operation immediately after the sensor replacement is encouraging.