RSQ3 Engine Light: Faulty Temperature Sensor Alert

Had a similar issue on my 2018 RS3 last winter. Have some experience working on cars but mainly basic maintenance stuff. The engine management light came on and the car felt sluggish. After scanning, it showed problems with the exhaust temperature sensor readings. Initially thought it was just the sensor, but the workshop found a small leak in the exhaust system near the sensor mount that was causing incorrect readings. The full fix involved: Complete diagnostic scan, Replacing the faulty heat sensor, Repairing the exhaust leak, Clearing fault codes, Test drive to confirm fix Total cost was 265 Euro for parts and labor. The car has been running perfectly since, with normal power and no more warning lights. The sensor replacement solved both the performance and fuel economy issues. To better assist with your case, could you share: Any unusual sounds from the exhaust? Did the issue start suddenly or develop gradually? What diagnostic codes are you getting? Any other warning lights besides check engine? The symptoms sound very similar, but exhaust system issues can be tricky to diagnose without more details about your specific situation.

Latest service was at 167000 KM, about 2 months ago. The same issue happened again this morning while driving on the highway. Called the dealer and they confirmed the emission control system might need recalibration due to the temperature sensor malfunction. They mentioned possible software updates too. Looking at previous forums, temperature fluctuation seems common with these sensors. Has anyone successfully fixed this through recalibration alone, or is sensor replacement inevitable? The dealer quoted 380 Euro for diagnosis and recalibration, which feels steep if the sensor needs replacing anyway. The engine management system is showing the same error code as before. Starting to think I should get a second opinion from an independent specialist.

Thanks for the update on your RSQ3 situation. On my RS3, I initially tried the recalibration route at the dealer too, hoping to avoid the full sensor replacement. Unfortunately, the temperature fluctuations returned within a week, and I ended up replacing the exhaust temperature sensor anyway. The emission control system recalibration might help temporarily, but in my experience, when these sensors start acting up, replacement becomes inevitable. The 380 Euro diagnostic fee does seem high, especially since youre already experiencing the same symptoms and error codes. My suggestion based on dealing with this twice now: Skip the expensive dealer diagnosis, Go straight for the exhaust component replacement, Have them perform the necessary recalibration after installation The temperature sensor is a critical exhaust component that directly affects both performance and emissions. When it fails, temporary fixes usually dont provide lasting results. Independent specialists typically charge significantly less for the same work, and many have extensive experience with these specific sensor issues. The fact that your issue reoccurred after just 2 months suggests this isnt just a calibration problem. Would strongly recommend getting that second opinion from a specialist who can focus directly on the sensor replacement.

Thanks for all the input everyone. After tracking down a reputable independent shop nearby, I decided to go ahead with the sensor replacement rather than just recalibration. They confirmed the exhaust temperature sensor was failing and causing the engine management system to reduce power. Total repair cost came to 310 Euro including parts and labor, definitely better than the dealer quote. The shop also did a full diagnostic scan of the exhaust system to check for any other potential issues. They found and fixed a small exhaust leak near the sensor mount that could have contributed to the temperature fluctuation problems. Its been about a week since the repair and the car is running perfectly again. No more check engine light, power is back to normal, and fuel economy has improved. The independent shop explained that these sensors commonly fail around this mileage, so Im glad I went straight for replacement rather than expensive dealer diagnostics. For anyone else facing similar issues, definitely worth checking for exhaust leaks along with sensor replacement. Getting a second opinion from a specialist saved both time and money in my case.