Q3 Power Loss + CEL Points to Failed Temp Sensor

Had a similar situation with my 2014 Audi A4 2.0 TFSI. The symptoms matched exactly, check engine light, power loss, and increased fuel consumption. The exhaust temperature sensor failure was affecting the engine management system and emission control performance. The repair required replacing both the sensor and a small section of the exhaust system due to a minor leak where the sensor connects. The leak was causing false readings and incorrect fuel mixture adjustments. Temperature fluctuation readings were way off normal parameters. This was a serious issue that needed immediate attention, as continuing to drive with these symptoms could have led to catalytic converter damage. The car exhaust system showed signs of heat stress around the sensor mounting point, which is common in these engines after 90000km. The repair took about 3 hours, including diagnostic time. After fixing both the sensor and the leak, the engine performance returned to normal, and fuel consumption improved significantly. The check engine light cleared and hasnt returned since. Would recommend getting it checked soon, as temperature sensor issues can cascade into more expensive problems if left unaddressed.

Thanks for sharing your experience. I have been dealing with similar symptoms on my Q3 recently and your description matches what I am seeing. The exhaust sensor replacement sounds like the likely fix. Before I schedule an appointment with my mechanic, could you remember roughly how much you paid for the full repair? Also, have you experienced any other issues since the sensor replacement was done?

The faulty exhaust temperature sensor repair went smoothly in my case. Final cost was 265 Euro which covered fixing the leak in the exhaust system and replacing the sensor itself. The engine management system has been working perfectly since the repair, with no further issues over the past few months. The heat sensor replacement restored normal fuel consumption and power output immediately. My mechanic explained that the emission control system now receives accurate temperature readings, which helps maintain optimal engine performance. The car exhaust system inspection revealed the leak was causing incorrect sensor readings, so addressing both problems together was crucial. Getting this fixed prevented potential damage to other components. The check engine light hasnt returned and everything runs like new.

Just brought my Q3 to the mechanic yesterday after reading these responses. Turned out you were right, it was indeed the exhaust temperature sensor causing the issues. The repair cost came to 290 Euro, slightly more than expected due to some minor exhaust component damage around the sensor mounting area. The engine management system is now working perfectly again. Fuel consumption has dropped back to normal levels and the power loss issue is completely gone. The mechanic also performed a full exhaust system check to ensure there were no additional leaks or problems. Definitely glad I addressed this promptly instead of waiting. The whole repair took about 4 hours and the service was much better than my previous shop experience. Really appreciate the advice, it helped me understand the issue before going in for repairs.