Q4 e-tron Blower Dead: AUC Sensor Failure Alert

Had the same issue on my e-tron GT. The complete blower failure was traced to a faulty connection between the air quality sensor and the climate control module. The auto recirculation feature had been inconsistent for weeks before the total shutdown. The root cause was corrosion in the wiring harness connecting the AUC sensor to the main climate control unit. While the sensor itself was functional, the degraded connection was causing the system to misread air quality data and eventually led to system failure. This is a serious issue that requires proper diagnosis and repair. The entire wiring harness needed replacement along with a recalibration of the odor sensor system. Its not a DIY job due to the complexity of the climate control electronics in EVs. Main signs to watch for: Erratic auto climate control behavior, Inconsistent blower speeds, Auto recirculation engaging out of nowhere, Climate control screen showing sensor errors Best to have it checked by a certified EV technician as damaged wiring can potentially affect other electronic systems.

Thanks for sharing your experience with the GT. The symptoms match exactly what I experienced with my Q4. After reading this, I had mine checked and it was indeed the same issue with the cabin air sensor wiring. This seems to be a common failure point with these models. Just curious, do you remember roughly how much the repair cost? Also, has everything been working properly since the fix? Im particularly interested if the auto recirculation system is now functioning as it should.

Great news, after getting the repair done last month, my BMW AUC system and air conditioning sensor setup has been working flawlessly. The issue was exactly as suspected, a faulty cable connection to the air quality sensor which was causing the erratic behavior in the auto climate control. The total repair cost came to 95 Euro, which covered fixing the defective plug connection. Much more reasonable than I initially feared. Since the fix, the auto recirculation feature has been working perfectly, and the odor sensor is now correctly detecting and responding to external air quality changes. The mechanics confirmed this is a known weak point in these models where the sensor fault often stems from connection issues rather than actual sensor failure. If anyone else experiences similar symptoms, getting it checked early can prevent more extensive climate control system problems down the line.

Thanks for the input. After reading about similar experiences, I visited my local EV specialist last week. They diagnosed the same wiring issue with the AUC sensor connection. Total repair cost was 780 Euro including labor and parts, a bit steep but still cheaper than the dealership quote. The repair process took about 4 hours. They had to remove several panels to access the climate control wiring harness. Found significant corrosion near the sensor connections, which explained the erratic behavior. They replaced the entire wiring section and recalibrated the system. Now everything works perfectly. The auto climate control responds correctly, blower speeds are consistent, and the air quality sensor functions as intended. Best part is no more unusual system shutdowns or error messages. Worth noting they mentioned this is becoming a common repair on these models around the 150000-180000km mark, so others might want to watch for early warning signs.