Audi Q5 TDI Warning Lights Won't Clear After Reset

I had a similar issue with my 2020 Audi Q3 TDI last month. Have moderate experience working on cars, mostly basic maintenance and troubleshooting. The check engine light and error messages you describe sound familiar. In my case, it turned out the system needed to complete a full drive cycle after the computer reset. The car diagnostics showed incomplete readiness monitors, which is normal after clearing codes. To resolve this, I performed a specific drive cycle sequence: Started with a cold engine, Let it idle for 2 minutes, Drove at steady speeds on different roads, Made sure to include both acceleration and deceleration phases, Total drive time about 20 minutes The error messages cleared up after completing the drive cycle properly. Since you mentioned having OBD2 diagnostics done recently, this might be your solution too. The exhaust system sensors need time to calibrate and communicate with the engine computer after a reset. Could you share: How long after the reset did the errors return? Were any specific error codes shown during the scan? Has any recent maintenance been performed? This information would help determine if your situation matches what I experienced or if there might be other underlying issues.

The error messages reappeared right after my last service at 184762 KM. My scan tool showed a P0172 code. I completed multiple drive cycles but the check engine light stays on consistently. The emissions test readiness monitors remain incomplete despite following the recommended driving patterns. I tried idle periods up to 5 minutes and various speed combinations during my test drives but the vehicle inspection system still shows unready status. My Audi has had all scheduled maintenance completed on time. Recent repairs included replacing the mass airflow sensor and cleaning the throttle body, but neither resolved the persistent system readiness issues. Has anyone successfully fixed similar symptoms by replacing specific sensors or other components?

Thanks for the additional details about the P0172 code and your recent repairs. In my Q3, I initially faced similar symptoms even after replacing the MAF sensor, but the root cause turned out different from what the initial car diagnostics suggested. The P0172 code indicates a rich fuel mixture, which in my case was related to a faulty oxygen sensor rather than the MAF sensor. After multiple failed drive cycles and incomplete system readiness monitors, my mechanic found the O2 sensor wasnt properly calibrating during the emissions test procedures. The actual fix involved: Replacing the upstream O2 sensor, Cleaning fuel injectors, Performing a specific drive cycle sequence After these repairs, the system readiness monitors completed successfully within 2 drive cycles. The check engine light stayed off and the vehicle inspection status returned to normal. Given your similar symptoms and the fact that basic maintenance hasnt resolved the issue, you might want to have your O2 sensors tested. The persistent rich condition despite the new MAF sensor suggests the system isnt getting accurate feedback about the fuel mixture. Consider checking: O2 sensor response times, Fuel pressure readings, Intake air leaks, ECU fuel trim values

Thanks for the detailed feedback regarding the O2 sensor diagnosis. I will have my mechanic check the oxygen sensors next week. Your experience definitely matches my situation, especially with the rich fuel mixture readings persisting after the MAF sensor replacement. The exhaust system and O2 sensor testing makes sense as the next step since multiple computer reset attempts and drive cycles havent resolved my OBD readiness status. I specifically want to verify the upstream sensor operation since that seems to be the common element between our cases. I will request detailed fuel trim data during the next vehicle inspection. Hopefully addressing the O2 sensor calibration will finally clear the emissions test monitors and resolve the check engine warnings that keep returning. Will update once I have the sensor diagnostics completed and know if that fixes the incomplete readiness status.