A4 TDI MAF Sensor Issues Causing Multiple Problems

Having some experience with similar issues, I can relate to this problem. My 2020 A5 TDI had nearly identical symptoms last year. The check engine light came on, followed by increased fuel consumption and occasional engine stalling at idle. The mass air flow sensor was indeed the culprit. Initially, I tried cleaning the air filter, thinking it might be a simple fix, but the problems persisted. When I took it to the workshop, their diagnostic confirmed sensor failure. The entire repair, including parts and labor, cost 365 Euro and took about 2 hours to complete. The symptoms you describe match my experience exactly, particularly the black smoke during acceleration and engine stalling. These are classic signs of a malfunctioning MAF sensor disrupting the air-fuel mixture. Before suggesting a definitive solution, could you share: Current mileage on your A4, When was the last air filter change, Are there any other warning lights besides check engine, Does the problem occur more frequently when the engine is cold or warm This information would help determine if your case mirrors mine or if there might be other factors to consider.

Last service done at 194000 KM. Based on the previous responses, I can confirm the MAF sensor seems to be the issue. The air-fuel ratio problems started shortly after my last service. When I first noticed higher fuel consumption and stalling, I also had the black smoke issue mentioned. I would add that in my case the engine stalling happens mostly during cold starts, and the idle is very rough for the first few minutes. The check engine light has been the only warning indicator. My air filter was replaced during the last service, and it looks clean when checked. The fuel economy has dropped significantly, getting about 15% less range per tank now. I will schedule an appointment to have the MAF sensor diagnosed and likely replaced based on these matching symptoms.

Thanks for the additional details about your A4. You are describing exactly what I experienced with my A5 before getting the MAF sensor replaced. The cold start issues and rough idle were particularly telling signs in my case too. Something I noticed post-repair that might interest you, the performance decline was actually more gradual than I initially realized. The sensor failure had been developing over time, which explains the progressive increase in fuel consumption. After replacing the MAF sensor, my fuel efficiency improved immediately. The engine ran smoother, especially during cold starts, and the check engine light cleared up. The black smoke during acceleration completely disappeared. One tip from my experience: when they replace the sensor, ask them to check the air intake system for any leaks or debris. In my case, they found some residue in the intake tract that could have contributed to the sensor failure. Having this cleaned at the same time prevented future issues. The repair truly resolved all symptoms, and fuel consumption returned to normal within 2 tank fills. Keep us updated on your results after the repair.

Based on all this helpful feedback and shared experiences, I feel much more confident about my diagnosis. The symptoms match perfectly, from the cold start issues to the specific combination of check engine light, black smoke, and increased fuel consumption. My A4s behavior mirrors the described MAF sensor failure pattern exactly. I have booked the car in for next week. The quoted repair cost of around 350 Euro matches what others paid, and the 2-hour timeframe works well with my schedule. I will make sure to request that additional inspection of the air intake system for potential debris or damage that could have contributed to the sensor failure. Will update once the repair is done, but given the matching symptoms and especially the cold start problems affecting the air-fuel ratio, I am fairly certain the MAF sensor replacement will resolve my issues. Thanks for helping confirm my initial suspicions about the check engine warnings and performance problems. For anyone searching later with similar issues, tracking fuel consumption changes and monitoring cold start behavior seems key to identifying MAF sensor problems early.