S4 Exhaust Flap Issues Causing Performance Problems

I had a very similar issue with my 2017 S5. The exhaust noise became unusually loud and I noticed performance issues. After some research, I discovered the exhaust flap actuator was malfunctioning, which explained both the noise and performance problems. I have moderate experience with car maintenance, but this repair required professional expertise. The workshop diagnosed a faulty flap actuator in the exhaust system. They performed a complete diagnostic check and found that the actuator motor had failed, preventing proper exhaust flow control. The repair cost me 190 Euro, which included labor and parts. The fix resolved both the excessive exhaust noise and restored normal engine performance. After the repair, the error codes cleared and haven't returned. To better assist with your S4 issue, could you share: Are you getting any specific error codes? Does the exhaust noise change with different driving modes? Have you noticed any vibrations from the exhaust system? When did you first notice these symptoms? This information would help determine if your issue matches what I experienced and could guide you toward the right repair solution.

Last service completed at 187134 KM, I had the exact same symptoms. The workshop confirmed a faulty exhaust flap actuator causing exhaust blockage and incorrect valve operation. After swapping the actuator and recalibrating the system, the noise levels returned to normal and engine performance improved significantly. The error codes cleared immediately. Total repair cost was 220 Euro. Based on this experience, it seems this is a common exhaust components issue on these models.

Your experience matches mine exactly. After my actuator replacement, I also noticed how the entire exhaust system returned to its proper function. Makes sense since the exhaust flaps need to work correctly for optimal performance. The repair cost difference between your 220 Euro and my 190 Euro likely comes down to parts pricing changes. Still seems reasonable for fixing such a crucial exhaust component. A few notes from my long-term experience since the repair: The cold start noise returned to normal factory levels, No more error codes related to exhaust components, Engine performance remained stable, Regular operation of exhaust flaps confirmed during subsequent services For preventive maintenance, I now have the workshop check the flap actuator operation during each service. The exhaust noise levels serve as a good indicator, any unusual changes could signal early actuator wear. Watch out for the symptoms coming back. In rare cases, the new actuator might need adjustment after a few thousand kilometers. Mine has been solid for 45000 km now with no issues.

Thanks for the input. I just wanted to follow up and confirm that after 4000 km since my repair, everything is working perfectly. The exhaust noise levels remain normal and engine performance is great. The workshop explained that the exhaust flap actuator failure is indeed a known issue with these models. Having the actuator checked during regular service intervals makes sense as preventive maintenance. Total cost of 220 Euro seems standard based on other experiences shared here. The exhaust components are all functioning as intended now, with no error codes or abnormal operation of the exhaust valves. Definitely worth fixing rather than risking potential exhaust blockage issues down the line.