RS6 Exhaust Flap Issue Causes Loud Cold Starts

I had a similar issue with my 2017 RS7 last winter. Having some experience with exhaust systems, I recognized the symptoms immediately, especially that distinctive loud cold start noise. The root cause turned out to be a defective exhaust flap motor. The flap mechanism was stuck in the open position, causing excessive exhaust noise and triggering the error code. Workshop diagnosis confirmed an electrical failure in the flap actuator system. The repair involved replacing the complete flap motor assembly. Total cost was 190 Euro including parts and labor. The exhaust repair resolved both the noise issue and cleared the error code. Engine performance returned to normal after the fix. To provide more specific advice for your situation, could you share: Current mileage on your RS6, Whether the noise level varies with engine temperature, If you notice any changes in engine performance, What exact error code is showing up These details would help determine if your issue matches the exhaust blockage pattern I experienced or if it might be related to different exhaust components.

Thanks for the detailed response. The car has 48510 KM and was last serviced 3 months ago. The noise level does vary with engine temperature, its much louder during cold starts and gradually becomes less noticeable as the engine warms up. No significant changes in engine performance noticed so far. The error code points to the right exhaust flap motor malfunction, which aligns with your experience. Based on what you described, it seems our issues are quite similar. Will have the workshop check the flap actuator system specifically. Good to know the repair costs were reasonable in your case.

This does sound identical to what I experienced. After reading your mileage and symptoms, I am even more convinced we dealt with the exact same exhaust flap motor failure. The pattern of noise variation with engine temperature perfectly matches the behavior I observed. In my case, the exhaust repair took about 2 hours. The workshop found corrosion in the flap actuator electrical connections, which caused the flap to remain in the open position. The replacement part came with improved sealing to prevent future moisture damage to the electrical components. Since our repair, the exhaust noise returned to normal levels and the car has been running perfectly for the past year. No error codes have reappeared. The exhaust components are working as intended, with the flaps responding correctly to different driving modes. Just make sure the workshop tests the full range of motion of the new flap motor during installation. A proper calibration of the flap actuator system is crucial for optimal performance.

Thank you for sharing those details about your experiences. The symptoms indeed match exactly, especially regarding how the noise level changes with engine temperature and the specific error code for the right exhaust flap motor. The mileage on my car is relatively low at 48510 KM, which makes the flap actuator failure somewhat unexpected. I will schedule a workshop visit next week and have them focus on checking the exhaust flap system. Your input about the repair costs being around 190 Euro helps set realistic expectations. Good to know the fix should only take about 2 hours and that the replacement parts come with better sealing against moisture. Will make sure they properly test the full range of motion on the new flap motor and calibrate the system correctly. Really hoping this resolves both the cold start noise and error code, just as it did in your case. The fact that your repair has held up well for a year without any recurring issues is encouraging.