RS4 Exhaust Flap Malfunction Causes Excessive Noise

Had the same exhaust noise issue on my 2014 RS5. The exhaust flap actuator was completely stuck, causing excessive noise and engine performance issues. The problem showed similar symptoms, extremely loud cold starts and inconsistent exhaust sound. The diagnostic revealed a failed vacuum actuator in the exhaust system plus corroded electrical connections to the flap motor. This required replacing the entire actuator unit and rewiring the exhaust components. The repair was relatively serious since a malfunctioning exhaust flap can lead to exhaust blockage and potential engine damage if left unfixed. The fix involved: Full diagnostic of exhaust system, Replacement of flap actuator, New wiring harness installation, Control module reset, System testing Total shop time was about 4-5 hours. The exhaust flap issue is fairly common on RS models, especially ones with higher mileage where the actuator starts failing due to heat exposure and regular wear. Would recommend getting it checked soon, as continuing to drive with faulty exhaust flaps can create more expensive problems down the line.

Thanks for sharing your RS5 experience. I had nearly identical exhaust noise problems with my 2016 RS4 last summer. The symptoms and repair process you described match exactly what I went through. The exhaust system definitely needs proper attention when these flaps start acting up. Did you remember roughly what the total repair cost came out to? Also curious if youve had any other exhaust components need work since getting it fixed? My repair has held up well so far but always good to know what to watch out for.

Thanks for asking about the costs. After seeing the mechanic for the exhaust flap issues, everything got sorted properly. The total repair came to 190 Euro, which covered the actuator replacement and all related work to fix the exhaust system. Since the repair, the exhaust noise has returned to normal levels and the engine performance is back to where it should be. No additional exhaust components have needed attention in the months following the fix. The exhaust flaps are working exactly as designed now, with smooth operation during both cold starts and regular driving. Its worth mentioning that proper maintenance of the exhaust system after such a repair is important. Regular checks of the flap mechanisms can help catch any potential issues early before they develop into more serious exhaust blockage problems. The initial diagnosis was spot on, it was definitely the flap actuator causing all that excessive noise. Having it fixed properly the first time seems to have prevented any cascade of related exhaust repairs that sometimes happen when these issues are left unaddressed.

Thanks everyone for the helpful input. Finally got my RS4 fixed last week and wanted to share how it went. Took it to a certified shop after hearing about the repair experiences here. Total bill came to 210 Euro for the actuator replacement and labor, pretty reasonable considering the work involved. The exhaust repair went smoothly and took about 4 hours. They found exactly what was described, worn actuator and some corroded wiring in the exhaust system. The mechanic showed me the old parts and explained how the exhaust components had degraded over time. The engine performance is noticeably better now and the cold start sound is back to normal. No more error codes or excessive noise from the exhaust flaps. Really glad I got it sorted before any major exhaust blockage issues developed. For anyone else facing similar problems, definitely worth getting it checked out early. The repair cost was way less than I initially feared and the improvement in how the car runs made it totally worth it.