SM5 Exhaust Flap Issue

Sounds familiar. I had a similar problem with my old BMW 3 Series. The symptoms were almost identical – error code, louder exhaust, and a rattling sound on startup. In my case, it turned out to be the flap actuator. Have you checked if the actuator is getting power? It's like a little motor that controls the flaps, and if it fails, the flaps just stay in one position.

Thanks for the quick response. The actuator getting power - that's a good point. How exactly did you check that on your BMW? Was it a straightforward process, or did you need any special tools? I'm trying to avoid a trip to the workshop if I can manage it myself, but I also don't want to mess anything up.

On the BMW, I used a multimeter to check if the actuator was receiving voltage when the engine was running. But honestly, even if you confirm it's getting power, the actuator itself might be faulty internally. Considering the symptoms, it’s probably best to take it to a workshop. They can properly diagnose the issue and replace the defective part. My repair cost around 250€ back then. I think 190€ sounds reasonable.

Okay, that's helpful. I appreciate the insight. I'll take it to a workshop to get it properly diagnosed and repaired, as you suggested. They found the exhaust flap to be defective, it cost 190€ to replace.