SM5 Knocking Combustion Issue

Sounds familiar! I had similar symptoms with my SM5. Reduced power and jerking were the worst. Have you checked your knock sensor? Or considered the fuel octane you're using?

Thanks for the quick reply. I haven't checked the knock sensor directly, but the error code doesn't specifically point to it. I've consistently used the recommended fuel grade. Could deposits in the combustion chamber really cause such significant issues, even with proper fuel?

Yeah, the deposits can definitely cause pre-ignition, which the knock sensor might not directly flag. I ended up taking mine to a workshop, and they confirmed deposits were the problem. Saved me a lot of headache. I'd suggest getting it checked out.

Appreciate the insight. I'll schedule an appointment with a trusted mechanic to inspect the combustion chamber for deposits. Turns out you were right. The mechanic confirmed significant deposits. They cleaned everything out, and the knocking is gone. Cost me 425€, but well worth it to have the car running smoothly again.