Mini Cabrio Diesel Check Engine Light and Fuel Consumption

That's interesting. I had a similar issue with my old Vauxhall, although it wasn't a BMW VANOS system. The symptoms sound familiar check engine light and increased fuel consumption. I am not sure if it is exactly the same issue as yours. Have you checked the VANOS solenoid? Maybe a faulty one could be the culprit. I am also unsure of how old the timing chain is, maybe it could cause the issue. What about oil changes? Oil sludge can definitely mess things up with the VANOS.

Thanks for the advice. You mentioned checking the VANOS solenoid. Is there a way to test it, or is it something I'd need a mechanic for? And how would oil sludge affect the VANOS?

Well, I am unsure about how to test the solenoid valve yourself. I think you'd need some specialized equipment. As for the oil sludge, from my understanding, it can block the small oil passages in the VANOS system, preventing it from working correctly. It seems like you already suspect the VANOS solenoid, so maybe it's worth having a mechanic take a look at it. It's probably the best thing to do.

I appreciate you sharing your experience. I took my Mini Cabrio to the workshop, and they confirmed it was indeed a faulty VANOS solenoid. They replaced it, and the check engine light is now off. The mechanic also mentioned there was some oil sludge buildup, so they cleaned that out as well. Hopefully, my fuel consumption will return to normal soon. Thank you again!