Mini One Diesel Check Engine Light

I had a similar issue with my Mini One. Symptoms sound identical: higher fuel consumption, engine stalling, check engine light, and even some smoke on acceleration. For me, it was a defective mass air flow meter. A faulty sensor will mess with the air-fuel ratio, leading to all sorts of performance decline. Have you checked the air intake for any obstructions or leaks? A visual inspection is always a good first step.

Thanks for the quick response! So, when you say 'messed with the air-fuel ratio,' did you notice a significant drop in fuel economy? And how bad was the performance decline? I'm also curious, did you try cleaning the sensor before replacing it, or did you just go straight to replacing the mass air flow meter?

Yeah, the fuel economy tanked! I was filling up way more often than usual. Performance decline was noticeable; the car felt sluggish, especially when accelerating. Honestly, I didn't even bother trying to clean the sensor. Given the symptoms, I figured it was just plain defective. I suggest taking it to a workshop and having them confirm the diagnosis. They can also check for any other underlying issues that might be contributing to the problem.

Just wanted to close the loop on this. You were spot on! Took the Mini to a workshop, and they confirmed it was indeed the mass air flow sensor. Repair cost me about 365€, but the car is running like a champ again. No more stalling or smoke, and the fuel economy seems to be back to normal. Thanks a bunch for your help!