Mini One Smoke and Warning Light Issue

Whoa, that sounds like a serious issue! Smoke when accelerating is never a good sign. The exhaust back pressure sensor on the Mini One is crucial for your vehicle emissions and regeneration of the DPF. It monitors how efficiently your car is running and, as you've noted, supports emission control by managing diesel particulate filter regeneration. If it's faulty, the car's computer won't know what's going on, leading to all sorts of problems. Does the smoke smell particularly rich or oily? A faulty sensor can sometimes trigger incorrect fuel mixtures, leading to incomplete combustion. Have you noticed any changes in your fuel economy?

Thanks for the quick reply! The smoke doesn't smell particularly oily, more like just exhaust. Regarding fuel economy, it's difficult to say if it changed. How is the fuel mixture related to a defective sensor?

OK, thanks for the extra information, so it's likely a faulty sensor causing issues for your vehicle diagnostics. The sensor provides data to the engine control unit (ECU). This data enables the ECU to manage engine parameters, including the fuel mixture. If the exhaust back pressure sensor is faulty, the ECU might misinterpret the exhaust conditions and adjust the fuel mixture improperly. This could potentially cause incomplete combustion, thus increasing emissions and the black smoke you reported. Given the symptoms and your suspicion, plus that you cannot regenerate the DPF, replacing the sensor is likely the right step. I recommend taking it to a repair shop to confirm before doing anything, though. It's best to be absolutely certain to avoid unnecessary car maintenance. Good luck, and I hope it’s resolved quickly!

Just wanted to give you an update. You were spot on! Took my Mini One to a repair shop, and they confirmed it was the exhaust back pressure sensor. Cost me 245€ to get it fixed, but now the warning light is gone, and no more smoke! Thanks a lot for your help!