Mini One Overheating and Check Engine Light

Sounds suspiciously like a communication fault. I had a similar issue with my old Renault where a software glitch caused intermittent engine overheating due to a bad signal from a sensor. Do you have any diagnostic trouble codes?

Diagnostic trouble codes, you say? Is there a way to check these? I'm moderately tech-savvy but not fully up to speed on that sort of thing.

Yes, you'd need an OBD2 scanner to read the diagnostic trouble codes. If you don't have one, most workshops will be able to pull them for you. It definitely sounds like a potential data link issue between the control unit and other components. Given the overheating, I wouldn't drive it too much until you get it checked. Better safe than sorry. Could be a simple fix, could be something more involved, hard to say without those codes.

Just wanted to update the thread. Took the Mini to a local shop. They found a defective connection in the control unit's data link. New plug and cable, 95€ all in. Runs like a champ again. Thanks for the help!