Mini Roadster transmission issues

Sounds like you're having a rough time. I had a similar issue with my Mini (not sure what year yours is). Check the radiator pressure sensor wiring and the connector itself. A coolant leak can cause pressure issues. Is the pressure gauge reading correctly? My gearbox acted up in almost the same way you described. Might be worth checking that sensor before you do anything else.

That's incredibly helpful information! When you say 'radiator pressure sensor wiring and the connector itself,' could you be a little more specific? Was there visible damage, or was it more of a continuity issue? Any tips on where exactly to look, so I don't start tearing apart the whole engine bay? Was the error stored in the error memory the same?

Yes, the error stored in the error memory was the same. Honestly, I'd recommend taking it to a trusted workshop. While it could be a simple fix like the cable, it's best to have it properly diagnosed. If the radiator coolant is leaking and impacting the pressure sensor, it could lead to further damage. They'll be able to check the wiring thoroughly and confirm if the pressure sensor itself is faulty. Just my two cents.

Wow, thanks a million for sharing that experience! I took your advice and brought my Mini Roadster to a local mechanic. Turns out the radiator oil pressure sensor cable was indeed the culprit, just as you suspected! They replaced the cable and the pressure sensor, did a radiator repair, and now everything is running smoothly. The transmission shifts like new again. The whole thing, including labor, came out to about 95€. Seriously, you saved me a ton of guesswork and probably a much bigger bill down the line. I really appreciate your help!