Mini Cabrio engine starting issue

Sounds like an immobilizer issue indeed. I had something similar happen with my Mini, though it wasn't the Cabrio version. Engine would start, then immediately die. Does the security light on your dashboard behave strangely? Does it flash rapidly, stay on constantly, or not illuminate at all when you try to start the car? This could give a clue about the key signal. Have you tried your spare key to see if it makes a difference?

Thanks so much for the quick reply! The security light…hmm, I hadn't paid much attention. I think it was flashing pretty fast when it wouldn't start. With my spare key, the same thing happens. What exactly did you do to fix your Mini?

Okay, rapid flashing with both keys definitely points towards a key programming issue or a fault in the ignition control module not recognizing the key signal. Since both keys are affected, it's less likely to be a simple key malfunction and more likely an issue with the car's immobilizer system itself. In my case, the key needed to be reprogrammed. Given the error code and the symptoms, it's best to visit a workshop that can diagnose and reprogram the key. They will likely use diagnostic tools to communicate with the car's computer and re-establish the link between the key and the immobilizer. They can also check the anti-theft system.

Just wanted to give a final update! Took your advice and went to a local workshop. Turns out the key programming was indeed the problem. They fixed it for 45€! Now my Mini Cabrio is running like a charm again. Huge thanks for your help!