Mini Countryman Diesel Stalling at Idle

Sounds like the purge valve might be acting up. I had a similar issue with my Mini Countryman a while back. Check engine light, rough idling... Does it happen more when the fuel tank is full or nearly empty? It could also be a faulty pressure sensor. Have you checked the hoses connected to the tank ventilation system for any cracks or blockages?

Interesting. You mention the fuel tank level. Is there a specific reason why the level would influence the purge valve behavior? Also, where exactly are those hoses located? I want to inspect them before throwing parts at it. Is a faulty pressure sensor detectable via diagnostic tool?

Yeah, the fuel level thing is because the purge valve is more stressed when the tank is either very full or very empty, affecting the pressure. The hoses are usually near the fuel tank and the engine intake manifold; trace them back from the purge valve. Regarding the pressure sensor, yes, a decent diagnostic tool should be able to read the pressure values and tell you if it's within the correct range. Honestly, if you're not comfortable with this, I'd suggest taking it to a workshop. Messing with the emission system can be tricky.

Just wanted to close the loop on this. You were spot on! Took the Countryman to a trusted shop and they confirmed it was the tank ventilation valve and clogged hoses. They replaced the valve, cleared the emission system errors, and cleaned everything out. Runs like a champ now. Total damage was 175€. Thanks again for your help!