Mini Cooper NOx storage catalyst aging issue

That sounds familiar. I had a similar issue with my old Volkswagen. Check engine light and everything. Turned out to be a small crack in the exhaust manifold. Is your car consuming more fuel than usual, or is it louder than before? That might be an indication of an exhaust leak.

Interesting! I haven't noticed any significant change in fuel consumption, but I must admit the exhaust does seem a tad louder than usual. When you had the exhaust manifold issue, did it also trigger errors related to NOx emissions or the catalytic converter? The error code I'm getting specifically mentions NOx storage catalyst aging.

Yep, the crack in my exhaust manifold definitely messed with the readings and triggered all sorts of emissions-related errors, including ones about nitrogen oxides. If you suspect a leak and it's louder, best get your exhaust system checked ASAP. Could be a simple fix, but if left unattended, it could damage the catalytic converter. In my experience, it is worth the hassle. Find a reliable workshop and get it sorted before it becomes a costly automotive repair. Best of luck!

Just wanted to update I took my Mini Cooper to the workshop. Turns out, as suspected, it was a leak in the exhaust system, causing the NOx emissions issue. They replaced a section of the exhaust, and the check engine light is now off. Cost me 265€, but at least it's sorted. Thanks a bunch for your insight!