Mini One NOx Storage Catalyst Aging and Exhaust Leak

That's quite concerning. I had a similar issue with my Mini One. Check engine light, error codes... the whole nine yards. Was there also a noticeable decrease in fuel efficiency? In my case, the problem stemmed from a faulty oxygen sensor, which, in turn, affected the catalytic converter's performance and generated nitrogen oxides. I suspect the catalytic converter itself may be compromised due to the leak in your exhaust system.

Interesting. When you say 'similar issue,' are you referring specifically to the error related to the NOx storage catalyst aging, or just the generic check engine light and error codes? And how did you pinpoint the oxygen sensor as the root cause?

Yes, the error was specifically related to the NOx storage catalyst. The garage identified the oxygen sensor as the problem. Given you already have an exhaust leak, I would strongly advise taking it to a workshop for proper diagnosis. Prolonged exhaust leaks can certainly damage the catalytic converter over time and lead to further issues with nitrogen oxides emissions. Is it worth risking further damage?

Acknowledged. Thank you for the information. Upon inspection at the workshop, a small leak was indeed discovered in the exhaust system, close to the catalytic converter. The NOx storage catalyst aging error was likely a consequence of this. The exhaust system was repaired, which resolved the issue. The expense was 265€. Hopefully, this will also improve fuel efficiency.