Renault Wind NOx Catalyst Error

That sounds remarkably similar to an issue I encountered with my Opel Astra a while back. The check engine light, the error codes pointing towards emissions, and the exhaust leak all scream the same thing. The exhaust leak, even a small one, could drastically affect the efficiency of the NOx catalyst. Was the diagnostic specific about where the leak is located?

The diagnostic wasn't precise about the leak's location, unfortunately. It only confirmed its existence within the exhaust system. Considering your experience with the Astra, could this exhaust leak be the primary culprit behind the NOx storage catalyst aging error, or could there be other contributing factors?

In my case with the Astra, the exhaust leak was indeed the root cause. The leak introduced extra oxygen into the exhaust stream, throwing off the delicate balance needed for the catalytic converter to function correctly and store the NOx. I strongly advise getting the exhaust leak professionally inspected and repaired without delay. If you keep driving with that leak, the system might be clogged, and the cost could be much higher. Afterwards, clear the error codes and see if they return. If so, further inspection could be necessary, but I'd bet the leak is the main problem.

I took your suggestion and brought the car to the workshop. It turned out to be a corroded exhaust pipe, which was causing the leak. After replacing it for 265€, the error code disappeared, and the check engine light went off. Your shared experience was instrumental in guiding me toward the correct solution.