Peugeot 4008 NOx Catalyst Aging and Exhaust Leak

The exhaust leak could be a significant factor. A leak upstream of the NOx storage catalyst can introduce excess oxygen, disrupting its function. Is the leak significant? Have you noticed changes in engine performance or fuel economy?

The leak isn't severe, but I've noticed a slight decrease in fuel economy. Engine performance seems fine. Could the exhaust leak alone cause the NOx catalyst to age prematurely, or are there other factors to consider before repairs?

While fuel quality or engine management could contribute long term, the leak is the most probable cause given the symptoms and error code. Addressing it is crucial, as continuing to drive with the leak may accelerate catalyst degradation. I recommend a professional exhaust system inspection and repair.

Thanks for the advice. I had the exhaust system inspected and repaired; the leak was indeed the source of the problem. The repair cost 265€. After the repair and clearing the error, the check engine light hasn't reappeared. Your insights were helpful.