Nissan Clipper NOx catalyst and exhaust leak

I had a similar problem with my old 2012 Opel Astra, also a gasoline engine. Check engine light, error codes related to emissions, the whole shebang. Turned out to be a small crack in the exhaust manifold. Made the system think things were way off. Is your Clipper blowing fumes?

Yes, I can definitely smell exhaust. Is there a way to pinpoint the leak?

With my Astra, a mechanic used a smoke machine to find the exact spot. It's tricky to see otherwise. Because you have similar symptoms with the error code and exhaust leaking I would suggest you to bring the car to the workshop, they will fix it for you.

Thanks for the tip! You were right. Took it to a shop, and it was a leak in the exhaust system, costing 265€ to repair. All sorted now.