Ccrosser NOx Catalyst Error and Exhaust Leak

Greetings! I had a similar ordeal with my 2016 Volvo XC60, diesel engine. NOx catalyst issues can be a real headache, especially with modern emission controls. The exhaust leak is almost certainly the culprit. Even a small leak can throw off the entire exhaust system's parameters, leading to incorrect readings from the sensors and triggering the NOx catalyst error. Is the leak before or after the catalyst?

Interesting! I wasn't sure if a small leak could cause such big problems. As far as the leak location, I'm not entirely sure. I haven't gotten under the car yet. Any tips on how to check that, or is it best left to a pro?

It's often difficult to pinpoint the exact leak location without proper equipment. Given the connection to the NOx catalyst and the complexity of the exhaust system, I would advise against DIY repairs. You risk damaging other components or misdiagnosing the problem. Take it to a trusted mechanic; they can perform a smoke test to find the leak and properly assess the catalyst's condition. Ignoring it will lead to further degradation of the NOx catalyst and potential MOT failure.

Thanks a bunch for the advice! You were spot on. Took it to the shop, and it turned out to be a small crack in the exhaust manifold, right before the catalytic converter. They welded it up and reset the codes. Total cost was 265€. Check engine light is gone, and it seems to be running much smoother. I really appreciate the help!