Seat Arona NOx Storage Catalyst Aging and Exhaust Leak

A 2017 Arona with the check engine light on and exhaust leak sounds familiar. The NOx storage catalyst aging error is a pain. Have you had the car diagnostics done? What codes are showing up? And how bad is the exhaust leak? Is it loud, or just a faint smell? A leak in the exhaust system before the catalytic converter will definitely throw off your emissions and cause that error. Could be something simple like a cracked exhaust manifold or a bad gasket.

Okay, with the NOx catalyst aging error and a noticeable exhaust leak, it really does point to a problem in the exhaust system before the catalytic converter. The catalytic converter's job is to clean up the exhaust gases, including nitrogen oxides (NOx). If there's a leak upstream, it throws off the oxygen sensor readings and messes with the whole emissions system. Basically, the catalytic converter isn't getting the right mix of gases to work properly. Should you get it to the workshop?

Yeah, I got the car diagnostics done, and it showed the NOx storage catalyst aging error. The exhaust leak isn't super loud, but I can definitely hear it, especially when the engine is cold. It also smells a bit more exhaust-y than usual. What do you mean by 'before the catalytic converter'? Does that make a big difference?

Just wanted to say I got the Arona back from the shop. It was a small exhaust leak, like you thought! They replaced a gasket and did some welding, cost 265€. Thanks for your help!