Insignia NOx Sensor Exhaust Leak

NOx sensor, huh? I had something similar happen, though I never got around to checking the mileage back then. Got an Insignia too. Is it actually leaking exhaust or are you just smelling it more because of the sensor issue? Did you check the connections yourself yet? NOx sensors are part of the exhaust system, specifically to measure nitrogen oxides which are pollutants. The engine computer uses that data to adjust the air-fuel ratio to keep the catalytic converter working efficiently and reduce emissions. So, yeah, could be a bad connection messing everything up.

Thanks. The exhaust leak seems to be coming from near the sensor, or maybe a joint nearby. I've looked at the connections, and while I didn't see anything obvious, I'm going to check again more closely. Thanks for explaining the NOx sensor and how it relates to the air-fuel ratio and catalytic converter.

Right, leaking near the sensor makes me think it's probably the sensor itself then. If you've checked the connections, and it's still showing a fault and leaking, there's not much more you can do without proper tools. Best bet is to get it to a workshop. They'll have the kit to properly diagnose it. Could save you money in the long run compared to just swapping parts and hoping.

Thanks. I took it to a workshop, and they said the NOx sensor was the problem, a faulty connection. The total cost for the repair, including the sensor replacement and labor, was 95€.