Astra NOx Sensor Fault

Hi, I'm having trouble with my 2008 Vauxhall Astra, gasoline engine. The check engine light keeps popping up. It's throwing a NOx sensor failure code, and I'm getting a distinct whiff of exhaust fumes. I've checked the connections as best I can, but I'm no expert. Could a dodgy cable or plug really cause all this? Anyone else had similar issues?

4 comment(s)

I had a similar problem with my Astra, although I didn't notice exhaust leaking. NOx sensor failure is common. Have you checked the sensor's electrical connections thoroughly? Sometimes the OBD throws that error but is misleading. Does the diagnostic show a specific fault code?

Yeah, the diagnostic shows a P0420 code related to the catalytic converter efficiency, but the guy at the shop said it's probably the NOx sensor messing with the readings. Where exactly should I be looking for cable or plug issues? I'm not sure where the NOx sensor is located...

P0420 can be triggered by a faulty NOx sensor. If you're not comfortable locating and testing the sensor and its wiring, your best bet is to take it to a workshop. They'll have the tools and experience to diagnose it properly.

Thanks for the advice! It was indeed a faulty connection to the NOx sensor. Cost me 95€ to get it sorted at the garage. At least the check engine light is gone, and the exhaust smell is gone too! Cheers!

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