Citan check engine light and NOx sensor issue

Sounds familiar. I had a similar issue with my old BMW. Check engine light, the whole shebang. Is it running rough? Could be a bad air-fuel ratio messing with the emission sensor. Diesel engines are especially sensitive to that. Did you check the sensor's wiring harness for corrosion or damage?

Thanks for the swift reply. I did a visual inspection of the wiring, but didn't see anything obvious. You mentioned air-fuel ratio. Is there a straightforward way to check that without specialized tools?

Without proper diagnostic tools, checking the air-fuel ratio precisely is tough. Given the exhaust leak and NOx sensor error, plus the check engine light, it's probably best to get it hooked up to a diagnostic system. Could be a simple fix, but it's better to be sure before things get worse with your exhaust system. My gut feeling is that the defective cable or plug is causing this.

Understood. I appreciate the advice. I'll take it to a workshop for a proper diagnostic check. It was indeed the plug connection of the NOx sensor that was defective, as suspected. Thanks again!