Jeep Commander NOx Sensor Failure, Exhaust Issue Alert

Had a similar situation with my 2011 Jeep Grand Cherokee diesel engine. The exhaust smell combined with check engine alerts pointed to sensor failure in the pollution control system. The NOx sensor diagnosis proved correct, but the root cause was a damaged wiring harness connector leading to the sensor. The catalytic converter was functioning properly, but the faulty connection was causing incorrect air-fuel ratio readings. This triggered the system to run rich, leading to the exhaust smell. The repair involved replacing the wiring harness section and recalibrating the sensor. While not a major mechanical issue, it required proper diagnostic equipment to pinpoint the exact problem. A failing NOx sensor can mimic other emission system issues, so getting accurate readings is crucial. The repair process also included checking the surrounding components since wiring problems often affect multiple systems in the pollution control setup. This is a relatively common issue on these models, especially as they age. Getting it fixed promptly prevents potential damage to other emission components.

Thanks for sharing your experience. I had almost identical symptoms on my Commander last year, including the strong exhaust fumes and check engine warnings. The nitrogen oxide sensor replacement fixed it completely. The original issue started affecting my exhaust system performance before I got it sorted. Did you track the repair cost for your air-fuel ratio and wiring repairs? Also curious if you have had any other emission-related problems since the fix?

Since fixing the cable connection issue on my Commander, the nitrogen oxide sensor has been working perfectly. The total repair came to 95 Euro, which was mainly labor costs to trace and fix the defective plug connection. The air-fuel ratio readings returned to normal immediately after the repair. The pollution control system has been running smoothly for months now, with no additional sensor failure or emission problems. Getting the proper diagnosis saved me from unnecessarily replacing the entire NOx sensor unit, which would have been much more expensive. One tip: having the catalytic converter checked during the repair confirmed it was still in good condition, which was reassuring given the exhaust symptoms we both experienced. Regular maintenance since the fix has kept all emission components working as they should.

After reading your feedback, I finally took my Commander to a certified mechanic last week. The diagnostic scan revealed a deteriorating NOx sensor, just as suspected. The repair totaled 320 Euro, including parts and labor. They also discovered and fixed a loose connection in the pollution control system. The check engine light disappeared right after the fix, and the exhaust smell is completely gone. The air-fuel ratio is now optimal according to the scan results. My mechanic mentioned the catalytic converter looked fine during inspection, which was a relief since that would have been a much costlier repair. The whole process took about 3 hours, and I already notice better engine performance. Lesson learned about not delaying repairs when emission system warnings appear. No issues since the fix, and the engine runs smoother than before.