Ford Flex NOx Sensor Issue

Sounds frustrating! Had almost the same thing happen on my old Saab 9-3. Check engine light, stored error, the whole shebang. Turned out to be a corroded connector on the sensor itself. Like a bad garden hose connection; even a small leak throws everything off. Did you check the connector thoroughly for any signs of damage or corrosion?

Thanks for the quick reply. Your Saab experience is good to know. Can you say where the connector was? Easy to get to, or did you have to take stuff apart?

Sure thing. On the Saab, it was a pain to get to – almost hidden behind the catalytic converter. I think you will need a flexible wrench. It was definitely worth checking before replacing the sensor. However, I still recommend you go to the workshop if you aren't confident enough.

Appreciate the guidance on the NOx sensor issue. The corroded connector idea was helpful. Based on your experience and what I'm seeing, I'm going to the workshop. Estimate is about 95€. Thanks again.