Check exhaust system message on Ford Transit - NOx sensor fault

A check exhaust system message on a Euro 6 Transit MK8 or MK9, often accompanied by fault code P2200 and a mileage countdown to a no-start condition, usually indicates a failed NOx sensor. An SCR-equipped engine has two of these sensors, one before and one after the catalyst, and each has a different part number. A diagnostic scan is therefore essential before ordering a replacement, as it will identify which sensor has failed. Practical note: the new sensor must be adapted with diagnostic equipment after installation. Ignoring the warning will result in a genuine start lockout. Once the mileage counter reaches zero, the van will not start, even if the AdBlue tank is full.