Technical Service Bulletin 21N05 — 2016 FORD F-250 SD

Certain 2013-2016 Model Year F-Series Super Duty 6.7L Diesel and 2015-2019 Model Year Transit 3.2L Diesel Vehicles – Rear NOx Sensor Warranty Extension In all of the affected vehicles, the onboard diagnostic (OBD) system initially contained a software error that prevented illumination of the malfunction indicator light (MIL) if a certain fault was present in the front or rear nitrogen oxide (NOx) sensor or in the Selective Catalyst Reduction (SCR) system. Since the PCM was reprogrammed under Emissions Recall 21E01, the OBD system is now able to detect this NOx sensor fault previously masked by the software error and can light the MIL if this fault is found to be present