P0451 code ford f150?

The Ford F-150's P0451 code is related to the emissions system and possibly a bad pressure sensor. The code is universal across vehicles and not Ford specific. Your truck's "check engine" light will illuminate and the small of gas may be present. You also might experience a reduction in fuel economy too A simple cause of this is a loose gas cap or faulty wiring in and around the EVAP cannister. Examine the wiring harness where it connects to the EVAP pressure sensor. The EVAP cannister or the sensor itself could need replacing as well. Other causes include a faulty fuel tank pressure relief valve. The cost to have the valve replaced ranges from $250-$350 in parts and labor.