Some 2021 F-Super Duty and 2021-2022 E-Series vehicles equipped with a 6.2L or 7.3L gasoline engine may exhibit an illuminated malfunction indicator lamp (MIL) with diagnostic trouble code (DTC) P0457 stored in the powertrain control module (PCM). This may be due to a loose fuel filler cap. The fuel filler cap design has changed, requiring multiple turns to seal properly. Advise the customer to turn the fuel filler cap clockwise until there is at least one audible click to seal properly. For further diagnostics, refer to the Powertrain Control/Emissions Diagnosis (PC/ED) manual, pinpoint test HX.
