DTC P0457: Evaporative Emission (EVAP) System Malfunction
WARNING: This page is about a different car, the 2003 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Evaporative Emission System Malfunction Troubleshooting Procedure
Courtesy of FORD MOTOR CO.
Fig 2: Evaporative Emission System Malfunction Inspection Procedure