2021 Ford Explorer XLT, RWDFACTORY OEM SERVICE PROCEDURE

P04F0 - EVAP System High Load Purge Line A Performance

DTC DESCRIPTION P04F0 - EVAP SYSTEM HIGH LOAD PURGE LINE A PERFORMANCE

Description:  The EVAP check valve test is performed during minimal boost conditions, once per drive cycle, when entry conditions are met. This DTC sets when the fuel tank pressure exceeds a calibrated amount within a specified amount of time during the test (single path check valve), or when the fuel tank vacuum is less than a calibrated amount within a specified amount of time or when the fuel tank pressure exceeds a calibrated amount within a specified amount of time during the test (dual path check valve).
Possible Causes: 
  • Incorrect EVAP system hose or line connections
  • Restricted EVAP ejector connections at the intake air system
  • Stuck open EVAP check valve
  • Stuck closed EVAP check valve
  • Damaged EVAP ejector
  • Damaged EVAP check valve
Diagnostic Aids:   
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to Pinpoint Test HX.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
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  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
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