2021 Ford Bronco Base, 4D Utility, 2.3L Eng VIN H, Part Time T/Case ControlFACTORY OEM SERVICE PROCEDURE

P0455 - EVAP System Leak Detected (Large Leak)

DTC DESCRIPTION P0455 - EVAP SYSTEM LEAK DETECTED (LARGE LEAK)

Description:  The PCM monitors the complete evaporative emission (EVAP) control system for no purge flow, the presence of a large fuel vapor leak, or multiple small fuel vapor leaks. This DTC sets when no purge flow, which is attributed to fuel vapor restrictions, a large fuel vapor leak, or multiple fuel vapor leaks are detected by the EVAP running loss monitor test with the engine running, but not at idle.
Possible Causes: 
  • Damaged, missing or loosely installed fuel filler cap (if equipped)
  • Aftermarket EVAP hardware that does not conform to the required specifications
  • Disconnected or cracked fuel EVAP canister tube, EVAP canister purge outlet tube, or EVAP return tube
  • EVAP purge valve stuck closed
  • Slow responding EVAP purge valve
  • Capless fuel tank filler pipe damaged or not sealed correctly (if equipped)
  • Restrictions in the fuel vapor hoses or tubes
  • Loose fuel vapor hose or tube connections to the EVAP system components
  • EVAP canister vent valve stuck open
  • Damaged fuel tank pressure (FTP) sensor
  • Damaged EVAP canister
Diagnostic Aids:  Check for audible vacuum noise or significant fuel odor in the engine compartment or near the EVAP canister and fuel tank. Verify the capless fuel tank filler pipe is sealed correctly. Install and remove the supplemental fueling adapter five times in the capless fuel tank filler pipe to clear debris on the seal. Refer to the Owner Literature for the location of the supplemental fueling adapter in the vehicle.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to Pinpoint Test HX.
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