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DTC P0455: EVAP System Large Leak Detected; DTC P0456: EVAP System Very Small Leak Detected

NOTE: The fuel system is designed to allow specified maximum vacuum and pressure conditions Do not deviate from the vacuum and pressure tests as indicated in these procedures Excessive pressure/vacuum would damage the EVAP components or cause eventual fuel tank failure

Special Tools Required 

Vacuum pump/gauge, 0-30 in Hg, Snap-on YA4000A or equivalent, commercially available

NOTE:
  • Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION )
  • Fresh fuel has a higher volatility that will create greater pressure/vacuum The optimum condition for testing is less than a full tank of fresh fuel If possible, to assist in leak detection, add 1 gallon of fresh fuel to the tank (as long as it will not fill the tank), just before starting these procedures
  1. Check the fuel fill cap (the cap must say TIGHTEN TO CLICK) It should turn 1/4 turn after it's tight, then it clicks

    Is the correct fuel fill cap installed and properly tightened? 

    YES  -go to step 2

    NO  -Replace or tighten the cap, then go to step  22

  2. Check the fuel fill cap seal (A) and the fuel fill pipe mating surface (B) Verify that the fuel fill cap tether cord (C) is not caught under the cap
    Fig 1: Identifying Fuel Fill Cap Seal And Fuel Fill Pipe Mating Surface
    G05992598Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is the fuel fill cap seal missing or damaged, is the fuel fill pipe damaged, or is the tether cord caught under the cap? 

    YES  -Replace the fuel fill cap or the fuel fill pipe, then go to step  22

    NO  -go to step 3

  3. Turn the ignition switch to ON (II)
  4. Clear the DTC with the HDS
  5. Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS

    Is the result OK? 

    YES  -Intermittent failure, the system is OK at this time Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, or the EVAP canister vent shut valve and the ECM/PCM

    NO  -go to step 6

  6. Turn the ignition switch to LOCK (0)
  7. Check for a poor connection or damage at the fuel tank vapor recirculation tube.

    Is the tube OK? 

    YES  -go to step 8

    NO  -

    • Replace the fuel tank vapor recirculation tube, then go to step  22
    • If necessary, replace the fuel tank (see FUEL TANK REPLACEMENT ), then go to step  22

  8. Disconnect the fuel tank vapor recirculation tube (A) from the EVAP canister (B), and plug the EVAP canister port (C)
    Fig 2: Identifying Fuel Tank Vapor Recirculation Tube From EVAP Canister
    G05992599Courtesy of AMERICAN HONDA MOTOR CO., INC.
  9. Disconnect the vacuum hose (purge line) (A) from the EVAP canister purge valve (B) in the engine compartment, and connect a vacuum pump/gauge, 0-30 in Hg, to the vacuum hose as shown
    Fig 3: Identifying Vacuum Hose (Purge Line) From EVAP Canister Purge Valve
    G05992600Courtesy of AMERICAN HONDA MOTOR CO., INC.
  10. Turn the ignition switch to ON (II)
  11. Select EVAP CVS ON in the INSPECTION MENU with the HDS
  12. Apply vacuum to the hose until the FTP reads 1 90 V (-0 59 in Hg, -15 1 mmHg)
    NOTE: Be careful not to exceed the vacuum If you exceed the vacuum, the FTP sensor can be damaged
  13. Monitor the FTP SENSOR in the DATA LIST for 1 minute with the HDS

    Does the voltage increase more than 02 V (0 1 in Hg, 0 5 mmHg)? 

    YES  -go to step 14

    NO  -go to step  19

  14. Select EVAP CVS OFF in the INSPECTION MENU with the HDS
  15. Disconnect the fresh air hose (A) from the EVAP canister (B), and plug the EVAP canister port (C)
    Fig 4: Identifying Fresh Air Hose From EVAP Canister
    G05992601Courtesy of AMERICAN HONDA MOTOR CO., INC.
  16. Apply vacuum to the EVAP system until the FTP reads 1 90 V (-0 59 in Hg,-15 1 mmHg)
    NOTE: Be careful not to exceed the vacuum If you exceed the vacuum, the FTP sensor can be damaged
  17. Monitor the FTP SENSOR in the DATA LIST for 1 minute with the HDS

    Does the voltage increase more than 0 2V (0 1 in Hg, 2 5 mmHg)? 

    YES  -go to step 18

    NO  -Replace the EVAP canister vent shut valve, then go to step  21

  18. Check for a loose or damaged EVAP canister purge line between the EVAP canister and the EVAP canister purge valve, or a leaking EVAP canister purge valve

    Are the line and the EVAP canister purge valve OK? 

    YES  -Replace these parts, then go to step  21

    • FTP sensor O-ring
    • EVAP canister vent shut valve case and O-ring
    • EVAP canister

    NO  -Reconnect or repair the EVAP canister purge hose, then go to step  21

  19. Select EVAP CVS OFF in the INSPECTION MENU with the HDS
  20. Check these parts for looseness or damage
    • Fuel fill pipe
    • Fuel vapor return pipe

    Are the parts OK? 

    YES  -Check the fuel tank unit base gasket (see FUEL TANK UNIT REMOVAL AND INSTALLATION ), and check the fuel tank, then go to step  21

    NO  -Repair or replace the damaged parts, then go to step  21

  21. Reconnect all hoses and connectors
  22. Turn the ignition switch to ON (II)
  23. Reset the ECM/PCM with the HDS
  24. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE )
  25. Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS

    Is the result OK? 

    YES  -Troubleshooting is complete

    NO  -Check for poor connections or loose terminals at the FTP sensor, the EVAP canister purge valve, the EVAP canister vent shut valve, and the ECM/PCM, then go to step  1

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