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Home >> Acura >> 2011 >> RL >> Repair and Diagnosis >> Engine Performance >> System >> EVAP System >> DTC Troubleshooting >> DTC P0455: EVAP System Large Leak Detected; DTC P0456: EVAP System Very Small Leak Detected

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 inHg 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 creates greater pressure/vacuum. The best 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  31.

  2. Check the fuel fill cap seal (A) and the fuel fill pipe mating surface (B). Make sure 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
    G07362102Courtesy 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  31.

    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, the EVAP canister vent shut valve, and the 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  -

    • Reconnect or replace the fuel tank vapor recirculation tube, then go to step  31.
    • If needed, replace the fuel tank (see FUEL TANK REPLACEMENT ), then go to step  31.
  8. Remove the trunk floor trim panel (see TRIM REMOVAL/INSTALLATION - TRUNK AREA ).
  9. Remove the EVAP access panel from the floor.
  10. Disconnect the fuel tank vapor recirculation tube (A) and the fresh air hose (B) from the EVAP canister (C), and plug the EVAP canister ports (D).
    Fig 2: Disconnecting Fuel Tank Vapor Recirculation Tube And Fresh Air Hose From EVAP Canister
    G07362103Courtesy of AMERICAN HONDA MOTOR CO., INC.
  11. Disconnect the vacuum hose (engine side) (A) from the EVAP canister purge valve (B) in the engine compartment, then connect a vacuum pump/gauge, 0-30 inHg, to the purge valve as shown.
    Fig 3: Disconnecting Vacuum Hose (Engine Side) From EVAP Canister Purge Valve
    G07362104Courtesy of AMERICAN HONDA MOTOR CO., INC.
  12. Turn the ignition switch to ON (II).
  13. Select EVAP PCS ON in the INSPECTION MENU with the HDS.
  14. Apply vacuum to the hose until the FTP reads 1.90 V (-0.59 inHg,-15.1 mmHg).
    NOTE: Be careful not to exceed the vacuum. If you do, the FTP sensor can be damaged.
  15. Select EVAP PCS OFF in the INSPECTION MENU with the HDS, then remove the vacuum pump/gauge from the purge valve.
  16. Monitor the FTP SENSOR in the DATA LIST for 1 minute with the HDS.

    Does the voltage increase more than 0.2 V (0.1 inHg, 2.5 mmHg)? 

    YES  -Go to step 17.

    NO  -Go to step  22.

  17. Reconnect the vacuum hose (engine side) to the EVAP canister purge valve.
  18. Disconnect the vacuum hose (EVAP canister side) (A) from the EVAP canister purge valve (B) in the engine compartment, then connect the vacuum pump/gauge to the vacuum hose as shown.
    Fig 4: Disconnecting Vacuum Hose (Evap Canister Side) From EVAP Canister Purge Valve
    G07362105Courtesy of AMERICAN HONDA MOTOR CO., INC.
  19. Apply vacuum to the hose until the FTP reads 1.90 V (-0.59 inHg,-15.1 mmHg).
    NOTE: Be careful not to exceed the vacuum. If you do, the FTP sensor can be damaged.
  20. Monitor the FTP SENSOR in the DATA LIST for 1 minute with the HDS.

    Does the voltage increase more than 0.2 V (0.1 inHg, 2.5 mmHg)? 

    YES  -Go to step 21.

    NO  -Replace the EVAP canister purge valve (see EVAP CANISTER PURGE VALVE REPLACEMENT  ), then go to step  30.

  21. Check for a loose or damaged EVAP canister purge line between the EVAP canister and the EVAP canister purge valve. Also check for a leaking EVAP canister.

    Are the line and the canister OK? 

    YES  -Replace these parts, then go to step  30:

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

    NO  -Reconnect or repair the EVAP canister purge line, then go to step  30.

  22. Reconnect the fresh air hose (A) to the EVAP canister.
    Fig 5: Connecting Fresh Air Hose To EVAP Canister
    G07362106Courtesy of AMERICAN HONDA MOTOR CO., INC.
  23. Reconnect the vacuum hose (engine side) to the EVAP canister purge valve.
  24. Disconnect the vacuum hose (EVAP canister side) (A) from EVAP canister purge valve (B) in the engine compartment, then connect the vacuum pump/gauge to the vacuum hose as shown.
    Fig 6: Disconnecting Vacuum Hose (Evap Canister Side) From EVAP Canister Purge Valve
    G07362107Courtesy of AMERICAN HONDA MOTOR CO., INC.
  25. Select the EVAP CVS ON in the INSPECTION MENU with the HDS.
  26. Apply vacuum to the fuel tank vapor recirculation tube (disconnected in step  10) until the FTP reads 1.90 V (-0.59 inHg, -15.1 mmHg).
    NOTE: Be careful not to exceed the vacuum. If you do, the FTP sensor can be damaged.
  27. Monitor the FTP SENSOR in the DATA LIST for 1 minute with the HDS.

    Does the voltage increase more than 0.2 V(0.1 inHg, 2.5 mmHg)? 

    YES  -Replace the EVAP canister vent shut valve (see EVAP CANISTER VENT SHUT VALVE REPLACEMENT  ), then go to step  30.

    NO  -Go to step 28.

  28. Select EVAP CVS OFF in the INSPECTION MENU with the HDS.
  29. 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 the fuel tank, then go to step 30.

    NO  -Repair or replace the damaged parts, then go to step 30.

  30. Reconnect all hoses and connectors.
  31. Turn the ignition switch to ON (II).
  32. Reset the PCM with the HDS.
  33. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  34. 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 PCM, then go to step  1.

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