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DTC P0442: EVAP System Small Leak Detected (2006 model); DTC P0456: EVAP System Very Small Leak Detected (2006 model)

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

NOTE:
  • 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.
  • Before you troubleshoot, record all freeze data and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
  1. Check the fuel fill cap (the cap must say "If not tightened 3 clicks check engine light may come on").

    Is the correct fuel fill cap installed and properly tightened? 

    1. YES  -Go to step 2.
    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). Make sure the fuel fill cap tether cord (C) is not caught under the cap.
    Fig 1: Checking Fuel Fill Cap Seal And Fuel Fill Pipe Mating Surface
    G03681115Courtesy 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? 

    1. YES  -Replace the fuel fill cap or the fuel fill pipe, then go to step  22.
    2. NO  -Go to step 3.
  3. Turn the ignition switch 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? 

    1. YES  -Intermittent failure, 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.
    2. NO  -Go to step 6.
  6. Turn the ignition switch OFF.
  7. Turn the ignition switch ON (II).
  8. Check for a poor connection or damage at the fuel tank vapor recirculation tube.

    Is the tube OK? 

    1. YES  -Go to step 9.
    2. NO  -
      • Replace the fuel tank vapor recirculation tube, then go to step  22.
      • If necessary, replace the fuel tank (see 2006 MODEL ), then go to step  22.
  9. Disconnect the fuel tank vapor recirculation tube (A) from the EVAP canister (B), and plug the EVAP canister port (C).
    Fig 2: Disconnecting Fuel Tank Vapor Recirculation Tube From EVAP Canister And Plug EVAP Canister Port
    G03681116Courtesy of AMERICAN HONDA MOTOR CO., INC.
  10. Disconnect the vacuum hose (purge line) from the EVAP canister purge valve (A) and connect a T-fitting (B) from the vacuum gauge and the vacuum pump/gauge, 0-30 in.Hg, to the hose as shown.
    Fig 3: Disconnecting Vacuum Hose (Purge Line) From EVAP Canister Purge Valve
    G03681117Courtesy of AMERICAN HONDA MOTOR CO., INC.
  11. Select EVAP CVS ON in the INSPECTION MENU with the HDS.
  12. Apply vacuum to the hose until FTP reads 1.90 V (2 kPa (0.6 in.Hg, 15mmHg)).
  13. Moniter the FTP SENSOR in the DATA LIST for 1 minute with the HDS.

    Does the voltage increase more than 0.2 V (0.1 in.Hg, 0.5 mmHg)? 

    1. YES  -Go to step  19.
    2. NO  -Go to step 14.
  14. Select EVAP CVS OFF in the INSPECTION MENU with the HDS.
  15. Disconnect the fresh air hose (A) from the EVAP canister vent shut valve (B), and plug the EVAP canister vent shut valve ports (C).
    Fig 4: Disconnecting Fresh Air Hose From EVAP Canister Vent Shut Valve
    G03681118Courtesy of AMERICAN HONDA MOTOR CO., INC.
  16. Apply vacuum to the hose (disconnected in step 10) until FTP reads 1.90 V (2 kPa (0.6 in.Hg, 14.6 mmHg)).
  17. Moniter the FTP SENSOR in the DATA LIST for 1 minute with the HDS.

    Does the voltage increase more than 0.2 V (0.1 in.Hg, 0.5 mmHg)? 

    1. YES  -Go to step 18.
    2. NO  -Replace the EVAP canister vent shut valve, then go to step  21.
  18. Check for a loose or damaged PCS line between the EVAP canister and the EVAP canister purge valve.

    Is the line OK? 

    1. YES  -Replace the these parts, then go to step  21.
      • FTP sensor O-ring
      • EVAP canister vent shut valve case and O-ring
      • EVAP canister
    2. NO  -Reconnect or repair the PCS 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? 

    1. YES  -Check the fuel tank unit base gasket (see FUEL FILTER REPLACEMENT ), and check the fuel tank, then go to step 21.
    2. NO  -Repair or replace any damaged parts, then go to step 21.
  21. Reconnect all hoses and connectors.
  22. Turn the ignition switch ON (II).
  23. Reset the ECM with the HDS.
  24. Do the ECM idle learn procedure (see ECM IDLE LEARN PROCEDURE ).
  25. Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.

    Is the result OK? 

    1. YES  -Troubleshooting is complete.
    2. NO  -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, then Go to step  1.
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