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Home >> Acura >> 2003 >> MDX Touring >> Repair and Diagnosis >> Engine Mechanical >> Auxiliary Emission Control Systems >> EVAP System >> DTC Troubleshooting >> DTC P0497: EVAP System Low Purge Flow (2003-2004 models)

DTC P0497: EVAP System Low Purge Flow (2003-2004 models)

Special Tools Required 

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, 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 fuel fill cap, then go to step  33.
  2. Turn the ignition switch ON (II).
  3. Clear the DTC with the HDS.
  4. Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.

    Is the EVAP SYSTEM normal? 

    1. YES  - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the FTP sensor, the EVAP bypass solenoid valve, and the EVAP canister purge valve, or at the EVAP canister vent shut valve and the PCM.
    2. NO  - Go to step 5.
  5. Check for looseness or damage on PCS line between the intake manifold and the EVAP canister purge valve.

    Is the line OK? 

    1. YES  - Go to step 6.
    2. NO  - Reconnect or repair the PCS line, then go to step  33.
  6. Disconnect the PCS hose at the purge joint (A), and connect a vacuum pump to the PCS hose (B).
    Fig 1: Disconnecting PCS Hose At Purge Joint, And Connect Vacuum Pump To PCS Hose
    G03640092Courtesy of AMERICAN HONDA MOTOR CO., INC.
  7. Slowly apply 2.0 kPa (0.6 in.Hg, 15 mmHg) of vacuum to the PCS hose.
  8. Do the EVAP PCS ON in the INSPECTION MENU with the HDS.

    Does it hold vacuum? 

    1. YES  - Go to step 9.
    2. NO  - Check for leakage on the PCS line between the intake manifold and the EVAP canister purge valve. If the vacuum hose is OK, replace the EVAP canister purge valve, then go to step  33.
  9. Keep about 2.0 kPa (0.6 in.Hg, 15 mmHg) of vacuum in the hose.
  10. Reconnect the PCS hose to the EVAP canister purge valve.
  11. Do the EVAP PCS ON in the INSPECTION MENU with the HDS.

    Does It change to atmospheric pressure? 

    1. YES  - Go to step 12.
    2. NO  - Check for blockage on the PCS line between the intake manifold and the EVAP canister purge valve. If the vacuum hose is OK, replace the EVAP canister purge valve, then go to step  33.
  12. Disconnect the PCS hose (A) from the EVAP canister purge valve (B).
    Fig 2: Disconnecting PCS Hose From EVAP Canister Purge Valve
    G03640093Courtesy of AMERICAN HONDA MOTOR CO., INC.
  13. Connect a T-fitting (C) from the vacuum gauge and the vacuum pump to the PCS hose.
  14. Do the EVAP PCS OFF in the INSPECTION MENU with the HDS.
  15. Slowly apply 2.0 kPa (0.6 in.Hg, 15 mmHg) of vacuum to the PCS hose.

    Does it hold vacuum? 

    1. YES  - Go to step 16.
    2. NO  - Check for a looseness or damage on PCS line between the EVAP canister purge valve and the EVAP canister, then go to step  33.
  16. Do the EVAP PCS ON in the INSPECTION MENU with the HDS.

    Does it change to atmospheric pressure? 

    1. YES  - Go to step 17.
    2. NO  - Check for a clogged PCS line between the EVAP canister purge valve and the EVAP canister, then go to step  33.
  17. Disconnect the vacuum hose (A) from the FTP sensor (B).
    Fig 3: Disconnecting Vacuum Hose From FTP Sensor
    G03640094Courtesy of AMERICAN HONDA MOTOR CO., INC.
  18. Disconnect the vacuum hose (A) between the EVAP canister (B) and the EVAP two way valve (C) at EVAP canister side.
    Fig 4: Disconnecting Vacuum Hose Between EVAP Canister And EVAP Two Way Valve At EVAP Canister Side
    G03640095Courtesy of AMERICAN HONDA MOTOR CO., INC.
  19. Connect a T-fitting (D) from the vacuum gauge and the vacuum pump to the vacuum hose.
  20. Slowly apply 2.0 kPa (0.6 in.Hg, 15 mmHg) of vacuum to the hose.

    Does it hold vacuum? 

    1. YES  - Go to step 21.
    2. NO  - Reconnect or repair the vacuum hose between the EVAP canister and the EVAP two way valve, then go to step  33.
  21. Do the EVAP BPS ON in the INSPECTION MENU with the HDS.

    Does it change to atmospheric pressure? 

    1. YES  - Go to step 22.
    2. NO  - Check for a clogged vacuum hose (BPS line) between the EVAP canister and the EVAP two way valve, and between the EVAP two way valve and the FTP sensor. If the vacuum hoses are OK, replace the EVAP two way valve, then go to step  33.
  22. Connect a vacuum pump to the hose previously disconnected from the FTP sensor on step  14.
  23. Slowly apply 2.0 kPa (0.6 in.Hg, 15 mmHg) of vacuum to the hose disconnected from the FTP sensor.

    Does it hold vacuum? 

    1. YES  - Go to step 24.
    2. NO  - Reconnect or repair the vacuum hose between the EVAP two way valve and the FTP sensor, then go to step  33.
  24. Connect a T-fitting (A) from the vacuum gauge and the vacuum pump to the FTP sensor (B) as shown.
    Fig 5: Connecting T-Fitting From Vacuum Gauge And Vacuum Pump To FTP Sensor
    G03640096Courtesy of AMERICAN HONDA MOTOR CO., INC.
  25. Slowly apply 1.3 kPa (0.4 in.Hg, 10 mmHg) of vacuum to the FTP sensor (B).
  26. Check the FTP SENSOR in the DATA LIST with the HDS.

    Is the difference 1.1 kPa (0.31 in.Hg, 8 mmHg) or more? 

    1. YES  - Go to step 27.
    2. NO  - Replace the FTP sensor, then go to step  33.
  27. Disconnect the vacuum hose (A) to the EVAP two way valve (B) at the EVAP canister (C) side, and plug the EVAP canister port (D).
    Fig 6: Disconnecting Vacuum Hose To EVAP Two Way Valve At EVAP Canister Side, And Plug EVAP Canister Port
    G03640097Courtesy of AMERICAN HONDA MOTOR CO., INC.
  28. Disconnect the PCS hose (E) from the EVAP canister.
  29. Connect a T-fitting (F) from the vacuum gauge and the vacuum pump to the PCS hose.
  30. Do the EVAP PCS OFF in the INSPECTION MENU with the HDS.
  31. Do the EVAP CVS ON in the INSPECTION MENU with the HDS.
  32. Slowly apply 2.0 kPa (0.6 in.Hg, 15 mmHg) of vacuum to the PCS hose.

    Does it hold vacuum? 

    1. YES  - Check for a clogged the EVAP canister port, then go to step 33.
    2. NO  - Replace the EVAP canister vent shut valve, then go to step 33.
  33. Turn the ignition switch ON (II).
  34. Reset the PCM with the HDS.
  35. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  36. Do the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.

    Is the EVAP SYSTEM normal? 

    1. YES  - Troubleshooting is complete.
    2. NO  - Reconnect or repair the fuel tank vapor control vent tube and the hose between the EVAP vent shut valve and the EVAP canister, if the tube and hose are OK, check for poor connections or loose terminals at the FTP sensor, the EVAP bypass solenoid valve, the EVAP canister purge valve, or the EVAP canister vent shut valve and the PCM, then go to step  1.
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