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DTC P0404: EGR Valve Circuit Range/Performance Problem

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
  1. Turn the ignition switch to ON (II).
  2. Clear the DTC with the HDS.
  3. Start the engine. Hold the engine speed at 3, 000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.
  4. Do the EGR TEST in the INSPECTION MENU with the HDS.

    Is the result OK? 

    YES  -Intermittent failure, the system is OK at this time. Clean any carbon build-up on the EGR valve with throttle plate cleaner.

    NO  -Go to step 5.

  5. Turn the ignition switch to LOCK (0).
  6. Disconnect the EGR valve 5P connector.
  7. At the EGR valve side, measure the resistance between EGR valve 5P connector terminals No. 2 and No. 3.
    Fig 1: Measuring Resistance Between EGR Valve 5P Connector Terminals No. 2 And No. 3
    G07354011Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 100 kΩ or more? 

    YES  -Go to step 26 26.

    NO  -Go to step 8.

  8. At the EGR valve side, measure the resistance between EGR valve 5P connector terminals No. 2 and No. 4.
    Fig 2: Measuring Resistance Between EGR Valve 5P Connector Terminals No. 2 And No. 4
    G07354012Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 100 kΩ or more? 

    YES  -Go to step 26 26.

    NO  -Go to step 9.

  9. Check for continuity between EGR valve 5P connector terminal No. 5 and body ground.
    Fig 3: Checking Continuity Between EGR Valve 5P Connector Terminal No. 5 And Body Ground
    G07354013Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 10.

    NO  -Repair an open in the wire between the EGR valve and G101, then go to step 27 27.

  10. Jump the SCS line with the HDS.
  11. Disconnect PCM connector C (49P).
  12. Check for continuity between PCM connector terminal C10 and body ground.
    Fig 4: Checking Continuity Between PCM Connector Terminal C10 And Body Ground
    G07354014Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short in the wire between the PCM (C10) and the EGR valve, then go to step 27 27.

    NO  -Go to step 13.

  13. Connect EGR valve 5P connector terminal No. 1 to body ground with a jumper wire.
    Fig 5: Connecting EGR Valve 5P Connector Terminal No. 1 To Body Ground With Jumper Wire
    G07354015Courtesy of AMERICAN HONDA MOTOR CO., INC.
  14. Check for continuity between PCM connector terminal C10 and body ground.
    Fig 6: Checking Continuity Between PCM Connector Terminal C10 And Body Ground
    G07354016Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 15.

    NO  -Repair an open in the wire between the PCM (C10) and the EGR valve, then go to step 27 27.

  15. Remove the EGR valve (see EGR VALVE REPLACEMENT ).
  16. Clean any carbon build-up on the EGR valve with throttle plate cleaner.
  17. Install the EGR valve (see EGR VALVE REPLACEMENT ).
  18. Reconnect the EGR valve 5P connector.
  19. Reconnect PCM connector C (49P).
  20. Turn the ignition switch to ON (II).
  21. Reset the PCM with the HDS.
  22. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  23. Start the engine. Hold the engine speed at 3, 000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.
  24. Do the EGR TEST in the INSPECTION MENU with the HDS.

    Is the result OK? 

    YES  -Go to step 33 33.

    NO  -Go to step 25.

  25. Turn the ignition switch to LOCK (0).
  26. Replace the EGR valve (see EGR VALVE REPLACEMENT ).
  27. Reconnect all connectors.
  28. Turn the ignition switch to ON (II).
  29. Reset the PCM with the HDS.
  30. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  31. Start the engine. Hold the engine speed at 3, 000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.
  32. Do the EGR TEST in the INSPECTION MENU with the HDS.
  33. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P0404 indicated? 

    YES  -Check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 1 1. If the connections and terminals are OK, go to step 34.

    NO  -Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.

  34. Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
  35. Start the engine. Hold the engine speed at 3, 000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.
  36. Do the EGR TEST in the INSPECTION MENU with the HDS.
  37. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P0404 indicated? 

    YES  -Check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step 35. If the PCM was substituted, go to step 1 1.

    NO  -If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT ). If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.

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