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DTC P0404: EGR Control 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
    G08092591Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 100 kΩ or more? 

    YES  -Go to step  23.

    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
    G08092592Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 100 kΩ or more? 

    YES  -Go to step  23.

    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
    G08092593Courtesy 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 (see CONNECTOR TO FUSE/RELAY BOX INDEX ), then go to step  24.

  10. Jump the SCS line with the HDS.
  11. Disconnect PCM connector B (49P).
  12. Check for continuity between PCM connector terminal B2 and body ground.
    Fig 4: Checking Continuity Between PCM Connector Terminal B2 And Body Ground
    G08092594Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short in the wire between the PCM (B2) and the EGR valve, then go to step  24.

    NO  -Go to step 13.

  13. Check for continuity between PCM connector terminal B2 and EGR valve 5P connector terminal No. 1.
    Fig 5: Checking Continuity Between PCM Connector Terminal B2 And EGR Valve 5P Connector Terminal No. 1
    G08092595Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 14.

    NO  -Repair an open in the wire between the PCM (B2) and the EGR valve, then go to step  24.

  14. Remove the EGR valve (see EGR VALVE REPLACEMENT ).
  15. Clean any carbon build-up on the EGR valve with throttle plate cleaner.
  16. Install the EGR valve (see EGR VALVE REPLACEMENT ).
  17. Reconnect all connectors.
  18. Reset the PCM with the HDS.
  19. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  20. 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.
  21. Do the EGR TEST in the INSPECTION MENU with the HDS.

    Is the result OK? 

    YES  -Go to step  30.

    NO  -Go to step 22.

  22. Turn the ignition switch to LOCK (0).
  23. Replace the EGR valve (see EGR VALVE REPLACEMENT ).
  24. Reconnect all connectors.
  25. Turn the ignition switch to ON (II).
  26. Reset the PCM with the HDS.
  27. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  28. 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.
  29. Do the EGR TEST in the INSPECTION MENU with the HDS.
  30. 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. If the connections and terminals are OK, go to step 31.

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

  31. Update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
  32. 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.
  33. Do the EGR TEST in the INSPECTION MENU with the HDS.
  34. 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  33. If the PCM was substituted, go to step  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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