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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 ON (II).
  2. Clear the DTC with the HDS.
  3. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) 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 and induction cleaner.

    NO  - Go to step  5.

  5. Turn the ignition switch OFF.
  6. Disconnect the EGR valve 6P connector.
  7. At the EGR valve side, measure resistance between EGR valve 6P connector terminals No. 1 and No. 2.
    Fig 1: Measuring Resistance Between EGR Valve 6P Connector Terminals No. 1 And No. 2
    G05454837Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 100 kΩ or more? 

    YES  - Go to step  26.

    NO  - Go to step  8.

  8. Measure resistance between EGR valve 6P connector terminals No. 1 and No. 3.
    Fig 2: Measuring Resistance Between EGR Valve 6P Connector Terminals No. 1 And No. 3
    G05454838Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 100 kΩ or more? 

    YES  - Go to step  26.

    NO  - Go to step  9.

  9. Check for continuity between EGR valve 6P connector terminal No. 6 and body ground.
    Fig 3: Checking Continuity Between EGR Valve 6P Connector Terminal No. 6 And Body Ground
    G05454839Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step  10.

    NO  - Repair open in the wire between the EGR valve and G101 (see ENGINE WIRE HARNESS ), then go to step  27.

  10. Jump the SCS line with the HDS.
  11. Disconnect ECM/PCM connector B (24P).
  12. Check for continuity between ECM/PCM connector terminal B16 and body ground.
    Fig 4: Checking Continuity Between ECM/PCM Connector Terminal B16 And Body Ground
    G05454840Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the ECM/PCM (B16) and the EGR valve, then go to step  27.

    NO  - Go to step  13.

  13. Connect EGR valve 6P connector terminal No. 4 to body ground with a jumper wire.
    Fig 5: Connecting EGR Valve 6P Connector Terminal No. 4 To Body Ground With Jumper Wire
    G05454841Courtesy of AMERICAN HONDA MOTOR CO., INC.
  14. Check for continuity between ECM/PCM connector terminal B16 and body ground.
    Fig 6: Checking Continuity Between ECM/PCM Connector Terminal B16 And Body Ground
    G05454842Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step  15.

    NO  - Repair open in the wire between the ECM/PCM (B16) and the EGR valve, then go to step  27.

  15. Remove the EGR valve (see EGR VALVE REPLACEMENT ).
  16. Clean the intake manifold EGR port with throttle plate and induction cleaner. Also, clean the passage inside the EGR valve with throttle plate and induction cleaner.
  17. Install the EGR valve (see EGR VALVE REPLACEMENT ).
  18. Reconnect the EGR valve 6P connector.
  19. Reconnect ECM/PCM connector B (24P).
  20. Turn the ignition switch ON (II).
  21. Reset the ECM/PCM with the HDS.
  22. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
  23. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) 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.

    NO  - Go to step  25.

  25. Turn the ignition switch OFF.
  26. Replace the EGR valve (see EGR VALVE REPLACEMENT ).
  27. Reconnect all connectors.
  28. Turn the ignition switch ON (II).
  29. Reset the ECM/PCM with the HDS.
  30. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
  31. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) 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 Temporary DTCs or DTCs with the HDS.

    Is DTC P0404 indicated? 

    YES  - Check for poor connections or loose terminals at the EGR valve and the ECM/PCM, then go to step  1. If the connections and terminals are OK, go to step  35.

    NO  - Go to step  34.

  34. Monitor the OBD STATUS for DTC P0404 in the DTCs MENU with the HDS.

    Does the screen indicate PASSED? 

    YES  - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 33, go to the indicated DTCs troubleshooting.

    NO  - If the screen indicates FAILED, go to step  1 and recheck. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step  31.

  35. Update the ECM/PCM if it does not have the latest software (see UPDATING THE ECM/PCM ), or substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ).
  36. Do the EGR TEST in the INSPECTION MENU with the HDS.
  37. Check for Temporary DTCs or DTCs with the HDS.

    Is DTC P0404 indicated ? 

    YES  - Check for poor connections or loose terminals at the EGR valve and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then go to step  36. If the ECM/PCM was substituted, go to step  1.

    NO  - Go to step  38.

  38. Monitor the OBD STATUS for DTC P0404 in the DTCs MENU with the HDS.

    Does the screen indicate PASSED? 

    YES  - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ). If any other Temporary DTCs or DTCs were indicated in step 37, go to the indicated DTCs troubleshooting.

    NO  - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM (see SUBSTITUTING THE ECM/PCM ), then go to step  36. If the ECM/PCM was substituted, go to step  1. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step  36.

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