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Home >> Honda >> 2004 >> Pilot LX >> Repair and Diagnosis >> Engine Performance >> System >> PGM-FI System >> DTC Troubleshooting >> DTC P0301: No. 1 Cylinder Misfire Detected; DTC P0302: No. 2 Cylinder Misfire Detected; DTC P0303: No. 3 Cylinder Misfire Detected; DTC P0304: No. 4 Cylinder Misfire Detected; DTC P0305: No. 5 Cylinder Misfire Detected; DTC P0306: No. 6 Cylinder Misfire Detected

DTC P0301: No. 1 Cylinder Misfire Detected; DTC P0302: No. 2 Cylinder Misfire Detected; DTC P0303: No. 3 Cylinder Misfire Detected; DTC P0304: No. 4 Cylinder Misfire Detected; DTC P0305: No. 5 Cylinder Misfire Detected; DTC P0306: No. 6 Cylinder Misfire Detected

  1. Remove the intake manifold cover and the ignition coil cover (see IGNITION COIL REMOVAL/INSTALLATION ).
  2. After checking and recording the freeze data, reset the PCM (see HOW TO RESET THE PCM ). If there is no freeze data of the misfire, just clear the DTC.
  3. Start the engine, and listen for a clicking sound at the injector of the problem cylinder.

    Does the injector click? 

    1. YES  -Go to step 4.
    2. NO  -Go to step  31.
  4. Turn the ignition switch OFF, and reset the PCM.
  5. Exchange the ignition coil from the problem cylinder with one from another cylinder.
  6. Test-drive the vehicle for several minutes in the range of the freeze data or under various conditions if there was no freeze data.
  7. Check for a DTC or a Temporary DTC with the scan tool or the HDS.

    Is DTC P0301, P0302, P0303, P0304, P0305, P0306, or Temporary DTC P1399 indicated? 

    1. YES  -Go to step 8.
    2. NO  -Intermittent misfire due to poor contact at the ignition coil connector (no misfire at this time). Make sure the coil connections are secure.
  8. Determine which cylinder had the misfire.

    Does the misfire occur in the cylinder where the ignition coil was exchanged? 

    1. YES  -Replace the faulty ignition coil (see IGNITION COIL REMOVAL/INSTALLATION ).
    2. NO  -Go to step 9.
  9. Turn the ignition switch OFF, and reset the PCM.
  10. Exchange the spark plug from the problem cylinder with one from another cylinder.
  11. Test-drive the vehicle for several minutes in the range of the freeze data or under various conditions if there was no freeze data.
  12. Check for a DTC or a Temporary DTC with the scan tool or the HDS.

    Is DTC P0301, P0302, P0303, P0304, P0305, P0306, or Temporary DTC P1399 indicated? 

    1. YES  -Go to step 13.
    2. NO  -Intermittent misfire due to spark plug fouling (no misfire at this time).
  13. Determine which cylinder had the misfire.

    Does the misfire occur in the cylinder where the spark plug was exchanged? 

    1. YES  -Replace the faulty spark plug.
    2. NO  -Go to step 14.
  14. Turn the ignition switch OFF, and reset the PCM (see HOW TO RESET THE PCM ).
  15. Exchange the injector from the problem cylinder with one from another cylinder.
  16. Let the engine idle for 2 minutes.
  17. Test-drive the vehicle for several minutes in the range of the freeze data or under various conditions if there was no freeze data.
  18. Check for a DTC or a Temporary DTC with the scan tool or the HDS.

    Is DTC P0301, P0302, P0303, P0304, P0305, P0306, or Temporary DTC P1399 indicated? 

    1. YES  -Go to step 19.
    2. NO  -Intermittent misfire due to bad contact in the injector connector (no misfire at this time). Check for poor connections or loose terminals at the injector.
  19. Determine which cylinder had the misfire.

    Does the misfire occur in the cylinder where the injector was exchanged? 

    1. YES  -Replace the faulty injector (see Injector Replacement  ).
    2. NO  -Go to step 20.
  20. Turn the ignition switch OFF.
  21. Disconnect the ignition coil 3P connector from the problem cylinder.
  22. Turn the ignition switch ON (II).
  23. Measure voltage between ignition coil 3P connector terminal No. 3 and body ground.
    Fig 1: Measuring Voltage Between Ignition Coil 3P Connector Terminal No. 3 & Body Ground
    G01464045Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  -Go to step 24.
    2. NO  -Repair open in the wire between the No. 11 COIL (15 A) fuse and the ignition coil.
  24. Turn the ignition switch OFF.
  25. Check for continuity between ignition coil 3P connector terminal No. 2 and body ground.
    Fig 2: Checking For Continuity Between Ignition Coil 3P Connector Terminal No. 2 & Body Ground
    G01464046Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  -Go to step 26.
    2. NO  -Repair open in the wire between the ignition coil and G101 (or G102).
  26. Disconnect PCM connector C (31P).
  27. Check for continuity between body ground and the appropriate PCM connector terminal (see table).
    Fig 3: Checking For Continuity Between Body Ground & PCM Connector Terminals
    G01464047Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 4: Body Ground-To-PCM Connector Terminal Test Table
    G01464048Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  -Repair short in the wire between the PCM and the ignition coil.
    2. NO  -Go to step 28.
  28. Connect the appropriate ignition coil 3P connector terminal No. 1 to body ground with a jumper wire (see table).
    Fig 5: Connecting Ignition Coil 3P Connector Terminal No. 1 To Body Ground With A Jumper Wire
    G01464049Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 6: Ignition Coil 3P Connector Terminal No. 1-To-Body Ground Test Table
    G01464050Courtesy of AMERICAN HONDA MOTOR CO., INC.
  29. Check for continuity between body ground and the appropriate PCM connector terminal (see table).
    Fig 7: Checking For Continuity Between Body Ground & PCM Connector Terminals
    G01464051Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 8: Body Ground-To-PCM Connector Terminals Test Table
    G01464052Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  -Go to step 30.
    2. NO  -Repair open in the wire between the PCM and the ignition coil.
  30. Check the engine compression (see ENGINE COMPRESSION INSPECTION ).

    Is the engine compression OK? 

    1. YES  -Substitute a known-good PCM and recheck (see HOW TO SUBSTITUTE THE PCM FOR TESTING ). If the symptom/indication goes away, replace the original PCM.
    2. NO  -Repair the engine.
  31. Turn the ignition switch OFF.
  32. Disconnect PCM connector B (25P).
  33. Turn the ignition switch ON (II).
  34. Measure voltage between body ground and the appropriate PCM connector terminal (see table).
    Fig 9: Measuring Voltage Between Body Ground & PCM Connector Terminals
    G01464053Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 10: Body Ground-To-PCM Connector Terminals Test Table
    G01464054Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  -Go to step 35.
    2. NO  -Go to step  43.
  35. Turn the ignition switch OFF.
  36. Disconnect the injector 2P connector from the problem cylinder.
  37. Measure resistance between injector 2P connector terminals No. 1 and No. 2.
    Fig 11: Measuring Resistance Between Injector 2P Connector Terminals No. 1 & No. 2
    G01464055Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 13-15Ω? 

    1. YES  -Go to step 38.
    2. NO  -Replace the injector (see Injector Replacement  ).
  38. Exchange the injector from the problem cylinder with one from another cylinder, and reset the PCM.
  39. Let the engine idle for 2 minutes.
  40. Test-drive the vehicle for several minutes in the range of the freeze data or under various conditions if there was no freeze data.
  41. Check for a DTC or a Temporary DTC with the scan tool or the HDS.

    Is DTC P0301, P0302, P0303, P0304, P0305, P0306, or Temporary DTC P1399 indicated? 

    1. YES  -Go to step 42.
    2. NO  -Intermittent misfire due to injector malfunction, etc. Make sure the injector connections are secure. Check for poor connections or loose terminals at the injector connector.
  42. Determine which cylinder(s) had the misfire.

    Does the misfire occur in the cylinder where the injector was exchanged? 

    1. YES  -Replace the faulty injector.
    2. NO  -Substitute a known-good PCM and recheck (see HOW TO SUBSTITUTE THE PCM FOR TESTING ). If the symptom/indication goes away, replace the original PCM.
  43. Turn the ignition switch OFF.
  44. Disconnect the injector 2P connector from the problem cylinder.
  45. Turn the ignition switch ON (II).
  46. Measure voltage between injector 2P connector terminal No. 1 and body ground.
    Fig 12: Measuring Voltage Between Injector 2P Connector Terminal No. 1 & Body Ground
    G01464056Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  -Go to step 47.
    2. NO  -Repair open in the wire between the injector and the PGM-FI main relay.
  47. Turn the ignition switch OFF.
  48. Check for continuity between body ground and the appropriate PCM connector terminal (see table).
    Fig 13: Checking For Continuity Between Body Ground & PCM Connector Terminals
    G01464057Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 14: Body Ground-To-PCM Connector Terminals Test Table
    G01464058Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  -Repair short in the wire between the PCM and the injector.
    2. NO  -Go to step 49.
  49. Connect the appropriate injector 2P connector terminal No. 2 to body ground with a jumper wire (see table).
    Fig 15: Connecting Injector 2P Connector Terminal No. 2 To Body Ground With A Jumper Wire
    G01464059Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 16: Injector 2P Connector Terminal No. 2-To-Body Ground Test Table
    G01464060Courtesy of AMERICAN HONDA MOTOR CO., INC.
  50. Check for continuity between body ground and the appropriate PCM connector terminals (see table).
    Fig 17: Checking For Continuity Between Body Ground & PCM Connector Terminals
    G01464061Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 18: Body Ground-To-PCM Connector Terminals Test Table
    G01464062Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  -Replace the injector, then recheck.
    2. NO  -Repair open in the wire between the PCM and the injector.
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