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Home >> Honda >> 2005 >> Pilot EX >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> PGM-FI System >> DTC Troubleshooting >> DTC P0301, P0302, P0303, P0304, P0305, P0306: No. 1-6 Cylinder Misfire Detected

DTC P0301, P0302, P0303, P0304, P0305, P0306: No. 1-6 Cylinder Misfire Detected

  1. Note this freeze data:
    • Engine speed
    • Vehicle speed
    • Throttle position
    • CLV (Calculated Load Value)
    • Engine coolant temperature
  2. Clear the DTC with the HDS.
  3. Start the engine, and let it idle (in Park or neutral) without load until the radiator fan comes on.
  4. Monitor the OBD STATUS for DTC P0301, P0302, P0303, P0304, P0305, or P0306 in the DTCs MENU with the HDS.

    Does the screen indicate FAILED? 

    YES  - Go to step  9.

    NO  - If the screen indicates PASSED, go to step 5. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, wait for several minutes, and recheck.

  5. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE in the DATA LIST for 10 minutes with the HDS.

    Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE show misfire counts? 

    YES  - Go to step  9.

    NO  - Go to step 6.

  6. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
  7. Monitor the OBD STATUS for DTC P0301, P0302, P0303, P0304, P0305, or P0306 in the DTCs MENU with the HDS.

    Does the screen indicate FAILED? 

    YES  - Go to step  9.

    NO  - If the screen indicates PASSED, go to step 8. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step  6 and recheck.

  8. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE in the DATA LIST for 10 minutes with the HDS.

    Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE show misfire counts? 

    YES  - Go to step 9.

    NO  - Intermittent failure, system is OK at this time. Check the fuel and ignition system circuit Connectors for loose wires or poor connections.

  9. Turn the ignition switch OFF.
  10. Exchange the ignition coil from the problem cylinder with one from another cylinder.
  11. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
  12. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE in the DATA LIST for 10 minutes with the HDS.

    Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE show misfire counts? 

    YES  - Go to step 13.

    NO  - Intermittent misfire due to poor contact at the ignition coil Connector (no misfire at this time). Make sure the coil connections are secure.

  13. Determine which cylinder had the misfire.

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

    YES  - Replace the faulty ignition coil (see IGNITION COIL REMOVAL/INSTALLATION ), then go to step  60.

    NO  - Go to step 14.

  14. Turn the ignition switch OFF.
  15. Exchange the spark plug from the problem cylinder with one from another cylinder.
  16. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
  17. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE in the DATA LIST for 10 minutes with the HDS.

    Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE show misfire counts? 

    YES  - Go to step 18.

    NO  - Intermittent misfire due to spark plug fouling (no misfire at this time).

  18. Determine which cylinder had the misfire.

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

    YES  - Replace the faulty spark plug, then go to step  60.

    NO  - Go to step 19.

  19. Turn the ignition switch OFF.
  20. Exchange the injector from the problem cylinder with one from the another cylinder.
  21. Start the engine, and let it idle for 2 minutes.
  22. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
  23. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE in the DATA LIST for 10 minutes with the HDS.

    Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE show misfire counts? 

    YES  - Go to step 24.

    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.

  24. Determine which cylinder had the misfire.

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

    YES  - Replace the faulty injector (see INJECTOR REPLACEMENT  ), then go to step  60.

    NO  - Go to step 25.

  25. Turn the ignition switch OFF.
  26. Disconnect the ignition coil 3P Connector from the problem cylinder.
  27. Turn the ignition switch ON (II).
  28. 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 And Body Ground
    G04545926Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  - Go to step 29.

    NO  - Repair open in the wire between the ignition coil and the ignition coil relay, then go to step  60.

  29. Turn the ignition switch OFF.
  30. 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 And Body Ground
    G04545927Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Go to step 31.

    NO  - Repair open in the wire between the ignition coil and G101, then go to step  60.

  31. Turn the ignition switch OFF.
  32. Jump the SCS line with the HDS.
  33. Disconnect PCM Connector B (44P).
  34. Check for continuity between body ground and the appropriate PCM Connector terminal (see table).
    Fig 3: Checking Continuity Between Body Ground And Appropriate PCM Connector Terminal
    G04545928Courtesy of AMERICAN HONDA MOTOR CO., INC.
    PCM TERMINAL AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 B26 YEL/GRN
    No. 2 P0302 B27 BLU/RED
    No. 3 P0303 B20 WHT/BLU
    No. 4 P0304 B21 BRN
    No. 5 P0305 B10 BLK/RED
    No. 6 P0306 B11 BRN/WHT

    Is there continuity? 

    YES  - Repair short in the wire between the PCM and the ignition coil, then go to step  60.

    NO  - Go to step 35.

  35. Connect appropriate ignition coil 3P Connector terminal No. 1 to body ground with a jumper wire (see table).
    Fig 4: Connecting Ignition Coil 3P Connector Terminal No. 1 To Body Ground With Jumper Wire
    G04545929Courtesy of AMERICAN HONDA MOTOR CO., INC.
    WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC WIRE COLOR
    No. 1 P0301 YEL/GRN
    No. 2 P0302 BLU/RED
    No. 3 P0303 WHT/BLU
    No. 4 P0304 BRN
    No. 5 P0305 BLK/RED
    No. 6 P0306 BRN/WHT
  36. Check for continuity between body ground and the appropriate PCM Connector terminal (see table).
    Fig 5: Checking Continuity Between Body Ground And PCM Connector Terminal
    G04545930Courtesy of AMERICAN HONDA MOTOR CO., INC.
    PCM TERMINAL AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 B26 YEL/GRN
    No. 2 P0302 B27 BLU/RED
    No. 3 P0303 B20 WHT/BLU
    No. 4 P0304 B21 BRN
    No. 5 P0305 B10 BLK/RED
    No. 6 P0306 B11 BRN/WHT

    Is there continuity? 

    YES  - Go to step 37.

    NO  - Repair open in the wire between the PCM and the ignition coil, then go to step  60.

  37. Reconnect the ignition coil 3P Connector and PCM Connector B (44P).
  38. Do an engine compression and a cylinder leakdown test.

    Did the engine pass both tests? 

    YES  - Go to step 39.

    NO  - Repair the engine, then go to step  60.

  39. Do the VTEC rocker arm test (see VTEC ROCKER ARM TEST ).

    Did the engine pass the test? 

    YES  - Go to step 40.

    NO  - Repair the VTEC rocker arm, then go to step  60.

  40. Turn the ignition switch OFF.
  41. Jump the SCS line with the HDS.
  42. Disconnect PCM Connector B (44P).
  43. Turn the ignition switch ON (II).
  44. Measure voltage between body ground and the appropriate PCM Connector terminal (see table).
    Fig 6: Measuring Voltage Between Body Ground And PCM Connector Terminal
    G04545931Courtesy of AMERICAN HONDA MOTOR CO., INC.
    PCM TERMINAL AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 B4 BRN
    No. 2 P0302 B8 RED
    No. 3 P0303 B7 BLU
    No. 4 P0304 B6 YEL
    No. 5 P0305 B5 BLK/RED
    No. 6 P0306 B9 WHT/BLU

    Is there battery voltage? 

    YES  - Go to step  54.

    NO  - Go to step 45.

  45. Turn the ignition switch OFF.
  46. Remove the intake manifold (see REMOVAL ).
  47. Disconnect the injector 2P Connector from the problem cylinder.
  48. Turn the ignition switch ON (II).
  49. Measure voltage between injector 2P Connector terminal No. 1 and body ground.
    Fig 7: Measuring Voltage Between Injector 2P Connector Terminal No. 1 And Body Ground
    G04545932Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  - Go to step 50.

    NO  - Repair open in the wire between the injector and the PGM-FI main relay 1 (FI MAIN), then go to step  60.

  50. Turn the ignition switch OFF.
  51. Check for continuity between body ground and the appropriate PCM Connector terminal (see table).
    Fig 8: Checking Continuity Between Body Ground And PCM Connector Terminal
    G04545933Courtesy of AMERICAN HONDA MOTOR CO., INC.
    PCM TERMINAL AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 B4 BRN
    No. 2 P0302 B8 RED
    No. 3 P0303 B7 BLU
    No. 4 P0304 B6 YEL
    No. 5 P0305 B5 BLK/RED
    No. 6 P0306 B9 WHT/BLU

    Is there continuity? 

    YES  - Repair short in the wire between the PCM and the injector, then go to step  60.

    NO  - Go to step 52.

  52. Connect appropriate injector 2P Connector terminal No. 2 to body ground with a jumper wire (see table).
    Fig 9: Connecting Appropriate Injector 2P Connector Terminal No. 2 To Body Ground With A Jumper Wire
    G04545934Courtesy of AMERICAN HONDA MOTOR CO., INC.
    WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC WIRE COLOR
    No. 1 P0301 BRN
    No. 2 P0302 RED
    No. 3 P0303 BLU
    No. 4 P0304 YEL
    No. 5 P0305 BLK/RED
    No. 6 P0306 WHT/BLU
  53. Check for continuity between body ground and the appropriate PCM Connector terminal (see table).
    Fig 10: Checking Continuity Between Body Ground And Appropriate PCM Connector Terminal
    G04545935Courtesy of AMERICAN HONDA MOTOR CO., INC.
    PCM TERMINAL AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 B4 BRN
    No. 2 P0302 B8 RED
    No. 3 P0303 B7 BLU
    No. 4 P0304 B6 YEL
    No. 5 P0305 B5 BLK/RED
    No. 6 P0306 B9 WHT/BLU

    Is there continuity? 

    YES  - Go to step 54.

    NO  - Repair open in the wire between the PCM and the injector, then go to step  60.

  54. Measure the resistance between injector 2P Connector terminals No. 1 and No. 2.
    Fig 11: Measuring Resistance Between Injector 2P Connector Terminals No. 1 And No. 2
    G04545936Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 10-13 Ω? 

    YES  - Go to step 55.

    NO  - Replace the injector (see INJECTOR REPLACEMENT  ), then go to step  60.

  55. Substitute a known-good injector from another cylinder to the problem cylinder.
  56. Reconnect PCM Connector B (44P).
  57. Start the engine, and let it idle for 2 minutes.
  58. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
  59. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE in the DATA LIST for 10 minutes with the HDS.

    Does CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE show misfire counts? 

    YES  - Go to step  68.

    NO  - Replace the original injector (see INJECTOR REPLACEMENT  ), then go to step 60.

  60. Turn the ignition switch ON (II).
  61. Reset the PCM with the HDS.
  62. Clear the CKP pattern with the HDS.
  63. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  64. Do the CKP pattern learn procedure (see CKP PATTERN CLEAR/CKP PATTERN LEARN ).
  65. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
  66. Check for Temporary DTCs or DTCs with the HDS.

    Are any Temporary DTCs or DTCs indicated? 

    YES  - If DTC P0301, P0302, P0303, P0304, P0305, or P0306 are indicated, check for poor connections or loose terminals at the ignition coil, the injector, and the PCM, then go to troubleshooting DTC P0301, P0302, P0303, P0304, P0305, or P0306 (see DTC P0300: RANDOM MISFIRE DETECTED AND ANY COMBINATION OF THE FOLLOWING: 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  ). If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC'S TROUBLESHOOTING .

    NO  - Go to step 67.

  67. Monitor the OBD STATUS for DTC P0301, P0302, P0303, P0304, P0305, or P0306 in the DTCs MENU with the HDS.

    Does the screen indicate PASSED? 

    YES  - Troubleshooting is complete.

    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  65 and recheck.

  68. Update the PCM if it does not have the latest software, or substitute a known-good PCM (see PCM UPDATING AND SUBSTITUTION FOR TESTING ).
  69. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
  70. Check for Temporary DTCs or DTCs with the HDS.

    Are any Temporary DTCs or DTCs indicated? 

    YES  - If DTC P0301, P0302, P0303, P0304, P0305, or P0306 are indicated, check for poor connections or loose terminals at the injector, the ignition coil, and the PCM, then go to step  1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC'S TROUBLESHOOTING .

    NO  - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see PCM REPLACEMENT  ).

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