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Home >> Honda >> 2012 >> Insight Base >> 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 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

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, and let it idle without load (in P or N).
  4. Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 in the DTCs MENU with the HDS.

    Does the HDS indicate FAILED? 

    YES  -Go to step  9.

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

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

    Does the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 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 these recorded freeze data parameters:
    • ENGINE SPEED
    • VEHICLE SPEED
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
    • ECT SENSOR 1
  7. Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 in the DTCs MENU with the HDS.

    Does the HDS indicate FAILED? 

    YES  -Go to step  9.

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

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

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

    YES  -Go to step 9.

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

  9. Turn the ignition switch to LOCK (0).
  10. Exchange the ignition coils from the problem cylinder with those from another cylinder.
  11. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VEHICLE SPEED
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
    • ECT SENSOR 1
  12. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

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

    YES  -Go to step 13.

    NO  -Intermittent misfire due to poor contact at an ignition coil connector (no misfire at this time). Check for poor connections or loose terminals at the ignition coils.

  13. Determine which cylinder had the misfire.

    Does the misfire occur in the cylinder where the ignition coils were exchanged? 

    YES  -Replace the faulty ignition coils (see IGNITION COIL AND SPARK PLUG REMOVAL/INSTALLATION ), then go to step  48.

    NO  -Go to step 14.

  14. Turn the ignition switch to LOCK (0).
  15. Exchange the spark plugs from the problem cylinder with those from another cylinder.
  16. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VEHICLE SPEED
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
    • ECT SENSOR 1
  17. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

    Does the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 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 plugs were exchanged? 

    YES  -Replace the faulty spark plugs, then go to step  47.

    NO  -Go to step 19.

  19. Turn the ignition switch to LOCK (0).
  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 these recorded freeze data parameters:
    • ENGINE SPEED
    • VEHICLE SPEED
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
    • ECT SENSOR 1
  23. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

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

    YES  -Go to step 24.

    NO  -Intermittent misfire due to bad contact at 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  48.

    NO  -Go to step 25.

  25. Turn the ignition switch to LOCK (0).
  26. Disconnect the ignition coil 3P connectors from the problem cylinder.
  27. Turn the ignition switch to ON (II).
  28. Measure the 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
    G08092262Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 29.

    NO  -Repair an open in the wire between the ignition coil and the No. 1 INTAKE SIDE IGNITION COILS (15A) fuse (or the No. 2 EXHAUST SIDE IGNITION COILS (15A) fuse)*, then go to step  47.

    *: exhaust side

  29. Turn the ignition switch to LOCK (0).
  30. Check for continuity between ignition coil 3P connector terminal No. 2 and body ground.
    Fig 2: Checking Continuity Between Ignition Coil 3P Connector Terminal No. 2 And Body Ground
    G08092263Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 31.

    NO  -Repair an open in the wire between the ignition coil and G101 (see CONNECTOR TO FUSE/RELAY BOX INDEX ), then go to step  47.

    *: exhaust side

  31. Jump the SCS line with the HDS.
  32. Disconnect PCM connector B (49P) and C (49P).
  33. Check for continuity between body ground and the appropriate PCM connector terminal of the problem cylinder (see table below).
    FRONT (INTAKE) SIDE

    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 C15 WHT
    No. 2 P0302 C16 WHT/GRN
    No. 3 P0303 C17 WHT/BLK
    No. 4 P0304 C18 WHT/BLU
    REAR (EXHAUST) SIDE

    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 B37 WHT
    No. 2 P0302 B43 WHT/GRN
    No. 3 P0303 B46 WHT/BLK
    No. 4 P0304 B47 WHT/BLU
    Fig 3: Checking Continuity Between Body Ground And PCM Connector C Terminal Of Problem Cylinder
    G08092264Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 4: Checking Continuity Between Body Ground And PCM Connector B Terminal Of Problem Cylinder
    G08092265Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short in the wire between the PCM and the ignition coil, then go to step  47.

    NO  -Go to step 34.

  34. Check for continuity between appropriate ignition coil 3P connector terminal No. 1 and the appropriate PCM connector terminal of the problem cylinder (see table below).
    FRONT (INTAKE) SIDE

    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 C15 WHT
    No. 2 P0302 C16 WHT/GRN
    No. 3 P0303 C17 WHT/BLK
    No. 4 P0304 C18 WHT/BLU
    REAR (EXHAUST) SIDE

    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 B37 WHT
    No. 2 P0302 B43 WHT/GRN
    No. 3 P0303 B46 WHT/BLK
    No. 4 P0304 B47 WHT/BLU
    Fig 5: Checking Continuity Between Ignition Coil 3P Connector Terminal No. 1 And PCM Connector Terminal
    G08092266Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 35.

    NO  -Repair an open in the wire between the PCM and the ignition coil, then go to step  47.

  35. Do an engine compression and a cylinder leakdown test (see ENGINE COMPRESSION INSPECTION ).

    Did the engine pass both tests? 

    YES  -Go to step 36.

    NO  -Repair the engine, then go to step  47.

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

    Did the engine pass the test? 

    YES  -Go to step 37.

    NO  -Repair the VTEC rocker arm (see ROCKER ARM AND SHAFT DISASSEMBLY/REASSEMBLY ), then go to step  47.

  37. Turn the ignition switch to LOCK (0).
  38. Disconnect the injector 2P connector from the problem cylinder.
  39. Turn the ignition switch to ON (II).
  40. Measure the voltage between injector 2P connector terminal No. 1 and body ground.
    Fig 6: Measuring Voltage Between Injector 2P Connector Terminal No. 1 And Body Ground
    G08092267Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 41.

    NO  -Repair an open in the wire between the injector and PGM-FI main relay 1, then go to step  47.

  41. Turn the ignition switch to LOCK (0).
  42. Check for continuity between body ground and the appropriate PCM connector terminal of the problem cylinder (see chart below).
    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 C5 BRN
    No. 2 P0302 C6 RED
    No. 3 P0303 C7 BLU
    No. 4 P0304 C8 YEL
    Fig 7: Checking Continuity Between Body Ground And PCM Connector C Terminal
    G08092268Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair a short in the wire between the PCM and the injector, then go to step  47.

    NO  -Go to step 43.

  43. Check for continuity between appropriate injector 2P connector terminal No. 2 and the appropriate PCM connector terminal of the problem cylinder (see chart below).
    PROBLEM CYLINDER DTC PCM TERMINAL WIRE COLOR
    No. 1 P0301 C5 BRN
    No. 2 P0302 C6 RED
    No. 3 P0303 C7 BLU
    No. 4 P0304 C8 YEL
    Fig 8: Checking Continuity Between Injector 2P Connector Terminal No. 2 And PCM Connector Terminal
    G08092269Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 44.

    NO  -Repair an open in the wire between the PCM and the injector, then go to step  47.

  44. Turn the ignition switch to LOCK (0).
  45. Disconnect the injector 2P connector from the problem cylinder.
  46. At the injector side, measure the resistance between injector 2P connector terminals No. 1 and No. 2.
    Fig 9: Measuring Resistance Between Injector 2P Connector Terminals No. 1 And No. 2
    G08092270Courtesy 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  47.

  47. Reconnect all connectors.
  48. Turn the ignition switch to ON (II).
  49. Reset the PCM with the HDS.
  50. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  51. Do the CKP pattern clear/CKP pattern learn procedure (see CKP PATTERN CLEAR/CKP PATTERN LEARN ).
  52. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VEHICLE SPEED
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
    • ECT SENSOR 1
  53. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P0301, P0302, P0303, or P0304 indicated? 

    YES  -Check for poor connections or loose terminals at the ignition coil, the injector, and the PCM, then go to the troubleshooting for DTC P0300, P0301, P0302, P0303, or P0304  (see ).

    NO  -Go to step 54.

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

    Does the HDS indicate PASSED? 

    YES  -Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated in step  53, go to the indicated DTC'S TROUBLESHOOTING .

    NO  -If the HDS indicates FAILED, check for poor connections or loose terminals at the ignition coil, the injector, and the PCM, then go to step  1. If the HDS indicates EXECUTING, keep driving until a result comes on. If the HDS indicates OUT OF CONDITION, go to step  52.

  55. Reconnect all connectors.
  56. Update the PCM if it does not have the latest software (see PCM UPDATE  ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ).
  57. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VEHICLE SPEED
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
    • ECT SENSOR 1
  58. Check for Pending or Confirmed DTCs with the HDS.

    Is DTC P0301, P0302, P0303, or P0304 indicated? 

    YES  -Check for poor connections or loose terminals at the ignition coil, the injector, and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step  57. If the PCM was substituted, go to step  1.

    NO  -Go to step 59.

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

    Does the HDS indicate PASSED? 

    YES  -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 were indicated in step  58, go to the indicated DTC'S TROUBLESHOOTING .

    NO  -If the HDS indicates FAILED, check for poor connections or loose terminals at the ignition coil, the injector, and the PCM. If the PCM was updated, substitute a known-good PCM (see SUBSTITUTING THE PCM ), then go to step  57. If the PCM was substituted, go to step  1. If the HDS indicates EXECUTING, keep driving until a result comes on. If the HDS indicates OUT OF CONDITION, go to step  57.

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