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Home >> Acura >> 2007 >> TSX Standard >> 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 ON (II).
  2. Clear the DTC with the HDS.
  3. Start the engine without load (in Park or neutral), then let it idle.
  4. Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 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 or OUT OF CONDITION, keep idling until a result comes on.

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

    Does 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
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
  7. Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 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, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

    Does 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 loose wires or poor connections in the fuel system circuit.

  9. Turn the ignition switch OFF.
  10. Remove the engine cover; '04-05 models (see step 3 of REMOVAL ('04-05 MODELS) ), '06-08 models (see step 3 of REMOVAL ('06-08 MODELS) ).
  11. Start the engine, and listen for a clicking sound at the injector of the problem cylinder.

    Does the injector click? 

    YES  -Go to step 12.

    NO  -Go to step  43.

  12. Turn the ignition switch OFF.
  13. Exchange the ignition coil from the problem cylinder with one from another cylinder.
  14. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
  15. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

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

    YES  -Go to step 16.

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

  16. 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  62.

    NO  -Go to step 17.

  17. Turn the ignition switch OFF.
  18. Exchange the spark plug from the problem cylinder with one from another cylinder.
  19. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
  20. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

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

    YES  -Go to step 21.

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

  21. 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  62.

    NO  -Go to step 22.

  22. Turn the ignition switch OFF.
  23. Exchange the injector from the problem cylinder with one from another cylinder.
  24. Start the engine, and let it idle for 2 minutes.
  25. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
  26. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

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

    YES  -Go to step 27.

    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.

  27. Determine which cylinder had the misfire.

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

    YES  -Replace the faulty injector (see INJECTOR REPLACEMENT  ), then go to step  62.

    NO  -Go to step 28.

  28. Turn the ignition switch OFF.
  29. Disconnect the ignition coil 3P connector from the problem cylinder.
  30. Turn the ignition switch ON (II).
  31. 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
    G05490465Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 32.

    NO  -Repair open in the wire between the ignition coil and the ignition coil relay, then go to step  62.

  32. Turn the ignition switch OFF.
  33. 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
    G05490466Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 34.

    NO  -Repair open in the wire between the ignition coil and G101, then go to step  62.

  34. Turn the ignition switch OFF.
  35. Jump the SCS line with the HDS.
  36. Disconnect ECM/PCM connector A (31P).
  37. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see table).
    PROBLEM CYLINDER, ECM/PCM TERMINALS AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 A16 YEL/GRN
    No. 2 P0302 A15 BLU/RED
    No. 3 P0303 A14 WHT/BLU
    No. 4 P0304 A13 BRN
    Fig 3: Checking Continuity Between Body Ground And ECM/PCM Connector Terminals
    G05490467Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair short in the wire between the ECM/PCM and the ignition coil, then go to step  62.

    NO  -Go to step 38.

  38. Connect appropriate ignition coil 3P connector terminal No. 1 to body ground with a jumper wire (see table).
    PROBLEM CYLINDER, ECM/PCM TERMINALS AND 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
    Fig 4: Connecting Appropriate Ignition Coil 3P Connector Terminal No 1 To Body Ground With Jumper Wire
    G05490468Courtesy of AMERICAN HONDA MOTOR CO., INC.
  39. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see table).
    PROBLEM CYLINDER, ECM/PCM TERMINALS AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 A16 YEL/GRN
    No. 2 P0302 A15 BLU/RED
    No. 3 P0303 A14 WHT/BLU
    No. 4 P0304 A13 BRN
    Fig 5: Checking Continuity Between Body Ground And Appropriate ECM/PCM Connector Terminals
    G05490469Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 40.

    NO  -Repair open in the wire between the ECM/PCM and the ignition coil, then go to step  62.

  40. Reconnect the ignition coil 3P connector and ECM/PCM connector A (31P).
  41. Do an engine compression and a cylinder leakdown test (see ENGINE COMPRESSION INSPECTION ).

    Did the engine pass both tests? 

    YES  -Go to step 42.

    NO  -Repair the engine, then go to step  62.

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

    Did the VTEC rocker arm pass the test? 

    YES  -Go to step  71.

    NO  -Repair as necessary, then go to step  62.

  43. Turn the ignition switch OFF.
  44. Jump the SCS line with the HDS.
  45. Disconnect ECM/PCM connector B (24P).
  46. Turn the ignition switch ON (II).
  47. Measure voltage between body ground and the appropriate ECM/PCM connector terminal (see table).
    PROBLEM CYLINDER, ECM/PCM TERMINALS AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 B5 BRN
    No. 2 P0302 B4 RED
    No. 3 P0303 B3 BLU
    No. 4 P0304 B2 YEL
    Fig 6: Measuring Voltage Between Body Ground And Appropriate ECM/PCM Connector Terminals
    G05490470Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step  56.

    NO  -Go to step 48.

  48. Turn the ignition switch OFF.
  49. Disconnect the injector 2P connector from the problem cylinder.
  50. Turn the ignition switch ON (II).
  51. 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
    G05490471Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    YES  -Go to step 52.

    NO  -Repair open in the wire between the injector and PGM-FI main relay 1 (FI MAIN), then go to step  62.

  52. Turn the ignition switch OFF.
  53. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see table).
    PROBLEM CYLINDER, ECM/PCM TERMINALS AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 B5 BRIM
    No. 2 P0302 B4 RED
    No. 3 P0303 B3 BLU
    No. 4 P0304 B2 YEL
    Fig 8: Checking Continuity Between Body Ground And Appropriate ECM/PCM Connector Terminals
    G05490472Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair short in the wire between the ECM/PCM and the injector, then go to step  62.

    NO  -Go to step 54.

  54. Connect appropriate injector 2P connector terminal No. 2 to body ground with a jumper wire (see table).
    PROBLEM CYLINDER, ECM/PCM TERMINALS AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC WIRE COLOR
    No. 1 P0301 BRN
    No. 2 P0302 RED
    No. 3 P0303 BLU
    No. 4 P0304 YEL
    Fig 9: Connecting Appropriate Injector 2P Connector Terminal No 2 To Body Ground With Jumper Wire
    G05490473Courtesy of AMERICAN HONDA MOTOR CO., INC.
  55. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see table).
    PROBLEM CYLINDER, ECM/PCM TERMINALS AND WIRE COLOR REFERENCE

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 B5 BRN
    No. 2 P0302 B4 RED
    No. 3 P0303 B3 BLU
    No. 4 P0304 B2 YEL
    Fig 10: Checking Continuity Between Body Ground And Appropriate ECM/PCM Connector Terminals
    G05490474Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Go to step 56.

    NO  -Repair open in the wire between the ECM/PCM and the injector, then go to step  62.

  56. Measure 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
    G05490475Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 10-13 Ω? 

    YES  -Go to step 57.

    NO  -Replace the injector (see INJECTOR REPLACEMENT  ), then go to step  62.

  57. Substitute a known-good injector into the problem cylinder.
  58. Reconnect all connectors.
  59. Start the engine, and let it idle for 2 minutes.
  60. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
  61. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, and/or CYL4 MISFIRE in the DATA LIST for 10 minutes with the HDS.

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

    YES  -Go to step  71.

    NO  -Replace the original injector (see INJECTOR REPLACEMENT  ), then go to step 62.

  62. Reconnect all connectors.
  63. Turn the ignition switch ON (II).
  64. Reset the ECM/PCM with the HDS.
  65. Clear the CKP pattern with the HDS.
  66. Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
  67. Do the CKP pattern learn procedure (see CRANK (CKP) PATTERN CLEAR/CRANK (CKP) PATTERN LEARN ).
  68. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
  69. Check for Temporary DTCs or DTCs with the HDS.

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

    YES  -Check for poor connections or loose terminals at the ignition coils, the injectors, and the ECM/PCM, then go to troubleshooting DTC P0300, P0301, P0302, P0303, or P0304 (see DTC P0300: RANDOM MISFIRE 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  ).

    NO  -Go to step 70.

  70. Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 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  69, go to the INDICATED DTCS TROUBLESHOOTING .

    NO  -If the screen indicates FAILED, check for poor connections or loose terminals at the ignition coils, the injectors, and the ECM/PCM, then 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  68.

  71. 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 ).
  72. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
    • REL TP SENSOR
    • CLV (calculated load value)
    • APP SENSOR
  73. Check for Temporary DTCs or DTCs with the HDS.

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

    YES  -Check for poor connections or loose terminals at the injectors, the ignition coils, 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  72. If the ECM/PCM was substituted, go to step  1.

    NO  -Go to step 74.

  74. Monitor the OBD STATUS for DTC P0301, P0302, P0303, or P0304 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; '04-05 models (see ECM/PCM REPLACEMENT  ), '06-08 models (see '06-08 MODELS  ). If any other Temporary DTCs or DTCs were indicated in step  73, go to the INDICATED DTCS TROUBLESHOOTING .

    NO  -If the screen indicates FAILED, check for poor connections or loose terminals at the ignition coils, the injectors, 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  72. 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  72.

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