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Home >> Acura >> 2005 >> TL Standard >> Repair and Diagnosis >> Engine Performance >> System >> PGM-FI System >> DTC Troubleshooting >> DTC P0301, P0302, P0303, P0304, P0305, P0306: No. 1 Cylinder Misfire Detected (2006 Model); No. 2 Cylinder Misfire Detected (2006 Model); No. 3 Cylinder Misfire Detected (2006 Model); No. 4 Cylinder Misfire Detected (2006 Model); No. 5 Cylinder Misfire Detected (2006 Model); No. 6 Cylinder Misfire Detected (2006 Model)

DTC P0301, P0302, P0303, P0304, P0305, P0306: No. 1 Cylinder Misfire Detected (2006 Model); No. 2 Cylinder Misfire Detected (2006 Model); No. 3 Cylinder Misfire Detected (2006 Model); No. 4 Cylinder Misfire Detected (2006 Model); No. 5 Cylinder Misfire Detected (2006 Model); No. 6 Cylinder Misfire Detected (2006 Model)

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the GENERAL TROUBLESHOOTING INFORMATION .
  1. Clear the DTC with the HDS.
  2. Start the engine (in Park or neutral), then let it idle without load.
  3. 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? 

    1. YES  - Go to step  8.
    2. NO  - If the screen indicates PASSED, go to step  4. 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.
  4. 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? 

    1. YES  - Go to step  8.
    2. NO  - Go to step  5.
  5. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • Engine speed
    • Engine coolant temperature
    • Vehicle speed
    • Throttle position
    • CLV (calculated load value)
  6. 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? 

    1. YES  - Go to step  8.
    2. NO  - If the screen indicates PASSED, go to step  7. 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.
  7. 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? 

    1. YES  - Go to step  8.
    2. NO  - Intermittent failure, system is OK at this time. Check the fuel and ignition system circuit connectors for loose wires or poor connections.
  8. Turn the ignition switch OFF.
  9. Exchange the ignition coil from the problem cylinder with one from another cylinder.
  10. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • Engine speed
    • Engine coolant temperature
    • Vehicle speed
    • Throttle position
    • CLV (calculated load value)
  11. 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? 

    1. YES  - Go to step  12.
    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.
  12. Determine which cylinder had the misfire.

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

    1. YES  - Replace the faulty ignition coil (see IGNITION COIL REMOVAL/INSTALLATION ), then go to step  54.
    2. NO  - Go to step  13.
  13. Turn the ignition switch OFF.
  14. Exchange the spark plug from the problem cylinder with one from another cylinder.
  15. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • Engine speed
    • Engine coolant temperature
    • Vehicle speed
    • Throttle position
    • CLV (calculated load value)
  16. 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? 

    1. YES  - Go to step  17.
    2. NO  - Intermittent misfire due to spark plug fouling (no misfire at this time).
  17. Determine which cylinder had the misfire.

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

    1. YES  - Replace the faulty spark plug, then go to step  54.
    2. NO  - Go to step  18.
  18. Turn the ignition switch OFF.
  19. Exchange the injector from the problem cylinder with one from the another cylinder.
  20. Start the engine, and let it idle 2 minutes.
  21. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • Engine speed
    • Engine coolant temperature
    • Vehicle speed
    • Throttle position
    • CLV (calculated load value)
  22. 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? 

    1. YES  - Go to step  23.
    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.
  23. 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  ), then go to step  54.
    2. NO  - Go to step  24.
  24. Turn the ignition switch OFF.
  25. Disconnect ignition coil 3P connector from the problem cylinder.
  26. Turn the ignition switch ON (II).
  27. 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
    G03659300Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  - Go to step  28.
    2. NO  - Repair open in the wire between the ignition coil and the ignition coil relay, then go to step  54.
  28. Turn the ignition switch OFF.
  29. 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 & Body Ground
    G03659301Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity 

    1. YES  - Go to step  30.
    2. NO  - Repair open in the wire between the ignition coil and G101, then go to step  54.
  30. Turn the ignition switch OFF.
  31. Jump the SCS line with the HDS.
  32. Disconnect ECM/PCM connector A (31P).
  33. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see ECM/PCM CONNECTOR TERMINAL SPECIFICATION  ).
    Fig 3: Checking Continuity Between Body Ground & Appropriate ECM/PCM Connector Terminal
    G03659302Courtesy of AMERICAN HONDA MOTOR CO., INC.
    ECM/PCM CONNECTOR TERMINAL SPECIFICATION

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 A20 YEL/GRN
    No. 2 P0302 A19 BLU/RED
    No. 3 P0303 A18 WHT/BLU
    No. 4 P0304 A17 BRN
    No. 5 P0305 A16 BLK/RED
    No. 6 P0306 A15 BRN/WHT

    Is there continuity? 

    1. YES  - Repair short in the wire between the ECM/PCM and the ignition coil, then go to step  54.
    2. NO  - Go to step  34.
  34. Connect appropriate ignition coil 3P connector terminal No. 1 to body ground with a jumper wire (see JUMPER WIRE SPECIFICATION  ).
    Fig 4: Connecting Ignition Coil 3P Connector Terminal No. 1 To Body Ground With Jumper Wire
    G03659303Courtesy of AMERICAN HONDA MOTOR CO., INC.
    JUMPER WIRE SPECIFICATION

    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
  35. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see ECM/PCM CONNECTOR TERMINAL SPECIFICATION  ).
    Fig 5: Checking Continuity Between Body Ground & ECM/PCM Connector Terminal
    G03659304Courtesy of AMERICAN HONDA MOTOR CO., INC.
    ECM/PCM CONNECTOR TERMINAL SPECIFICATION

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 A20 YEL/GRN
    No. 2 P0302 A19 BLU/RED
    No. 3 P0303 A18 WHT/BLU
    No. 4 P0304 A17 BRN
    No. 5 P0305 A16 BLK/RED
    No. 6 P0306 A15 BRN/WHT

    Is there continuity? 

    1. YES  - Go to step  36.
    2. NO  - Repair open in the wire between the ECM/PCM and the ignition coil, then go to step  54.
  36. Reconnect the ignition coil 3P connector and ECM/PCM connector A (31P).
  37. Do an engine compression and a cylinder leakdown test.

    Did the engine pass both tests? 

    1. YES  - Go to step  38.
    2. NO  - Repair the engine, then go to step  54.
  38. Do the VTEC ROCKER ARM TEST .

    Did the engine pass the test? 

    1. YES  - Go to step  39.
    2. NO  - Repair the VTEC rocker arm, then go to step  54.
  39. Turn the ignition switch OFF.
  40. Jump the SCS line with the HDS.
  41. Disconnect ECM/PCM connector A (31P).
  42. Turn the ignition switch ON (II).
  43. Measure voltage between body ground and the appropriate ECM/PCM connector terminal (see ECM/PCM CONNECTOR TERMINAL SPECIFICATION  ).
    Fig 6: Measuring Voltage Between Body Ground & ECM/PCM Connector Terminal
    G03659305Courtesy of AMERICAN HONDA MOTOR CO., INC.
    ECM/PCM CONNECTOR TERMINAL SPECIFICATION

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 A21 BRN
    No. 2 P0302 A31 RED
    No. 3 P0303 A30 BLU
    No. 4 P0304 A29 YEL
    No. 5 P0305 A28 BLK/RED
    No. 6 P0306 A27 WHT/BLU

    Is there battery voltage? 

    1. YES  - Go to step  53.
    2. NO  - Go to step  44.
  44. Turn the ignition switch OFF.
  45. Remove the intake manifold (see REMOVAL ).
  46. Disconnect the injector 2P connector from the problem cylinder.
  47. Turn the ignition switch ON (II).
  48. Measure voltage between injector 2P connector terminal No. 1 and body ground.
    Fig 7: Measuring Voltage Between Injector 2P Connector Terminal No. 1 & Body Ground
    G03659306Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  - Go to step  49.
    2. NO  - Repair open in the wire between the injector and PGM-FI main relay 1 (Fl MAIN), then go to step  54.
  49. Turn the ignition switch OFF.
  50. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see ECM/PCM CONNECTOR TERMINAL SPECIFICATION  ).
    Fig 8: Checking Continuity Between Body Ground & ECM/PCM Connector Terminal
    G03659307Courtesy of AMERICAN HONDA MOTOR CO., INC.
    ECM/PCM CONNECTOR TERMINAL SPECIFICATION

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 A21 BRN
    No. 2 P0302 A31 RED
    No. 3 P0303 A30 BLU
    No. 4 P0304 A29 YEL
    No. 5 P0305 A28 BLK/RED
    No. 6 P0306 A27 WHT/BLU

    Is there continuity? 

    1. YES  - Repair short in the wire between the ECM/PCM and the injector, then go to step  54.
    2. NO  - Go to step  51.
  51. Connect appropriate injector 2P connector terminal No. 2 to body ground with a jumper wire (see JUMPER WIRE SPECIFICATION  ).
    Fig 9: Connecting Appropriate Injector 2P Connector Terminal No. 2 To Body Ground With Jumper Wire
    G03659308Courtesy of AMERICAN HONDA MOTOR CO., INC.
    JUMPER WIRE SPECIFICATION

    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
  52. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see ECM/PCM CONNECTOR TERMINAL SPECIFICATION  ).
    Fig 10: Checking Continuity Between Body Ground & ECM/PCM Connector Terminal
    G03659309Courtesy of AMERICAN HONDA MOTOR CO., INC.
    ECM/PCM CONNECTOR TERMINAL SPECIFICATION

    PROBLEM CYLINDER DTC ECM/PCM TERMINAL WIRE COLOR
    No. 1 P0301 A21 BRN
    No. 2 P0302 A31 RED
    No. 3 P0303 A30 BLU
    No. 4 P0304 A29 YEL
    No. 5 P0305 A28 BLK/RED
    No. 6 P0306 A27 WHT/BLU

    Is there continuity? 

    1. YES  - Go to step  53.
    2. NO  - Repair open in the wire between the ECM/PCM and the injector, then go to step  54.
  53. 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
    G03659310Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 10-13 Ω? 

    1. YES  - Go to step  63.
    2. NO  - Replace the injector (see INJECTOR REPLACEMENT  ), then go to step  54.
  54. Reconnect all connectors.
  55. Turn the ignition switch ON (II).
  56. Reset the ECM/PCM with the HDS.
  57. Clear the CKP pattern with the HDS.
  58. Do the ECM/PCM IDLE LEARN PROCEDURE .
  59. Do the CKP pattern learn procedure (see CRANK (CKP) PATTERN CLEAR/CRANK (CKP) PATTERN LEARN ).
  60. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • Engine speed
    • Engine coolant temperature
    • Vehicle speed
    • Throttle position
    • CLV (calculated load value)
  61. Check for Temporary DTCs or DTCs with the HDS.

    Are any Temporary DTCs or DTCs indicated? 

    1. 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 ECM/PCM, then go to troubleshooting DTC P0301, P0302, P0303, P0304, P0305, or P0306 (see DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306: RANDOM MISFIRE AND ANY COMBINATION OF THE FOLLOWING; NO. 1 CYLINDER MISFIRE DETECTED; NO. 2 CYLINDER MISFIRE DETECTED; NO. 3 CYLINDER MISFIRE DETECTED; NO. 4 CYLINDER MISFIRE DETECTED; NO. 5 CYLINDER MISFIRE DETECTED; NO. 6 CYLINDER MISFIRE DETECTED ). If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.
    2. NO  - Go to step  62.
  62. 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? 

    1. YES  - Troubleshooting is complete.
    2. 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  60. and recheck.
  63. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM (see HOW TO TROUBLESHOOT CIRCUITS AT THE ECM/PCM ).
  64. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • Engine speed
    • Engine coolant temperature
    • Vehicle speed
    • Throttle position
    • CLV (calculated load value)
  65. Check for Temporary DTCs or DTCs with the HDS.

    Are any Temporary DTCs or DTCs indicated? 

    1. 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 ECM/PCM, then go to step  1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTCs troubleshooting.
    2. NO  - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM (see ECM/PCM REPLACEMENT  ).
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