| DTC P0301: | No. 1 Cylinder Misfire Detected |
| DTC P0303: | No. 3 Cylinder Misfire Detected |
| 1. | Turn the ignition switch ON (II). |
| 2. | Clear the DTC with the HDS. |
| 3. | Start the engine, and let it idle without load (in Park or neutral). |
| 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 9. NO - If the screen indicates PASSED, go to 5. If the screen indicates EXECUTING, let the engine idle 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, 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 9. NO - Go to 6. |
| 6. | Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
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| 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 9. NO - If the screen indicates PASSED, go to 8. If the screen indicates EXECUTING, keep driving until a result comes on. If he screen indicates OUT OF CONDITION, go to 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 9. NO - Intermittent failure, system is OK at this time. Check for loose wires or poor connections in the fuel system circuit.n |
| 9. | Turn the ignition switch OFF. |
| 10. | Remove the intake manifold cover. |
| 11. | Start the engine, and listen for a clicking sound at the injector of the problem cylinder. Does the injector click? YES - Go to 12. NO - Go to 42. |
| 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:
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| 15. | 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 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. n |
| 16. | Determine which cylinder had the misfire. Does the misfire occur in the cylinder where the ignition coil was exchanged? YES - Replace the faulty ignition coil, then go to 60. NO - Go to 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:
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| 20. | 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 21. NO - Intermittent misfire due to spark plug fouling (no misfire at this time).n |
| 21. | Determine which cylinder had the misfire. Does the misfire occur in the cylinder where the spark plug was exchanged? YES - Replace the faulty spark plug, then go to 60. NO - Go to 22. |
| 22. | Turn the ignition switch OFF. |
| 23. | Exchange the injector from the problem cylinder with one from the 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:
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| 26. | 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 27. 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.n |
| 27. | Determine which cylinder had the misfire. Does the misfire occur in the cylinder where the injector was exchanged? YES - Replace the faulty injector, then go to 60. NO - Go to 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.
Is there battery voltage? YES - Go to 32. NO - Repair open in the wire between the ignition coil and the ignition coil relay, then go to 60. |
| 32. | Turn the ignition switch OFF. |
| 33. | Check for continuity between ignition coil 3P connector terminal No. 2 and body ground.
Is there continuity? YES - Go to 34. NO - Repair open in the wire between the ignition coil and G101, then go to 60. |
| 34. | Turn the ignition switch OFF. |
| 35. | Jump the SCS line with the HDS. |
| 36. | Disconnect ECM/PCM connector C (44P). |
| 37. | Check for continuity between body ground and the appropriate ECM/PCM connector terminal of the problem cylinder (see table).
Is there continuity? YES - Repair short in the wire between the ECM/ PCM and the ignition coil, then go to 60. NO - Go to 38. |
| 38. | Check for continuity between appropriate ignition coil 3P connector terminal No. 1 and the appropriate ECM/PCM connector terminal of the problem cylinder (see table).
Is there continuity? YES - Go to 39. NO - Repair open in the wire between the ECM/ PCM and the ignition coil, then go to 60. |
| 39. | Reconnect all connectors. |
| 40. | Do an engine compression and a cylinder leakdown test. Did the engine pass both tests? YES - Go to 41. NO - Repair the engine, then go to 60. |
| 41. | Do the VTEC rocker arm test. Did the engine pass the test? YES - Go to step ecu. NO - Repair the VTEC rocker arm, then go to 60. |
| 42. | Turn the ignition switch OFF. |
| 43. | Jump the SCS line with the HDS. |
| 44. | Disconnect ECM/PCM connector C (44P). |
| 45. | Turn the ignition switch ON (II). |
| 46. | Measure voltage between body ground and the appropriate ECM/PCM connector terminal of the problem cylinder (see table).
Is there battery voltage? YES - Go to 54. NO - Go to 47. |
| 47. | Turn the ignition switch OFF. |
| 48. | Disconnect the injector 2P connector from the problem cylinder. |
| 49. | Turn the ignition switch ON (II). |
| 50. | Measure voltage between injector 2P connector terminal No. 1 and body ground.
Is there battery voltage? YES - Go to 51. NO - Repair open in the wire between the injector and PGM-FI main relay 1 (C), then go to 60. |
| 51. | Turn the ignition switch OFF. |
| 52. | Check for continuity between body ground and the appropriate ECM/PCM connector terminal of the problem cylinder (see table).
Is there continuity? YES - Repair short in the wire between the ECM/ PCM and the injector, then go to 60. NO - Go to 53. |
| 53. | Check for continuity between appropriate injector 2P connector terminal No. 2 and the appropriate ECM/PCM connector terminal of the problem cylinder (see table).
Is there continuity? YES - Go to 54. NO - Repair open in the wire between the ECM/ PCM and the injector, then go to 60. |
| 54. | At injector side, measure resistance between injector 2P connector terminals No. 1 and No. 2.
Is there 10-13 W? YES - Go to 55. NO - Replace the injector, then go to 60. |
| 55. | Substitute a known-good injector from the problem cylinder. |
| 56. | Reconnect all connectors. |
| 57. | Start the engine, and let it idle for 2 minutes. |
| 58. | Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
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| 59. | 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 70. NO - Replace the original injector, then go to 60. |
| 60. | Turn the ignition switch OFF. |
| 61. | Reconnect all connectors. |
| 62. | Turn the ignition switch ON (II). |
| 63. | Reset the ECM/PCM with the HDS. |
| 64. | Clear the crank pattern with the HDS. |
| 65. | Do the ECM/PCM idle learn procedure. |
| 66. | Do the crank pattern learn procedure. |
| 67. | Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
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| 68. | Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated? YES - If DTC P0301, P0302, P0303 or P0304 indicated, check for poor connections or loose terminals at the ignition coil, the injector, and the ECM/PCM, then go to troubleshooting DTC P0300, P0301, P0302, P0303 or P0304. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting. NO - Go to 69. |
| 69. | 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.n NO - If the screen indicates FAILED, check for poor connections or loose terminals at the ignition coil, the injector, and the ECM/PCM, then go to 1. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to 67 and recheck. |
| 70. | Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM. |
| 71. | Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
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| 72. | Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated? YES - If DTC P0301, P0302, P0303 or P0304 indicated, check for poor connections or loose terminals at the ignition coil, the injector, and the ECM/PCM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting. NO - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM.n |