DTC Troubleshooting
DTC P0301: No. 1 Cylinder Misfire DetectedDTC 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
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
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, 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 these recorded freeze data parameters:
- ENGINE SPEED
- VSS
- REL TP SENSOR
- CLV (calculated load value)
- ECT SENSOR 1
- GEAR POSITION
- APP SENSOR
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, the 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. Reconnect all connectors.
12. 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)
- ECT SENSOR 1
- GEAR POSITION
- APP SENSOR
13. 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 14.
NO - Intermittent misfire due to poor contact at the ignition coil connector (no misfire at this time). Make sure the coil connections are secure.
14. 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, then go to step 56.
NO - Go to step 15.
15. Turn the ignition switch OFF.
16. Exchange the spark plug from the problem cylinder with one from another cylinder.
17. Reconnect all connectors.
18. 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)
- ECT SENSOR 1
- GEAR POSITION
- APP SENSOR
19. 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 20.
NO - Intermittent misfire due to spark plug fouling (no misfire at this time).
20. 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 56.
NO - Go to step 21.
21. Turn the ignition switch OFF.
22. Disconnect the ignition coil 3P connector from the problem cylinder.
23. Turn the ignition switch ON (II).
24. Measure voltage between ignition coil 3P connector terminal No. 3 and body ground.
Is there battery voltage?
YES - Go to step 25.
NO - Repair open in the wire between the ignition coil and the ignition coil relay, then go to step 56.
25. Turn the ignition switch OFF.
26. Check for continuity between ignition coil 3P connector terminal No. 2 and body ground.
Is there continuity?
YES - Go to step 27.
NO - Repair open in the wire between the ignition coil and G101, then go to step 56.
27. Turn the ignition switch OFF.
28. Jump the SCS line with the HDS.
29. Disconnect ECM/PCM connector A (31P).
30. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see table).
Is there continuity?
YES - Repair short in the wire between the ECM/PCM and the ignition coil, then go to step 56.
NO - Go to step 31.
31. Connect appropriate ignition coil 3P connector terminal No. 1 to body ground with a jumper wire (see table).
32. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see table).
Is there continuity?
YES - Go to step 33.
NO - Repair open in the wire between the ECM/PCM and the ignition coil, then go to step 56.
33. Turn the ignition switch ON (II).
34. Measure voltage between body ground and the appropriate ECM/PCM connector terminal (see table).
35. Turn the ignition switch OFF.
36. Remove the intake manifold.
37. Disconnect the injector 2P connector from the problem cylinder.
38. Turn the ignition switch ON (II).
39. Measure voltage between injector 2P connector terminal No. 1 and body ground.
Is there battery voltage?
YES - Go to step 40.
NO - Repair open in the wire between the injector and PGM-FI main relay 1,then go to step 56.
40. Turn the ignition switch OFF.
41. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see table).
YES - Repair short in the wire between the ECM/PCM and the injector, then go to step 56.
NO - Go to step 42.
42. Connect appropriate injector 2P connector terminal No. 2 to body ground with a jumper wire (see table).
43. Check for continuity between body ground and the appropriate ECM/PCM connector terminal (see table).
Is there continuity?
YES - Go to step 44.
NO - Repair open in the wire between the ECM/PCM and the injector, then go to step 56.
44. At the injector side, measure resistance between injector 2P connector terminals No. 1 and No. 2.
Is there 10 - 13 ohms?
YES - Go to step 45.
NO - Replace the injector, then go to step 56.
45. Exchange the injector from the problem cylinder with one from the another cylinder.
46. Reconnect all connectors, and install the intake manifold.
47. Turn the ignition switch ON (II).
48. Clear the DTCs with the HDS.
49. Start the engine, and let it idle without load (in Park or neutral) for 2 minutes.
50. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
51. 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 52.
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.
52. 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 step 56.
NO - Go to step 53.
53. Turn the ignition switch OFF.
54. Do an engine compression and a cylinder leakdown test.
Did the engine pass both tests?
YES - Go to step 55.
NO - Repair the engine, then go to step 56.
55. Do the VTEC rocker arm test.
Did the engine pass the test?
YES - Go to step 66.
NO - Repair the VTEC rocker arm, then go to step 56.
56. Reconnect all connectors.
57. Turn the ignition switch ON (II).
58. Reset the ECM/PCM with the HDS.
59. Clear the CKP pattern with the HDS.
60. Do the ECM/PCM idle learn procedure.
61. Do the CKP pattern learn procedure.
62. 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)
- ECT SENSOR 1
- GEAR POSITION
- APP SENSOR
63. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0301, P0302, P0303, P0304, P0305, or P0306 indicated?
YES - Check for poor connections or loose terminals at the ignition coil, the injector, and the ECM/PCM, then go to DTC P0301, P0302, P0303, P0304, P0305, or P0306 troubleshooting.
NO - Go to step 64.
64. 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. If any other Temporary DTCs or DTCs were indicated in step 63, 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 62.
65. Reconnect all connectors.
66. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
67. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
68. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0301, P0302, P0303, P0304, P0305, or P0306 indicated?
YES - Check for poor connections or loose terminals at the injectors, the ignition coils, and the ECM/PCM, then go to step 1. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to step 67. If the ECM/PCM was substituted, go to step 1.
NO - Go to step 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 - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. If any other Temporary DTCs or DTCs were indicated in step 68, go to the indicated DTCs troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the ignition coil, the injector, and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to step 67. 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 67.