P0303
DTC P0303: No.3 Cylinder Misfire Detected1. Note this freeze data:
- Engine speed
- Vehicle speed
- Throttle position
- CLV (Calculated Load Value)
- Engine coolant temperature
2. Clear the DTC with the HDS.
3. Start the engine, and let it idle (in Park or neutral) without load until the radiator fan comes on.
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. lithe screen indicates OUT OF CONDITION, wait for several minutes, and recheck.
5. Check the CYL 1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL 5 MISFIRE, and/or CYL8 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 the recorded freeze data.
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, 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. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
12. Check the CYL 1 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 13.
NO - Intermittent misfire due to poor contact at the ignition coil connector (no misfire at this time). Make sure the coil connections are secure.
13. 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 60.
NO - Go to step 14.
14. Turn the ignition switch OFF.
15. Exchange the spark plug from the problem cylinder with one from another cylinder.
16. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
17. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL 5 MISFIRE, and/or CYL6 MISFIRE in the DATA LIST for 10 minutes with the HDS.
Does CYL 1 MISFIRE, CY12 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 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 plug was moved?
YES - Replace the faulty spark plug, then go to step 60.
NO - Go to step 19.
19. Turn the ignition switch OFF.
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 the recorded freeze data.
23. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL 5 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 24.
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.
24. 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 60.
NO - Go to step 25
25. Turn the ignition switch OFF.
26. Disconnect the ignition coil 3P connector from the problem cylinder.
27. Turn the ignition switch ON (II).
28. Measure voltage between ignition coil 3P connector terminal No.3 and body ground.
Is there battery voltage?
YES - Go to step 29.
NO - Repair open in the wire between the ignition coil and the ignition coil relay, then go to step 60.
29. Turn the ignition switch OFF.
30. Check for continuity between ignition coil 3P connector terminal No.2 and body ground.
Is there continuity?
YES - Go to step 31.
NO - Repair open in the wire between the ignition coil and G101 then go to step 60.
31. Turn the ignition switch OFF.
32. Jump the SCS line with the HDS.
33. Disconnect PCM connector B (44P).
34. Check for continuity between body ground and the appropriate PCM connector terminal (see table).
Is there continuity?
YES - Repair short in the wire between the PCM and the ignition coil, then go to step 60.
NO - Go to step 35.
35. Connect appropriate ignition coil 3P connector terminal No.1 to body ground with a jumper wire (see table).
36. Check for continuity between body ground and the appropriate PCM connector terminal (see table).
Is there continuity?
YES - Go to step 37.
NO - Repair open in the wire between the PCM and the ignition coil, then go to step 60.
37. Reconnect the ignition coil 3P connector and PCM connector B (44P).
38. Do an engine compression and a cylinder leakdown test.
Did the engine pass both tests?
YES - Go to step 39.
NO - Repair the engine, then go to step 60.
39. Do the VTEC rocker arm test.
Did the engine pass the test?
YES - Go to step 40.
NO - Repair the VTEC rocker arm, then go to step 60.
40. Turn the ignition switch OFF.
41. Jump the SCS line with the HDS.
42. Disconnect PCM connector B (44P).
43. Turn the ignition switch ON (II).
44. Measure voltage between body ground and the appropriate PCM connector terminal (see table).
45. Turn the ignition switch OFF.
46. Remove the intake manifold.
47. Disconnect the injector 2P connector from the problem cylinder.
48. Turn the ignition switch ON (II).
49. Measure voltage between injector 2P connector terminal No.1 and body ground.
Is there battery voltage?
YES - Go to step 50.
NO - Repair open in the wire between the injector and the PGM-FI main relay 1 (FI MAIN) then go to step 60.
50. Turn the ignition switch OFF.
51. Check for continuity between body ground and the appropriate PCM connector terminal (see table).
Is there continuity?
YES - Repair short in the wire between the PCM and the injector, then go to step 60.
NO - Go to step 52.
52. Connect appropriate injector 2P connector terminal No.2 to body ground with a jumper wire (see table).
53. Check for continuity between body ground and the appropriate PCM connector terminal (see table).
Is there continuity?
YES - Go to step 54.
NO - Repair open in the wire between the PCM and the injector, then go to step 60.
54. Measure the resistance between injector 2P connector terminals No.1 and No.2.
Is there 10 - 13 Ohms?
YES - Go to step 55.
NO - Replace the injector, then go to step 60.
55. Substitute a known-good injector from another cylinder to the problem cylinder.
56. Reconnect PCM connector B (44P).
57. Start the engine, and let it idle for 2 minutes.
58. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
59. Check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL 5 MISFIRE, and/or CYL6 MISFIRE in the DATA LIST for 10 minutes with the HDS.
Does CYL 1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE, and/or CYL6 MISFIRE show misfire counts?
YES - Go to step 68.
NO - Replace the original injector, then go to step 60.
60. Turn the ignition switch ON (II).
61. Reset the PCM with the HDS.
62. Clear the CKP pattern with the HDS.
63. Do the PCM idle learn procedure.
64. Do the CKP pattern learn procedure.
65. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
66. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
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 PCM, then go to troubleshooting DTC P0301, P0302, P0303, P0304, P0305, or P0306. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - Go to step 67.
67. 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.
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 65 and recheck.
68. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
69. Test-drive the vehicle for several minutes in the range of the recorded freeze data.
70. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
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 PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM.