P0301
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
NOTE:
- Information marked with an asterisk (*) applies to 2000-2004 models.
- Information marked with double asterisk (**) applies to 2005 model.
- Before you troubleshoot, record all freeze data and review the general troubleshooting information.
1. After checking and recording the freeze data, reset the ECM. If there is no freeze data of the misfire, just clear the DTC.
2. Start the engine, listen for a clicking sound at the injector at the problem cylinder.
Does it click?
YES - Go to step 3.
NO - Go to step 30.
3. Turn the ignition switch OFF.
4. Exchange the ignition coil from the problem cylinder with one from another cylinder.
5. Test-drive the vehicle several times in the range of the freeze data or under various conditions if there was no freeze data.
6. Check for a DTC or Temporary DTC with a scan tool or the HDS.
Is DTC P0301, P0302. P0303, or P0304, or Temporary DTC P1399* (P0301, P0302, P0303, or P0304)** indicated?
YES - Go to step 7.
NO - Intermittent misfire due to poor contact at the ignition coil connector (no misfire at this time).
7. Determine which cylinder(s) had the misfire.
Does the misfire occur in the other cylinder where the ignition coil was exchanged?
YES - Replace the faulty ignition coil.
NO - Go to step 8.
8. Turn the ignition switch OFF.
9. Exchange the spark plug from the problem cylinder with one from another cylinder.
10. Test-drive the vehicle several times in the range of the freeze data or under various conditions if there was no freeze data.
11. Check for DTC or Temporary DTC with a scan tool or the HDS.
Is DTC P0301, P0302, P0303 or P0304, or Temporary DTC P1399* (P0301, P0302, P0303, or P0304)** indicated?
YES - Go to step 12.
NO - Intermittent misfire due to spark plug fouling, etc. (no misfire at this time).
12. Determine which cylinder had the misfire.
Does the misfire occur in the other cylinder where the spark plug was exchanged?
YES - Replace the faulty spark plug.
NO - Go to step 13.
13. Turn the ignition switch OFF.
14. Exchange the injector from the problem cylinder with one from the another cylinder.
15. Let the engine idle for 2 minutes.
16. Test-drive the vehicle several times in the range of the freeze data or under various conditions if there was no freeze data.
17. Check for a DTC or Temporary DTC with a scan tool or the HDS.
Is DTC P0301, P0302, P0303, or P0304, or Temporary DTC P1399* (P0301, P0302, P0303, or P0304)** indicated?
YES - Go to step 18.
NO - Intermittent misfire due to bad contact in the injector connector (no misfire at this time).
18. Determine which cylinder had the misfire.
Does the misfire occur in the other cylinder where the injector was exchanged?
YES - Replace the faulty injector.
NO - Go to step 19.
19. Turn the ignition switch OFF.
20. Disconnect the ignition coil 3P connector from the problem cylinder.
21. Turn the ignition switch ON (II).
22. Measure voltage between ignition coil 3P connector terminal No. 3 and body ground.
Is there battery voltage?
YES - Go to step 23.
NO - Repair open in the wire between the No. 4 IGN COIL (15 A) fuse and the ignition coil.
23. Turn the ignition switch OFF.
24. Check for continuity between ignition coil 3P connector terminal No. 2 and body ground.
Is there continuity?
YES - Go to step 25.
NO - Repair open in the wire between the ignition coil and G101.
25. Disconnect ECM connector C (31P).
26. Check for continuity between body ground and the ECM connector terminal (see table).
Is there continuity?
YES - Repair short in the wire between the ECM and the ignition coil.
NO - Go to step 27.
27. Connect appropriate ignition coil 3P connector terminal No. 1 to body ground with a jumper wire (see table).
28. Check for continuity between body ground and the ECM connector terminal (see table).
Is there continuity?
YES - Go to step 29.
NO - Repair open in the wire between the ECM and the ignition coil.
29. Check the engine compression.
Is the engine compression OK?
YES - Substitute a known-good ECM and recheck. If the symptom/indication goes away, replace the original ECM.
NO - Repair the engine.
30. Turn the ignition switch OFF.
31. Disconnect ECM connector B (25P).
32. Turn the ignition switch ON (II).
33. Measure voltage between body ground and the ECM connector terminal (see table).
Is there battery voltage?
YES - Go to step 34.
NO - Go to step 42.
34. Turn the ignition switch OFF.
35. Disconnect the injector 2P connector from the problem cylinder.
36. At the injector side, measure resistance between injector 2P connector terminals No. 1 and No. 2.
Is there 10 - 13Ohm?
YES - Go to step 37.
NO - Replace the injector.
37. Exchange the injector from the problem cylinder with one from another cylinder.
38. Let the engine idle for 2 minutes.
39. Test-drive the vehicle several times in the range of the freeze data or under various conditions if there was no freeze data.
40. Check for a DTC or Temporary DTC with a scan tool.
Is DTC P0301, P0302, P0303, or P0304, or Temporary DTC P1399* (P0301, P0302, P0303, or P0304)** indicated?
YES - Go to step 41.
NO - Intermittent misfire due to injector malfunction, etc.
41. Determine which cylinder had the misfire.
Does the misfire occur in the other cylinder where the injector was exchanged?
YES - Replace the faulty injector.
NO - Substitute a known-good ECM and recheck. If the symptom/indication goes away, replace the original ECM.
42. Turn the ignition switch OFF.
43. Disconnect injector 2P connector from the problem cylinder.
44. Turn the ignition switch ON (II).
45. Measure voltage between injector 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES - Go to step 46.
NO - Repair open in the wire between the injector and the PGM-FI main relay.
46. Turn the ignition switch OFF.
47. Check for continuity between body ground and the ECM connector terminal (see table).
Is there continuity?
YES - Repair short in the wire between the ECM and the injector.
NO - Go to step 48.
48. Connect injector 2P connector terminal No. 1 to body ground with a jumper wire (see table).
49. Check for continuity between body ground and the ECM connector terminals (see table).
Is there continuity?
YES - Replace the injector, then recheck.
NO - Repair open in the wire between the ECM and the injector.