DTC Troubleshooting
DTC Troubleshooting: P0300, P0300
DTC P0300:
Random Misfire and Any Combination of the Following:
DTC P0301:
No. 1 Cylinder Misfire Detected
DTC 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
Special Tools Required
- Pressure Gauge Adapter 07NAJ-P07010A
- A/T Low Pressure Gauge w/Panel 07406-0070301
- A/T Pressure Test Hose 07AAJ-PY4A100
- A/T Pressure Adapter 07MAJ-PY40120
- Oil Pressure Hose 07ZAJ-S5AA200
NOTE:
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information Initial Inspection and Diagnostic Overview.
- If the misfire is frequent enough to trigger detection of increased emissions during two consecutive driving cycles, the MIL will come on, and DTC P0300 (and some combination of P0301 through P0306) will be stored.
- If the misfire is frequent enough to damage the catalyst, the MIL will blink whenever the misfire occurs, and DTC P0300 (and some combination of P0301 through P0306) will be stored. When the misfire stops, the MIL will remain on.
- Troubleshoot the following DTCs first, if any of them were stored along with the random misfire DTC(s) (Because parts can sometimes fail without setting DTCs you should also do a physical inspection of the systems listed below):
P0101, P0102, P0103: MAF sensor
P0107, P0108, P1128, P1129: MAP sensor
P0171, P0172, P0174, P0175: Fuel system
P0335, P0339: CKP sensor
P0506, P0507: Idle control system
P0365, P0369: CMP sensor
P0401, P0404, P0406, P2413: EGR system
P2646, P2647, P2648, P2649: VTEC system
1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
2. Clear the DTC with the HDS.
3. Start the engine, and let it idle without load (A/T in P or N, M/T in 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 idling until a result comes on. If the screen indicates OUT OF CONDITION, wait for several minutes, then 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
- 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.�
9. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
10. Check the fuel quality.
Is the quality good?
YES -
Go to step 11.
NO -
Drain the fuel tank, and fill it with known-good fuel, then go to step 23.
11. Inspect the spark plugs Testing and Inspection. If the spark plugs are fouled or worn, replace them.
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
- 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 -
Go to step 23.
14. Check the fuel pressure Testing and Inspection.
Is the fuel pressure OK?
YES -
Go to step 15.
NO -
- If the pressure is too high, replace the fuel pressure regulator; without SH-AWD Service and Repair, with SH-AWD Service and Repair, then go to step 23.
- If the pressure is too low, check the fuel pump, the fuel feed lines, and the fuel filter. If they are OK, replace the fuel pressure regulator; without SH-AWD Service and Repair, with SH-AWD Service and Repair, then go to step 23.
15. Start the engine. Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.
16. Check under these conditions:
- Engine coolant temperature (ECT SENSOR 1) above 176 °F (80 °C)
- A/T in N, M/T in neutral
- All electrical loads off
17. Monitor the ENGINE SPEED in the DATA LIST with the HDS, and hold the engine speed at 2,500 rpm. Once the engine speed is met, hold the accelerator pedal steady for more than 10 seconds.
Did the engine speed vary more than 100 rpm from 2,500 rpm?
YES -
Repeat step 17.
NO -
Go to step 18.
18. While holding the engine speed at 2,500 rpm, check the MAF SENSOR in the DATA LIST with the HDS.
Is there about 11.0-15.5 gm/s (J35Z6 engine) or 11.8-16.6 gm/s (J37A4 engine)?
YES -
Go to step 19.
NO -
Replace the MAF sensor/IAT sensor Service and Repair, then go to step 23.
19. Remove the rocker arm oil pressure switch (A), and attach the special tools as shown, then attach the rocker arm oil pressure switch to the pressure gauge adapter (B).
20. Reconnect the rocker arm oil pressure switch 2P connector.
21. Start the engine. Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on.
22. Check the oil pressure at engine speeds of 1,000 and 2,000 rpm. Keep the measuring time as short as possible (less than 1 minute) because the engine is running without load.
Is the oil pressure below 49 kPa (0.5 kgf/cm2, 7 psi)?
YES -
Remove the special tools, and reinstall the rocker arm oil pressure switch with a new O-ring, then go to step 23.
NO -
Inspect the VTEC system, then go to step 23.
23. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
24. Reset the ECM/PCM with the HDS.
25. Do the ECM/PCM idle learn procedure ECM/PCM Idle Learn Procedure.
26. Do the CKP pattern clear/CKP pattern learn procedure.
27. 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
- APP SENSOR
28. Check for Pending or Confirmed DTCs with the HDS.
Is DTC P0300 and any combination of DTC P0301, P0302, P0303, P0304, P0305, or P0306 indicated?
YES -
Check for poor connections or loose terminals at the ignition coils, the injectors, and the ECM/PCM, then go to the DTC P0301, P0302, P0303, P0304, P0305, or P0306 troubleshooting P0301.
NO -
Go to step 29.
29. 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 Pending or Confirmed DTCs were indicated in step 28, go to the indicated DTC's troubleshooting.�
NO -
If the screen indicates FAILED, check for poor connection 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 27.