Misfires
Misfires at random times and any combination of the following.
DTC P0302: Cylinder 2 misfire detected.
DTC P0304: Cylinder 4 Misfire Detected
Note: Before troubleshooting, record all freeze data and any on-board snapshot data and review the general troubleshooting instructions.
If misfires occur frequently enough to affect emissions detection over two consecutive driving cycles, the MIL will illuminate and DTC P0300 will be stored in the computer's memory (and any combination of codes from P0301 to P0304).
If misfires occur frequently enough to damage the catalytic converter, the MIL will flash each time a misfire occurs and DTC P0300 will be stored in the computer's memory (and any combination of codes from P0301 to P0304). Once the misfire stops, the MIL will remain on.
If some of the following DTC codes are stored in memory at the same time as the combustion skip DTC code, first perform a fault search according to the DTC codes listed below, and then repeat the check for the combustion skip DTC code.
P0102, P0103: Mass Air Flow (MAF) Sensor.
P0107, P0108: Manifold Absolute Pressure Sensor.
P0171, P0172: Fuel system.
P0335, P0339: Crankshaft Position Sensor (CKP).
P0351, P0352, P0353, P0354, P0355, P0356, P0357, P0358: Ignition Coil.
P0365, P0369: Camshaft Position (CMP) Sensor.
P0401, P0404, P2413: Exhaust Gas Recirculation (EGR) System.
1. Turn the ignition on by turning the key to the "ON" (II) position.
2. Clear the DTC message using the HDS.
3. Start the engine and let it idle without load (in neutral mode).
4. Follow up "OBD STATUS" (on-board diagnostics status) for DTC code P0301, P0302, P0303, or P0304 in the DTCs MENU (dTC codes menu) using the HDS diagnostic system.
Is it displayed? "FAILED" ("Verification failed") on the screen?
- YES - go to step 9.
- NO - if the screen shows "PASSED" ("Verification was successful"), go to step 5. If the following message appears on the screen: "EXECUTING" ("in progress"), continue moving until the result appears. If the following message is displayed on the screen: "OUT OF CONDITION" ("Failure to meet conditions"), wait a few minutes, then check again.
5. Check "CYL1 MISFIRE" ("combustion misfire in cyl. 1"), "CYL2 MISFIRE" ("combustion misfire in cyl. 2"), "CYL3 MISFIRE" ("combustion error in cyl. 3") and/or "CYL4 MISFIRE" ("combustion misfire in cyl. 4") in "DATA LIST" (data list) within 10 minutes using the HDS diagnostic system.
Does "CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE" show the number of misfires?
- YES - go to step 9.
- NO - go to step 6.
6. Test drive the vehicle for several minutes to allow its operating parameters to vary within the range of the associated data retrieved from memory.
7. Follow up "OBD STATUS" ("On-Board Diagnostic Status") for DTC P0301, P0302, P0303, or P0304 in "DTC MENU" ("DTC Menu") using the HDS.
Is it displayed? "FAILED" ("Verification failed") on the screen?
- YES - go to step 9.
- NO - if the screen shows "PASSED" ("The check was successful"), go to step 8. If the message "EXECUTING" appears on the screen, continue driving until the result appears, if the message "OUT OF CONDITION", go to step 6 and double check.
8. Check "CYL1 MISFIRE" (combustion misfire in cyl. 1), "CYL2 MISFIRE" (combustion misfire in cyl. 2), "CYL3 MISFIRE" (combustion misfire in cyl. 3) and/or "CYL4 MISFIRE" (combustion misfire in cyl. 4) v "DATA LIST" ("Data List") within 10 minutes using the HDS diagnostic system.
Does "CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE" show the number of misfires?
- YES - go to step 9.
- NO - temporary malfunction, the system is currently operational.
9. Turn the ignition key to the "OFF" position.
10. Check the fuel quality. Is the quality normal?
- YES - go to step 11.
- NO - Empty the fuel tank and fill it with good quality fuel, then proceed to step 19.
11. Check the spark plugs. If the spark plugs are damaged or worn, replace them.
12. Test drive the vehicle for several minutes to allow its operating parameters to vary within the range of associated data retrieved from memory.
13. Check "CYL1 MISFIRE" (combustion misfire in cyl. 1), "CYL2 MISFIRE" (combustion misfire in cyl. 2), "CYL3 MISFIRE" (combustion misfire in cyl. 3) and/or "CYL4 MISFIRE" (combustion misfire in cyl. 4) v "DATA LIST" ("Data List") within 10 minutes using the HDS diagnostic system.
Does "CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE and/or CYL4 MISFIRE" show the number of misfires?
- YES - go to step 14.
- NO - go to step 19.
14. Check the fuel pressure.
Is the fuel pressure normal?
- YES - go to step 15.
- NO - If the pressure is too high, replace the fuel pressure regulator, then go to step 19. If the pressure is too low, check the fuel pump, fuel feed line, and fuel filter. If they are OK, replace the fuel pressure regulator, then go to step 19.
15. Start the engine. Maintain the crankshaft speed at 3,000 rpm without load (in neutral position of manual transmission) until the radiator fan turns on and let it idle.
16. Check the following:
- ECT SENSOR 1 above 80°C;
- gearbox in neutral mode;
- load shedding of all electrical equipment.
17. Follow the information "ENGINE SPEED" ("Crankshaft speed") in the menu "DATA LIST" ("Data List") using the HDS and maintain engine speed at 4,500 rpm. Once engine speed is reached, hold the accelerator pedal for more than 10 seconds.
The rotation speed changed by more than 100 rpm from 4500 rpm.?
- YES - repeat 17.
- NO - go to step 18.
Maintain the engine speed at 4,500 rpm and check "MAF SENSOR" in the "DATA LIST" menu using the HDS system.
The value is approximately 14-20 gm/s?
- YES - check for air in the fuel line, then go to step 19.
- NO - Replace the MAF sensor/IAT sensor, then go to step 19.
19. Turn the ignition on by turning the key to the "ON" (II) position.
20. Perform the ECM Reset procedure using the HDS.
21. Clear the rotation sensor reference position memory using the HDS.
22. Perform the ECM idle speed training procedure.
23. Perform the diagnostic procedure using the reference position indicated by the rotation sensor.
24. Test drive the vehicle for several minutes to allow its operating parameters to vary within the range of associated data retrieved from memory.
25. Check for Temporary DTCs or DTCs using the HDS.
Are there any Temporary DTCs or DTCs being output?
- YES - If DTCs P0300, P0301, P0302, P0303, or P0304 are indicated, check for poor connections or loose terminals at the ignition coil, injector, and ECM, then GO to troubleshooting for DTC P0301, P0302, P0303, or P0304. If other Temporary DTCs or DTCs are indicated, GO to troubleshooting for those DTCs.
- NO - go to step 26.
26. Follow up "OBD STATUS" ("On-board diagnostic status") for DTC code P0301, P0302, ROSOZ or P0304 in the DTC code menu" MENU " using the HDS diagnostic system.
Is it displayed? "PASSED" ("Check passed") on the screen?
- YES - The troubleshooting procedure is complete.
- NO - if the screen shows "FAILED" ("The test failed"), go back to 1 and run the test again. If the screen displays "EXECUTING" ("In progress"), continue moving until the result appears. If the following message is displayed on the screen: "OUT OF CONDITION" ("Failure to meet conditions"), go back to 24 and perform the check again.
Checking for faults according to DTC codes when misfires are detected in cylinders No.1 and No.3 is carried out according to a similar scheme.
Original material on the website: HONDABOOK