Misfire Monitor

OBD System Description - Misfire Monitor

System Description / Monitoring Procedure
ECM (PCM) measures the angle speed of the crankshaft based on the pulse signal from the CKP sensor and CMP sensor for each cylinder. If it detects a large change in the angle speed of the crankshaft, it concludes occurrence of a misfire. When the number of misfire is counted by the ECM (PCM) beyond the DTC detecting condition, it determines the cylinder where the misfire occurred and outputs it as DTC.

DTC P0300 / P0301 / P0302 / P0303 / P0304: Random / Cylinder 1 / Cylinder 2 / Cylinder 3 / Cylinder 4 Misfire Detected.

System Description
ECM measure the angle of the crankshaft based on the pulse signal from the CKP sensor and CMP sensor for each cylinder. If it detects a large change in the angle speed of the crankshaft, it concludes occurrence of a misfire. When the number of misfire is counted by ECM beyond the DTC detecting condition, it determine the cylinder where the misfire occurred and output it as DTC.

DTC Detecting Condition:

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure
WARNING:
- When performing a road test, select a place where there is no traffic or possibility of a traffic accident and very careful during testing to avoid occurrence of an accident.
- Road test should be carried out with 2 persons, a driver and tester, on a level road.

NOTE:
- Check to make sure that the following conditions are satisfied when using this DTC Confirmation Procedure.
- Altitude (barometric pressure): 2500 m, 8202 ft or less (560 mmHg, 75 kPa or more)

1. With ignition switch turned OFF, connect scan tool.
2. Turn ON ignition switch and clear DTC using scan tool.
3. Drive vehicle under freeze frame data condition as noted for 1 min. or more.
4. Stop vehicle and check DTC and pending DTC.

Step 1 - 2:

Step 3 - 10:

DTC Troubleshooting

Operation:

Enable Condition:

Typical Malfunction Thresholds:

Misfire Monitor