DTC P0300: Random / Multiple Cylinder Misfire Detected; DTC P0301: Cylinder 1 Misfire Detected; DTC P0302: Cylinder 2 Misfire Detected; DTC P0303: Cylinder 3 Misfire Detected; DTC P0304: Cylinder 4 Misfire Detected: Description
| *1 | Camshaft Position Sensor |
| *2 | Crankshaft Position Sensor |
| *3 | ECM |
When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause increases in exhaust emissions levels. High concentrations of HC can also cause increases in the Three-way Catalytic Converter (TWC) temperature, which may cause damage to the Three-way Catalytic Converter (TWC). To prevent these increases in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the Three-way Catalytic Converter (TWC) reaches the point of thermal degradation, the MIL blinks. To monitor misfires, the ECM uses both the camshaft position sensor and the crankshaft position sensor. The camshaft position sensor is used to identify any misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted as when the crankshaft rotation speed variations exceed predetermined thresholds.
If the misfire rate exceeds the threshold, the ECM illuminates the MIL and stores a DTC.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0300 | Simultaneous misfiring of several cylinders occurs and one of the following conditions below is detected (2 trip detection logic):
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| P0301 P0302 P0303 P0304 |
Misfiring of specific cylinder occurs and one of the following conditions below is detected (2 trip detection logic):
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When multiple DTCs for misfiring cylinders are stored, but DTC P0300 is not stored, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only stored when several misfiring cylinders are detected at the same time.