Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0300-00: Random/Multiple Cylinder Misfire Detected; DTC P0300-27: Random/Multiple Cylinder Misfire Detected (Emission) Signal Rate of Change Above Threshold; DTC P0300-85: Random / Multiple Cylinder Misfire Detected (Over Temperature) Signal Above Allowable Range; DTC P0301-00: Cylinder 1 Misfire Detected; DTC P0302-00: Cylinder 2 Misfire Detected; DTC P0303-00: Cylinder 3 Misfire Detected; DTC P0304-00: Cylinder 4 Misfire Detected [10/2022 - 11/2023]: Description
When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high hydrocarbon concentration levels can cause an increase in exhaust emission levels. Extremely high concentrations of hydrocarbons can also cause increases in the three-way catalytic converter temperature, which may cause damage to the three-way catalytic converter. To prevent this increase in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire count. When the temperature of the three-way catalytic converter reaches the point of thermal degradation, the ECM blinks the MIL. 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 when the crankshaft rotation speed variations exceed predetermined thresholds. If the misfire count exceeds the threshold levels, and could cause emission control system performance deterioration, the ECM illuminates the MIL and stores a DTC.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Note |
|---|---|---|---|---|---|
| P0300-00 | Random/Multiple Cylinder Misfire Detected | Simultaneous misfiring of several cylinders occurs and one of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
SAE Code: P0300 |
| P0300-27 | Random/Multiple Cylinder Misfire Detected (Emission) Signal Rate of Change Above Threshold | An emission deterioration misfire occurs (2 trip detection logic). |
|
Comes on | SAE Code: - |
| P0300-85 | Random / Multiple Cylinder Misfire Detected (Over Temperature) Signal Above Allowable Range | A misfire occurs that may damage the three-way catalytic converter (2 trip detection logic). |
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
SAE Code: - |
| P0301-00 | Cylinder 1 Misfire Detected | Misfiring of a specific cylinder occurs and one of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
SAE Code: P0301 |
| P0302-00 | Cylinder 2 Misfire Detected | Misfiring of a specific cylinder occurs and one of the following conditions is met (2 trip detection logic):
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|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
SAE Code: P0302 |
| P0303-00 | Cylinder 3 Misfire Detected | Misfiring of a specific cylinder occurs and one of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
SAE Code: P0303 |
| P0304-00 | Cylinder 4 Misfire Detected | Misfiring of a specific cylinder occurs and one of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
SAE Code: P0304 |
When DTCs for misfiring cylinders are randomly stored, but DTC P0300-00 is not stored, it indicates that misfires have been detected in different cylinders at different times. DTC P0300-00 is only stored when several misfiring cylinders are detected at the same time.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.