OBD2 code P0300: Misfire / Ignition System – symptoms, causes & step-by-step diagnosis
P0300: Misfire detected Common symptoms: Engine light on (MIL/Check Engine), Rough or unstable slow motion. Inspect Worn spark plug and related wiring.
Detected Root Component
Powertrain Component
Observed Symptoms
- Engine light on (MIL/Check Engine)
- Rough or unstable slow motion
- Loss of engine power
- Abnormal engine vibrations
- Engine stalling
Possible Causes
- Worn spark plug
- Defective ignition coil
- Clogged or faulty injector
- Vacuum leak
Tools Required
Interactive Diagnostic
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Diagnostic Result
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Parts likely to be the cause (Allumage / Bobine)
Allumage / Bobine
Photo d'illustration : Allumage / Bobine
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Frequently asked questions about code P0300
What does code P0300 mean? ▾
OBD2 code P0300: Misfire / Ignition System – symptoms, causes & step-by-step diagnosis. P0300: Misfire detected Common symptoms: Engine light on (MIL/Check Engine), Rough or unstable slow motion. Inspect Worn spark plug and related wiring.
What are the symptoms of code P0300? ▾
Code P0300 may cause: Engine light on (MIL/Check Engine), Rough or unstable slow motion, Loss of engine power, Abnormal engine vibrations. The intensity of these symptoms varies depending on the vehicle and driving conditions.
What causes code P0300? ▾
The most common causes of code P0300 are: Worn spark plug, Defective ignition coil, Clogged or faulty injector, Vacuum leak. A proper OBD2 diagnostic will pinpoint the exact cause.
Is it serious to drive with code P0300? ▾
Yes, code P0300 is critical (Critical). Avoid driving and consult a professional promptly to prevent major damage.
How do I fix code P0300? ▾
Start by reading the code with an OBD2 scanner, then follow the interactive decision tree on this page. Priority causes to check: Worn spark plug, Defective ignition coil, Clogged or faulty injector, Vacuum leak. Difficulty: Medium · Estimated time: 30-60min.