P0303
Cylinder 3 Misfire Detected
High — address promptly / stopPowertrain (engine & transmission)
System
Powertrain (engine & transmission)
Type
Generic (standardized)
Subsystem
Ignition system or misfire
What it means
Cylinder 3 is misfiring — combustion there is incomplete or absent.
Symptoms
Rough running, vibration, reduced power, possible flashing light.
Common causes
Plug/coil on cylinder 3, injector, low compression, or wiring.
Recommended action
Swap components with a neighbouring cylinder to confirm; fix promptly.
Related codes
P0300Random/Multiple Cylinder Misfire DetectedP0301Cylinder 1 Misfire DetectedP0302Cylinder 2 Misfire DetectedP0304Cylinder 4 Misfire DetectedP0420Catalyst System Efficiency Below Threshold (Bank 1)P0430Catalyst System Efficiency Below Threshold (Bank 2)P0171System Too Lean (Bank 1)P0174System Too Lean (Bank 2)P0172System Too Rich (Bank 1)P0175System Too Rich (Bank 2)P0101Mass Air Flow (MAF) Circuit Range/PerformanceP0113Intake Air Temperature Sensor Circuit High
FAQ — P0303
What does code P0303 mean?
Cylinder 3 Misfire Detected. Cylinder 3 is misfiring — combustion there is incomplete or absent.
What are the symptoms of P0303?
Rough running, vibration, reduced power, possible flashing light.
What causes P0303?
Plug/coil on cylinder 3, injector, low compression, or wiring.
What should I do about P0303?
Swap components with a neighbouring cylinder to confirm; fix promptly.
General reference based on the SAE J2012 standard. Exact causes for your vehicle may differ — when in doubt, consult a workshop.
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