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P0303

Overview

Code

P0303

Code Type

P

Code Class

P0

System

Engine

Severity Level

High

Emissions Related

true

Drivability Impact

Major

Diagnostic Protocol

OBD2

Freeze Frame Useful

true

Code Definition

Diagnostic trouble code P0303 indicates a misfire detected in cylinder 3

Symptoms

Rough idle; Loss of power

Overview applies to this diagnostic code.

Affected Systems

On This Page

  • Code Definition

  • Symptoms

  • Affected Systems

  • Possible Causes

  • Diagnostic Steps

  • Drive Safety Notes​

More Resources

Engine balance and emissions control are affected by cylinder misfires

Possible Causes

Faulty ignition components; Injector issues

Diagnostic Steps

1 Identify misfire cylinder; 2 Inspect spark plug and coil; 3 Test injector operation

Drive Safety Notes

Continued misfires may damage the catalytic converter

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