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P0304

Overview

Code

P0304

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 P0304 indicates a misfire detected in cylinder 4

Symptoms

Rough running engine; Engine vibration

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

Misfires affect engine smoothness and emissions

Possible Causes

Faulty spark plug or coil; Injector failure

Diagnostic Steps

1 Confirm misfire data; 2 Inspect ignition components; 3 Test injector

Drive Safety Notes

Immediate repair is recommended to avoid catalyst damage

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