SAE J2012 / ISO 15031-6 · powertrain

P0304: Fallo de encendido detectado en el cilindro 4

Fallo de encendido detectado en el cilindro 4: Combustion misfire isolated to Cylinder 4.

P0304 — Diagnostic Summary
Trouble Code (DTC)P0304
Official SAE DefinitionFallo de encendido detectado en el cilindro 4
Vehicle Subsystempowertrain
Driving SeverityHIGH

Observable Symptoms

  • Engine vibration
  • Loss of power
  • MIL on

Most Probable Root Causes

  • Cylinder 4 spark plug or ignition coil degradation
  • Fuel injector restriction
  • Head gasket or exhaust valve wear

Step-by-Step Diagnostic Procedure

  1. Swap Cylinder 4 coil with Cylinder 1 or 3
  2. Check spark plug for oil or coolant fouling
  3. Run relative compression test