how to fix P0304 misfire code on my Volkswagen Passat B8 (2015-2022)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Volkswagen Passat B8 (2015-2022). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a level surface with the engine off and cool.
• Disconnect the battery to avoid electrical shock.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 4:
  • Unplug the electrical connector from the ignition coil.
  • Unscrew and remove the ignition coil.
• Remove the old spark plug:
  • Use a spark plug socket to unscrew the spark plug from the cylinder head.
• Install a new spark plug:
  • Apply anti-seize compound to the threads of the new spark plug.
  • Torque the spark plug to the manufacturer's specifications (typically around 22 lb-ft).
• Reinstall the ignition coil:
  • Position the ignition coil over the new spark plug and press down until it clicks into place.
  • Reconnect the electrical connector.

3. Replace Ignition Coil (if needed)

• Tools Required: Socket set.
• If the ignition coil was found to be faulty during diagnostics, replace it:
  • Remove the old ignition coil as described in the previous step.
  • Install the new ignition coil by reversing the removal process.

4. Replace Fuel Injector (if needed)

• Tools Required: Socket set, fuel injector puller.
• If the fuel injector was found to be faulty:
  • Relieve the fuel system pressure by removing the fuel pump fuse and starting the engine until it stalls.
  • Disconnect the electrical connector and fuel line from the fuel injector.
  • Remove the fuel injector from the rail using a puller or by gently prying it out.
  • Install the new fuel injector and reassemble the fuel line and connector.