how to diagnose and fix P0304 code in Volkswagen Golf MK6 (2009-2014)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and set the parking brake.

2. Replace Ignition Coil

1. Disconnect the Battery: Disconnect the negative battery terminal to prevent electrical shocks.
2. Remove Engine Cover: If applicable, take off the engine cover by unscrewing any bolts or clips.
3. Locate Ignition Coil: Identify the ignition coil for cylinder 4 (refer to engine layout diagram if necessary).
4. Remove the Ignition Coil:
   • Disconnect the electrical connector from the ignition coil.
   • Remove the bolt(s) securing the coil and gently pull it out.
5. Install New Ignition Coil:
   • Insert the new ignition coil into the cylinder head.
   • Secure it with the bolt(s) and reconnect the electrical connector.

3. Replace Spark Plug

1. Remove Spark Plug: Using a 5/8" spark plug socket, remove the spark plug from cylinder 4.
2. Inspect the Spark Plug: Check for signs of wear or fouling. Replace if necessary.
3. Install New Spark Plug:
   • Apply anti-seize compound to the threads (if recommended).
   • Torque to manufacturer specifications (usually around 22 lb-ft).

4. Replace Fuel Injector (if needed)

1. Remove Fuel Rail: If fuel injector replacement is necessary, remove the fuel rail by disconnecting it from the manifold and unscrewing any bolts.
2. Take Out Injector: Pull the fuel injector out of its seat.
3. Install New Injector: Lubricate the O-ring of the new injector and insert it into the rail, ensuring it seals properly.

5. Reassemble and Test

• Reassemble any components removed during the process.
• Reconnect the battery and start the engine to check for improvement.