how to fix P0304 code in Volkswagen Golf Seventh Generation (2013-2020)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect and Replace Spark Plug

• Remove the ignition coil cover if applicable.
• Disconnect the ignition coil connector and unbolt the ignition coil from cylinder 4.
• Remove the spark plug using a spark plug socket and ratchet.
• Inspect the spark plug for wear, carbon buildup, or damage. Replace if necessary.
• Install a new spark plug with a torque specification of 22 ft-lbs (30 Nm).

3. Check and Replace Ignition Coil

• Inspect the ignition coil for cracks or damage.
• If replacing, install a new ignition coil onto the spark plug.
• Reconnect the ignition coil connector securely.

4. Inspect Fuel Injector

• Remove the fuel rail cover if needed.
• Disconnect the fuel injector connector for cylinder 4.
• Remove the fuel injector from the rail and inspect for clogs or failure.
• If necessary, replace the fuel injector and ensure it is seated properly in the intake manifold.

5. Compression Test

• Remove the spark plug from cylinder 4 again.
• Insert a compression gauge into the spark plug hole and crank the engine.
• Record the compression reading; it should be within the manufacturer's specifications (typically around 150 psi or higher).
• If compression is low, further diagnosis of mechanical components may be needed.

6. Reassemble and Test

• Reinstall all components in reverse order.
• Reconnect the battery terminal.
• Start the engine and monitor for any check engine light reappearance.