how to fix P0301 misfire code on my BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool completely.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil covering.
• Unplug the ignition coil connector and remove the ignition coil.
• Remove the spark plug using the spark plug socket.
• Inspect the spark plug for wear or carbon deposits; replace if necessary.
• Install the new spark plug to the manufacturer’s torque specifications (typically around 22 Nm).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Inspect and Replace Ignition Coil (if needed)

• If the spark plug is fine but misfire persists, test the ignition coil.
• Swap the cylinder 1 ignition coil with another cylinder (e.g., cylinder 2).
• Clear the codes and run the engine to see if the misfire moves to the new cylinder.
• If the misfire follows the coil, replace the ignition coil with a new one.

4. Fuel Injector Cleaning/Replacement

• If ignition components are confirmed functional, check the fuel injector.
• Remove the fuel injector from cylinder 1.
• Inspect for clogs or leaks; clean or replace as necessary.
• Reinstall the fuel injector and ensure all connections are secure.

5. Check for Vacuum Leaks

• Inspect all vacuum hoses and intake manifold gaskets for cracks or loose connections.
• Replace any damaged hoses or gaskets to ensure proper airflow.