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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the engine cover (if applicable) to access the spark plug.
• Using the spark plug socket, carefully remove the spark plug from cylinder 1.
• Inspect the spark plug for wear, carbon buildup, or damage.
• If necessary, replace the spark plug with a new one, ensuring it matches OEM specifications (e.g., NGK, Bosch).
• Torque the new spark plug to the manufacturer’s recommended specification (usually around 20 Nm).

3. Test and Replace Ignition Coil

• Tools Required: Socket set, multimeter.
• Disconnect the electrical connector from the ignition coil for cylinder 1.
• Remove the ignition coil using the socket set.
• Test the ignition coil with a multimeter to ensure it is within the manufacturer’s specifications.
• If faulty, replace the ignition coil with a new one.
• Reinstall the ignition coil and reconnect the electrical connector.

4. Inspect and Replace Fuel Injector

• Tools Required: Fuel injector removal tool, socket set.
• Relieve the fuel system pressure by removing the fuel pump fuse and starting the engine until it stalls.
• Disconnect the fuel lines and electrical connectors from the fuel injector in cylinder 1.
• Remove the fuel injector using the appropriate removal tool.
• Inspect the fuel injector for clogs or damage; clean or replace if necessary.
• Reinstall the injector, ensuring proper seating and connection.

5. Check for Vacuum Leaks

• Tools Required: Smoke machine or carb cleaner.
• Inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
• Use a smoke machine to identify any vacuum leaks; alternatively, spray carb cleaner around suspected areas while the engine is running to detect changes in RPM.
• Repair or replace any faulty hoses or gaskets.