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

Solution

1. Preparation

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

2. Replace Spark Plug and Ignition Coil

• Tools Required: Socket set, torque wrench, dielectric grease, spark plug socket.
• Remove the engine cover if applicable.
• Disconnect the ignition coil connector from cylinder 1.
• Unbolt and remove the ignition coil from cylinder 1.
• Remove the spark plug using a spark plug socket.
• Inspect the old spark plug for signs of wear or fouling.
• Install the new spark plug and torque it to the manufacturer's specifications (typically around 20 Nm).
• Apply dielectric grease to the ignition coil boot and reinstall it, ensuring it is fully seated.

3. Inspect and Replace Fuel Injector (if necessary)

• Tools Required: Fuel line disconnect tool, socket set.
• Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
• Disconnect the negative battery terminal again.
• Remove the fuel line from the injector using a fuel line disconnect tool.
• Unbolt and remove the fuel injector from cylinder 1.
• Inspect the injector for clogs and replace it with a new one if needed.
• Reinstall the fuel injector and reconnect the fuel line securely.

4. Verify Engine Compression (if misfire persists)

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole.
• Crank the engine for a few seconds and record the compression reading.
• Compare the reading with the manufacturer's specifications to check for potential internal engine problems.