how to resolve the P0301 misfire code in my BMW 3 Series G20/G21 (2019-2024)?

Solution

1. Preparation

• Gather tools and parts necessary for the repair. Ensure the vehicle is parked on a flat surface and the engine is cool.
• Tools Required: Socket set, torque wrench, spark plug socket, compression tester, multimeter, fuel injector cleaning kit.

2. Replace Spark Plug

1. Disconnect the battery to prevent electrical shorts.
2. Remove the engine cover (if applicable) to access the ignition coil.
3. Unplug the electrical connector from the ignition coil.
4. Remove the ignition coil from cylinder 1 by unscrewing the bolts.
5. Extract the spark plug using a spark plug socket.
6. Inspect the old spark plug; if it shows signs of wear (such as burning or excessive carbon), replace it with a new one. Use a spark plug with the correct heat range as specified in the owner’s manual.
7. Install the new spark plug and tighten it to the manufacturer’s specified torque (usually around 15-20 Nm).
8. Reinstall the ignition coil and reconnect the electrical connector.

3. Replace Ignition Coil (if necessary)

1. If the ignition coil is found to be faulty during inspection, replace it by following the steps in section 2, ensuring to use a compatible replacement part.
2. Test the new ignition coil with a multimeter to confirm it is operating correctly.

4. Clean or Replace Fuel Injector (if necessary)

1. If the fuel injector is clogged, use a fuel injector cleaning kit to clean it. Follow the kit's instructions carefully.
2. If cleaning does not resolve the issue, replace the fuel injector. Disconnect the fuel line and electrical connector, then remove any retaining clips and extract the injector.
3. Install the new fuel injector, ensuring proper seating and connection.

5. Check for Vacuum Leaks

1. Inspect vacuum lines connected to the intake manifold for cracks or disconnections.
2. If a leak is found, replace the damaged hose or reconnect any loose connections.