how do I fix the P0301 misfire code on my BMW 3 Series F30/F31 (2012-2019)?

Solution

1. Preparation

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

2. Inspect and Replace Spark Plug

1. Remove the engine cover (if applicable) to access the ignition system.
2. Using a socket set, carefully remove the spark plug for cylinder 1.
3. Inspect the spark plug for signs of wear, such as fouling or electrode damage.
4. If necessary, replace the spark plug with a new one that matches OEM specifications (e.g., NGK or Bosch).
5. Torque the new spark plug to the manufacturer's recommended specification (typically around 22 Nm).

3. Inspect and Replace Ignition Coil

1. Disconnect the electrical connector from the ignition coil for cylinder 1.
2. Remove the bolt securing the ignition coil using a socket wrench.
3. Pull the ignition coil out from the cylinder head.
4. Inspect the ignition coil for cracks or carbon tracking.
5. Replace with a new ignition coil if necessary, ensuring it is seated properly.
6. Reconnect the electrical connector securely.

4. Test Fuel Injector

1. Disconnect the fuel injector connector for cylinder 1.
2. Use a multimeter to check the injector resistance; it should be within the manufacturer’s specifications (typically around 12-16 ohms).
3. If the injector is faulty, remove the fuel rail to access the injector.
4. Replace the faulty injector with a new one, ensuring to use new O-rings.

5. Compression Test (if required)

1. Remove the spark plug from cylinder 1 again.
2. Insert a compression gauge into the spark plug hole.
3. Crank the engine a few times and record the compression reading.
4. Compare the reading to the manufacturer’s specifications (usually around 130-200 psi).
5. If compression is low, further investigation into the engine’s mechanical condition is needed.