how to fix P0301 misfire code in BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, spark plug socket.
• Disconnect the negative battery terminal to prevent electrical shorts and shocks.

2. Replace Spark Plug

1. Remove the engine cover if applicable.
2. Use the spark plug socket to remove the spark plug from cylinder 1.
3. Inspect the old spark plug for signs of wear (color, gap).
4. Install a new spark plug, ensuring it is gapped to the manufacturer’s specifications.
5. Torque the spark plug to the manufacturer’s specifications (typically around 22 ft-lbs).

3. Test and Replace Ignition Coil

1. Disconnect the electrical connector from the ignition coil at cylinder 1.
2. Remove the ignition coil using a socket set.
3. Test the ignition coil using a multimeter to ensure it is within specifications (check primary and secondary resistance).
4. If faulty, replace the ignition coil with a new one. Reinstall and securely reconnect.

4. Inspect and Clean Fuel Injector

1. Remove the intake manifold if necessary to access the fuel injector for cylinder 1.
2. Disconnect the fuel injector electrical connector and fuel line (be cautious of fuel spillage).
3. Remove the injector from the rail and inspect for clogs or damage.
4. Clean the injector using an appropriate cleaning solution or replace it if it is faulty.
5. Reinstall the injector and ensure all connections are secure.

5. Compression Test (if necessary)

1. Remove the spark plug from cylinder 1.
2. Insert the compression tester into the spark plug hole.
3. Crank the engine and record the compression reading.
4. Compare the reading to the manufacturer’s specifications. If low, further engine diagnostics may be needed.