how to diagnose and fix P0301 code on BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plug

1. Remove the engine cover (if applicable) using a socket set.
2. Disconnect the ignition coil connector from the ignition coil on cylinder 1.
3. Remove the ignition coil using a socket wrench.
4. Use a spark plug socket to remove the old spark plug.
5. Inspect the new spark plug for correct gap and condition.
6. Install the new spark plug and torque it to manufacturer specifications (typically around 18 lb-ft).
7. Reinstall the ignition coil and reconnect the ignition coil connector.

3. Test Ignition Coil

1. If the ignition coil was found defective, install a new ignition coil.
2. Reconnect the ignition coil connector.
3. Reinstall the engine cover.

4. Inspect and Clean Fuel Injector

1. Access the fuel injector for cylinder 1 (may require removal of the intake manifold).
2. Disconnect the fuel line and electrical connector from the injector.
3. Remove the injector and inspect it for clogs.
4. Clean the injector using a fuel injector cleaning solution or replace it if necessary.
5. Reinstall the injector, reconnect the fuel line, and electrical connector.

5. Verify Compression

1. If compression was low, address mechanical issues (i.e., valve adjustment or piston ring replacement).
2. Reassemble any components removed during the diagnostic process.