how to fix P0301 misfire code on BMW 3 Series G20/G21 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety.
• Allow the engine to cool down.

2. Replace Spark Plug

• Tools Required: Spark plug socket, torque wrench, ratchet.
• Remove the ignition coil for cylinder 1:
  1. Disconnect the electrical connector from the ignition coil.
  2. Remove the mounting bolts using a socket and ratchet.
  3. Pull the ignition coil straight out of the spark plug well.
• Remove the old spark plug:
  1. Use the spark plug socket to unscrew the spark plug from the cylinder head.
  2. Inspect the old spark plug for signs of fouling or damage.
• Install the new spark plug:
  1. Apply a small amount of anti-seize compound to the threads of the new spark plug.
  2. Hand-tighten the new spark plug into the cylinder head and then torque it to 23 Nm (17 ft-lb).

3. Replace Ignition Coil

• Tools Required: Ratchet, socket set.
• Remove the old ignition coil:
  1. If not already removed, take out the ignition coil as described in the previous step.
• Install the new ignition coil:
  1. Push the new ignition coil into place over the new spark plug.
  2. Secure it with the mounting bolts and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector

• Tools Required: Fuel injector cleaner, cleaning kit.
• If necessary, remove the fuel injector:
  1. Disconnect the fuel line and electrical connector from the fuel injector.
  2. Remove any retaining clips and unscrew the injector from the intake manifold.
• Clean the fuel injector using a fuel injector cleaning kit.
• Reinstall the injector and ensure it is secured correctly.

5. Reconnect Battery and Start Vehicle

• Reconnect the battery terminals.
• Start the engine and allow it to idle.