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

Solution

1. Preparation

• Gather tools and necessary parts.
• Disconnect the negative battery terminal.
• Allow the engine to cool to prevent burns.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug gap tool
• Remove the ignition coil from cylinder 1:
  1. Unclip the electrical connector and remove the retaining bolts.
  2. Gently pull the coil out of the spark plug well.
• Remove the spark plug:
  1. Use a spark plug socket to unscrew the old spark plug.
  2. Inspect the old spark plug for signs of wear (e.g., carbon buildup, electrode damage).
• Install the new spark plug:
  1. Set the gap as per manufacturer specifications (usually around 0.028 inches for BMW).
  2. Hand-tighten the new spark plug and then torque it to the specified value (typically 18-22 lb-ft).
• Reinstall the ignition coil:
  1. Align the coil and press it into place.
  2. Reattach the electrical connector and secure with retaining bolts.

3. Replace Ignition Coil (if necessary)

• Tools Required: Socket set
• Remove the ignition coil as described above if it was found faulty.
• Install the new ignition coil:
  1. Align the coil over the spark plug and push it down until it clicks into place.
  2. Secure with retaining bolts and reconnect the electrical connector.

4. Inspect and Clean Fuel Injector (if necessary)

• Tools Required: Fuel injector cleaning kit, O-rings (if replacing)
• Disconnect the fuel injector connector and remove the fuel rail (if applicable).
• Remove the injector:
  1. Gently pull the injector out of the intake manifold.
  2. Inspect the O-rings for damage and replace if needed.
• Clean or replace the injector using the cleaning kit as per the manufacturer's instructions.

5. Perform Compression Test (if necessary)

• Tools Required: Compression tester
• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole and crank the engine.
• Record the compression reading and compare it to manufacturer specifications.