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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative terminal of the battery to ensure safety during repairs.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable using a socket set.
  2. Disconnect the ignition coil connector for cylinder 1.
  3. Remove the ignition coil by unscrewing the retaining bolt and gently pulling it out.
  4. Remove the spark plug using a spark plug socket and ratchet.
  5. Inspect the spark plug for wear or damage; replace if necessary.
  6. Install the new spark plug (torque to manufacturer's specification, typically 18-22 lb-ft).
  7. Reinstall the ignition coil and reconnect the connector.

3. Inspect and Replace Ignition Coil

• Sub-steps:
  1. If the spark plug is in good condition, inspect the ignition coil for damage.
  2. If necessary, replace the ignition coil with a new unit.
  3. Reinstall the ignition coil and reconnect the electrical connector.

4. Check Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Test the injector with a noid light or multimeter to ensure it is firing correctly.
  3. Replace the fuel injector if it is faulty.
  4. Reconnect the fuel injector connector.

5. Clear Codes and Test

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0301 code.
  3. Start the engine and allow it to reach operating temperature.