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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety while working on the ignition system.

2. Inspect and Replace Spark Plug

• Tools Required: Ratchet and socket set, torque wrench, gap gauge
• Remove the engine cover if necessary to access the spark plug.
• Use the ratchet and socket to remove the spark plug from cylinder 1.
• Inspect the spark plug for wear, carbon buildup, or oil contamination.
• If necessary, replace the spark plug with a new one, ensuring it is gapped correctly according to manufacturer specifications (typically 0.028-0.032 inches).
• Torque the new spark plug to the manufacturer's specifications (usually around 18-22 ft-lbs).

3. Inspect and Replace Ignition Coil

• Tools Required: Ratchet and socket set
• Disconnect the electrical connector from the ignition coil of cylinder 1.
• Remove the ignition coil using the ratchet and socket.
• Inspect the ignition coil for damage or wear.
• If defective, replace it with a new ignition coil and reconnect the electrical connector.

4. Test and Clean Fuel Injector

• Tools Required: Fuel injector cleaning kit (if applicable)
• Disconnect the fuel injector connector for cylinder 1.
• Perform a resistance test on the injector with a multimeter to ensure it is within specifications.
• If necessary, clean or replace the fuel injector, ensuring proper installation and connection.

5. Perform Compression Test

• Tools Required: Compression tester
• Remove the spark plug from cylinder 1 and insert the compression tester.
• Crank the engine several times to obtain a reading.
• Compare the compression reading to the manufacturer's specifications. If low, further investigation into the engine internals may be required.