how to fix P0302 misfire code in BMW 3 Series G20/G21 (2019-2024)?

Solution

1. Preparation

• Tools Required: OBD-II scanner, torque wrench, spark plug socket, compression tester, multimeter, fuel injector test kit.
• Ensure the vehicle is parked on a level surface and the engine is turned off and cool.
• Disconnect the battery to prevent electrical shorts.

2. Replace Spark Plug

1. Remove the engine cover (if applicable) by unbolting any fasteners.
2. Locate the ignition coil for cylinder 2, disconnect the electrical connector.
3. Remove the ignition coil by unbolting it and gently pulling it upward.
4. Use a spark plug socket to remove the spark plug from cylinder 2.
5. Inspect the spark plug for wear or damage. Replace it with a new spark plug if necessary (follow manufacturer specifications for type).
6. Install the new spark plug hand-tight, then torque to the manufacturer’s specification (typically around 22 lb-ft).
7. Reinstall the ignition coil and connect the electrical connector securely.

3. Replace Ignition Coil

1. If the ignition coil was found defective, proceed to replace it.
2. Attach the new ignition coil onto the spark plug, ensuring it is seated correctly.
3. Reconnect the electrical connector to the ignition coil.
4. Repeat the process for any other faulty ignition coils if multiple misfires are detected.

4. Inspect and Replace Fuel Injector

1. Disconnect the fuel injector connector for cylinder 2.
2. Remove the fuel rail (if necessary) by unbolting it and disconnecting fuel lines (ensure to relieve fuel pressure first).
3. Remove the fuel injector from the rail or directly from the cylinder head.
4. Inspect the injector for clogs or damage. Replace it with a new one if necessary.
5. Reinstall the injector and ensure all connections are tight.