how to fix P0302 misfire code on my BMW 5 Series F10/F11 (2010-2017)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts during repairs.

2. Replace Spark Plug and Ignition Coil (if needed)

• Remove the engine cover (if applicable) using a socket set.
• Disconnect the ignition coil connector for cylinder 2.
• Remove the ignition coil using a socket set (typically 10mm).
• Inspect and replace the spark plug in cylinder 2 using a spark plug socket. Ensure proper gap is set as per manufacturer specifications.
• Reinstall the ignition coil, ensuring it clicks into place, and reconnect the ignition coil connector.

3. Inspect and Clean Fuel Injector

• Locate the fuel injector for cylinder 2.
• Disconnect the fuel injector connector.
• Remove the fuel injector using a fuel injector puller (or carefully with pliers).
• Clean the injector or replace it if it appears faulty. If cleaning, use a suitable fuel injector cleaner.
• Reinstall the fuel injector, ensuring it seats properly, and reconnect the connector.

4. Perform Compression Test (if misfire persists)

• Remove the spark plug from cylinder 2 and insert a compression tester.
• Crank the engine and note the compression reading. Compare it to the specifications for your engine.
• If the compression is low, further investigation into the cylinder’s mechanical condition may be necessary (e.g., valve issues, piston rings).

5. Check for Vacuum Leaks

• Inspect the intake manifold and associated vacuum lines for leaks.
• Use a smoke machine or carburetor cleaner spray to detect leaks while the engine is running. Repair or replace any damaged hoses or gaskets.