how to fix P0302 misfire code on BMW X3 F25 (2011-2018)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to avoid electrical issues.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket, dielectric grease.
• Remove the engine cover if necessary.
• Locate the spark plug for cylinder 2.
• Use the spark plug socket to remove the old spark plug.
• Inspect the old spark plug for signs of wear (e.g., burnt electrodes, oil fouling).
• Apply a small amount of dielectric grease to the threads of the new spark plug.
• Install the new spark plug and torque to the manufacturer’s specifications (typically around 16-22 ft-lbs for BMW).

3. Inspect and Replace Ignition Coil (if necessary)

• Tools Required: Socket set, multimeter (for testing).
• Remove the ignition coil for cylinder 2 by unscrewing the retaining bolts or clips.
• Test the coil with a multimeter to ensure it is functioning properly (check primary and secondary resistance).
• If defective, replace with a new coil, ensuring it fits properly.

4. Inspect and Clean Fuel Injector

• Tools Required: Fuel injector cleaning kit (or replacement injector), safety goggles.
• Remove the fuel rail if necessary to access the fuel injector for cylinder 2.
• Disconnect the electrical connector and fuel line from the injector.
• Remove the injector from the rail.
• If cleaning, use a fuel injector cleaning kit to clean the injector.
• If replacing, install the new injector ensuring proper O-ring seating.

5. Reassemble and Reconnect

• Reinstall the fuel rail and ensure all connections are secure.
• Reconnect the battery and reattach any removed engine covers.