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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Replace Spark Plug

• Remove the ignition coil from cylinder 2:
  • Use a socket wrench to detach the bolt holding the coil.
  • Gently pull the coil out of the spark plug well.
• Remove the spark plug:
  • Use a spark plug socket to unscrew and remove the old spark plug.
• Install the new spark plug:
  • Hand-tighten the new spark plug, then use a torque wrench to tighten it to 22 Nm (16 lb-ft).
• Reinstall the ignition coil, ensuring it clicks into place.

3. Replace Ignition Coil (if necessary)

• If the ignition coil was found to be faulty during inspection:
  • Follow the same steps as above to remove the old coil.
  • Install the new ignition coil, ensuring proper alignment and secure fit.

4. Check and Replace Fuel Injector (if necessary)

• If the fuel injector is not functioning properly:
  • Remove the fuel rail: Disconnect fuel lines and electrical connectors, then unbolt the rail.
  • Extract the injector from the rail.
  • Install the new injector and reassemble the fuel rail, making sure to use new O-rings and torque the bolts to manufacturer's specifications.

5. Reassemble and Test

• Reconnect the battery.
• Start the engine to verify that the misfire code has cleared and the engine runs smoothly.