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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before beginning work.

2. Replace Ignition Coil (if faulty)

• Tools Required: Socket set, ratchet, torque wrench.
• Sub-steps:
  1. Remove the engine cover (if applicable) by unscrewing the necessary bolts.
  2. Disconnect the electrical connector from the ignition coil on cylinder 2.
  3. Remove the bolt securing the ignition coil and pull the coil out of the spark plug well.
  4. Install the new ignition coil by reversing the removal steps, ensuring it clicks into place and reconnect the electrical connector.
  5. Torque the ignition coil bolt to the manufacturer's specification (typically around 10 Nm).

3. Replace Spark Plug (if faulty)

• Tools Required: Spark plug socket, torque wrench.
• Sub-steps:
  1. Using the spark plug socket, carefully remove the old spark plug from cylinder 2.
  2. Inspect the old spark plug for wear. If necessary, clean any debris from the spark plug well.
  3. Install the new spark plug, ensuring it is gapped correctly according to specifications (usually around 0.8-1.0 mm for BMW).
  4. Torque the spark plug to the manufacturer's specification (typically around 25 Nm).

4. Inspect/Replace Fuel Injector (if faulty)

• Tools Required: Fuel injector puller (if necessary), O-rings.
• Sub-steps:
  1. Relieve fuel system pressure by removing the fuel pump fuse and starting the engine until it stalls.
  2. Disconnect the electrical connector from the fuel injector on cylinder 2.
  3. Remove any retaining clips or bolts securing the fuel injector.
  4. Carefully pull out the fuel injector and inspect for damage.
  5. If necessary, replace the injector with a new unit and apply new O-rings.
  6. Reconnect everything and check for leaks after re-pressurizing the fuel system.