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

Solution

1. Preparation

• Gather tools and materials: OBD-II scanner, socket set, torque wrench, spark plug socket, multimeter, compression tester, replacement spark plugs, ignition coils, or fuel injectors if needed.
• Disconnect the negative battery terminal to ensure safety.

2. Replace Spark Plug

• Tools Required: Spark plug socket, torque wrench.
• Remove the engine cover if applicable.
• Locate cylinder 2 spark plug (consult repair manual for exact location).
• Use the spark plug socket to unscrew and remove the old spark plug.
• Inspect the spark plug for wear; if damaged or worn, replace it with a new one.
• Torque the new spark plug to the manufacturer's specifications (typically around 20 Nm).

3. Check and Replace Ignition Coil

• Tools Required: Socket set.
• Identify the ignition coil for cylinder 2 and remove the electrical connector.
• Unbolt the ignition coil using the socket set and remove it.
• If swapping with another cylinder, reinstall the swapped coil and check for misfire code change.
• If replacing, install the new ignition coil and connect the wiring harness.

4. Inspect and Replace Fuel Injector

• Tools Required: Fuel injector puller (if necessary), socket set.
• Disconnect the fuel injector connector for cylinder 2.
• Remove the fuel rail bolts (if applicable) and gently pull the rail to access the injector.
• Remove the old injector and replace it with a new one, ensuring it is seated properly.
• Reconnect the fuel rail and injector connectors.

5. Perform Compression Test

• Tools Required: Compression tester.
• Remove spark plugs from all cylinders to allow for accurate testing.
• Insert the compression tester into cylinder 2 and crank the engine.
• Compare the compression reading to manufacturer specifications; if low, further investigation into engine internals may be necessary.