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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, fuel pressure gauge.
• Disconnect the battery to ensure safety while working on the electrical components.

2. Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coil connector for cylinder 2.
  3. Remove the ignition coil using a socket.
  4. Unscrew the spark plug using a spark plug socket.
  5. Inspect the spark plug for wear and replace if necessary (use OEM specifications for the new spark plug gap).
  6. Install the new spark plug and torque to manufacturer specifications (generally around 20 Nm).
  7. Reinstall the ignition coil and reconnect the connector.

3. Replace Ignition Coil (if faulty)

• Sub-steps:
  1. If the ignition coil was determined to be faulty during diagnostics, remove it from cylinder 2.
  2. Install the new ignition coil and ensure it is seated correctly.
  3. Reconnect the ignition coil connector.

4. Replace Fuel Injector (if faulty)

• Sub-steps:
  1. Remove the intake manifold if necessary to access the fuel injector.
  2. Disconnect the fuel injector connector.
  3. Unscrew the fuel injector retaining clips and carefully remove the injector.
  4. Install the new fuel injector, ensuring it is seated properly.
  5. Reconnect the injector connector and reinstall the intake manifold if removed.

5. Finalize and Test

• Sub-steps:
  1. Reconnect the battery.
  2. Clear the trouble codes using the OBD-II scanner.
  3. Start the engine and let it idle to check for smooth operation.
  4. Test drive the vehicle to verify that the misfire issue is resolved.