how to address a P0302 misfire code in my BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety.
• Allow the engine to cool before starting any work.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover (if applicable).
  2. Disconnect the ignition coil connector for cylinder 2.
  3. Unscrew and remove the ignition coil.
  4. Remove the spark plug using a spark plug socket.
  5. Inspect the spark plug for wear or carbon buildup; replace if necessary.
  6. Install the new spark plug to the manufacturer's torque specification (typically around 18-22 lb-ft).
  7. Reinstall the ignition coil and reconnect the connector.

3. Test and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. Use a multimeter to test the ignition coil's primary and secondary resistance according to manufacturer specifications.
  2. If the coil is faulty, remove the old ignition coil.
  3. Install a new ignition coil and ensure it is properly seated.
  4. Reconnect the ignition coil connector.

4. Inspect and Replace Fuel Injector (if necessary)

• Sub-steps:
  1. Remove the intake manifold if needed to access the fuel injector.
  2. Disconnect the fuel injector connector.
  3. Remove the fuel rail to access the injector.
  4. Remove the fuel injector and check for clogs or damage; replace if necessary.
  5. Install the new fuel injector, ensuring proper alignment and sealing.
  6. Reattach the fuel rail and reconnect the fuel injector connector.

5. Compression Test (if needed)

• Sub-steps:
  1. Remove the spark plug from cylinder 2.
  2. Insert a compression gauge into the spark plug hole.
  3. Crank the engine and record the compression reading.
  4. Compare the reading to manufacturer specifications (typically around 150-200 psi).
  5. If compression is low, further investigation into piston rings or valves may be required.