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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter, fuel injector tester, vacuum gauge.
• Ensure the vehicle is parked on a level surface, and the engine is cool before starting work.

2. Replace Spark Plug and Ignition Coil

• Sub-steps:
  1. Disconnect the negative battery terminal.
  2. Remove the engine cover if applicable.
  3. Locate and remove the ignition coil for cylinder 2 by unscrewing the retaining screws and disconnecting the electrical connector.
  4. Remove the spark plug using a spark plug socket and ratchet.
  5. Inspect and clean the spark plug hole; replace with a new spark plug, torquing to the manufacturer's specification (typically around 20 Nm).
  6. Install the new ignition coil, ensuring it clicks into place and reconnect the electrical connector.

3. Inspect and Replace Fuel Injector

• Sub-steps:
  1. Disconnect the fuel pump relay and start the engine until it stalls to relieve fuel pressure.
  2. Remove the intake manifold if required for access to the fuel injector.
  3. Disconnect the electrical connector from the fuel injector in cylinder 2.
  4. Remove the fuel injector by carefully pulling it from the fuel rail.
  5. Install a new fuel injector, ensuring proper seating and reconnect the electrical connector.
  6. Reassemble the intake manifold and reconnect the fuel pump relay.

4. Perform Compression Test (if needed)

• Sub-steps:
  1. Remove the spark plug from cylinder 2 to access the combustion chamber.
  2. Insert the compression tester into the spark plug hole.
  3. Crank the engine for a few seconds, then read the compression level.
  4. Compare the reading with the manufacturer's specifications (typically between 120-200 psi).