why does my BMW 5 Series F10/F11 (2010-2017) have a check engine light with code P0302?

Solution

1. Preparation

• Tools Required: OBD-II scanner, spark plug socket, torque wrench, multimeter, compression tester, fuel pressure gauge.
• Sub-steps:
  • Gather necessary tools and parts.
  • Ensure vehicle is parked on a level surface and the engine is cool.
  • Disconnect the negative terminal of the battery.

2. Inspect and Replace Spark Plug

• Sub-steps:
  • Remove the ignition coil from cylinder 2 using a socket set.
  • Remove the spark plug using a spark plug socket.
  • Inspect the spark plug for signs of wear or fouling; replace with a new spark plug if necessary (OEM recommended).
  • Reinstall the spark plug and torque to the manufacturer's specification (typically 15-20 Nm).

3. Test and Replace Ignition Coil

• Sub-steps:
  • Use a multimeter to check the resistance of the ignition coil for cylinder 2.
  • If the resistance is out of spec, replace the ignition coil with a new one.
  • Reconnect the ignition coil ensuring it seats properly.

4. Check Fuel Injector

• Sub-steps:
  • Disconnect the fuel injector connector for cylinder 2.
  • Perform a continuity test on the injector with a multimeter to ensure it is functioning.
  • If faulty, replace the fuel injector with a new one.
  • Reconnect the injector connector.

5. Compression Test

• Sub-steps:
  • Remove the spark plug from cylinder 2.
  • Insert the compression tester into the spark plug hole.
  • Crank the engine several times and record the compression reading.
  • Compare the reading to the manufacturer’s specifications (typically 120-200 psi). If compression is low, further investigation is needed.

6. Final Assembly

• Sub-steps:
  • Ensure all connectors are properly seated.
  • Reconnect the battery's negative terminal.
  • Start the engine and monitor for any abnormal sounds or behaviors.