how to fix P0303 code on my BMW 5 Series F10/F11 (2010-2017)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery negative terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench.
• Sub-steps:
  1. Remove the ignition coil from cylinder 3 by unscrewing it.
  2. Extract the spark plug using a spark plug socket.
  3. Inspect the spark plug for wear or carbon buildup; replace if necessary.
  4. Install the new spark plug and torque it to the manufacturer’s specification (typically around 25 Nm).
  5. Reinstall the ignition coil.

3. Check and Replace Ignition Coil (if necessary)

• Tools Required: Socket set.
• Sub-steps:
  1. If the ignition coil appears damaged or the spark plug replacement did not resolve the issue, remove the faulty ignition coil.
  2. Replace it with a new ignition coil for cylinder 3.
  3. Reattach the connector ensuring a secure fit.

4. Inspect and Replace Fuel Injector (if necessary)

• Tools Required: Fuel injector removal tool, O-rings.
• Sub-steps:
  1. If fuel injector operation is faulty, relieve fuel pressure by removing the fuel pump fuse and cranking the engine.
  2. Disconnect the fuel line and electrical connector from the injector.
  3. Remove the fuel injector and replace it with a new one, ensuring new O-rings are used.
  4. Reconnect the fuel line and electrical connector.

5. Final Checks

• Reconnect the battery negative terminal.
• Clear the error codes using the OBD-II scanner.