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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent any electrical shorts.
• Allow the engine to cool before beginning work.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, torque wrench.
• Remove the ignition coil for cylinder 3 by unscrewing the bolts and disconnecting the electrical connector.
• Remove the spark plug using a spark plug socket. Inspect for wear or fouling.
• If necessary, replace with a new spark plug, ensuring it meets OEM specifications. Torque the spark plug to the manufacturer's recommended value (typically around 20 Nm).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set.
• If the spark plug is in good condition, inspect the ignition coil for any signs of damage.
• If damaged, remove the coil by unscrewing it and disconnecting the electrical connector.
• Install a new ignition coil, ensuring it is seated properly and reconnect the electrical connector.

4. Check Fuel Injector

• Tools Required: Fuel injector puller (if necessary).
• Confirm that the fuel injector for cylinder 3 is functioning. If it is clogged or not working, remove the injector.
• Clean or replace the fuel injector as necessary. Ensure proper seating during reinstallation.

5. Reconnect Battery and Test

• Reconnect the battery terminals.
• Start the engine and monitor for any check engine lights or misfire symptoms after repairs.