how to fix P0303 code on BMW X3 G01 (2018-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to avoid electrical shorts.
• Allow the engine to cool completely before beginning work.

2. Replace Spark Plug and Ignition Coil

• Tools Required: Socket set, torque wrench, spark plug socket, dielectric grease.
• Remove the engine cover if applicable.
• Disconnect the electrical connector from the ignition coil.
• Remove the ignition coil bolt using the socket set.
• Carefully pull out the ignition coil from cylinder 3.
• Remove the spark plug using the spark plug socket; inspect for wear or damage.
• Install a new spark plug, torquing it to manufacturer specifications (typically around 25 Nm).
• Apply a small amount of dielectric grease to the inside of the ignition coil boot for easier installation.
• Reinstall the ignition coil and secure it with the bolt, reconnecting the electrical connector.

3. Check and Replace Fuel Injector (if necessary)

• Tools Required: Fuel injector puller, fuel line disconnect tool, torque wrench.
• If the fuel injector was determined to be faulty, relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
• Disconnect the fuel lines using the fuel line disconnect tool.
• Remove the retaining clips and disconnect the electrical connector from the fuel injector.
• Use the fuel injector puller to remove the injector from the rail.
• Install the new fuel injector, ensuring proper seating and installation of clips.
• Reconnect the fuel lines and electrical connectors.

4. Reassemble and Reconnect Battery

• Reinstall any components removed during the preparation phase (e.g., engine cover).
• Reconnect the negative battery terminal securely.