my BMW 5 Series F10/F11 (2010-2017) has an error code P0303, what does it mean?

Solution

1. Preparation

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

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil by unscrewing the retaining bolts or clips.
• Carefully pull the ignition coil out of the spark plug well.
• Remove the old spark plug using a spark plug socket.
• Inspect the spark plug gap and ensure it is within manufacturer specifications.
• Install the new spark plug and torque it to the manufacturer's specifications (typically around 20 Nm).
• Reinstall the ignition coil and secure it.

3. Test Ignition Coil

• If the ignition coil is suspected to be faulty, replace it with a new one.
• Tools Required: Socket set, multimeter.
• Disconnect the electrical connector from the ignition coil.
• Remove it from the engine and replace it with a new one.
• Reconnect the electrical connector securely.

4. Inspect Fuel Injector

• Tools Required: Fuel injector removal tool, safety glasses.
• Disconnect the fuel line and electrical connector from the fuel injector in cylinder 3.
• Remove the fuel injector using the appropriate tool.
• Inspect for blockages and clean or replace the fuel injector if necessary.
• Reinstall the fuel injector, reconnect the fuel line and electrical connector.

5. Perform Compression Test (if necessary)

• Tools Required: Compression gauge.
• Remove the spark plug from cylinder 3.
• Insert the compression gauge into the spark plug hole.
• Have an assistant crank the engine several times while you read the gauge.
• Compare the compression reading to the specifications; if low, further diagnostics are needed.