how to fix P0300 code in BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Gather tools and parts required.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Ignition Components

• Tools Required: Socket set, torque wrench, ratchet, spark plug socket.
• Remove the engine cover if applicable.
• Unscrew and remove the ignition coils from the spark plugs.
• Inspect spark plugs for wear or damage; replace if necessary (gap to manufacturer specifications).
• Check ignition coils for cracks or carbon tracking; replace faulty coils.
• Reinstall the ignition coils and ensure they are seated properly.

3. Inspect Fuel System

• Tools Required: Fuel pressure gauge, screwdriver set.
• Locate the fuel rail and connect the fuel pressure gauge to the Schrader valve.
• Turn the ignition on (do not start) to check pressure; refer to manufacturer specifications.
• If pressure is low, inspect the fuel pump, filter, and injectors for blockages or failures.
• Replace any faulty components and ensure proper reassembly.

4. Check for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner.
• Start the engine and use a smoke machine to find leaks in vacuum lines, or spray carburetor cleaner at suspected locations while monitoring RPM changes.
• Repair or replace any damaged hoses or gaskets discovered during inspection.

5. Testing and Reassembly

• Reconnect the negative battery terminal.
• Clear the P0300 code using the OBD-II scanner.
• Start the engine and check for any reoccurring codes or symptoms.
• Test drive the vehicle to ensure the issue is resolved.