why is my BMW 5 Series G30/G31 (2017-2024) engine light on with a P0300 code?

Solution

1. Preparation

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

2. Inspect and Replace Ignition Components

• Remove the engine cover if applicable.
• Inspect spark plugs:
  • Remove each spark plug using a spark plug socket.
  • Check for wear, carbon buildup, or damage; replace if necessary.
• Check ignition coils:
  • Disconnect the wiring harness from each ignition coil.
  • Remove the ignition coils and inspect for cracks or corrosion; replace if needed.

3. Fuel System Inspection

• Inspect fuel injectors:
  • Remove the intake manifold if necessary to access the injectors.
  • Check for clogs or leaks; replace injectors if they are faulty.
• Check fuel filter and pump:
  • Inspect the fuel filter for clogs and replace if necessary.
  • Test the fuel pump's operation and pressure; replace if it does not meet specifications.

4. Vacuum Leak Inspection

• Inspect vacuum lines:
  • Visually check all vacuum lines for cracks or disconnections.
  • Use a smoke machine or carburetor cleaner to identify leaks; repair or replace as required.

5. Compression Test

• Perform a compression test:
  • Remove spark plugs and connect the compression tester to each cylinder.
  • Crank the engine and record the compression readings; compare to manufacturer specs.
  • Address any cylinders with low compression due to mechanical issues.