how to fix the P0300 code on my BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Ensure the vehicle is on a level surface and secure with wheel chocks.

2. Replace Spark Plugs

• Remove the engine cover if applicable.
• Use a socket wrench to remove old spark plugs.
• Check the gap on new plugs and adjust if required (typically 0.032-0.036 inches).
• Install new spark plugs by hand first to prevent cross-threading, then tighten to 13 lb-ft (17.6 Nm) with a torque wrench.

3. Inspect and Replace Ignition Coils

• Remove the connectors from the ignition coils.
• Use a socket wrench to remove the ignition coil bolts.
• Replace faulty coils with new OEM coils, ensuring they are seated properly.
• Reattach the connectors and confirm they click into place.

4. Clean/Replace Fuel Injectors

• If injectors are clogged, use a fuel injector cleaning kit to clean them according to the manufacturer's instructions.
• If cleaning does not resolve the issue, replace the fuel injectors with new ones.

5. Check for Vacuum Leaks

• Inspect all vacuum hoses and connections visually.
• Use a smoke machine or carb cleaner to detect leaks.
• Replace any damaged hoses or gaskets found during inspection.

6. Test Fuel Pressure

• Locate the fuel pressure test port on the fuel rail.
• Use a fuel pressure gauge to check the pressure; it should typically be within 50-60 PSI (3.4-4.1 bar).
• If pressure is low, inspect the fuel pump and fuel filter for issues.

7. Verify Engine Timing

• Remove the timing cover if necessary to inspect the timing chain/belt.
• Check alignment marks and ensure they are in the correct position.
• Replace the timing chain/belt if it is found to be worn or improperly aligned.