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

Solution

1. Preparation

• Tools Required: OBD-II scanner, spark plug socket, multimeter, compression tester, smoke machine (or propane), and basic hand tools.
• Ensure the vehicle is parked on a level surface.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Spark Plug Inspection and Replacement

1. Remove spark plug cover if applicable.
2. Use a spark plug socket to carefully remove each spark plug.
3. Inspect the condition of the spark plugs; look for signs of wear, fouling, or carbon buildup.
4. Replace with new spark plugs of the specified type for the BMW 5 Series G30/G31.
5. Torque new spark plugs to the manufacturer’s specification (usually around 25 Nm or 18 lb-ft).

3. Ignition Coil Testing and Replacement

1. Disconnect the electrical connector from each ignition coil.
2. Use a multimeter to measure the resistance of each coil; compare with specifications in the service manual.
3. Replace any faulty ignition coils with OEM parts.
4. Reconnect the electrical connectors and ensure they are secure.

4. Fuel Injector Inspection

1. Locate the fuel injectors; remove any necessary engine covers.
2. Inspect the injectors for leaks and clogs.
3. If necessary, clean the fuel injectors using a professional injector cleaning kit or replace them with new units.
4. Reassemble any components removed during inspection.

5. Vacuum Leak Test

1. Using a smoke machine, introduce smoke into the intake system to identify leaks.
2. If no smoke machine is available, carefully use propane around the intake manifold while the engine is running to identify changes in RPM.
3. Repair any identified leaks with new gaskets or hoses as needed.

6. Compression Test

1. Remove the spark plugs and insert the compression tester into the spark plug hole.
2. Crank the engine for a few revolutions and record the compression reading.
3. Repeat for each cylinder; compare results to manufacturer specifications.
4. Address any cylinders with low compression, which may require further investigation into engine internals.