how to fix P0301 code in my BMW 5 Series G30/G31 (2017-2024)

Solution

1. Preparation

• Tools Needed: OBD-II scanner, socket set, torque wrench, compression tester, fuel pressure gauge, smoke machine.
• Safety Warning: Disconnect the battery before working on electrical components and allow the engine to cool.

2. Replace Spark Plug and Ignition Coil

• Remove Engine Cover: Unscrew and carefully lift the engine cover.
• Remove Ignition Coil: Unplug the electrical connector and unscrew the ignition coil from cylinder 1.
• Replace Spark Plug: Use a spark plug socket to remove the old spark plug. Inspect for wear and deposits.
• Install New Spark Plug: Torque the new spark plug to the manufacturer's specification (typically around 20 Nm).
• Reinstall Ignition Coil: Attach the ignition coil and reconnect the electrical connector.

3. Check and Replace Fuel Injector (if necessary)

• Access Fuel Injector: Remove any components obstructing access to the fuel injector for cylinder 1.
• Test Fuel Injector: Use a multimeter to check the resistance of the fuel injector. Replace if out of specification.
• Install New Fuel Injector: Apply engine oil to the O-ring of the new injector and install it. Ensure it is secured properly.

4. Conduct Compression Test (if misfire persists)

• Remove Spark Plug: As previously described, remove the spark plug from cylinder 1.
• Attach Compression Tester: Insert the compression tester into the spark plug hole.
• Crank Engine: Turn the engine over several times to take a reading. Compare with manufacturer specifications.
• Evaluate Results: If compression is low, further investigation is required (e.g., valve issues, head gasket).