why is my BMW 3 Series F30/F31 (2012-2019) check engine light on and won't go off

Solution

1. Preparation

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

2. Scan for Error Codes

• Use an OBD-II scanner to read the trouble codes.
• Document the codes for reference in troubleshooting further.

3. Address Specific Codes

• Research the error codes to determine the underlying issue (e.g., P0171 for lean condition, P0300 for misfires).
• Depending on the code, proceed with targeted repairs, such as:
  • Replacing faulty spark plugs or ignition coils for misfire codes.
  • Checking and replacing fuel injectors if fuel delivery is suspected.
  • Repairing or replacing vacuum hoses if leaks are detected.

4. Inspect and Clean Engine Components

• Remove the throttle body and clean it using throttle body cleaner.
• Inspect and clean the Mass Air Flow (MAF) sensor using MAF cleaner.
• Check the air filter and replace if clogged.

5. Reassemble and Reconnect

• Reinstall any components that were removed during inspection/cleaning.
• Reconnect the battery terminals securely.

6. Clear Error Codes

• Use the OBD-II scanner to clear the error codes.
• Start the engine and observe if the check engine light remains off.