why does my BMW 3 Series F30/F31 (2012-2019) check engine light keep coming on?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.
• Allow the engine to cool down before starting work.

2. Address Fault Codes

• Connect the OBD-II scanner and retrieve the trouble codes.
• Research the codes to determine the specific issue (e.g., P0171 for lean condition, P0300 for misfire).
• Clear the error codes and monitor if they return after a test drive.

3. Inspect and Replace Components

A. Gas Cap

• Check for damage or wear on the gas cap.
• If damaged, replace with a new gas cap that meets OEM specifications.

B. Spark Plugs and Ignition Coils

• Remove the ignition coils using a socket set.
• Inspect spark plugs for wear; replace if worn or fouled.
• Reinstall new or inspected coils, ensuring they are securely fastened.

C. Air Filter

• Open the air filter housing and remove the old filter.
• Install a new air filter, ensuring proper fit and sealing.

D. Fuel System

• Use a fuel pressure gauge to check fuel system pressure.
• If pressure is low, inspect the fuel filter and pump; replace if necessary.
• Check fuel injectors for clogs; clean or replace as needed.