why does my BMW 5 Series F10/F11 (2010-2017) check engine light keep coming back

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before starting any work.

2. Code Resolution

• Using the OBD-II scanner, identify persistent trouble codes linked to the CEL.
• Research each code for associated repairs, such as replacing faulty sensors or components.

3. Inspect and Repair Vacuum Leaks

• Visually inspect all vacuum hoses and connections.
• Replace any damaged hoses with OEM parts.
• Use a smoke machine if available to locate hard-to-find leaks.

4. Fuel System Service

• Replace the fuel filter if it hasn't been changed recently.
• Clean the fuel injectors using a professional fuel injector cleaning kit.

5. Ignition Component Replacement

• Remove the ignition coils and inspect for cracks or burn marks.
• Replace any faulty coils and spark plugs according to manufacturer specifications.
• Torque spark plugs to manufacturer-recommended values, typically around 22 lb-ft.

6. Exhaust System Inspection

• Inspect the catalytic converter for blockages or damage.
• Replace any faulty O2 sensors if error codes indicate their malfunction.