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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to avoid electrical shorts.
• Ensure the vehicle is parked on a level surface with the engine cool.

2. Retrieve and Analyze Codes

• Connect the OBD-II scanner to the vehicle's diagnostic port.
• Retrieve and note down all stored DTCs.
• Research codes to determine potential issues related to the check engine light.

3. Address Faulty Components

• For Code P0300 (Random/Multiple Cylinder Misfire Detected):

  • Replace spark plugs and ignition coils if worn.
  • Inspect fuel injectors for clogs and clean or replace if necessary.

• For Code P0171 (System Too Lean):

  • Check the intake system for vacuum leaks and repair as necessary.
  • Inspect the mass air flow (MAF) sensor; clean or replace if faulty.

• For Code P0420 (Catalyst System Efficiency Below Threshold):

  • Inspect the catalytic converter for damage or blockage; replace if necessary.
  • Check oxygen sensors; replace if malfunctioning.

4. Clear Codes and Test

• Clear all DTCs using the OBD-II scanner.
• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.