my BMW 5 Series F10/F11 (2010-2017) has a check engine light with code P0171, what does it mean?

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the vehicle battery to ensure safety during repairs.
• Allow the engine to cool if it has been running recently.

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers, flashlight
• Remove the engine cover if applicable.
• Visually inspect the air intake hoses and the intake manifold for cracks or loose fittings.
• Tighten any loose connections or replace damaged hoses.
• If necessary, replace the intake manifold gasket.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, microfiber cloth
• Locate the MAF sensor in the air intake system.
• Disconnect the electrical connector and remove the sensor.
• Spray MAF sensor cleaner on the sensor's wire element; do not touch it with fingers or tools.
• Allow it to dry, then reinstall the sensor.
• Reconnect the electrical connector.

4. Check Fuel Delivery System

• Tools Required: Fuel pressure gauge, wrench set
• Locate the fuel rail and connect the fuel pressure gauge.
• Start the engine and check the fuel pressure; compare with specifications (typically 50-60 psi for most BMWs).
• If low, inspect the fuel pump, filter, and lines for restrictions or failures.

5. Inspect Vacuum Lines

• Tools Required: Visual inspection tools
• Check all vacuum lines for cracks, leaks, or disconnections.
• Replace any damaged vacuum lines.

6. Reconnect Battery and Clear Codes

• Reconnect the battery once all repairs are completed.
• Use the OBD-II scanner to clear the P0171 code.
• Start the engine and observe if the check engine light remains off.