how to fix my BMW 5 Series G30/G31 (2017-2024) with P0171 lean code

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the battery before starting work on electrical components.
• Allow the engine to cool down before working.

2. Inspect and Repair Air Intake System

• Tools Required: Visual inspection tools, flashlight
• Check for any damaged or disconnected vacuum hoses; replace as needed.
• Inspect the intake manifold gaskets for wear; replace if necessary.
• Tighten any loose clamps on the air intake.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner, screwdriver
• Remove the MAF sensor from the intake.
• Clean the sensor using MAF cleaner; do not touch the sensor element.
• If cleaning does not resolve the issue, replace the MAF sensor with a new one.

4. Test Fuel System

• Tools Required: Fuel pressure gauge
• Connect the fuel pressure gauge to the fuel rail.
• Start the engine and check the fuel pressure against the manufacturer's specifications (typically 50-60 psi).
• If pressure is low, inspect the fuel pump and filter for issues and replace as necessary.

5. Inspect Fuel Injectors

• Tools Required: Injector cleaning kit or replacement injectors
• Remove the fuel rail to access the injectors.
• Check for leaks and clogs; clean or replace injectors as needed.

6. Replace ECT Sensor (if necessary)

• Tools Required: Socket set
• Locate and disconnect the ECT sensor.
• Remove the sensor and replace it with a new one.
• Reconnect the wiring harness.