my BMW 5 Series G30/G31 (2017-2024) has a check engine light with code P0171, what should I do

Solution

1. Preparation

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

2. Inspect and Repair Air Intake System

• Tools Required: Socket set, screwdrivers, vacuum gauge
• Inspect all intake hoses and connections for leaks; replace any damaged components.
• Tighten or replace any loose clamps.

3. Clean or Replace the MAF Sensor

• Tools Required: MAF sensor cleaner, soft cloth
• Remove the MAF sensor from the air intake duct.
• Spray the MAF sensor with MAF cleaner and allow it to dry completely before reinstallation.

4. Test and Adjust Fuel Pressure

• Tools Required: Fuel pressure gauge
• Connect the fuel pressure gauge to the fuel rail.
• Turn the ignition to the "on" position without starting the engine to check the pressure.
• If the pressure is below manufacturer specifications, check the fuel pump and replace it if necessary.

5. Inspect and Clean Fuel Injectors

• Tools Required: Injector cleaning kit or ultrasonic cleaner
• Remove the fuel injectors from the fuel rail.
• Clean the injectors using the cleaning kit or ultrasonic cleaner, and recheck for proper spray pattern.

6. Check and Repair Vacuum Lines

• Tools Required: Vacuum gauge
• Use a vacuum gauge to test for leaks in the vacuum lines.
• Replace any damaged lines or repair connections as necessary.

7. Check PCV System

• Tools Required: Visual inspection tools
• Inspect the PCV valve for functionality; replace if it is clogged or malfunctioning.