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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety.
• Allow the engine to cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine or propane torch to locate any leaks by checking for changes in engine RPM.
  3. Replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor.
  3. Clean the MAF sensor using MAF sensor cleaner (do not use other cleaners).
  4. Reinstall the sensor and reconnect the electrical connector or replace it if damaged.

4. Test and Repair Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "On" position without starting the engine and check the fuel pressure; it should match the manufacturer's specifications.
  3. If pressure is low, inspect the fuel pump and filter.
  4. Replace the fuel filter and/or fuel pump if necessary.

5. Inspect and Clean Injectors

• Sub-steps:
  1. Use a fuel injector cleaner or remove the injectors for professional cleaning.
  2. Check for proper function and replace any faulty injectors.
  3. Reinstall injectors with new O-rings if removed.