how to fix BMW 3 Series F30/F31 (2012-2019) P0171 lean code

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Safety gear: gloves and eye protection.
• Disconnect the vehicle battery before working on electrical components.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Inspect all hoses connected to the intake system for cracks or disconnections.
  3. Tighten or replace any loose or damaged clamps and hoses.
  4. Replace any damaged vacuum lines with new ones.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector from the MAF sensor.
  3. Remove the MAF sensor using a Torx screwdriver.
  4. Clean the sensor with MAF cleaner spray or replace it if damaged.
  5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel System

• Sub-steps:
  1. Attach 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.
  3. If the pressure is below specifications (check manufacturer specifications), inspect the fuel pump and filter.
  4. Replace the fuel filter if it shows signs of clogging, or the fuel pump if it's not delivering adequate pressure.

5. Test Fuel Injectors

• Sub-steps:
  1. Remove the fuel injector connectors.
  2. Use a multimeter to check the resistance of each injector according to specifications.
  3. Replace any faulty injectors.
  4. Reconnect all components and clear the error codes.