how do I get rid of the P0171 code on my BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

• Tools Required: OBD-II scanner, vacuum gauge, fuel pressure gauge, multimeter, socket set, torque wrench, cleaning spray for MAF sensor.
• Disconnect the battery to ensure safety.
• Allow the engine to cool before beginning work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses and connections around the intake manifold for cracks or disconnections.
  2. Use a smoke machine or a vacuum gauge to detect leaks.
  3. Replace any damaged hoses or gaskets as necessary.
  4. Tighten any loose clamps or connections.

3. Check and Clean MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake system.
  2. Disconnect the electrical connector and remove the MAF sensor from the intake.
  3. Use MAF sensor cleaner to clean the sensor element; do not touch it with fingers.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Test and Adjust Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position without starting the engine and check the pressure.
  3. Start the engine and observe the fuel pressure. It should meet manufacturer specifications (usually around 50-60 psi).
  4. If pressure is low, check the fuel pump, fuel filter, and fuel injectors for issues.

5. Inspect Oxygen Sensors

• Sub-steps:
  1. Using a multimeter, check the voltage output of the upstream oxygen sensor; it should fluctuate between 0.1V and 0.9V.
  2. If the sensor is not functioning correctly, replace the oxygen sensor according to the manufacturer’s specifications.