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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, fuel pressure gauge, multimeter, vacuum gauge.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Intake System

• Sub-steps:
  1. Visually check the entire air intake system, including the air filter and intake hoses, for any signs of damage or loose connections.
  2. Tighten any loose clamps or fittings.
  3. Replace any damaged hoses or components.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor, usually situated between the air filter and the throttle body.
  2. Disconnect the electrical connector and remove the sensor from the intake.
  3. Clean the sensor with MAF sensor cleaner. Do not touch the sensor element.
  4. If the sensor is damaged or heavily contaminated, replace it with a new one.

4. Test and Repair Fuel Delivery System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail’s test port.
  2. Turn the ignition to the "ON" position without starting the engine and record the fuel pressure reading.
  3. Compare the reading to the manufacturer's specifications (typically around 50-60 psi).
  4. If the pressure is low, check the fuel pump, filter, and injectors for issues. Replace any faulty components.

5. Inspect for Vacuum Leaks

• Sub-steps:
  1. Use a vacuum gauge to check for vacuum leaks in the intake manifold and connected hoses.
  2. Listen for hissing sounds while the engine is running, indicating a leak.
  3. Repair any leaks found, including replacing gaskets or hoses as needed.