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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before working on components.

2. Inspect and Repair Intake Leaks

• Tools Required: Socket set, vacuum gauge, flashlight.
• Sub-steps:
  1. Visually inspect all intake hoses and connections for cracks or disconnections.
  2. Use a vacuum gauge to detect leaks in the intake manifold.
  3. Replace any damaged hoses or clamps.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver set.
• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Remove the MAF sensor carefully.
  3. Clean the sensor with MAF cleaner; do not touch the sensing element.
  4. Reinstall the MAF sensor securely.

4. Check and Adjust Fuel System

• Tools Required: Fuel pressure gauge, wrench set.
• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position without starting the engine to check fuel pressure.
  3. Compare the reading with the manufacturer specifications; it should typically be between 50-60 psi.
  4. If pressure is low, check the fuel pump and filter for issues and replace them if necessary.

5. Inspect and Test Fuel Injectors

• Tools Required: Multimeter, injector cleaner, basic hand tools.
• Sub-steps:
  1. Disconnect the fuel injector connectors.
  2. Use a multimeter to check the resistance of each injector; compare with specifications (usually around 12-16 ohms).
  3. If any injector is out of spec, replace it.
  4. Clean the injectors using an ultrasonic cleaner or replace them if they are clogged.