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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Hose clamp pliers, flashlight, vacuum gauge.
• Instructions:
  1. Visually inspect all vacuum hoses and connections for wear or damage.
  2. Use a vacuum gauge to check for leaks in the intake manifold.
  3. If leaks are found, replace damaged hoses or seals, ensuring tight connections.

3. Clean or Replace the MAF Sensor

• Tools Required: MAF cleaner, small screwdriver.
• Instructions:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor with the screwdriver.
  3. Spray MAF cleaner onto the sensor element without touching it.
  4. Allow it to dry and reinstall or replace if damaged.

4. Check and Adjust Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Instructions:
  1. Connect the fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition on (do not start the engine) and record the pressure reading.
  3. Compare the reading to the manufacturer specifications (typically around 50-60 psi).
  4. If pressure is low, check the fuel pump and filter; replace as necessary.

5. Inspect and Clean Fuel Injectors

• Tools Required: Injector cleaning kit, basic hand tools.
• Instructions:
  1. Remove the fuel injectors from the fuel rail.
  2. Use an injector cleaning kit to clean the injectors.
  3. Reinstall the injectors ensuring they seat properly and check O-rings for damage.