my BMW X3 F25 (2011-2018) has a check engine code for P0171 what's wrong

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety.
• Allow the engine to cool down before starting work.

2. Inspect for Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine to detect any leaks in the intake system.
  3. Replace any damaged hoses or gaskets as needed.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner
• Sub-steps:
  1. Locate the MAF sensor, typically between the air filter and throttle body.
  2. Disconnect the electrical connector and remove the sensor from the housing.
  3. Spray MAF sensor cleaner on the sensing elements and allow it to dry completely.
  4. Reinstall the sensor and reconnect the electrical connector.

4. Check Fuel Pressure

• Tools Required: Fuel pressure gauge
• Sub-steps:
  1. Locate the fuel rail and connect the fuel pressure gauge to the service port.
  2. Turn the ignition to the "ON" position (do not start the engine) to check fuel pressure.
  3. Compare the reading with the manufacturer's specifications (typically around 50-60 psi).
  4. If pressure is low, check the fuel pump and fuel filter for issues.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the engine cover to access fuel injectors.
  2. Visually inspect for any fuel leaks around the injectors.
  3. Use a noid light to check for injector pulse and ensure they are firing correctly.
  4. Clean or replace any clogged injectors as necessary.