my BMW X3 G01 (2018-2024) shows P0171 code, what does it mean

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Ensure the vehicle is on a level surface and securely lifted if necessary.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Hose clamps, vacuum gauge, socket set
• Sub-steps:
  1. Inspect all vacuum hoses for cracks or disconnections.
  2. Use a vacuum gauge to check for leaks in the intake manifold.
  3. Replace any damaged hoses and reseal connections.

3. Clean the MAF Sensor

• Tools Required: MAF sensor cleaner, torx driver
• Sub-steps:
  1. Remove the MAF sensor from the air intake duct.
  2. Spray MAF sensor cleaner on the sensing elements.
  3. Allow it to dry completely before reinstallation.

4. Check Fuel System

• Tools Required: Fuel pressure gauge, socket set
• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail.
  2. Start the engine and observe the fuel pressure; it should be within specifications.
  3. If pressure is low, inspect the fuel pump and filter for issues, replacing as necessary.

5. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, wrench set
• Sub-steps:
  1. Locate the upstream oxygen sensor(s).
  2. Disconnect the wiring harness and unscrew the sensor.
  3. Install a new oxygen sensor, ensuring proper torque specifications are followed (typically around 30 Nm).
  4. Reconnect the wiring harness.