how to fix P0171 fuel trim system lean code in Volkswagen Golf Eighth Generation (2020-present)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface, and the engine is off and cool.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  • Visually inspect all vacuum hoses and connections for wear or damage.
  • Using a smoke machine or carburetor cleaner, identify and locate any leaks by observing changes in engine RPM.
  • Replace any damaged or cracked hoses and reseal gaskets as necessary.

3. Check and Clean MAF Sensor

• Sub-steps:
  • Locate the MAF sensor in the air intake duct.
  • Disconnect the electrical connector and unscrew the sensor from the air duct.
  • Clean the sensor using MAF cleaner spray, ensuring no residue is left on the sensor.
  • Reinstall the sensor and reconnect the electrical connector.

4. Test Fuel Pressure

• Sub-steps:
  • Connect a fuel pressure gauge to the fuel rail service port.
  • Turn on the ignition to the "on" position (without starting the engine) to prime the fuel system and check the pressure reading.
  • Compare the reading to the manufacturer's specification (typically between 50-60 psi for most gasoline engines).
  • If low, check the fuel pump, filter, and lines for issues, replacing components as needed.

5. Inspect Fuel Injectors

• Sub-steps:
  • Remove the engine cover if applicable to access fuel injectors.
  • Inspect each injector for signs of leaks or clogs; listen for clicking sounds when the engine is running.
  • Clean or replace the injectors as necessary, using an injector cleaning kit if applicable.