how to fix P0171 code on my Volkswagen Golf MK7.5 (2020-Present)

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the battery (negative terminal) to ensure safety while working on electrical components.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum lines and hoses connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to identify any leaks while the engine is running.
  3. Replace any damaged hoses or gaskets as necessary.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor electrical connector and remove it from the air intake.
  2. Clean the MAF sensor using MAF cleaner spray (avoid touching the sensor wire).
  3. If cleaning does not resolve the issue, replace the MAF sensor with a new one.

4. Check Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail service port.
  2. Turn the ignition to the "ON" position without starting the engine and observe the fuel pressure reading.
  3. Compare the reading to the manufacturer's specifications (usually around 50-60 psi). If low, check the fuel pump and filter for issues.
  4. Replace the fuel filter if it has not been replaced recently.

5. Inspect and Clean Throttle Body

• Sub-steps:
  1. Remove the air intake duct to access the throttle body.
  2. Use throttle body cleaner and a soft cloth to clean the throttle plate and surrounding areas.
  3. Reinstall the air intake duct securely.