how to fix P0171 code in Volkswagen Golf MK7 (2015-2019)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, vacuum gauge, socket set, torque wrench, fuel pressure gauge, throttle body cleaner.
• Safely park the vehicle on a flat surface and engage the parking brake.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum lines and hoses for cracks, breaks, or disconnections.
  2. Use a smoke machine or carburetor cleaner to identify leaks; spray around suspected areas and watch for changes in engine RPM.
  3. Replace any damaged vacuum hoses or gaskets as necessary, ensuring proper routing and connections.

3. Clean or Replace the MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor electrical connector.
  2. Remove the MAF sensor from the air intake duct using a socket set.
  3. Clean the MAF sensor with a specialized MAF cleaner and allow it to dry.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Test and Repair Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the "ON" position (do not start) and check fuel pressure against manufacturer specifications.
  3. If pressure is low, inspect the fuel pump and filter; replace as necessary.
  4. Ensure proper fuel quality is being used.

5. Inspect and Clean Throttle Body

• Sub-steps:
  1. Remove the air intake duct to access the throttle body.
  2. Clean the throttle body with throttle body cleaner and a soft cloth, ensuring the throttle plate moves freely.
  3. Reinstall the intake duct and ensure all clamps are secure.