how to fix the P0171 code on my Volkswagen Golf MK7 (2015-2019)?

Solution

1. Preparation

• Tools Required: OBD-II scanner, vacuum gauge, pressure tester, socket set, multimeter, cleaning supplies (MAF cleaner), fuel pressure gauge.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Check for Vacuum Leaks

• Sub-steps:
  1. Start the engine and allow it to reach operating temperature.
  2. Use a vacuum gauge to check for proper vacuum levels; normal readings should be between 17-21 inHg.
  3. Spray a small amount of carburetor cleaner around the intake manifold and vacuum hoses; if the idle changes, a leak is present.
  4. Tighten or replace any loose or damaged hoses.

3. Inspect and Clean 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 MAF cleaner and allow it to dry completely.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Test Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position (do not start) and check the fuel pressure; it should match the specification (usually around 58-62 psi).
  3. If the pressure is low, check the fuel pump operation and replace the fuel filter if clogged.

5. Inspect and Test Injectors

• Sub-steps:
  1. Remove the fuel injectors from the fuel rail.
  2. Inspect for any signs of leaks or clogs.
  3. Use a multimeter to test the resistance of each injector; compare with manufacturer specifications.
  4. Replace any faulty injectors.

6. Clear Codes and Test Drive

• Sub-steps:
  1. Use the OBD-II scanner to clear the P0171 code.
  2. Test drive the vehicle under various conditions to monitor for any reoccurrence of the code.