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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum pump, hose clamps, RTV silicone.
• Instructions:
  1. Use a vacuum pump to test all hoses and connections in the intake system.
  2. Replace any damaged hoses or gaskets.
  3. Apply RTV silicone to any joints that show signs of wear to ensure a proper seal.

3. Clean or Replace the MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver.
• Instructions:
  1. Disconnect the MAF sensor electrical connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Spray the MAF sensor with MAF cleaner and allow it to dry completely.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel System

• Tools Required: Fuel pressure gauge, multimeter.
• Instructions:
  1. Connect the fuel pressure gauge to the fuel rail and turn the ignition to the "ON" position (do not start the engine).
  2. Check the fuel pressure against specifications for the Golf MK7 (typically around 50-60 psi).
  3. If pressure is low, inspect the fuel pump and fuel filter. Replace if necessary.

5. Replace Engine Coolant Temperature Sensor (if faulty)

• Tools Required: Socket set, coolant.
• Instructions:
  1. Locate the engine coolant temperature sensor (usually near the thermostat).
  2. Disconnect the electrical connector and remove the sensor using a socket.
  3. Install the new sensor and reconnect the connector.
  4. Refill any lost coolant.

6. Clear Codes and Test Drive

• Use the OBD-II scanner to clear the P0171 code.
• Test drive the vehicle under various conditions to ensure the code does not return.