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

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down before working on components.

2. Inspect and Repair Air Intake System

• Tools Required: Vacuum gauge, socket set, flashlight
• Check for vacuum leaks:
  • Use a vacuum gauge to measure vacuum at the intake manifold; if below specifications, check for leaks.
  • Visually inspect hoses and connectors for cracks or disconnections.
• Repair or replace any damaged hoses or components found during inspection.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner spray, screwdrivers
• Remove the MAF sensor from the air intake:
  • Disconnect the electrical connector.
  • Unscrew the sensor from the housing.
• Clean the MAF sensor using MAF cleaner spray and let it dry.
• Reinstall the MAF sensor and reconnect the electrical connector.

4. Test and Replace Fuel Filter

• Tools Required: Fuel pressure gauge, socket set
• Connect the fuel pressure gauge to the fuel line.
• Turn the ignition to the "ON" position (do not start the engine) to check the fuel pressure:
  • Refer to the service manual for the correct fuel pressure specification.
• If fuel pressure is low, replace the fuel filter.
• Ensure all connections are secure.

5. Inspect and Replace Fuel Injectors (if necessary)

• Tools Required: Socket set, injector puller (if needed)
• Remove the intake manifold to access the fuel injectors.
• Inspect injectors for clogs or leaks.
• Replace any faulty injectors with new ones.
• Reassemble the intake manifold after replacing injectors.

6. Clear Codes and Test Drive

• Tools Required: OBD-II scanner
• Reconnect the battery terminal.
• Use the OBD-II scanner to clear the error codes.
• Start the engine and monitor for any reoccurrence of the P0171 code during a test drive.