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

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a level surface.
• Disconnect the battery to prevent electrical issues.

2. Clean or Replace the MAF Sensor

• Remove the MAF sensor from the intake system.
• Use MAF cleaner to gently clean the sensor elements.
• Allow it to dry completely before reinstalling.
• If damaged, replace with a new MAF sensor.

3. Inspect and Repair Vacuum Leaks

• Use a smoke machine to introduce smoke into the intake system.
• Watch for smoke escaping from hoses or manifold joints.
• Replace any damaged or cracked hoses and re-tighten loose clamps.

4. Check and Adjust Fuel Pressure

• Connect a fuel pressure gauge to the fuel rail.
• Turn the ignition to the "on" position without starting the engine to check the pressure.
• If the pressure is outside the specified range (typically 50-60 PSI for most gasoline engines), replace the fuel pump or repair the fuel pressure regulator.

5. Clean or Replace Fuel Injectors

• Remove the fuel injectors from the engine.
• Use an injector cleaning kit or send them to a professional for cleaning.
• Reinstall or replace any malfunctioning injectors.

6. Clean the Throttle Body

• Remove the throttle body from the intake manifold.
• Use throttle body cleaner and a soft brush to remove carbon buildup.
• Reinstall the throttle body with a new gasket.