how to fix P0171 lean code in Volkswagen Golf MK7.5 (2020-Present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down if it has been running.

2. Inspect and Repair Air Intake System

• Tools Required: Screwdriver set, vacuum gauge, hose clamps.
• Check all intake hoses and connections for cracks or leaks.
• Replace any damaged hoses or connections with new OEM parts.
• Tighten hose clamps to ensure a secure fit.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, Torx screwdriver.
• Remove the MAF sensor from the air intake duct.
• Use a specialized MAF sensor cleaner to thoroughly clean the sensor.
• Allow the sensor to dry completely before reinstalling. If damaged, replace it with a new one.

4. Check Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Locate the fuel rail test port and connect the fuel pressure gauge.
• Turn the ignition to the "ON" position (do not start the engine) and check the pressure; it should meet the manufacturer's specifications.
• If pressure is low, inspect the fuel pump and fuel filter.

5. Inspect Fuel Injectors

• Tools Required: Injector cleaning kit or replacement injectors.
• Remove the fuel rail to access the injectors.
• Inspect each injector for clogs; clean them if necessary.
• If any injector is faulty, replace it with a new one.

6. Test Oxygen Sensors

• Tools Required: Multimeter.
• Locate the upstream oxygen sensor and check its voltage signal with a multimeter.
• If the readings are outside the specified range, consider replacing the sensor.