how to fix P0171 lean code in Volkswagen Golf Eighth Generation (2020-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent any electrical issues during the repair.

2. Inspect and Repair Vacuum Leaks

• Visually inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
• Use a smoke machine to detect hidden leaks if necessary.
• Replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Locate the MAF sensor in the air intake duct.
• Disconnect the electrical connector and remove the sensor from the housing.
• Clean the MAF sensor using MAF cleaner spray and a soft brush.
• If the sensor is damaged, replace it with a new one and reconnect the electrical connector.

4. Check and Repair Fuel System

• Use a fuel pressure gauge to check the fuel pressure; it should meet manufacturer specifications (typically between 50-60 PSI for most applications).
• If fuel pressure is low, inspect the fuel pump and replace it if necessary.
• Replace the fuel filter if it is clogged or hasn't been changed as per maintenance schedule.

5. Inspect Fuel Injectors

• Remove the fuel rail to access the fuel injectors.
• Inspect the injectors for clogs and clean them using an injector cleaning kit if dirty.
• Replace any faulty fuel injectors with new ones.

6. Inspect and Replace Oxygen Sensors

• Check the upstream oxygen sensor's functionality using a multimeter.
• If the readings are outside normal parameters, replace the oxygen sensor with a new one.
• Reconnect all electrical connectors and components.