how to fix P0171 code on Volkswagen Passat B8 (2015-2022)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid electrical shorts.

2. Inspect and Repair Air Intake

• Tools Required: Socket set, screwdriver set, vacuum gauge.
• Remove the air intake duct to access the MAF sensor and throttle body.
• Inspect the duct for cracks or leaks and replace if necessary.
• Reinstall the duct securely.

3. Check and Clean MAF Sensor

• Tools Required: MAF sensor cleaner.
• Disconnect the MAF sensor connector.
• Remove the MAF sensor from the intake.
• Spray MAF sensor cleaner onto the sensor element. Allow it to dry.
• Reinstall the MAF sensor and reconnect the connector.

4. Test 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 fuel pressure.
• If pressure is below specifications, check the fuel pump and filter; replace if necessary.

5. Inspect and Clean Fuel Injectors

• Tools Required: Fuel injector cleaning kit (if needed).
• Disconnect the fuel injector connectors and remove the fuel rail.
• Inspect the injectors for dirt or clogs; clean using an injector cleaner or replace if necessary.
• Reinstall the fuel rail and connectors securely.