what does it mean when my Volkswagen Golf MK7.5 (2020-Present) shows P0171 code

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to avoid electrical issues.

2. Inspect for Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, flashlight
• Visually inspect all vacuum hoses and connections for cracks or disconnections.
• Use a vacuum gauge to test for vacuum at the intake manifold.
• If a leak is found, replace the damaged hose or reconnect loose parts.

3. Clean the Mass Air Flow Sensor

• Tools Required: MAF sensor cleaner, soft cloth
• Locate the MAF sensor in the intake air duct.
• Remove the sensor carefully to avoid damage.
• Spray the MAF sensor with MAF cleaner and let it dry completely before reinstalling.

4. Check Fuel System

• Tools Required: Fuel pressure gauge
• Locate the fuel pressure test port on the fuel rail.
• Connect the fuel pressure gauge and turn the ignition to the "ON" position (do not start the engine).
• Compare the fuel pressure readings to manufacturer specifications. If low, check the fuel pump and filter.

5. Test Oxygen Sensors

• Tools Required: Multimeter
• Locate the upstream oxygen sensor near the exhaust manifold.
• Use a multimeter to check the voltage output of the sensor while the engine is running.
• If the readings are outside the normal range, consider replacing the oxygen sensor.

6. Reassemble and Reconnect

• Reinstall any components that were removed during the process.
• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.