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

Solution

1. Preparation

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

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to detect leaks around the intake manifold and vacuum lines.
  3. Replace any damaged hoses or gaskets.
• Tools Required: Smoke machine or carburetor cleaner, hose clamps.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor from the duct.
  3. Clean the sensor with MAF cleaner spray, avoiding contact with the sensing elements.
  4. Reinstall the sensor and reconnect the electrical connector. If the sensor is faulty, replace it with a new one.
• Tools Required: MAF cleaner spray, screwdriver.

4. Check Fuel System

• Sub-steps:
  1. Use a fuel pressure gauge to check the fuel pressure at the fuel rail, ensuring it meets the manufacturer specifications (typically between 50-60 psi).
  2. If pressure is low, check the fuel pump operation and replace the fuel filter if clogged.
  3. Inspect fuel injectors for proper operation and replace any faulty injectors.
• Tools Required: Fuel pressure gauge, socket set.

5. Replace or Test Oxygen Sensors

• Sub-steps:
  1. Locate the upstream oxygen sensor before the catalytic converter.
  2. Use an O2 sensor socket to remove the sensor and inspect for damage.
  3. If faulty, replace it with a new sensor. If testing, use a multimeter to verify the sensor’s voltage output during operation.
• Tools Required: O2 sensor socket, multimeter.