how to fix P0171 lean code in Volkswagen Golf MK7 (2015-2019)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent electrical shorts.
• Ensure the engine is cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  • Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  • Use a smoke machine to detect hard-to-find leaks.
  • Replace any damaged hoses or gaskets as necessary.
• Tools Required: Smoke machine, hose clamp pliers.

3. Clean or Replace MAF Sensor

• Sub-steps:
  • Remove the MAF sensor from the intake duct.
  • Clean the sensor with MAF cleaner and let it dry completely.
  • If damaged or excessively dirty, replace the MAF sensor.
• Tools Required: Torx screwdriver, MAF cleaner.

4. Check and Adjust Fuel Pressure

• Sub-steps:
  • Connect the fuel pressure gauge to the fuel rail.
  • Start the engine and observe the fuel pressure reading.
  • If the pressure is below specifications (consult service manual), check the fuel pump and filter.
• Tools Required: Fuel pressure gauge.

5. Inspect and Test Fuel Injectors

• Sub-steps:
  • Remove the fuel injectors from the rail.
  • Test each injector for proper spray pattern using a noid light or oscilloscope.
  • Clean or replace faulty injectors as needed.
• Tools Required: Injector puller tool, noid light.