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

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Visually inspect all air intake hoses for cracks or breaks.
  2. Use a smoke machine or carburetor cleaner to check for vacuum leaks.
  3. Replace any damaged hoses or clamps.
• Tools Required: Screwdrivers, pliers, smoke machine (optional).

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Clean the MAF sensor using MAF cleaner spray; do not touch the sensor elements.
  4. If cleaning does not resolve the issue, replace the MAF sensor with a new one.
• Tools Required: Torx or socket set, MAF cleaner spray.

4. Check Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition on (do not start the engine) to check the specified fuel pressure.
  3. If pressure is low, check the fuel pump and filter.
• Tools Required: Fuel pressure gauge.

5. Inspect and Clean Fuel Injectors

• Sub-steps:
  1. Remove the fuel injectors from the fuel rail.
  2. Clean injectors using a professional cleaning kit or replace them if clogged.
  3. Reinstall the fuel injectors ensuring proper seating and connections.
• Tools Required: Injector removal tools, cleaning kit.

6. Verify O2 Sensor Functionality

• Sub-steps:
  1. Disconnect the O2 sensor connector.
  2. Use a multimeter to check for voltage output while the engine is running.
  3. If readings are out of specification, replace the O2 sensor.
• Tools Required: Multimeter.