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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Visually inspect the air intake ducting for cracks or loose connections.
  2. Replace any damaged hoses or clamps.
  3. Ensure the air filter is clean and properly installed.

3. Test and Clean MAF Sensor

• Sub-steps:
  1. Remove the MAF sensor from the air intake system.
  2. Spray MAF sensor cleaner onto the sensor elements, avoiding contact with other components.
  3. Allow the sensor to dry completely before reinstalling it.

4. Check and Adjust Fuel Pressure

• Sub-steps:
  1. Connect the fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the "ON" position (without starting the engine) and check the fuel pressure reading.
  3. If the pressure is below specifications, check the fuel pump and filter for issues and replace if necessary.

5. Inspect Vacuum Lines

• Sub-steps:
  1. Visually inspect all vacuum lines for cracks or loose connections.
  2. Replace any damaged vacuum hoses with OEM or equivalent parts.
  3. Use a smoke machine or similar tool to verify that no additional leaks are present.

6. Verify Fuel Injector Functionality

• Sub-steps:
  1. Test each fuel injector using a multimeter to ensure they are within resistance specifications.
  2. Replace any faulty injectors identified during testing.