how to fix P0171 lean mixture code on Volkswagen Tiguan First Generation (2007-2018)

Solution

1. Preparation

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

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Visually inspect the air intake hoses and connections for any signs of wear or damage.
  2. Tighten any loose clamps and replace any cracked or damaged hoses.
  3. Use a smoke machine to identify any vacuum leaks if necessary.

3. Clean or Replace the MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Remove the electrical connector and the mounting screws.
  3. Clean the MAF sensor using MAF cleaner. Allow it to dry.
  4. Reinstall the sensor and connect the electrical connector. If damaged, replace with a new MAF sensor.

4. Test Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position (without starting) and check the pressure. It should be within the manufacturer's specifications (typically around 50-60 psi).
  3. If pressure is low, inspect the fuel pump and fuel filter for blockages or failures. Replace if necessary.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail assembly to access the fuel injectors.
  2. Clean the injectors with a suitable injector cleaner or replace them if they are clogged or malfunctioning.
  3. Reinstall the fuel rail and ensure all connections are secure.