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 negative battery terminal to ensure safety during the repair.

Tools Required:

• OBD-II scanner
• Vacuum gauge
• Fuel pressure gauge
• Socket set
• Torque wrench
• Multimeter
• Cleaning solvent

2. Inspect and Repair Intake System

• Sub-step 1: Visually inspect all vacuum hoses for cracks or disconnections. Replace any damaged hoses.
• Sub-step 2: Check the intake manifold gasket for leaks. Replace if necessary.
• Sub-step 3: Use a smoke machine to detect any hidden air leaks in the intake system.

3. Clean or Replace MAF Sensor

• Sub-step 1: Locate the MAF sensor in the intake system.
• Sub-step 2: Disconnect the electrical connector and remove the sensor from the housing.
• Sub-step 3: Clean the MAF sensor with an appropriate MAF sensor cleaner. Allow it to dry completely before reinstallation.
• Sub-step 4: Reinstall the MAF sensor and reconnect the electrical connector.

4. Check Fuel System

• Sub-step 1: Connect the fuel pressure gauge to the fuel rail.
• Sub-step 2: Turn on the ignition to prime the fuel system and check the pressure reading. It should be within the specified range (typically around 55-65 psi for this model).
• Sub-step 3: If fuel pressure is low, inspect the fuel pump and filter for blockages or failures. Replace as necessary.

5. Inspect Fuel Injectors

• Sub-step 1: Remove the engine cover to access the fuel injectors.
• Sub-step 2: Check for any fuel leaks around the injectors.
• Sub-step 3: Use a multimeter to test the resistance of each injector. Replace any that are out of specification.
• Sub-step 4: If injectors are clogged, clean them using an injector cleaning kit or replace them if cleaning is ineffective.