how to fix P0171 code in Volkswagen Golf Eighth Generation (2020-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool before working on components.

2. Inspect and Repair Vacuum Leaks

• Sub-step 1: Visually inspect all vacuum hoses for cracks or disconnections.
• Sub-step 2: Use a smoke machine to detect hidden vacuum leaks in the intake manifold and surrounding areas.
• Sub-step 3: Replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace the MAF Sensor

• Sub-step 1: Locate the MAF sensor in the air intake duct.
• Sub-step 2: Disconnect the electrical connector from the MAF sensor.
• Sub-step 3: Remove the MAF sensor using a Torx wrench.
• Sub-step 4: Clean the MAF sensor with MAF cleaner, being careful not to touch the sensor element.
• Sub-step 5: If the MAF sensor is damaged, replace it with a new one.

4. Check and Adjust Fuel Pressure

• Sub-step 1: Attach a fuel pressure gauge to the fuel rail.
• Sub-step 2: Turn the ignition to the "ON" position without starting the engine and check the pressure reading.
• Sub-step 3: If the pressure is below specifications, inspect the fuel pump and replace it if necessary.

5. Inspect and Replace Oxygen Sensors

• Sub-step 1: Locate the upstream oxygen sensor (pre-catalytic converter).
• Sub-step 2: Disconnect the electrical connector from the oxygen sensor.
• Sub-step 3: Remove the oxygen sensor using an oxygen sensor socket.
• Sub-step 4: Install a new oxygen sensor and reconnect the electrical connector.