how to fix P0171 code in my Volkswagen Golf MK6 (2009-2014)

Solution

1. Preparation

• Gather tools and parts required.
• Disconnect the negative terminal of the battery.
• Ensure the engine is cool before starting work.

2. Inspect and Repair Air Intake

• Sub-step 1: Visually inspect all vacuum hoses for cracks or disconnections. Replace any damaged hoses.
• Sub-step 2: Remove the air intake duct and inspect the intake manifold gasket for leaks. Replace if necessary.
• Sub-step 3: Clean the MAF sensor using an appropriate MAF cleaner. Allow it to dry before reinstallation.

3. Fuel System Inspection

• Sub-step 1: Attach a fuel pressure gauge to the fuel rail. Turn the ignition to the "ON" position without starting the engine to check for proper fuel pressure (typically around 50-60 PSI for MK6).
• Sub-step 2: If pressure is low, inspect the fuel pump and replace if faulty. Also, check the fuel filter and replace if clogged.
• Sub-step 3: If the fuel pressure is normal, remove the fuel injectors for cleaning or replacement if they are clogged.

4. Replace Faulty Sensors

• Sub-step 1: If the coolant temperature sensor is faulty, disconnect its connector, remove the sensor, and replace it with a new one.
• Sub-step 2: Reconnect all sensors, hoses, and components removed during the inspection.