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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety during repairs.
• Allow the engine to cool down before starting.

2. Inspect the Air Intake System

• Tools Required: Socket set, screwdrivers, vacuum gauge.
• Remove the engine cover if present.
• Inspect the air intake hose for cracks or leaks and replace if damaged.
• Ensure that the intake manifold is securely fastened and that there are no vacuum leaks.

3. Check Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Locate the fuel rail and connect the fuel pressure gauge.
• Turn the ignition key to the "On" position (do not start the engine) and check the pressure reading against Volkswagen specifications (typically around 50-60 psi).
• If pressure is low, check the fuel pump and fuel filter for issues, and replace as necessary.

4. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner or isopropyl alcohol, soft cloth.
• Locate the MAF sensor in the air intake duct.
• Disconnect the electrical connector and remove the sensor.
• Spray MAF cleaner onto the sensor element and gently clean it.
• Reinstall the sensor and reconnect the electrical connector.

5. Inspect Fuel Injectors

• Tools Required: Injector cleaning kit or multimeter.
• Remove the fuel rail to access the fuel injectors.
• Inspect each injector for clogs or leaks.
• If injectors are clogged, use an injector cleaning kit or replace them with new ones.

6. Verify Oxygen Sensor Operation

• Tools Required: OBD-II scanner, multimeter.
• Use the scanner to monitor the live data from the oxygen sensor(s) while the engine is running.
• Check for proper voltage readings (typically switching between 0.1V to 0.9V) indicating correct operation.
• Replace any faulty oxygen sensors.