how to fix P0171 lean condition code on my Volkswagen Golf MK7.5 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery to ensure safety.
• Allow the engine to cool before starting any work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, socket set
• Inspect all vacuum hoses for cracks or disconnections.
• Use a vacuum gauge to check for leaks and replace any damaged hoses.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, torx screwdriver
• Disconnect the MAF sensor electrical connector.
• Remove the MAF sensor from the intake duct.
• Clean the sensor with MAF cleaner (do not touch the sensor element).
• If damaged, replace with a new sensor and reconnect.

4. Check and Repair Fuel System

• Tools Required: Fuel pressure gauge, socket set
• Connect the fuel pressure gauge to the fuel rail.
• Start the engine and check the pressure; it should be within manufacturer specifications (typically 50-60 psi for the Golf MK7.5).
• If pressure is low, inspect the fuel pump and replace the fuel filter if necessary.

5. Inspect Oxygen Sensors

• Tools Required: O2 sensor socket, wrench
• Locate the upstream oxygen sensor (pre-catalytic converter).
• Check for proper operation using a multimeter or scan tool.
• Replace the sensor if it shows signs of failure or poor readings.

6. Replace Engine Coolant Temperature Sensor (if needed)

• Tools Required: Socket set, pliers
• Locate the coolant temperature sensor, usually near the thermostat housing.
• Disconnect the electrical connector and remove the sensor.
• Install a new sensor and reconnect the connector.