what does it mean when my Volkswagen Golf MK7.5 (2020-Present) shows a P0171 code?

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the battery to prevent any electrical issues while working.

2. Inspect and Repair Vacuum Leaks

• Inspect all vacuum hoses for cracks, leaks, or disconnections; replace any damaged hoses.
• Use a smoke machine or carburetor cleaner to identify any leaks around gaskets and connections.

3. Clean or Replace MAF Sensor

• Disconnect the MAF sensor connector.
• Remove the MAF sensor from the air intake duct.
• Clean the MAF sensor with a dedicated MAF cleaner; allow it to dry completely.
• If damaged, replace the MAF sensor with a new unit.

4. Test Fuel Pressure

• Locate the fuel pressure test port on the fuel rail.
• Attach the fuel pressure gauge and turn the ignition to the "On" position (do not start the engine).
• Check that fuel pressure is within the manufacturer's specifications (typically 50-60 psi). If not, inspect the fuel pump and filter.

5. Inspect Fuel Injectors

• Check the fuel injector connectors for secure fit and damage.
• Perform a resistance test on the fuel injectors using a multimeter; replace any malfunctioning injectors.
• If necessary, clean the injectors using a fuel injector cleaning kit.

6. Replace Engine Coolant Temperature Sensor (if faulty)

• Locate the coolant temperature sensor on the engine.
• Disconnect the wiring harness and remove the sensor.
• Install the new sensor and reconnect the wiring harness.