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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Screwdriver set, vacuum gauge, smoke machine (optional)
• Inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
• Replace any damaged hoses and ensure all connections are secure.
• If a smoke machine is available, perform a smoke test to find hidden leaks.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver
• Remove the MAF sensor from the air intake duct.
• Spray the sensor with MAF cleaner and allow it to dry completely.
• Reinstall the MAF sensor and ensure it is securely fastened.

4. Check Fuel Pressure

• Tools Required: Fuel pressure gauge
• Locate the fuel rail and connect the fuel pressure gauge.
• Turn the ignition to the "on" position (do not start the engine) to check fuel pressure.
• Compare the reading with the manufacturer's specifications; replace the fuel pump or filter if pressure is low.

5. Inspect Fuel Injectors

• Tools Required: Fuel injector cleaning kit or ultrasonic cleaner
• Remove the fuel injectors from the rail and inspect for clogs or damage.
• Clean the injectors using a cleaning kit or ultrasonic cleaner.
• Reinstall the injectors with new O-rings if necessary.

6. Clear Codes and Test Drive

• Reconnect the negative battery terminal and use the scanner to clear the P0171 code.
• Start the engine and check for any leaks or abnormal sounds.
• Conduct a test drive to verify the issue is resolved and the check engine light remains off.