what does the P0171 code indicate for my Volkswagen Golf MK7.5 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Air Intake System

• Inspect the air filter and replace if dirty.
• Check all intake hoses for cracks or loose connections. Tighten or replace as necessary.
• Clean the MAF sensor using MAF sensor cleaner. Do not touch the sensor element.

3. Check Fuel System

• Test fuel pressure using a fuel pressure gauge. Ensure it meets manufacturer specifications (typically around 50-60 psi).
• Inspect fuel injectors for blockage. Clean or replace as needed.
• If fuel pressure is low, check the fuel pump and fuel filter for proper operation.

4. Examine Vacuum Lines

• Visually inspect all vacuum lines for signs of wear or leaks. Replace any damaged lines.
• Use a smoke machine or spray soapy water to identify any leaks in vacuum lines.

5. Test Oxygen Sensors

• Use a multimeter to check the voltage of the upstream oxygen sensor. It should fluctuate between 0.1V and 0.9V.
• If the sensor is not functioning properly, replace it with a new one.

6. Clear Codes and Test Drive

• Reconnect the battery terminal and use the OBD-II scanner to clear the P0171 code.
• Test drive the vehicle to ensure the issue is resolved and the check engine light does not reappear.