what does it mean if my Volkswagen Golf MK7 (2015-2019) has a P0171 code

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Ensure the engine is cool before starting work.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or propane torch (without flame) to detect leaks.
  3. Replace any damaged hoses or gaskets.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor, usually between the air filter and the throttle body.
  2. Disconnect the electrical connector and remove the sensor from the housing.
  3. Clean the sensor using MAF cleaner spray. Avoid touching the sensing element.
  4. Reinstall the sensor and reconnect the electrical connector.

4. Check Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge at the fuel rail test port.
  2. Turn the ignition on (without starting the engine) and check the pressure reading against specified values.
  3. If the pressure is below the specification, check the fuel pump and fuel filter for issues.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel rail assembly to access the injectors.
  2. Inspect the injectors for clogs or leaks.
  3. Clean or replace any faulty injectors as necessary.
  4. Reassemble the fuel rail and reconnect it to the engine.