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

Solution

1. Preparation

• Gather tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is off.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, screwdriver.
• Sub-steps:
  1. Use a vacuum gauge to test for leaks in the intake system.
  2. Inspect hoses visually and feel for any cracks or loose connections.
  3. Replace any damaged hoses or tighten loose connections.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner or electrical contact cleaner, screwdriver.
• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor using a screwdriver.
  3. Clean the MAF sensor with MAF cleaner.
  4. Reinstall the sensor and reconnect the electrical connector.

4. Test Fuel System

• Tools Required: Fuel pressure gauge, fuel line disconnect tool.
• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position (do not start) and check the pressure reading.
  3. Compare the reading to the manufacturer's specifications (typically 50-60 psi).
  4. If the pressure is low, inspect the fuel pump and filter, replacing any faulty components.

5. Inspect Fuel Injectors

• Tools Required: Multimeter, fuel injector cleaning kit.
• Sub-steps:
  1. Disconnect the fuel injector connectors.
  2. Use a multimeter to test the resistance of each injector against specifications.
  3. If any injectors are out of specification, replace them.
  4. Clean the remaining injectors using a fuel injector cleaning kit.

6. Check Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter.
• Sub-steps:
  1. Use an OBD-II scanner to monitor the oxygen sensor data.
  2. Inspect the wiring harness for damage or corrosion.
  3. Test the voltage output of the sensors; replace any that are not functioning properly.