how to resolve P0171 code in my Volkswagen Golf MK7 (2015-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before beginning work.

2. Inspect and Repair Air Intake System

• Sub-steps:

  1. Visually inspect the air intake hoses for cracks or loose connections.
  2. Use a smoke machine or carburetor cleaner to detect vacuum leaks.
  3. Replace any damaged hoses or gaskets found during the inspection.

• Tools Required:

  • Smoke machine (optional)
  • Carburetor cleaner

3. Fuel Pressure Check

• Sub-steps:

  1. Connect the fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position without starting the engine to check the pressure.
  3. If the pressure is below specifications, inspect the fuel pump and filter for issues.

• Tools Required:

  • Fuel pressure gauge

4. MAF Sensor Inspection

• Sub-steps:

  1. Disconnect the MAF sensor connector.
  2. Clean the MAF sensor using MAF sensor cleaner; do not touch the sensor element.
  3. Reconnect the MAF sensor and clear the code from the ECM.

• Tools Required:

  • MAF sensor cleaner

5. Fuel Injector Examination

• Sub-steps:

  1. Remove the engine cover to access the fuel injectors.
  2. Inspect the fuel injectors for signs of leaks or clogs.
  3. Replace any faulty injectors with OEM parts.

• Tools Required:

  • Socket set
  • Torque wrench

6. Oxygen Sensor Testing

• Sub-steps:

  1. Locate the upstream oxygen sensor (pre-catalytic converter).
  2. Use a multimeter to measure the voltage output from the sensor while the engine is running.
  3. If the sensor shows a steady voltage or is unresponsive, replace it.

• Tools Required:

  • Multimeter