how to resolve the P0171 trouble code in Volkswagen Golf Seventh Generation (2013-2020)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. Use a smoke machine or carburetor cleaner to detect any leaks. Apply around suspected areas and watch for changes in RPM or smoke.
  3. Replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector and remove the sensor from the duct.
  3. Clean the sensor with MAF sensor cleaner. Avoid touching the sensor element.
  4. If damaged or malfunctioning, replace the MAF sensor with a new one.

4. Check Fuel System

• Sub-steps:
  1. Attach a fuel pressure gauge to the fuel rail.
  2. Turn the ignition to the "ON" position (do not start) and check the fuel pressure reading against manufacturer specifications.
  3. If pressure is low, inspect the fuel pump and fuel filter for issues. Replace as necessary.

5. Inspect Oxygen Sensors

• Sub-steps:
  1. Locate the upstream oxygen sensor (typically before the catalytic converter).
  2. Use a multimeter to check the sensor's voltage output. It should fluctuate between 0.1V and 0.9V.
  3. Replace the sensor if it fails to show the appropriate readings.