how to troubleshoot P0171 code in Volkswagen Golf Seventh Generation (2013-2020)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before beginning any work.

2. Inspect and Repair Intake System

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections. Replace any damaged hoses.
  2. Check the intake manifold for leaks using a smoke test or by spraying carb cleaner around the seams while the engine is running.
  3. Tighten or replace any loose or damaged clamps connecting the air intake components.

3. Clean MAF Sensor

• Tools Required: MAF cleaner
• Sub-steps:
  1. Disconnect the MAF sensor electrical connector.
  2. Remove the MAF sensor from the intake duct.
  3. Spray MAF cleaner onto the sensor elements, avoiding direct contact with other components.
  4. Allow the sensor to dry completely before reinstalling.

4. Check Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Start the engine and check the fuel pressure reading against the manufacturer specifications (typically around 50-60 psi).
  3. If pressure is low, check the fuel pump and filter for blockages or failure.

5. Inspect Oxygen Sensors

• Sub-steps:
  1. Locate the upstream oxygen sensor (pre-catalytic converter).
  2. Use a multimeter to test the sensor's voltage output (should fluctuate between 0.1-0.9 volts).
  3. Replace the sensor if it is not functioning correctly.