my Volkswagen Golf MK7 (2015-2019) has a P0171 code, what does it indicate?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool down if it has been running.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Visually inspect all vacuum hoses for cracks or disconnections.
  2. Use a smoke machine to detect any vacuum leaks if necessary.
  3. Replace any damaged hoses or connections.

3. Clean the Mass Air Flow Sensor

• Tools Required: MAF sensor cleaner
• Sub-steps:
  1. Disconnect the MAF sensor connector.
  2. Remove the MAF sensor from the air intake duct.
  3. Spray the MAF sensor with the MAF cleaner, avoiding touching the sensor elements.
  4. Allow the sensor to dry completely before reinstallation.

4. Check and Adjust Fuel System

• Sub-steps:
  1. Use a fuel pressure gauge to check the fuel pressure; ensure it matches the manufacturer's specifications.
  2. If pressure is low, inspect the fuel pump and filter for blockages or failure.
  3. Replace the fuel filter if necessary.

5. Inspect Exhaust System

• Sub-steps:
  1. Visually inspect the exhaust system for any leaks or damage.
  2. Use a smoke test to find leaks if necessary.
  3. Repair or replace any damaged exhaust components.

6. Verify Engine Coolant Temperature Sensor

• Sub-steps:
  1. Check the sensor's resistance with a multimeter to ensure it operates within specifications.
  2. Replace the sensor if it is not functioning correctly.