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

Solution

1. Preparation

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

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  1. Visually inspect all vacuum lines for cracks or disconnections.
  2. Use a smoke machine or a simple spray of carb cleaner around suspected areas while the engine is idling; listen for changes in engine RPM.
  3. Replace any damaged vacuum hoses.

3. Clean the MAF Sensor

• Tools Required: MAF sensor cleaner
• Sub-steps:
  1. Locate the MAF sensor, typically between the air filter and throttle body.
  2. Disconnect the electrical connector from the MAF sensor.
  3. Remove the MAF sensor from the housing carefully.
  4. Spray the MAF sensor with MAF cleaner and let it dry completely.
  5. Reinstall the sensor and reconnect the electrical connector.

4. Inspect and Replace Fuel Components

• Sub-steps:
  1. Check the fuel pressure using a fuel pressure gauge; it should meet manufacturer specifications.
  2. If the pressure is low, inspect or replace the fuel pump and fuel filter.
  3. Inspect the fuel injectors for clogging; if necessary, clean or replace them.

5. Oxygen Sensor Check

• Sub-steps:
  1. Locate the upstream oxygen sensor (before the catalytic converter).
  2. Use a multimeter to check the voltage output; it should fluctuate between 0.1V and 0.9V when the engine is running.
  3. If the sensor is not functioning correctly, replace it.