how to fix P0171 lean code on my Volkswagen Golf Seventh Generation (2013-2020)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, flashlight
• Steps:
  1. Visually inspect all vacuum lines and connections for cracks or disconnections.
  2. Use a vacuum gauge to check for leaks; a reading below specifications indicates a leak.
  3. Replace any damaged hoses or gaskets found during inspection.

3. Clean or Replace MAF Sensor

• Tools Required: MAF sensor cleaner, socket set
• Steps:
  1. Locate the MAF sensor in the air intake duct.
  2. Disconnect the electrical connector from the MAF sensor.
  3. Remove the MAF sensor using the appropriate socket.
  4. Clean the sensor element with MAF sensor cleaner and allow it to dry.
  5. Reinstall the MAF sensor and reconnect the electrical connector.

4. Test Fuel Pressure

• Tools Required: Fuel pressure gauge
• Steps:
  1. Locate the fuel rail and connect the fuel pressure gauge to the service port.
  2. Turn the ignition on (do not start the engine) to check the fuel pressure.
  3. Compare the reading to the manufacturer's specifications; if low, check the fuel pump and fuel filter.
  4. If necessary, replace the fuel filter and/or fuel pump.

5. Inspect Fuel Injectors

• Tools Required: Injector cleaning kit (if needed), multimeter
• Steps:
  1. Perform a visual inspection for fuel leaks around the injectors.
  2. Use a multimeter to check the resistance of each injector; replace any that are out of specifications.
  3. If injectors are clogged, use an injector cleaning kit to clean them or replace them if necessary.

6. Clean Throttle Body

• Tools Required: Throttle body cleaner, rag
• Steps:
  1. Remove the air intake duct leading to the throttle body.
  2. Spray throttle body cleaner onto the throttle plate and wipe clean with a rag.
  3. Ensure the throttle plate opens and closes without obstruction before reassembling.