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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before proceeding.

2. Inspect and Repair Vacuum Leaks

• Sub-steps:
  • Use a smoke machine or carburetor cleaner to detect leaks in the intake system.
  • If leaks are found, replace damaged hoses or gaskets.
  • Recheck all connections for proper fit.

3. Check and Clean MAF Sensor

• Sub-steps:
  • Locate the MAF sensor in the intake duct.
  • Disconnect the electrical connector and remove the sensor.
  • Spray MAF cleaner on the sensor element (do not touch it).
  • Allow it to dry completely, then reinstall the sensor.

4. Test and Regulate Fuel Pressure

• Sub-steps:
  • Connect a fuel pressure gauge to the fuel rail test port.
  • Start the engine and monitor the pressure; it should meet manufacturer specifications (typically around 50-60 psi).
  • If pressure is low, check the fuel pump and filter for issues and replace if necessary.

5. Inspect and Replace Oxygen Sensor

• Sub-steps:
  • Locate the upstream oxygen sensor on the exhaust manifold or downpipe.
  • Disconnect the electrical connector and use an oxygen sensor socket to remove it.
  • Install the new sensor and reconnect the electrical connector.

6. Verify Fuel Injector Functionality

• Sub-steps:
  • Remove the fuel injectors from the fuel rail (ensure fuel pressure is released beforehand).
  • Inspect the injectors for clogs and clean them if necessary using a professional injector cleaning kit or replace them if faulty.
  • Reinstall the injectors and ensure proper sealing.