my Volkswagen Passat B8 (2015-2022) has a check engine light and code P0171, what to do?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety.

Tools Required:

• OBD-II scanner
• Socket set
• Screwdrivers
• Multimeter
• Fuel pressure gauge
• Cleaning agent for MAF sensor

2. Inspect Air Intake System

• Sub-steps:
  1. Visually inspect all intake hoses and connections for cracks or loose fittings.
  2. Tighten any loose clamps or fittings.
  3. Replace any damaged hoses or components.

3. Check Fuel Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition key to the "on" position (do not start the engine) and check the pressure reading.
  3. If pressure is lower than specified (refer to manufacturer specifications), inspect the fuel pump and filter for issues.

4. Clean or Replace the MAF Sensor

• Sub-steps:
  1. Locate the MAF sensor in the air intake system.
  2. Disconnect the electrical connector and unscrew the MAF sensor from its housing.
  3. Clean the sensor with a dedicated MAF cleaner, allowing it to dry completely before reinstallation.
  4. If the sensor is damaged, replace it with a new one.

5. Inspect Fuel Injectors

• Sub-steps:
  1. Remove the fuel injectors from the fuel rail.
  2. Check for leaks or carbon buildup on the injector nozzles.
  3. Clean the injectors using an ultrasonic cleaner or replace them if necessary.

6. Check Exhaust System

• Sub-steps:
  1. Inspect the exhaust for any visible leaks or damage.
  2. Check the catalytic converter for blockages.
  3. Replace damaged exhaust components to ensure proper airflow.