how to diagnose P0171 code in Ford F-150 13th Generation (2015-2020)

Learn how to diagnose and fix P0171 engine lean condition in Ford F-150 (2015-2020). Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Ensure the vehicle is parked on a flat surface, and the engine is cool.
• Disconnect the battery before working on electrical systems.

2. Vacuum Leak Repair

• Locate and Repair Leaks:
  • Use a smoke machine or carburetor cleaner to identify vacuum leaks.
  • Replace any damaged hoses or gaskets.

3. Clean or Replace MAF Sensor

• Removal:

  • Disconnect the MAF sensor's electrical connector.
  • Unscrew the MAF sensor from its housing.

• Cleaning (if reusing):

  • Use MAF sensor cleaner. Do not use other cleaners as they can damage the sensor.
  • Allow the sensor to dry completely before reinstalling.

• Replacement (if necessary):

  • Install the new MAF sensor in reverse order of removal, ensuring a secure fit.

4. Fuel System Inspection

• Fuel Pressure Test:

  • Attach a fuel pressure gauge to the Schrader valve on the fuel rail.
  • Turn the ignition to the "On" position (do not start the engine) and record the pressure. Compare it to the specifications for the vehicle.

• Replace Fuel Filter:

  • If pressure is low, inspect and replace the fuel filter if it is clogged.

5. Throttle Body Cleaning

• Accessing the Throttle Body:

  • Remove the air intake duct to expose the throttle body.

• Cleaning:

  • Use throttle body cleaner and a soft cloth to remove carbon buildup around the throttle plate and inside the throttle body.
  • Ensure not to damage the throttle position sensor.

6. Exhaust Leak Repair

• Inspection:

  • Visually inspect the exhaust manifold, gaskets, and pipes for signs of leaks.

• Repair:

  • Replace any damaged gaskets or components as needed.