how to fix P0171 code on Ford F-150 Fourteenth Generation (2021-present)

Learn how to diagnose and fix P0171 engine system too lean issue in Ford F-150. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery negative terminal to prevent electrical shorts.

2. Inspect and Repair Air Intake System

• Sub-steps:
  1. Visually inspect the intake manifold and hoses for cracks or disconnections.
  2. Use a smoke machine to detect any vacuum leaks if visible inspection is inconclusive.
  3. Replace any damaged hoses or gaskets found during the inspection.

Tools Required: Smoke machine, basic hand tools.

3. Clean or Replace MAF Sensor

• Sub-steps:
  1. Disconnect the MAF sensor electrical connector.
  2. Remove the MAF sensor from the air intake system.
  3. Clean the sensor with MAF cleaner or replace it if damaged.
  4. Reinstall the MAF sensor and reconnect the electrical connector.

Tools Required: Torx or socket set, MAF sensor cleaner.

4. Test Fuel System

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition to the "ON" position (do not start the engine) and check fuel pressure. It should match manufacturer specifications (usually around 55-65 psi for F-150).
  3. If fuel pressure is low, check the fuel pump operation, fuel filter condition, and fuel injectors for clogs.
  4. Replace any faulty components as necessary.

Tools Required: Fuel pressure gauge.

5. Replace ECT Sensor (if necessary)

• Sub-steps:
  1. Locate the ECT sensor, usually near the thermostat housing.
  2. Disconnect the electrical connector and remove the sensor using a socket.
  3. Install the new ECT sensor and reconnect the electrical connector.

Tools Required: Socket set.