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

Learn how to diagnose and fix P0171 lean code in Ford F-150. Step-by-step guide with symptoms, diagnostic steps, tools, and repair instructions.

Solution

1. Preparation

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

2. Inspect and Clean the MAF Sensor

• Tools Required: MAF sensor cleaner, screwdriver.
• Remove the MAF sensor from the air intake duct.
• Spray the MAF sensor with MAF cleaner; allow it to dry completely.
• Reinstall the MAF sensor and reconnect the electrical connector.

3. Check for Vacuum Leaks

• Tools Required: Smoke machine or carburetor cleaner.
• With the engine running, inspect all vacuum lines and intake manifold gaskets for leaks.
• If using a smoke machine, introduce smoke into the intake system and look for smoke escaping.
• Repair or replace any damaged vacuum hoses or gaskets.

4. Test Fuel Pressure

• Tools Required: Fuel pressure gauge.
• Locate the fuel rail and connect the fuel pressure gauge.
• Start the engine and monitor the fuel pressure; refer to the manufacturer’s specifications (typically around 30-40 psi for F-150).
• If pressure is low, check the fuel pump and filter for blockage or failure.

5. Inspect Fuel Injectors

• Tools Required: Fuel injector cleaner, multimeter (optional).
• Remove the fuel injectors from the engine (may require removing the intake manifold).
• Clean the injectors with injector cleaner or replace them if they are clogged or malfunctioning.
• Reinstall the injectors ensuring proper sealing.

6. Check ECT Sensor

• Tools Required: Multimeter.
• Locate the ECT sensor and disconnect its electrical connector.
• Using a multimeter, test the resistance of the sensor at various temperatures to ensure it is functioning correctly.
• Replace the sensor if it is out of specification.