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

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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to avoid electrical shorts.
• Allow the engine to cool down if it has been running.

2. Inspect and Repair Air Intake System

• Sub-steps:

  1. Visually inspect all vacuum hoses connected to the intake manifold for cracks or disconnections.
  2. If any hoses are damaged, replace them with OEM parts.
  3. Check the intake manifold gasket for leaks and replace if necessary.

• Tools Required:

  • Socket set
  • Screwdrivers

3. Clean or Replace MAF Sensor

• Sub-steps:

  1. Disconnect the electrical connector from the MAF sensor.
  2. Remove the MAF sensor using the appropriate socket.
  3. Clean the MAF sensor with MAF cleaner spray (do not touch the sensor with your fingers).
  4. If cleaning doesn't resolve the issue, replace the MAF sensor with a new one.

• Tools Required:

  • Torque wrench
  • MAF sensor cleaner

4. Check Fuel System

• Sub-steps:

  1. Connect a fuel pressure gauge to the fuel rail.
  2. Turn the ignition on (do not start) and check the fuel pressure; it should meet manufacturer specifications (typically around 50-60 PSI).
  3. If pressure is low, inspect the fuel pump, filter, and injectors. Replace any faulty components.

• Tools Required:

  • Fuel pressure gauge
  • Multimeter (for electrical checks)

5. Inspect and Clean Throttle Body

• Sub-steps:

  1. Remove the air intake duct connected to the throttle body.
  2. Use throttle body cleaner to clean the inside of the throttle body, removing carbon deposits.
  3. Reinstall the air intake duct and ensure all connections are secure.

• Tools Required:

  • Throttle body cleaner
  • Socket set

6. Verify O2 Sensor Operation

• Sub-steps:

  1. Inspect the upstream O2 sensor wiring for damage.
  2. Use a multimeter to check the sensor's voltage output while the engine is running; it should fluctuate between 0.1 to 0.9 volts.
  3. Replace the O2 sensor if it is not functioning properly.

• Tools Required:

  • Multimeter