how to fix P0171 in Ford F-150 12th Generation (2009-2014)

Learn how to diagnose and fix P0171 fuel system issue in Ford F-150 12th Generation. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool down before beginning work.

2. Inspect and Repair Vacuum Leaks

• Tools Required: Vacuum gauge, hose clamps, and a screwdriver.
• Sub-steps:
  1. Use a vacuum gauge to check for low vacuum readings.
  2. Visually inspect all vacuum hoses for cracks or disconnections.
  3. Replace any damaged hoses and ensure all connections are tight.

3. Clean or Replace MAF Sensor

• Tools Required: MAF cleaner, torx screwdriver, and a clean cloth.
• Sub-steps:
  1. Locate the MAF sensor between the air filter and the throttle body.
  2. Disconnect the electrical connector and remove the sensor using a torx screwdriver.
  3. Spray the sensor with MAF cleaner and let it dry completely.
  4. Reinstall the sensor and reconnect the electrical connector.

4. Check and Repair Fuel System

• Tools Required: Fuel pressure gauge, fuel line disconnect tool, and replacement fuel filter (if necessary).
• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail test port.
  2. Turn the ignition key to the "ON" position (without starting) and check the fuel pressure against manufacturer specifications.
  3. If pressure is low, check the fuel pump operation and replace the fuel filter if clogged.
  4. If needed, replace the fuel pump.

5. Inspect and Test Oxygen Sensors

• Tools Required: OBD-II scanner and multimeter.
• Sub-steps:
  1. Use the OBD-II scanner to check the live data of the oxygen sensors.
  2. If readings are erratic or out of range, test the sensors with a multimeter.
  3. Replace any faulty oxygen sensors.