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Home/Cars/Ford/F-150/13th Generation (2015-2020)/how to diagnose P0171 code on Ford F-150 13th Generation (2015-2020)

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

Ford F-150 13th Generation (2015-2020)

Error Codes
Severity: mediumDifficulty: mediumError Code: P01712-4 hours
3 min read
590 words

Problem Statement

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

Error Code
P0171
Affected Component
Engine
Estimated Time
2-4 hours

Safety Warnings

  • ⚠Disconnect the battery before working on electrical systems.
  • ⚠Allow the engine to cool before opening any components to prevent burns.

Symptoms

  • •Check engine light illuminated
  • •Rough idle or stalling
  • •Decreased fuel efficiency
  • •Engine hesitation during acceleration
  • •Unusual engine noise (e.g., backfiring)
  • •Increased emissions

Diagnostic Steps

  1. 1Scan the vehicle's computer using an OBD-II scanner to confirm the P0171 code and check for any additional codes.
  2. 2Inspect the air intake system for vacuum leaks, including hoses, gaskets, and the intake manifold.
  3. 3Check the mass air flow (MAF) sensor for proper function by cleaning or replacing it if necessary.
  4. 4Inspect fuel pressure using a fuel pressure gauge to ensure it meets manufacturer specifications.
  5. 5Examine the fuel injectors for clogs or leaks and test their operation.
  6. 6Check the oxygen sensor for proper operation and response to changes in fuel mixture.

Solution

Solution

1. Preparation

  • Gather necessary tools and parts.
  • Disconnect the vehicle battery.
  • Allow the engine to cool down.

2. Inspect Air Intake System

  • Visually inspect all vacuum hoses for cracks or disconnections.
  • Check the intake manifold gasket for leaks.
  • Use a smoke machine to help identify vacuum leaks.

3. Clean or Replace MAF Sensor

  • Remove the MAF sensor from the intake system using a Torx or socket wrench.
  • Clean the sensor with MAF cleaner and let it dry completely before reinstalling.
  • If cleaning does not resolve the issue, replace the MAF sensor with a new part.

4. Check and Test Fuel Pressure

  • Connect a fuel pressure gauge to the fuel rail Schrader valve.
  • Turn the ignition to the "ON" position (do not start the engine) and read the pressure.
  • Compare the reading to the manufacturer's specifications (typically around 50-60 psi for the F-150).
  • If pressure is low, inspect the fuel pump and filter for issues.

5. Inspect Fuel Injectors

  • Remove the fuel injectors from the fuel rail.
  • Visually inspect for any signs of clogging or leaking.
  • Use an injector cleaner or replace the injectors if they are faulty.

6. Check Oxygen Sensor

  • Use a multimeter to test the oxygen sensor's voltage output while the engine is running.
  • The voltage should fluctuate between 0.1 to 0.9 volts; if it remains steady, replace the sensor.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •OBD-II scanner
  • •Vacuum gauge
  • •Fuel pressure gauge
  • •Multimeter
  • •Torx or socket set
  • •Smoke machine (optional)

Parts Required

  • •MAF sensor (if replacement is needed)
  • •Fuel injectors (if replacement is needed)
  • •Oxygen sensor (if replacement is needed)

Additional Information

Error Code
P0171
Affected Component
Engine
Estimated Time
2-4 hours
Difficulty
medium
Severity
medium
Tools Required
6 items
Parts Required
3 items

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