how to resolve P0171 and P0174 codes on my Ford F-150 13th Generation (2015-2020)?

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

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

Error Code: P0171, P0174

3 min read

514 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn to diagnose and fix P0171 and P0174 codes indicating a lean condition in Ford F-150 (2015-2020). Step-by-step guide with tools and tips.

Error Code

P0171, P0174

Affected Component

Engine

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems to avoid shock.
•Allow the engine to cool before working on the intake or fuel systems to prevent burns.

Symptoms

•Check engine light illuminated
•Rough idle or stalling
•Decreased fuel efficiency
•Unusual engine noises (e.g., popping, backfiring)
•Increased emissions
•Poor acceleration

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0171 and P0174.
2
Inspect the air intake system for any vacuum leaks, including hoses and gaskets.
3
Check the fuel system, including fuel pressure and the condition of the fuel filter.
4
Examine the Mass Air Flow (MAF) sensor for dirt or malfunction.
5
Inspect the throttle body for cleanliness and proper operation.
6
Look for exhaust leaks before the oxygen sensors.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

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
•Socket set
•Screwdriver set
•Torque wrench
•Multimeter

Parts Required

•Vacuum hoses (if damaged)
•MAF sensor (if faulty)
•Fuel filter (if clogged)
•Throttle body gasket (if needed)

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0171 and P0174.
2
Inspect the air intake system for any vacuum leaks, including hoses and gaskets.
3
Check the fuel system, including fuel pressure and the condition of the fuel filter.
4
Examine the Mass Air Flow (MAF) sensor for dirt or malfunction.
5
Inspect the throttle body for cleanliness and proper operation.
6
Look for exhaust leaks before the oxygen sensors.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the battery to ensure safety during repairs.

Tools Required:

OBD-II scanner
Socket set
Screwdriver set
Torque wrench
Multimeter (for electrical checks)

2. Inspect and Repair Vacuum Leaks

Visually inspect all vacuum lines for cracks or disconnections.
Use a smoke machine or propane torch to detect leaks.
Replace or repair any damaged hoses and gaskets.

3. Clean or Replace MAF Sensor

Remove the MAF sensor from the air intake duct.
Use MAF cleaner to gently clean the sensor wire or element.
Allow it to dry and reinstall it securely.

4. Check Fuel Pressure

Connect a fuel pressure gauge to the fuel rail.
Turn the ignition to the "On" position (do not start the engine) and check the fuel pressure reading.
If the pressure is below specification (refer to manufacturer’s specs), replace the fuel pump or filter as necessary.

5. Inspect Throttle Body

Remove the intake duct to access the throttle body.
Clean the throttle body using throttle body cleaner and a soft cloth.
Ensure the throttle plate opens and closes smoothly.