how to fix P0171 and P0174 codes on Ford Explorer Sixth Generation (2020-present)

Ford Explorer Sixth Generation (2020-present)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

Error Code: P0171, P0174

3 min read

545 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 how to diagnose and fix P0171 and P0174 lean condition codes in Ford Explorer. Step-by-step guide with diagnostic procedures and repair instructions.

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.
•Allow the engine to cool before inspecting the intake and exhaust systems.

Symptoms

•Check engine light illuminated
•Rough idle
•Decreased acceleration and power
•Poor fuel economy
•Possible engine stalling
•Increased emissions

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0171 and P0174.
2
Inspect the air intake system for leaks or damage, including hoses and clamps.
3
Check the mass air flow (MAF) sensor for contamination or failure.
4
Inspect fuel system components, including fuel pump pressure, fuel filter condition, and injector operation.
5
Examine the exhaust system for potential leaks before the oxygen sensors.
6
Verify the condition of the engine's vacuum lines for any cracks or disconnections.

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
•Vacuum gauge
•Multimeter
•Socket set
•Torque wrench
•Fuel pressure gauge

Parts Required

•Replacement air intake hoses (if damaged)
•Fuel filter (if clogged)
•Fuel injectors (if faulty)
•MAF sensor cleaner

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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 leaks or damage, including hoses and clamps.
3
Check the mass air flow (MAF) sensor for contamination or failure.
4
Inspect fuel system components, including fuel pump pressure, fuel filter condition, and injector operation.
5
Examine the exhaust system for potential leaks before the oxygen sensors.
6
Verify the condition of the engine's vacuum lines for any cracks or disconnections.

Solution

1. Preparation

Tools Required: OBD-II scanner, vacuum gauge, multimeter, socket set, torque wrench, fuel pressure gauge.
Ensure the vehicle is parked on a flat surface and the engine is off and cool.

2. Inspect and Repair Air Intake System

Visually inspect the air intake hoses for cracks or loose connections.
Tighten or replace any damaged hoses.
Clean the MAF sensor using MAF cleaner spray. Allow it to dry completely before reinstalling.

3. Check and Repair Fuel System

Fuel Pressure Test:
- Connect a fuel pressure gauge to the fuel rail.
- Turn the ignition to the "on" position without starting the engine and check the fuel pressure reading. It should match the manufacturer specifications (usually around 50-60 psi for most models).
- If the pressure is low, inspect the fuel filter and replace if clogged.
Injector Test:
- Disconnect the fuel injector connectors and check the resistance with a multimeter. It should be within the manufacturer’s specification (typically around 12-16 ohms).
- If any injector is out of spec, replace it.

4. Inspect Exhaust System

Inspect the exhaust manifold and pipes for leaks. Use a smoke test if necessary to find hidden leaks.
Repair any leaks found in the exhaust system.

5. Verify Vacuum Lines

Inspect all vacuum lines for cracks or disconnections.
Replace any damaged vacuum lines.