how to fix P0171 code on Ford Explorer Fifth Generation (2011-2019)

Ford Explorer Fifth Generation (2011-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

Error Code: P0171

4 min read

641 words

Problem Statement

Learn how to diagnose and fix P0171 engine too lean condition in Ford Explorer 2011-2019. Step-by-step guide with diagnostic procedures and repair instructions.

Error Code

P0171

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 opening any components to prevent burns.

Symptoms

•Check engine light illuminated
•Rough idle
•Loss of power during acceleration
•Poor fuel economy
•Increased engine noise
•Engine stalling during low-speed maneuvers

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0171 and check for any additional codes.
2
Inspect the air intake system for vacuum leaks, including hoses, gaskets, and the intake manifold.
3
Check the fuel pressure using a fuel pressure gauge to ensure it is within specification.
4
Inspect the Mass Air Flow (MAF) sensor for dirt or damage and ensure proper operation.
5
Examine the fuel injectors for clogs or leaks.
6
Check the engine coolant temperature sensor for proper operation, as incorrect readings can affect the air-fuel mixture.

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 or smoke machine
•Fuel pressure gauge
•Basic hand tools (sockets, wrenches)
•MAF cleaner
•Ultrasonic cleaner (optional)
•Torque wrench

Parts Required

•Fuel filter (if clogged)
•Mass Air Flow (MAF) sensor (if damaged)
•Engine coolant temperature sensor (if faulty)
•Vacuum hoses or gaskets (if damaged)

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to confirm P0171 and check for any additional codes.
2
Inspect the air intake system for vacuum leaks, including hoses, gaskets, and the intake manifold.
3
Check the fuel pressure using a fuel pressure gauge to ensure it is within specification.
4
Inspect the Mass Air Flow (MAF) sensor for dirt or damage and ensure proper operation.
5
Examine the fuel injectors for clogs or leaks.
6
Check the engine coolant temperature sensor for proper operation, as incorrect readings can affect the air-fuel mixture.

Solution

1. Preparation

Gather tools and parts required for the repair.
Disconnect the negative battery terminal to ensure safety.

2. Inspect and Repair Vacuum Leaks

Sub-steps:
1. Visually inspect all vacuum lines connected to the intake manifold for cracks or disconnections.
2. Use a smoke machine to identify any hidden vacuum leaks if visual inspection is inconclusive.
3. Replace any damaged hoses or gaskets.

3. Clean or Replace MAF Sensor

Sub-steps:
1. Locate the MAF sensor in the air intake duct.
2. Disconnect the electrical connector and remove the sensor.
3. Clean the MAF sensor with MAF cleaner. Do not touch the sensor element.
4. Reinstall the sensor and reconnect the electrical connector. If damaged, replace the sensor.

4. Check and Adjust Fuel Pressure

Sub-steps:
1. Connect a fuel pressure gauge to the fuel rail test port.
2. Turn the ignition to the "On" position (without starting the engine) to check the pressure.
3. Compare the reading to the manufacturer's specifications. If it is low, check the fuel pump and filter for issues.
4. Replace the fuel filter if clogged, and consider replacing the fuel pump if pressure remains low.

5. Inspect Fuel Injectors

Sub-steps:
1. Remove the fuel rail with the injectors attached.
2. Inspect each injector for clogs or leaks. Clean them using an ultrasonic cleaner if necessary.
3. Reinstall the fuel rail, ensuring all connections are secure.

6. Replace Engine Coolant Temperature Sensor (if faulty)

Sub-steps:
1. Locate the engine coolant temperature sensor, typically near the thermostat housing.
2. Disconnect the electrical connector and remove the sensor using a socket wrench.
3. Install a new sensor with the proper torque specification.
4. Reconnect the electrical connector.