AutoCodes – GMC – P257F 2014 GMC Sierra

P257F 2014 GMC Sierra Code - Engine Hood Switch Circuit High Voltage

Quick Answer

The Engine Control Module (ECM) applies 5 V to the hood ajar signal circuit and monitors the voltage to determine the position of the hood. Common causes include Faulty Hood Ajar Switch, Hood Ajar Switch harness is open or shorted, Hood Ajar Switch circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P257F 2014 GMC Sierra indicates Engine Hood Switch Circuit High Voltage.
Common causes: Common causes include Faulty Hood Ajar Switch, Hood Ajar Switch harness is open or shorted, Hood Ajar Switch circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 194

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 21, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P257F 2014 GMC Sierra Description

The Engine Control Module (ECM) applies 5 V to the hood ajar signal circuit and monitors the voltage to determine the position of the hood. The hood ajar switch contains a multiplexed resistor. This resistor will vary the voltage seen by the Engine Control Module by pulling down the applied voltage based on the position of the switch. The Diagnostic Trouble Code (DTC) will be set when the Engine Control Module detects a short to voltage or an open/high resistance in the hood ajar signal input to the Engine Control Module.

OBDII Code P257F 2014 GMC Sierra - Engine Hood Switch Circuit High Voltage - AutoCodes.com — P257F 2014 GMC Sierra Code - Engine Hood Switch Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P257F 2014 GMC Sierra?

Faulty Hood Ajar Switch
Hood Ajar Switch harness is open or shorted
Hood Ajar Switch circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P257F 2014 GMC Sierra?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P257F 2014 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P257F 2014 GMC Sierra code?

Need more information on how to fix the P257F 2014 GMC Sierra code? Get Access to Factory Service Manuals

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P257F 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code P257F in a 2014 GMC Sierra?

The common symptoms of code P257F include the hood ajar warning light staying illuminated on the dashboard even when the hood is closed, and potential issues with remote start functionality.

2. What does the OBDII code P257F Engine Hood Switch Circuit High Voltage mean for a 2014 GMC Sierra?

The code P257F indicates that there is an electrical circuit high voltage issue with the engine hood switch in a 2014 GMC Sierra.

3. What are the possible causes of the P257F trouble code in a 2014 GMC Sierra?

Common causes of code P257F in a 2014 GMC Sierra include a faulty hood switch, damaged wiring or connectors in the hood switch circuit, or a malfunctioning body control module.

4. How can I diagnose the P257F code in a 2014 GMC Sierra?

To diagnose the P257F code, you can visually inspect the hood switch and its wiring for any visible damage, test the switch for continuity, and use a multimeter to check for voltage fluctuations in the circuit.

5. Can driving with the P257F trouble code in a 2014 GMC Sierra cause further damage?

Continuing to drive with the P257F trouble code may not cause immediate damage to the vehicle, but it is recommended to address the issue promptly to avoid potential safety concerns or further electrical problems.

6. How can I repair the P257F code in a 2014 GMC Sierra?

To repair the P257F code, you may need to replace the hood switch if it is found to be faulty, repair any damaged wiring or connectors, or reprogram the body control module if necessary.

7. Is it safe to reset the OBDII code P257F in a 2014 GMC Sierra without fixing the underlying issue?

Resetting the code without addressing the underlying issue may temporarily turn off the check engine light, but the problem will likely persist and the code may reappear, indicating the need for proper diagnosis and repair.

8. Can a DIY enthusiast fix the P257F code in a 2014 GMC Sierra?

Depending on your skill level and access to tools, a DIY enthusiast may be able to address the P257F code by following repair guides, using a multimeter for testing, and replacing components as needed.

9. How long does it typically take to repair the P257F trouble code in a 2014 GMC Sierra?

The time required to repair the P257F code can vary based on the specific cause of the issue, but it may take anywhere from 30 minutes to a few hours to diagnose and fix the problem.

10. Will fixing the P257F trouble code in a 2014 GMC Sierra improve the vehicle's performance?

Fixing the P257F trouble code will primarily restore proper functionality to the hood switch circuit and related systems, rather than directly impacting the overall performance of the vehicle.