AutoCodes – GMC – C0379 2014 GMC Sierra

C0379 2014 GMC Sierra Code - Front Axle Switch Circuit

Quick Answer

The front axle control circuit consists of an electric motor actuator that engages and disengages the front axle. Common causes include Faulty Front Axle Engagement Actuator, Front Axle Engagement Actuator harness is open or shorted, Front Axle Engagement Actuator 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: C0379 2014 GMC Sierra indicates Front Axle Switch Circuit.
Common causes: Common causes include Faulty Front Axle Engagement Actuator, Front Axle Engagement Actuator harness is open or shorted, Front Axle Engagement Actuator 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 221

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 Jul 11, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0379 2014 GMC Sierra Description

The front axle control circuit consists of an electric motor actuator that engages and disengages the front axle. The front axle engagement actuator consists of a permanent magnetic motor, a worm gear-controlled plunger, a front axle switch, and an electronic control circuit within the actuator assembly.
The front axle engagement actuator contains the following circuits: A Run/Crank Ignition 1 Voltage circuit, a Four-Wheel Drive Wheel Lock Indicator circuit, a Front Axle Actuator Control circuit, and a ground circuit.
When a shift to 4WD Auto, 4WD High, or 4WD Low is requested, the Transfer Case Control Module engages the front axle by grounding the front axle actuator control circuit through a current limiting driver.
This Diagnostic Trouble Code (DTC) will be set when a short to ground, short to voltage, or open circuit is detected.

OBDII Code C0379 2014 GMC Sierra - Front Axle Switch Circuit - AutoCodes.com — C0379 2014 GMC Sierra Code - Front Axle Switch Circuit

What does this mean?

What are the Possible Causes of the DTC C0379 2014 GMC Sierra?

Faulty Front Axle Engagement Actuator
Front Axle Engagement Actuator harness is open or shorted
Front Axle Engagement Actuator circuit poor electrical connection
Faulty Transfer Case Control Module

How to Fix the DTC C0379 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 C0379 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.

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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 C0379 2014 GMC Sierra Code

1. What does the OBDII code C0379 mean on a 2014 GMC Sierra?

The code C0379 indicates an issue with the Front Axle Switch Circuit, which controls the engagement of the front axle in the 4WD system.

2. What are the common symptoms of code C0379 on a 2014 GMC Sierra?

Symptoms may include the 4WD system not engaging properly, a service 4WD light on the dashboard, or reduced performance in off-road or slippery conditions.

3. What causes the C0379 code to appear on a 2014 GMC Sierra?

Common causes include a faulty front axle actuator, damaged wiring or connectors in the Front Axle Switch Circuit, or a malfunctioning transfer case control module (TCCM).

4. How do I troubleshoot the C0379 code on my GMC Sierra?

Start by inspecting the wiring and connectors in the Front Axle Switch Circuit for damage or corrosion, then test the front axle actuator and verify the TCCM is functioning correctly.

5. Can I drive my 2014 GMC Sierra with the C0379 code?

Driving is usually possible, but you may lose 4WD functionality, which could impact performance in off-road or slippery conditions.

6. How do I fix the C0379 code on my 2014 GMC Sierra?

Repairs may include replacing the front axle actuator, repairing damaged wiring or connectors, or reprogramming/replacing the TCCM if necessary.

7. How much does it cost to repair the C0379 code on a GMC Sierra?

The cost depends on the exact issue but typically ranges from $100 to $400 for parts and labor, depending on whether the actuator, wiring, or TCCM needs repair or replacement.

8. Can a bad front axle actuator cause the C0379 code?

Yes, a faulty front axle actuator is one of the most common causes of this code.

9. Does the C0379 code require a professional mechanic to fix?

While some issues like checking connectors and wiring can be done by experienced DIYers, diagnosing and replacing components such as the TCCM may require a professional mechanic.

10. Will clearing the C0379 code fix the problem?

Clearing the code will reset the light temporarily, but the underlying issue must be resolved to prevent the code from returning.