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Engine-Codes – GMC – C0379 2017 GMC Sierra

C0379 2017 GMC Sierra Code - Front Axle Switch Circuit

Quick Answer

The C0379 diagnostic trouble code (DTC) for a 2017 GMC Sierra relates to the Front Axle Switch Circuit. Common causes include Faulty front axle switch, Wiring or electrical connection issues, Corrosion or damage to the circuit components. 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 2017 GMC Sierra indicates Front Axle Switch Circuit.
Common causes
Common causes include Faulty front axle switch, Wiring or electrical connection issues, Corrosion or damage to the circuit components.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 13, 2024
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Code C0379 2017 GMC Sierra Description

The C0379 diagnostic trouble code (DTC) for a 2017 GMC Sierra relates to the Front Axle Switch Circuit. This code indicates a problem with the circuit that controls the engagement of the front axle in the vehicle's four-wheel-drive system. The front axle switch is responsible for sending signals to the vehicle's control module to engage or disengage the front axle as needed. When this circuit malfunctions, it can lead to issues with the four-wheel-drive system, potentially causing drivability problems and compromising the vehicle's overall performance.

OBDII Code C0379 2017 GMC Sierra - Front Axle Switch Circuit
C0379 2017 GMC Sierra Code - Front Axle Switch Circuit

Common Causes of C0379 2017 GMC Sierra

  1. Faulty front axle switch
  2. Wiring or electrical connection issues
  3. Corrosion or damage to the circuit components
  4. Defective control module
  5. Environmental factors such as water intrusion or debris affecting the circuit

Symptoms of C0379 2017 GMC Sierra

  1. Difficulty engaging or disengaging four-wheel drive
  2. Abnormal noises or vibrations when switching between drive modes
  3. Four-wheel-drive system not functioning properly
  4. Dashboard warning light indicating an issue with the front axle switch circuit

How to Fix C0379 2017 GMC Sierra

  1. Diagnose the issue by using a scan tool to retrieve the DTC and inspecting the front axle switch circuit for any visible damage or corrosion.
  2. Test the front axle switch and related components for proper functionality using a multimeter to check for continuity and resistance.
  3. Replace the front axle switch if it is found to be faulty, ensuring proper installation and connection to the circuit.
  4. Repair any damaged wiring or electrical connections in the circuit.
  5. Clear the DTC from the vehicle's computer system and test the four-wheel-drive system to ensure proper operation.

Cost to Fix C0379 2017 GMC Sierra

The cost of repairing a Front Axle Switch Circuit issue in a 2017 GMC Sierra can vary depending on the specific cause of the problem and the labor rates in your area. On average, you can expect to pay between $200 and $500 for parts and labor. Keep in mind that diagnostic time and labor rates at auto repair shops can vary, so it's recommended to obtain quotes from multiple shops to ensure you're getting a fair price. Additionally, rates may be higher at dealerships or in metropolitan areas, while independent shops may offer more competitive pricing.

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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 2017 GMC Sierra Code

1. What does the OBDII code C0379 mean on a 2017 GMC Sierra?

C0379 indicates an issue with the front axle switch circuit, which is responsible for controlling the engagement of the front axle in 4WD systems.

2. What are the common symptoms of code C0379 in a 2017 GMC Sierra?

Symptoms may include the 4WD system not engaging properly, a service 4WD warning light, or unusual noises from the front axle.

3. What causes code C0379 to appear in a 2017 GMC Sierra?

The code can be triggered by a faulty front axle actuator, a damaged switch, wiring issues such as shorts or open circuits, or a malfunctioning transfer case control module (TCCM).

4. How can I diagnose code C0379 on my 2017 GMC Sierra?

Start by checking the front axle switch and actuator for proper operation. Inspect the wiring and connectors for damage, and use a scan tool to verify TCCM functionality.

5. Can a faulty front axle actuator cause code C0379?

Yes, a malfunctioning front axle actuator is a common cause of this code, as it prevents the proper engagement of the front axle.

6. Is it safe to drive with code C0379 on a 2017 GMC Sierra?

While the vehicle may still be drivable in 2WD, the 4WD system may not function correctly, which could be problematic in off-road or slippery conditions.

7. How do I fix code C0379 on a 2017 GMC Sierra?

Repair steps may include replacing a defective front axle actuator, repairing damaged wiring, or replacing the front axle switch. Always clear the code after repairs to confirm the fix.

8. Can a blown fuse cause code C0379 in a 2017 GMC Sierra?

Yes, a blown fuse in the 4WD system circuit can disrupt power to the front axle actuator or switch, triggering this code.

9. How much does it cost to repair code C0379 on a 2017 GMC Sierra?

Repair costs can vary depending on the cause, typically ranging from $100 for a simple wiring repair to $300-$500 for actuator or switch replacement.

10. Can a scan tool help resolve code C0379 on a 2017 GMC Sierra?

Yes, a scan tool can help pinpoint the issue by retrieving freeze frame data, testing the actuator and switch, and confirming communication with the TCCM.

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