C0379 on GMC
Transfer Case / Front Axle Actuator Circuit (manufacturer-specific)
C0379 on GMC vehicles indicates transfer case / front axle actuator circuit (manufacturer-specific). Au7o has documented this code across 1 GMC model — most commonly on Sierra 3500HD. C0379 is a manufacturer-specific chassis code generally associated with the transfer case and front axle actuator system on four-wheel-drive vehicles. It typically indicates the control module detected a fault related to engaging/disengaging the front axle (such as the front axle disconnect actuator) or its circuit. Because the exact definition varies by manufacturer and model, the precise meaning should be verified with OEM service data. The likely effect is impaired or unavailable 4WD engagement rather than a braking issue. Typical repair costs on GMC range from $150 to $800, depending on the specific model and root cause.
Common Causes of C0379
- •Faulty front axle disconnect actuator
- •Damaged actuator wiring or connector
- •Transfer case encoder/actuator fault
- •Corroded or poor ground connection
- •Failing transfer case control module
- •Mechanical binding in the front axle engagement
- •Low system voltage
C0379 on GMC by Model
GMC Sierra 3500HD(1 issue)
- Front Differential Actuator Failure Causing 4WD Engagement Problems2007-2022
The front axle disconnect actuator (also called the front axle engagement actuator or IWE—Integrated Wheel End) on four-wheel-drive Sierra 3500HD models is known to fail, preventing proper engagement or disengagement of 4WD. Owners report grinding noises from the front axle area in 2WD mode due to hubs failing to fully disengage, or the inability to engage 4WD when needed. Vacuum leaks in the actuator system are the most common root cause.
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View C0379 across all makes →Frequently Asked Questions
What does C0379 mean on GMC?▼
C0379 stands for "Transfer Case / Front Axle Actuator Circuit (manufacturer-specific)." C0379 is a manufacturer-specific chassis code generally associated with the transfer case and front axle actuator system on four-wheel-drive vehicles. It typically indicates the control module detected a fault related to engaging/disengaging the front axle (such as the front axle disconnect actuator) or its circuit. Because the exact definition varies by manufacturer and model, the precise meaning should be verified with OEM service data. The likely effect is impaired or unavailable 4WD engagement rather than a braking issue. On GMC specifically, this code is documented across 1 model.
What causes C0379 on GMC vehicles?▼
Common causes on GMC: Faulty front axle disconnect actuator, Damaged actuator wiring or connector, Transfer case encoder/actuator fault, Corroded or poor ground connection, Failing transfer case control module. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix C0379 on a GMC?▼
Repair costs on GMC range from $150 to $800, depending on the specific model and root cause.
Which GMC models have C0379 documented?▼
Au7o has documented C0379 on 1 GMC model: Sierra 3500HD.