C0379 on 2007-2022 GMC Sierra 3500HD — Transfer Case / Front Axle Actuator Circuit (manufacturer-specific)
1 vehicles · 1 makes · $150-$800 repair
Most Reported On
C0379 is an OBD-II diagnostic trouble code meaning “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. This code is most commonly reported on 2007-2022 GMC Sierra 3500HD, with repair costs ranging from $150 to $800.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
This is a chassis code. A basic engine-code reader will not show it — you need a scanner that reads chassis modules. These read C0379.
One caveat that applies to every scanner: only powertrain codes are standardised across manufacturers. Body, chassis and network coverage is "enhanced" diagnostics, and how deep it goes varies by make and model year — check your specific vehicle against the tool's coverage list before buying.
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
FAQ
What does C0379 mean?
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.
What are the most common causes of C0379?
The most common causes of C0379 are: 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. The specific cause varies by vehicle.
How much does it cost to fix C0379?
Repair costs for C0379 range from $150 to $800, depending on the vehicle and root cause.
Which vehicles are affected by C0379?
Au7o has documented C0379 across 1 vehicle models from 1 manufacturers: GMC.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.