P279C 2016 GMC Sierra Code - Four Wheel Drive Neutral Range Performance
Quick Answer
The Engine Control Module (ECM) uses the following two ways to determine if the transfer case is in 4WD Low, 4WD High, or Neutral. Common causes include Reprogram Engine Control Module (ECM), Faulty Engine Control Module, Engine Control Module harness is open or shorted. 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
- P279C 2016 GMC Sierra indicates Four Wheel Drive Neutral Range Performance.
- Common causes
- Common causes include Reprogram Engine Control Module (ECM), Faulty Engine Control Module, Engine Control Module harness is open or shorted.
- 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.
Code P279C 2016 GMC Sierra Description
1. The first way is to compare the transmission output speed sensor to the transfer case output speed sensor in order to calculate the transfer case range.
2. The second way is to use a LAN message sent by the transfer case shift control module to the ECM.
The ECM uses this message to determine motor torque required and transmission shifting.
The internal fault detection is handled inside the control module. No external circuit diagnosis is involved.
If the first way and second way of determining transfer case range do not match while in 4WD Low, 4WD High or Neutral, then the Diagnostic Trouble Code (DTC) is set.
What are the Possible Causes of the DTC P279C 2016 GMC Sierra?
- Reprogram Engine Control Module (ECM)
- Faulty Engine Control Module
- Engine Control Module harness is open or shorted
- Engine Control Module circuit poor electrical connection
- Transmission internal mechanical problems
How to Fix the DTC P279C 2016 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 P279C 2016 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 P279C 2016 GMC Sierra code?
Need more information on how to fix the P279C 2016 GMC Sierra code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P279C 2016 GMC Sierra code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P279C 2016 GMC Sierra Code
1. What does the OBDII code P279C mean on a 2016 GMC Sierra?
P279C indicates an issue with the Four-Wheel Drive Neutral Range Performance, meaning the transfer case is not engaging or disengaging the neutral range properly.
2. What are the common symptoms of the P279C code on a 2016 GMC Sierra?
Symptoms may include the "Service 4WD" warning light, inability to switch drivetrain modes, unusual noises from the transfer case, or the vehicle being stuck in neutral.
3. What causes the P279C code to appear on a 2016 GMC Sierra?
Common causes include a faulty transfer case shift motor, issues with the transfer case control module, wiring problems, or mechanical failure in the transfer case.
4. Can driving with the P279C code damage my 2016 GMC Sierra?
Yes, continuing to drive with this code can lead to further damage to the transfer case or drivetrain components, especially if the vehicle becomes stuck in an improper mode.
5. How is the P279C code diagnosed on a 2016 GMC Sierra?
A mechanic will use a scan tool to confirm the code, inspect the transfer case shift motor, check the wiring and connectors, and test the transfer case control module for proper operation.
6. How do I fix the P279C code on my 2016 GMC Sierra?
Repairs may involve replacing the transfer case shift motor, repairing or replacing damaged wiring, recalibrating the transfer case control module, or addressing mechanical failures in the transfer case.
7. Can a software issue cause the P279C code on a 2016 GMC Sierra?
Yes, outdated or corrupted software in the transfer case control module can cause this code, and a software update or reprogramming may resolve the issue.
8. How much does it cost to fix the P279C code on a 2016 GMC Sierra?
The cost can vary widely depending on the specific issue, ranging from $100 for a simple wiring repair to $1,500 or more for transfer case repairs or component replacements.
9. Can I clear the P279C code on my 2016 GMC Sierra without fixing the issue?
Clearing the code without addressing the root cause will only temporarily remove the warning, and the code will likely reappear as the issue persists.
10. Is the P279C code a common problem in 2016 GMC Sierra trucks?
While not extremely common, this code can occur in vehicles with frequent use of the four-wheel-drive system or in trucks with high mileage and transfer case wear.
Discuss the causes and fixes for P279C 2016 GMC Sierra OBDII Code
Code P279C 2016 GMC Sierra comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
