P279A 2015 GMC Sierra Code - Four Wheel Drive High 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
- P279A 2015 GMC Sierra indicates Four Wheel Drive High 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 P279A 2015 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 P279A 2015 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 P279A 2015 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 P279A 2015 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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Frequently Asked Questions about P279A 2015 GMC Sierra Code
1. What are the common symptoms of OBDII code P279A in a 2015 GMC Sierra related to Four Wheel Drive High Range Performance?
- Common symptoms may include difficulty engaging or disengaging four-wheel drive high range, erratic shifting between two-wheel drive and four-wheel drive modes, and illuminated warning lights on the dashboard.
2. What are the possible causes of OBDII code P279A in a 2015 GMC Sierra?
- Potential causes of this code may include a faulty transfer case control module, damaged wiring or connectors in the four-wheel drive system, or issues with the transfer case motor.
3. How can I diagnose the OBDII code P279A in my 2015 GMC Sierra?
- Diagnosis typically involves using a scan tool to retrieve the specific trouble code, checking for any visible damage to the transfer case components, and conducting a thorough inspection of the wiring harness and connectors.
4. Can I continue driving my 2015 GMC Sierra with OBDII code P279A?
- It is not recommended to drive the vehicle extensively with this code present, as it may lead to further damage to the four-wheel drive system. It is best to address the issue promptly to prevent potential safety hazards.
5. How can I repair OBDII code P279A in my 2015 GMC Sierra?
- Repair options may include replacing the transfer case control module, repairing or replacing damaged wiring, or addressing any issues with the transfer case motor. It is advisable to consult a professional mechanic for accurate diagnosis and repair.
6. Are there any DIY tips for troubleshooting OBDII code P279A in a 2015 GMC Sierra?
- DIY tips may include visually inspecting the transfer case components for any obvious damage, checking the wiring harness for loose connections, and ensuring all fuses related to the four-wheel drive system are intact.
7. Will resetting the OBDII code P279A in my 2015 GMC Sierra solve the issue?
- Simply resetting the code may temporarily clear the warning light, but it will not fix the underlying problem causing the code. It is important to diagnose and address the root cause of the issue for a lasting solution.
8. Can extreme weather conditions trigger OBDII code P279A in a 2015 GMC Sierra?
- Yes, extreme cold or hot weather conditions can sometimes affect the performance of the four-wheel drive system, potentially leading to issues that trigger this code. Ensuring proper maintenance and care of the vehicle can help prevent such occurrences.
9. Is OBDII code P279A specific to 2015 GMC Sierra models, or can it occur in other vehicles?
- While this particular code may be specific to certain GMC Sierra models, similar issues related to four-wheel drive high range performance can occur in other vehicles with electronic four-wheel drive systems.
10. How much can I expect to pay for repairing OBDII code P279A in a 2015 GMC Sierra?
- The cost of repairing this code can vary depending on the specific cause of the issue, labor rates in your area, and whether you choose to address the problem yourself or seek professional help. It is advisable to obtain estimates from reputable mechanics for an accurate cost assessment.
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