AutoCodes – GMC – P279B 2014 GMC Sierra

P279B 2014 GMC Sierra Code - Four Wheel Drive Low 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: P279B 2014 GMC Sierra indicates Four Wheel Drive Low 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.

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Code Popularity 162

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 29, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P279B 2014 GMC Sierra Description

The Engine Control Module (ECM) uses the following two ways to determine if the transfer case is in 4WD Low, 4WD High, or Neutral.
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.

OBDII Code P279B 2014 GMC Sierra - Four Wheel Drive Low Range Performance - AutoCodes.com — P279B 2014 GMC Sierra Code - Four Wheel Drive Low Range Performance

What does this mean?

What are the Possible Causes of the DTC P279B 2014 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 P279B 2014 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 P279B 2014 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 P279B 2014 GMC Sierra code?

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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 P279B 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code P279B in a 2014 GMC Sierra related to Four Wheel Drive Low Range Performance?

- Common symptoms include difficulty engaging or disengaging four-wheel drive low range mode, erratic shifting between gears, and a noticeable decrease in off-road performance.

2. What are the possible causes of OBDII code P279B in a 2014 GMC Sierra?

- The code P279B can be triggered by issues such as a faulty transfer case actuator, damaged wiring or connectors in the four-wheel drive system, low fluid levels in the transfer case, or a malfunctioning transfer case control module.

3. How can I diagnose the cause of OBDII code P279B in my 2014 GMC Sierra?

- To diagnose the issue, you can start by checking the fluid level in the transfer case, inspecting the wiring and connectors for any damage, and using a diagnostic scanner to retrieve additional fault codes and data related to the four-wheel drive system.

4. Is it safe to continue driving my 2014 GMC Sierra with OBDII code P279B triggered?

- It is not recommended to continue driving the vehicle with the code P279B active, as it can lead to further damage to the four-wheel drive system and affect the vehicle's overall drivability.

5. Can I repair OBDII code P279B in my 2014 GMC Sierra myself, or should I take it to a professional mechanic?

- The complexity of the repair for code P279B varies depending on the root cause, so it is advisable to consult a professional mechanic with experience in diagnosing and repairing four-wheel drive system issues.

6. Are there any quick fixes or temporary solutions for OBDII code P279B in a 2014 GMC Sierra?

- Quick fixes such as checking and refilling the transfer case fluid, ensuring proper electrical connections, and performing a system reset may help temporarily address the issue, but a proper diagnosis and repair are still recommended.

7. How much can I expect to pay for repairing OBDII code P279B in a 2014 GMC Sierra?

- The cost of repairing code P279B can vary depending on the root cause of the issue, but it may involve replacing components such as the transfer case actuator, wiring harness, or control module, which can range from a few hundred to over a thousand dollars.

8. Will resetting the OBDII code P279B in my 2014 GMC Sierra make it go away permanently?

- Resetting the code may temporarily clear the warning light, but if the underlying issue causing code P279B is not addressed, the code is likely to return once the system detects the fault again.

9. How long does it typically take to repair OBDII code P279B in a 2014 GMC Sierra?

- The repair time for code P279B can vary depending on the specific cause and the availability of parts, but it may take a few hours to a full day for a mechanic to diagnose, repair, and test the four-wheel drive system.

10. Can extreme off-road driving or harsh conditions trigger OBDII code P279B in a 2014 GMC Sierra?

- Yes, extreme off-road driving, exposure to harsh conditions, or water ingress into the four-wheel drive system can contribute to issues that may trigger code P279B in a 2014 GMC Sierra. Regular maintenance and inspections can help prevent such issues.