AutoCodes – GMC – B3979 2014 GMC Sierra

B3979 2014 GMC Sierra Code - Incorrect Environmental Identifier Received from HVAC Control Module

Quick Answer

When certain modules are programmed and configured during installation, the module learns a specific environment identifier which is unique to the vehicle. Common causes include Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module, HVAC Control Module harness is open or shorted, HVAC Control Module circuit poor electrical connection. 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: B3979 2014 GMC Sierra indicates Incorrect Environmental Identifier Received from HVAC Control Module.
Common causes: Common causes include Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module, HVAC Control Module harness is open or shorted, HVAC Control Module circuit poor electrical connection.
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 190

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 Jun 19, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3979 2014 GMC Sierra Description

When certain modules are programmed and configured during installation, the module learns a specific environment identifier which is unique to the vehicle. The environment identifier is used to prevent the swapping of control modules between vehicles. The Body Control Module (BCM) is the keeper of the environment identifier. The Instrument Cluster, Electronic Brake Control Module (EBCM), Heating, Ventilation, and Air Conditioning (HVAC) Control Module, Inflatable Restraint Sensing And Diagnostic Module, and Telematics Communication Interface Control Module each learn the environment identifier during their configuration process. During vehicle operation, the BCM sends the immobilizer identifier as a challenge and each module responds to the challenge by sending the environment identifier back to the BCM. If the BCM sends an incorrect immobilizer identifier or a specific number of incorrect environment identifiers are received, vehicle starting is disabled.

OBDII Code B3979 2014 GMC Sierra - Incorrect Environmental Identifier Received from HVAC Control Module - AutoCodes.com — B3979 2014 GMC Sierra Code - Incorrect Environmental Identifier Received from HVAC Control Module

What does this mean?

What are the Possible Causes of the DTC B3979 2014 GMC Sierra?

Faulty Heating, Ventilation, and Air Conditioning (HVAC) Control Module
HVAC Control Module harness is open or shorted
HVAC Control Module circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3979 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 B3979 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 B3979 2014 GMC Sierra code?

Need more information on how to fix the B3979 2014 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the 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 B3979 2014 GMC Sierra Code

1. What are the common symptoms of OBDII code B3979 in a 2014 GMC Sierra?

The common symptoms include erratic HVAC system operation, lack of response from HVAC controls, and incorrect environmental readings on the dashboard.

2. What does the OBDII code B3979 mean for a 2014 GMC Sierra?

OBDII code B3979 indicates that the HVAC control module has detected an incorrect environmental identifier, leading to issues with climate control within the vehicle.

3. What are the possible causes of OBDII code B3979 in a 2014 GMC Sierra?

Possible causes of this code include a faulty HVAC control module, wiring issues, sensor malfunctions, or a software glitch within the vehicle's system.

4. How can I diagnose OBDII code B3979 in my 2014 GMC Sierra?

Diagnosis typically involves using a diagnostic scan tool to read the code, checking the HVAC system for any visible issues, and inspecting the wiring and sensors related to climate control.

5. Can I continue driving my 2014 GMC Sierra with OBDII code B3979?

It is recommended to address the issue promptly to prevent further damage to the HVAC system. Continuing to drive the vehicle with this code may result in discomfort due to improper climate control.

6. How can I repair OBDII code B3979 in my 2014 GMC Sierra?

Repair options may include resetting the HVAC control module, replacing faulty sensors or wiring, updating the vehicle's software, or seeking assistance from a professional mechanic.

7. Is OBDII code B3979 a common issue in 2014 GMC Sierra vehicles?

While not extremely common, this code can occur in 2014 GMC Sierra models due to various factors such as sensor failures, wiring issues, or module malfunctions.

8. Can weather conditions affect the occurrence of OBDII code B3979 in a 2014 GMC Sierra?

Extreme temperatures or moisture levels can potentially impact the climate control system and trigger the incorrect environmental identifier received from the HVAC control module.

9. How much does it typically cost to fix OBDII code B3979 in a 2014 GMC Sierra?

The cost of repairs can vary depending on the exact cause of the issue and whether you choose to address it yourself or seek professional help. Costs may range from a simple sensor replacement to more complex module repairs.

10. Are there any preventive measures to avoid OBDII code B3979 in a 2014 GMC Sierra?

Routine maintenance of the HVAC system, checking for any wiring or sensor issues, and keeping the vehicle's software up to date can help prevent the occurrence of this code.