AutoCodes – GMC – B3979 2017 GMC Sierra

B3979 2017 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 2017 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 233

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
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code B3979 2017 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 2017 GMC Sierra - Incorrect Environmental Identifier Received from HVAC Control Module - AutoCodes.com — B3979 2017 GMC Sierra Code - Incorrect Environmental Identifier Received from HVAC Control Module

What does this mean?

What are the Possible Causes of the DTC B3979 2017 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 2017 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 2017 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 2017 GMC Sierra code?

Need more information on how to fix the B3979 2017 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3979 2017 GMC Sierra code diagnosed by a professional: Find a repair shop in your area

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 2017 GMC Sierra Code

1. What are the common symptoms of OBDII code B3979 in a 2017 GMC Sierra?

- Common symptoms include inconsistent interior temperature control, unusual HVAC system behavior, and potential issues with the vehicle's environmental controls.

2. What does the OBDII code B3979 mean in a 2017 GMC Sierra?

- OBDII code B3979 indicates that the HVAC control module has received an incorrect environmental identifier.

3. What are the possible causes of OBDII code B3979 in a 2017 GMC Sierra?

- Possible causes include a faulty HVAC control module, wiring issues, sensor malfunctions, or software glitches within the vehicle's system.

4. How can I diagnose OBDII code B3979 in my 2017 GMC Sierra?

- Diagnosis involves using a diagnostic scanner to retrieve the trouble codes, testing the HVAC control module and related components, and inspecting the wiring for any damage or loose connections.

5. Can I continue driving my 2017 GMC Sierra with OBDII code B3979?

- It is generally safe to drive the vehicle with this code, but it is recommended to address the issue promptly to avoid potential HVAC system malfunctions.

6. How can I repair OBDII code B3979 in my 2017 GMC Sierra?

- Repair options may include replacing the HVAC control module, repairing any damaged wiring, recalibrating the environmental controls, or updating the vehicle's software.

7. Is OBDII code B3979 a common issue in 2017 GMC Sierra vehicles?

- While not extremely common, some 2017 GMC Sierra owners have reported experiencing this code related to HVAC control module issues.

8. Can a DIY enthusiast fix OBDII code B3979 in a 2017 GMC Sierra?

- Depending on the individual's skill level and access to tools, some DIY enthusiasts may be able to address this code by following repair guides or consulting with a professional for assistance.

9. How much does it typically cost to repair OBDII code B3979 in a 2017 GMC Sierra?

- The cost of repairs can vary based on the specific issue causing the code, but it may range from a few hundred to over a thousand dollars, including parts and labor.

10. Are there any recalls or technical service bulletins related to OBDII code B3979 in the 2017 GMC Sierra?

- It is recommended to check with a GMC dealership or online databases for any relevant recalls or technical service bulletins related to this OBDII code and model year.