AutoCodes – GMC – B3978 2014 GMC Sierra

B3978 2014 GMC Sierra Code - Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic 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 Inflatable Restraint Sensing and Diagnostic Module, Inflatable Restraint Sensing and Diagnostic Module harness is open or shorted, Inflatable Restraint Sensing and Diagnostic 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: B3978 2014 GMC Sierra indicates Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic Module.
Common causes: Common causes include Faulty Inflatable Restraint Sensing and Diagnostic Module, Inflatable Restraint Sensing and Diagnostic Module harness is open or shorted, Inflatable Restraint Sensing and Diagnostic 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 197

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 B3978 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 B3978 2014 GMC Sierra - Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic Module - AutoCodes.com — B3978 2014 GMC Sierra Code - Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic Module

What does this mean?

What are the Possible Causes of the DTC B3978 2014 GMC Sierra?

Faulty Inflatable Restraint Sensing and Diagnostic Module
Inflatable Restraint Sensing and Diagnostic Module harness is open or shorted
Inflatable Restraint Sensing and Diagnostic Module circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3978 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 B3978 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 B3978 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 B3978 2014 GMC Sierra Code

1. What does OBDII code B3978 mean on a 2014 GMC Sierra?

Code B3978 indicates that the Inflatable Restraint Sensing and Diagnostic Module (SDM) has received an incorrect environmental identifier, often related to a communication or configuration issue.

2. What are the common symptoms of code B3978 on a 2014 GMC Sierra?

Common symptoms include the airbag warning light illuminating on the dashboard and potential issues with airbag deployment readiness.

3. What causes the B3978 code to appear on a 2014 GMC Sierra?

This code is typically caused by a mismatch or corruption in the environmental identifier data, faulty module programming, wiring issues, or a defective Inflatable Restraint Sensing and Diagnostic Module.

4. Can code B3978 affect the airbag system in my GMC Sierra?

Yes, this code can impact the airbag systemâ€™s functionality, potentially preventing proper airbag deployment during a collision.

5. How do you diagnose the B3978 code on a 2014 GMC Sierra?

Diagnosis involves using a scan tool to retrieve the code, inspecting the SDM and associated wiring, checking module programming, and verifying communication between the SDM and other vehicle modules.

6. Is it safe to drive with the B3978 code on my GMC Sierra?

Driving with this code is not recommended, as it may indicate a malfunction in the airbag system, compromising occupant safety in the event of an accident.

7. How can I fix the B3978 code on my 2014 GMC Sierra?

Repairs may include reprogramming the SDM, inspecting and repairing wiring or connectors, or replacing a faulty SDM if necessary.

8. Can I clear the B3978 code without performing repairs?

Clearing the code without addressing the underlying issue may temporarily turn off the warning light, but the problem may persist or reoccur.

9. What tools are needed to fix the B3978 code on a GMC Sierra?

A professional-grade scan tool with airbag system diagnostics and reprogramming capabilities is essential for identifying and fixing this issue.

10. Should I take my 2014 GMC Sierra to a professional for the B3978 code?

Yes, due to the complexity of airbag systems and the safety-critical nature of this issue, it is recommended to have the vehicle inspected and repaired by a qualified technician.