AutoCodes – GMC – B3978 2018 GMC Sierra

B3978 2018 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 2018 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 212

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 2018 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 2018 GMC Sierra - Incorrect Environmental Identifier Received from Inflatable Restraint Sensing and Diagnostic Module - AutoCodes.com — B3978 2018 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 2018 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 2018 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 2018 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 2018 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 2018 GMC Sierra Code

1. What are the common symptoms of OBDII code B3978 in a 2018 GMC Sierra?

The common symptoms include the airbag warning light being illuminated on the dashboard and potential issues with the vehicle's airbag system.

2. What does the OBDII code B3978 mean for a 2018 GMC Sierra?

OBDII code B3978 indicates that the Inflatable Restraint Sensing and Diagnostic Module has detected an incorrect environmental identifier.

3. What are some possible causes of OBDII code B3978 in a 2018 GMC Sierra?

Possible causes include a malfunctioning Inflatable Restraint Sensing and Diagnostic Module, wiring issues, or a faulty environmental sensor.

4. How can I diagnose OBDII code B3978 in my 2018 GMC Sierra?

Diagnosis typically involves using a professional OBDII scanner to retrieve the specific error code and inspecting the airbag system components for any visible damage or issues.

5. Can I continue driving my 2018 GMC Sierra with OBDII code B3978?

It is not recommended to drive the vehicle with the airbag warning light illuminated, as it indicates a potential issue with the airbag system's functionality and safety.

6. How can I repair OBDII code B3978 in my 2018 GMC Sierra?

Repairing this code may involve replacing the Inflatable Restraint Sensing and Diagnostic Module, repairing any damaged wiring, or addressing the faulty environmental sensor.

7. Is it safe to reset the OBDII code B3978 in a 2018 GMC Sierra without fixing the underlying issue?

Resetting the code without addressing the root cause may temporarily turn off the warning light, but it will not fix the underlying problem with the airbag system.

8. How much does it cost to repair OBDII code B3978 in a 2018 GMC Sierra?

The cost of repairing this OBDII code can vary depending on the specific cause of the issue, but it may involve parts and labor expenses associated with replacing components or repairing wiring.

9. Can a DIY enthusiast fix OBDII code B3978 in a 2018 GMC Sierra?

While some minor diagnosis and repairs can be performed by DIY enthusiasts, fixing OBDII code B3978 may require specialized tools and expertise, so it is recommended to consult a professional mechanic.

10. How often does OBDII code B3978 occur in 2018 GMC Sierra vehicles?

The occurrence of this OBDII code can vary, but it is relatively uncommon compared to other more prevalent issues in the airbag system of the 2018 GMC Sierra.