AutoCodes – GMC – B3902 2017 GMC Sierra

B3902 2017 GMC Sierra Code - Incorrect Immobilizer Identifier Received

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 Body Control Module (BCM), Body Control Module harness is open or shorted, Body 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: B3902 2017 GMC Sierra indicates Incorrect Immobilizer Identifier Received.
Common causes: Common causes include Faulty Body Control Module (BCM), Body Control Module harness is open or shorted, Body 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 215

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 16, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3902 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 modules between vehicles. The Body Control Module (BCM) is the keeper of the environment identifier. The instrument cluster, electronic brake control module, HVAC control module, inflatable restraint sensing and diagnostic module, Engine Control Module (ECM), and steering column lock module (if equipped) 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. The Diagnostic Trouble Code (DTC) sets when the control module's environment identifier does not match the environment identifier stored by the BCM.

OBDII Code B3902 2017 GMC Sierra - Incorrect Immobilizer Identifier Received - AutoCodes.com — B3902 2017 GMC Sierra Code - Incorrect Immobilizer Identifier Received

What does this mean?

What are the Possible Causes of the DTC B3902 2017 GMC Sierra?

Faulty Body Control Module (BCM)
Body Control Module harness is open or shorted
Body Control Module circuit poor electrical connection

How to Fix the DTC B3902 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 B3902 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 B3902 2017 GMC Sierra code?

Need more information on how to fix the B3902 2017 GMC Sierra code? Get Access to Factory Service Manuals

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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 B3902 2017 GMC Sierra Code

1. What does the OBDII code B3902 mean on a 2017 GMC Sierra?

The B3902 code indicates that the vehicleâ€™s immobilizer system has detected an incorrect identifier, preventing the engine from starting.

2. What are the common symptoms of the B3902 code in a GMC Sierra?

Symptoms include the engine not starting, the security light staying illuminated or flashing on the dashboard, and possible intermittent starting issues.

3. What causes the B3902 code in a 2017 GMC Sierra?

Common causes include a faulty key fob, a damaged or unprogrammed key, issues with the immobilizer control module, or wiring/connectivity problems in the security system.

4. Can a weak key fob battery cause the B3902 code?

Yes, a weak or dead key fob battery can interfere with proper communication between the key and the immobilizer system, triggering the code.

5. How can I fix the B3902 code on my GMC Sierra?

Start by replacing the key fob battery, ensuring the key is programmed correctly, and checking for any wiring or connection issues in the immobilizer system. If the problem persists, consult a professional.

6. Will clearing the B3902 code make my GMC Sierra start?

Clearing the code alone wonâ€™t resolve the issue unless the underlying cause is fixed. The immobilizer system must recognize the correct identifier to allow the engine to start.

7. Do I need to reprogram my key if I see the B3902 code?

If the key has lost its programming or is not recognized by the immobilizer system, reprogramming it may be necessary to resolve the issue.

8. Can a faulty immobilizer module trigger the B3902 code?

Yes, a malfunctioning immobilizer control module can fail to properly identify the key and trigger the B3902 code.

9. How much does it cost to fix a B3902 code on a 2017 GMC Sierra?

Repair costs can vary, but replacing a key fob or reprogramming it may cost $100â€“$300. If the immobilizer module needs replacement, costs could exceed $500, depending on labor rates.

10. Can a locksmith fix the B3902 code issue?

Yes, a qualified automotive locksmith can often reprogram or replace a key and troubleshoot immobilizer-related issues for less than a dealership.