AutoCodes – GMC – B3902 GMC

B3902 GMC 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 GMC 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 6,076

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

What does this mean?

What are the Possible Causes of the DTC B3902 GMC?

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 GMC?

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 GMC 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 GMC code?

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

Need Help with the Code?

Get the B3902 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

B3902 2014 GMC Sierra — Incorrect Immobilizer Identifier Received
B3902 2015 GMC Sierra — Incorrect Immobilizer Identifier Received
B3902 2016 GMC Sierra — Incorrect Immobilizer Identifier Received
B3902 2017 GMC Sierra — Incorrect Immobilizer Identifier Received
B3902 2018 GMC Sierra — Incorrect Immobilizer Identifier Received

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 GMC Code

1. What does the OBDII code B3902 mean for a GMC vehicle?

B3902 indicates that the immobilizer system has detected an incorrect identifier received from a key or related module, preventing the vehicle from starting.

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

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

3. What causes the B3902 code to appear in a GMC?

Common causes include a faulty key fob, a malfunctioning immobilizer module, damaged wiring, or interference in the communication between the key and the immobilizer system.

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

Fixes may involve reprogramming the key, replacing the key fob battery, checking and repairing wiring, or replacing a faulty immobilizer module.

5. Can a weak key fob battery trigger the B3902 code?

Yes, a weak or drained key fob battery can cause communication errors and trigger the B3902 code.

6. Is it safe to drive a GMC with the B3902 code?

No, since this code prevents the engine from starting, the vehicle will usually not be drivable until the issue is resolved.

7. How much does it cost to repair the B3902 code on a GMC?

Repair costs vary depending on the issue but can range from $50 for a key fob battery replacement to over $500 for programming or replacing the immobilizer module.

8. Do I need to go to a dealership to fix the B3902 code on my GMC?

While some repairs, like a key fob battery replacement, can be done yourself, reprogramming keys or replacing the immobilizer module often requires specialized tools available at a dealership or qualified locksmith.

9. Can B3902 be caused by interference from other electronic devices?

Yes, electronic interference or nearby strong signals can sometimes disrupt communication between the key and the immobilizer system, triggering the code.

10. How do I prevent the B3902 code from recurring?

To prevent recurrence, maintain your key fob by replacing the battery regularly, avoid physical damage to the key, and address any wiring or module issues promptly.