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DTC B3902

DTC B3902

Diagnostic Instructions


• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• Diagnostic Procedure Instructions provides an overview of each diagnostic category.


DTC Descriptor

DTC B3902 00

Incorrect Immobilizer Identifier Received

Circuit/System 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 (EBCM), HVAC control module, sensing and diagnostic module (SDM), engine control module (ECM), and steering column lock control module, if equipped, each learn the environment identifier during their configuration process. During vehicle operation, each of these modules compare their environment identifier to that of the BCM. If the identifiers match, vehicle starting is allowed. If an environment identifier does not match, vehicle starting is disabled.

Conditions for Running the DTC

Ignition is in the ACCESSORY or RUN position.

Conditions for Setting the DTC

The control module's environment identifier does not match the environment identifier stored by the BCM.

Action Taken When the DTC Sets


• The security indicator in the instrument cluster will illuminate.

• Vehicle starting will be disabled.


Conditions for Clearing the DTC

A current DTC will be cleared when the module learns a correct environment identifier.

Reference Information

Schematic Reference

Immobilizer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Immobilizer Description and Operation

Electrical Information Reference


• Circuit Testing

• Connector Repairs

• Testing for Intermittent Conditions and Poor Connections

• Wiring Repairs


Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Perform the Programming and Setup procedure for the control module that set DTC B3902. Verify the DTC does not reset after programming.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for instrument cluster, EBCM, HVAC control module, SDM, ECM, or steering column lock control module replacement, setup, and programming