2024-2026 Stellantis TBM Battery Failure DTC B1E21-96

Symptoms of Telematics Box Module Backup Battery Failure

Owners of affected 2024-2026 Stellantis vehicles may notice a Malfunction Indicator Lamp (MIL) illuminating on the dashboard. This is often accompanied by a specific message displayed on the radio or infotainment screen. The message warns about the status of the Uconnect Box battery. This Stellantis TBM B1E21-96 problem is directly related to the vehicle's telematics system.

The verbatim message you might see is:

• "Battery of Uconnect Box requires service. SOS call and related functions may be unavailable. Please visit an authorized dealer."

These symptoms point to an issue with the Telematics Box Module (TBM) backup battery, specifically in vehicles equipped with a Global Telematics Box Module (Sales Code RDG).

Fault Codes (DTCs)

When the Telematics Box Module (TBM) backup battery experiences an internal failure, technicians will typically find the following Diagnostic Trouble Code (DTC) stored in the vehicle's system:

Code	Description
B1E21-96	Backup Battery Component Internal Failure

This DTC specifically indicates a problem with the backup battery within the Uconnect Box.

Important Warnings for Owners and Technicians

This Technical Service Bulletin (TSB) 08-394-25, Revision A, dated December 12, 2025, contains a critical instruction regarding the repair of this issue. It states:

• "The TBM should not be replaced if DTC B1E21-96 is present."

This means that simply replacing the entire Telematics Box Module (TBM) is not the correct procedure for addressing the B1E21-96 code. The issue lies with the backup battery component itself, not necessarily the entire module. This bulletin supersedes the previous TSB 08-394-25 dated December 05, 2025, and includes a corrected model year.

Diagnosis and Trigger Conditions

The presence of DTC B1E21-96 is the primary diagnostic indicator for this issue. This code, combined with the "Battery of Uconnect Box requires service. SOS call and related functions may be unavailable. Please visit an authorized dealer." message, confirms a backup battery failure within the Telematics Box Module (TBM). Technicians are advised to refer to the detailed diagnostic procedures available in DealerCONNECT > Service Library for specific instructions on how to proceed.

Repair Procedure Summary

This Technical Service Bulletin (TSB) 08-394-25 provides guidance for service technicians on how to address the Telematics Box Module (TBM) backup battery issue. The bulletin emphasizes that the TBM itself should not be replaced if DTC B1E21-96 is present. Instead, the detailed diagnostic and repair procedures for this specific DTC are located within the DealerCONNECT Service Library. Technicians must consult this resource for the precise steps to resolve the "Backup Battery Component Internal Failure" indicated by DTC B1E21-96. This ensures that the correct component is serviced without unnecessary replacement of the entire module.

Owner Action

If you experience MIL illumination or see the message "Battery of Uconnect Box requires service. SOS call and related functions may be unavailable. Please visit an authorized dealer." in your 2024-2026 Stellantis vehicle, it is recommended to schedule an appointment with an authorized dealer. Inform them about the message and any illuminated warning lights. The dealer will diagnose the Stellantis TBM B1E21-96 issue using the appropriate procedures for DTC B1E21-96, as outlined in TSB 08-394-25.

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Source: NHTSA ID: 11026677