Backup Battery And Low-Voltage Disconnect: General Motors

I-CAR · March 27, 2026 · Chevrolet, GMC, Buick, Cadillac

Summary

This article outlines General Motors' requirements for disconnecting the low-voltage battery on OnStar-equipped vehicles. It warns that disconnecting the main battery or removing the OnStar fuse while the ignition is on will permanently damage the non-rechargeable telematics backup battery, requiring its replacement.

What to do on the job

Ensure the ignition is completely OFF and Retained Accessory Power is deactivated before disconnecting the main battery or removing the OnStar fuse to prevent damaging the backup battery.

How to use it

Use this document to justify the necessity of following specific battery disconnection protocols on GM vehicles. If the backup battery is accidentally activated due to improper disconnect, this document supports the required replacement of the backup battery (or entire telematics module) and the subsequent Backup Battery Reset procedure.

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