TechnicianVision · Knowledge base
Backup Battery And Low-Voltage Disconnect
I-CAR · August 6, 2025 · General Motors, Kia, Mazda, Toyota, Lexus
Summary
This article explains the function of backup and auxiliary batteries, which maintain power to critical systems like telematics when the main 12-volt battery is disconnected. It highlights that these batteries are often non-rechargeable, must be replaced if depleted, and require specific OEM procedures to prevent damage during repairs.
What to do on the job
Identify if the vehicle is equipped with a system backup battery and follow OEM-specific procedures for low-voltage disconnection to avoid depleting or damaging the backup battery.
How to use it
Use this document to justify the necessary labor and research time required to locate and safely isolate backup batteries during the low-voltage disconnect process. It can also be used to support the replacement of a depleted backup battery or telematics module if OEM procedures dictate replacement after power loss.
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