TechnicianVision · Knowledge base
Battery Backup And Low-Voltage Disconnect: Toyota/Lexus
I-CAR · January 22, 2026 · Toyota, Lexus
Summary
This article outlines Toyota and Lexus requirements for telematics backup batteries (Mayday/BUB/Mobilephone batteries) located in the DCM. It highlights the need to check vehicle-specific precautions for low-voltage disconnect wait times, battery replacement after Automatic Collision Notification (ACN) activation, and required initialization procedures using Techstream.
What to do on the job
Consult vehicle-specific OEM service information under Audio/Visual/Telematics to determine low-voltage disconnect wait times, replace the backup battery if ACN was activated, and perform initialization using Techstream after battery replacement.
How to use it
Use this document to justify line items for scanning, terminating the ACN call via Techstream, replacing the one-time-use backup battery after an airbag deployment or collision event, and performing the required initialization procedures. Reference the specific OEM service paths (Audio/Visual/Telematics) to support these operations during the estimating and supplement process.
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