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Backup Battery And Low-Voltage Disconnect: Mazda
I-CAR · September 19, 2025 · Mazda
Summary
This article outlines Mazda's requirements for vehicles equipped with a backup lead-acid battery (sub), which powers critical modules like the PCM and DMCM. It highlights the necessity of disconnecting both the main and sub-battery terminals during electric welding and explains how the vehicle manages low-voltage battery charging.
What to do on the job
Disconnect both the negative and positive terminals of both the main battery and the lead-acid sub-battery before performing any electric welding to protect electronic components from overcurrent.
How to use it
When writing an estimate or supplement for welding repairs on a Mazda, include labor for disconnecting and reconnecting both the primary battery and the auxiliary sub-battery. Additionally, ensure post-repair operations account for disabling connected vehicle maintenance mode, restoring vehicle settings, and performing required system initializations and calibrations.
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