BMS family
BMS_a128_SW_shunt_MIA
Vehicle may not restart
What does the BMS_a128_SW_shunt_MIA alert mean?
The battery management system (BMS) detects that the shunt is missing (MIA).
What you'll see in your Tesla
- Vehicle may not restart
- Service is required
What triggers it
The BMS does not receive one or more expected CAN messages from the shunt.
When it clears
The BMS receives all expected CAN messages from the shunt.
Potential impact
Inability to charge, drive, or support the low voltage (LV) system
Affected models
Model 3 2017-2023
Model 3 2024+
Model S 2021+
Model X 2021+
Model Y
Model Y 2025+
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Alerts like this reach MyTeslaMate through your car's Tesla telemetry API. MyTeslaMate logs every alert your Tesla reports and turns it into readable history and real-time notifications — hosted TeslaMate with no server to run.