BMS family
BMS_a171_SW_Stack_Voltage_Sense
Unable to charge
What does the BMS_a171_SW_Stack_Voltage_Sense alert mean?
The battery management system (BMS) has detected an issue with brick voltage measurement.
What you'll see in your Tesla
- Unable to charge
- Service is required
What triggers it
The BMS detects a mismatch between a stack's voltage and the sum of its brick voltages.
When it clears
The BMS detects that the condition clears.
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+
Track your Tesla's alerts automatically
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.