BMS family
BMS_a035_SW_Isolation
Vehicle may not restart
What does the BMS_a035_SW_Isolation alert mean?
There is an external or internal isolation alert while pack contactors are closed.
What you'll see in your Tesla
- Vehicle may not restart
- Service is required
What triggers it
The BMS detects that isolation is below the minimum threshold while contactors are closed.
When it clears
Isolation restores to the nominal threshold.
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.