BMS family
BMS_f151_SW_external_isolation
Unable to start vehicle
What does the BMS_f151_SW_external_isolation alert mean?
The battery management system (BMS) has detected that high voltage (HV) isolation is too low while pack contactors are closed.
What you'll see in your Tesla
- Unable to start vehicle
- Service is required
What triggers it
The BMS detects that HV isolation is below the warning threshold while contactors are closed.
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 S 2012-2020
Model X 2015-2020
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.