STO family
STO_a003_pwrSupUnderVolt
Not Available
What does the STO_a003_pwrSupUnderVolt alert mean?
Steering Torque Overlay (STO) assist halted due to low Power Supply voltage.
What you'll see in your Tesla
- Not Available
What triggers it
Critical Power Supply voltage <= 7.3 Volts for 1 second
When it clears
Voltage reaches over 9 volts
Potential impact
Steering Assist reduced
Affected models
Semitruck
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.