VCTRAILER_a201_hsdTestFailed
Trailer brakes may be unavailable
What does the VCTRAILER_a201_hsdTestFailed alert mean?
The vehicle trailer controller (VCTRAILER) ran a High Side Field-Effect Transistor (FET) functional test, but the voltage feedback was below the necessary threshold to confirm High Side FET functionality.
What you'll see in your Tesla
- Trailer brakes may be unavailable
- Exiting and re-entering vehicle may restore functionality
What triggers it
High Side FET functional test does not measure voltage greater than 2V, but a trailer is still detected based on open electrical load.
When it clears
The High Side FET functional test passes, or a trailer is no longer detected (no open electrical load).
Potential impact
Trailer brakes may be unavailable or may not function as expected.
Affected models
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.