IBST family
IBST_a121_RPSVectorRangeLow
Power braking assist reduced
What does the IBST_a121_RPSVectorRangeLow alert mean?
iBooster (IBST) detected Rotation Position Sensor (RPS) raw signals (sine and cosine): Vector length too low.
What you'll see in your Tesla
- Power braking assist reduced
- Braking may require increased effort
What triggers it
IBST detected RPS raw signals (sine and cosine): Vector length too low.
When it clears
iBooster can not recover from this condition. iBooster replacement may be required.
Potential impact
IBST may not operate as expected.
Affected models
Cybertruck
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.