IBST family
IBST_a151_PSCGearRatioReadFault
Power braking assist reduced
What does the IBST_a151_PSCGearRatioReadFault alert mean?
iBooster (IBST) detected the value in the Non-volatile Memory (NvM) block 'Gear_Ratio' is incorrect or 'empty'.
What you'll see in your Tesla
- Power braking assist reduced
- Braking may require increased effort
What triggers it
IBST detected the value in the NvM block 'Gear_Ratio' is incorrect or 'empty'.
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+
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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.