RCU family
RCU_a008_pressureNotCalibrated
Backup power braking assist unavailable
What does the RCU_a008_pressureNotCalibrated alert mean?
The Redundant Control Unit (RCU) pressure sensor is not calibrated.
What you'll see in your Tesla
- Backup power braking assist unavailable
- OK to drive - Schedule service
What triggers it
The RCU pressure sensor is not calibrated.
When it clears
The RCU pressure sensor calibration routine has been successfully executed.
Potential impact
The RCU may not be able to perform backup power braking assist.
Affected models
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.