EPASTS family
EPASTS_a121_mcusscMbistEccErr
Not Available
What does the EPASTS_a121_mcusscMbistEccErr alert mean?
This alert is reported by MCUSafetyStartupChecks_TC3x (MCUSSC) component when the memory Built-In-SelfTest failed, errors in the critical memory units. MCU failure
What you'll see in your Tesla
- Not Available
What triggers it
EPAS memory BIST found any errors in critical memory units (CPU0, CPU1, DMA).
When it clears
EPAS HW failure. EPAS power cycle N times and if persists, the gear needs to be changed.
Potential impact
EPAS reset. If reset more than 6 then EPAS fallback to bootloader.
Affected models
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.