EPAS3S family
EPAS3S_a155_backupEacActive
Not Available
What does the EPAS3S_a155_backupEacActive alert mean?
Electric Power Assisted Steering (EPAS) reports its secondary Electronic Control Unit (ECU) activated External Angle Control (EAC).
What you'll see in your Tesla
- Not Available
What triggers it
The EPAS secondary ECU activates EAC due to a condition affecting the primary ECU.
When it clears
Vehicle completes a power cycle. The alert will remain present for the remainder of the current drive cycle.
Potential impact
Backup EAC is active due to a detected condition on the primary steering ECU.
Affected models
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.