FC family
FC_a146_CA_flybackBusLoadHi
Unable to DC Fast Charge
What does the FC_a146_CA_flybackBusLoadHi alert mean?
The Fast Charge (FC) Electronic Control Unit (ECU) has detected a flyback bus heavy and timeout condition.
What you'll see in your Tesla
- Unable to DC Fast Charge
- Contact charging station operator
What triggers it
FC ECU detects flyback has been on for more than 2000ms.
When it clears
FC ECU set the flyback target mode to OFF.
Potential impact
Charging session may not start or may become interrupted.
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.