E05
FLO
AC Line Undervoltage / Brownout Detection
Charger shows E05 / ‘Undervoltage’ and refuses to charge or stops mid-session.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Loose line connection at breaker or charger lugs, Undersized supply wiring causing voltage drop, Utility brownout or low service voltage, Faulty AC voltage sensing circuit
How to Fix / Troubleshooting
Safety first: Turn OFF the breaker before tightening any connections. Only a qualified electrician should work on live circuits.
- Inspect terminations: With power OFF, have an electrician check and tighten line and ground lugs at the breaker and inside the charger per torque specs in the FLO manual.
- Check wire gauge and run length: Long runs with undersized wire can cause significant voltage drop under load. Compare installed wire gauge and distance to FLO’s installation guidelines.
- Monitor supply voltage: Measure voltage at the charger while a heavy load (like an oven or dryer) is running. If voltage drops below the charger’s minimum, consult the utility or upgrade wiring.
- Power-cycle and retest: After corrections, reset the breaker and attempt charging again.
- If E05 persists with stable, in-spec voltage: The internal voltage sensing on the main control board may be faulty and require replacement.
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Repair Difficulty
Hard
4/5
Required Part
Main Control Board
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