Charger shows E03 / ‘Overcurrent’ and stops charging shortly after starting.

Safety first: Turn OFF the breaker and verify no voltage is present before opening any covers. Only a qualified electrician should work inside the electrical panel.

• Verify breaker and wiring: Confirm the charger is on the correct breaker size and wire gauge per FLO installation manual (e.g., 40A breaker for 30A continuous output, or as specified). Undersized wiring can cause nuisance trips and overheating.
• Inspect the cable and connector: Look for burn marks, melted plastic, or hot spots on the J1772 handle and cable. If present, discontinue use and replace the cable/handle assembly.
• Test with another EV: If only one vehicle causes E03 and others charge normally, the vehicle’s onboard charger may be drawing excessive current—contact the vehicle manufacturer.
• Power-cycle and monitor: After inspection, reset the breaker and start a charge while monitoring for heat or repeated E03. If the error returns quickly with any vehicle, the internal current sensor or control board may be faulty.
• Technician step: A technician can measure output current with a clamp meter and compare to the charger’s set current. If readings are normal but E03 persists, replace the current sensor assembly or main control board.