Charger refuses to energize; app or LEDs show E03 ground fault / GFCI trip.

Safety first: Do not continue using the charger if you smell burning or see arcing. Turn off power at the breaker before inspection.

• Dry the connector: If the charger or vehicle has been exposed to rain or washing, disconnect and allow the J1772 handle and vehicle inlet to dry completely for several hours. Do not use heat guns or open flames.
• Inspect for moisture and corrosion: With power OFF, look inside the J1772 connector for water droplets, green/white corrosion, or dirt. Gently blow out with dry compressed air and clean with a dry cloth. If corrosion is severe, replace the J1772 charge cable assembly.
• Check cable jacket: Run your hand along the cable to feel for cuts or crushed areas that could expose conductors to ground. Replace the cable if any damage is found.
• Test on a different circuit (if portable model): For plug-in JuiceBox units, try a known-good outlet on a different circuit to rule out upstream GFCI issues.
• Internal GFCI check (advanced): With power OFF and cover removed, inspect the GFCI current transformer (toroid) and its wiring to the main control board. Ensure the sensor is not cracked and wires are firmly seated. If E03 persists with a known-dry cable and vehicle, the GFCI sensor or main control board likely needs replacement by a technician.