Charger displays E04 or indicates overvoltage; charging will not start or stops abruptly.

Safety first: Only qualified persons should measure live voltages. Turn off power before opening the unit.

• Confirm supply voltage: Using a multimeter, have a qualified person measure line-to-line (or line-to-neutral) voltage at the breaker panel and at the JuiceBox input terminals. Ensure it matches the unit rating (typically ~240 V AC for North America).
• Inspect input wiring: With power OFF, remove the front cover and verify that line, line/neutral, and ground are correctly landed on the input terminal block. Tighten all screws to spec. Incorrectly landed neutrals or swapped legs can cause sensing errors.
• Check for shared or multi-wire branch circuits: Ensure the JuiceBox is on a dedicated circuit with a properly tied 2-pole breaker. Improperly shared neutrals can cause overvoltage readings.
• Power-cycle and retest: After correcting any wiring issues, turn the breaker OFF for 2 minutes, then ON, and attempt charging again.
• Persistent E04 with correct voltage: If measured voltage is normal but E04 remains, the voltage sensing circuit on the main control board may be faulty. Board replacement should be performed by a qualified technician.