Charger shows E05 or 'Overvoltage' and refuses to charge; may occur during grid fluctuations or storms.

Safety first: Turn OFF the charger breaker. Only a qualified person should measure live voltages.

• Check supply voltage (electrician recommended): Using a multimeter, measure line‑to‑neutral (and line‑to‑line if applicable) at the charger input. Compare with the rated voltage on the charger nameplate. If voltage exceeds limits, contact your utility or an electrician.
• Verify wiring configuration: Confirm that the charger is wired according to the Volvo installation manual (single‑phase vs three‑phase, correct phase and neutral connections). Correct any miswiring.
• Inspect neutral connection: With power OFF, check that the neutral conductor is securely landed and not shared improperly with other circuits.
• Power‑cycle and monitor: After correcting any wiring issues, restore power and observe if E05 clears. Monitor during different times of day to see if the issue correlates with grid fluctuations.

If supply voltage is within spec and wiring is correct but E05 persists, the internal voltage sensing circuit on the main control board may be defective. Board replacement should be carried out by a qualified technician.