Stop drivingred light
EV / Hybrid Battery Warning
The high-voltage battery has a fault — this is serious and potentially dangerous.
What it means
A red or amber icon of a battery (sometimes with a plug, lightning bolt or the words HV), usually accompanied by a message. The car’s high-voltage battery pack or its management system has detected a fault. This can mean degraded cells, overheating, an isolation fault (high-voltage leaking to the chassis) or a complete failure. It can affect drivability and, in rare cases, safety.
What to do
- 1If red: pull over safely, switch off and do not attempt to drive or charge the car. Call your breakdown service or dealership — high-voltage systems require specialist handling.
- 2If amber: you may have reduced power or electric range. Drive gently to a dealer or specialist EV garage as soon as possible.
- 3Never attempt to open or repair the high-voltage battery yourself — it can deliver lethal voltages.
Likely causes
- •Battery cell degradation or failure
- •Battery management system (BMS) fault
- •Overheating of the battery pack
- •High-voltage isolation fault
- •Cooling system failure for the battery
Rough UK cost
Diagnostics: £100–£250. Module replacement: £1,000–£4,000. Full pack: £5,000–£20,000+ depending on model.
Prices are a guide only — always get a written quote before any work.
Heads up: Carautonomy is for general guidance only. If your car is behaving oddly or any red light is on, get it inspected by a qualified mechanic.