What does the red lightning bolt warning light mean on an electric car?

It is the high-voltage system warning, and it means the car has detected a fault in the part of itself that carries several hundred volts. Most often that is an isolation fault, where the high-voltage system has lost its electrical separation from the car body, or a break in the interlock loop that runs through every high-voltage connector. Stop as soon as it is safe, switch off, get out, and call for recovery. Do not open the bonnet or touch any orange cabling.

Is it dangerous to sit in an electric car with a high voltage warning?

Sitting in an undamaged car for the moment it takes to pull over and switch off is not itself dangerous, and the car isolates the battery automatically when it detects a serious fault. The reason the advice is to get out and stay out is that you cannot tell from the driver's seat whether the fault is a failed sensor or water in the battery pack. If there is any smell of burning, hissing, smoke or heat from underneath, get well away from the car and call 999.

Can an electric car be towed?

Not on a rope or a conventional tow, in almost every case. The driven wheels are connected to the motor, so towing spins it and generates current into a high-voltage system that may be exactly what has just failed, and many EVs also need their electronics live to release the parking brake. Recovery is on a flatbed, or with the driven axle lifted on dollies. Check the handbook, and tell the recovery operator on the phone that it is an electric car so they send the right vehicle.

Why should you never touch the orange cables in an electric car?

Orange is the agreed industry marking for high-voltage cabling on every electric and hybrid vehicle, and it carries hundreds of volts of direct current. Direct current at that level is more dangerous than mains alternating current in one important respect: it tends to cause a sustained muscular contraction rather than a shock that throws you off. The system also stays energised inside the pack even when the car looks and sounds completely dead. That is why manufacturers require specific training and insulated tools, and why the honest advice for a driver is to leave it entirely alone.

Dashboard warning light

High voltage system warning light

Last updated 27 July 2026

Quick answer

The high-voltage system has reported a fault serious enough that the car wants you out of it and away from it. This is the one lamp in the electric and hybrid set that means stop, get out, and call for recovery rather than open anything.

What to do: Stop as soon as it is safe
Can you drive?: No

Why it is red

Reserved for hazards and for faults where continuing could injure somebody or destroy something expensive. Most red lamps mean stop, though a few mean the opposite, so read the lamp rather than the colour.

What turns it on

The car continuously monitors the insulation between the high-voltage system and the vehicle body, the continuity of the interlock loop that runs through every high-voltage connector, and the temperature and voltage of the battery pack. A failure in any of those, or a crash severe enough to trigger the pyrotechnic disconnect, lights this lamp and normally opens the contactors to isolate the pack.

What to do about it

Pull over as soon as it is safe, switch the car off and get everyone out. Do not sit in it to think about it.
Move away from the vehicle, particularly if there is any smell of burning, any hissing, any smoke or any heat coming from underneath. If there is smoke or fire, get well clear and call 999 — an electric vehicle fire is fought differently and the fire service needs to know it is electric.
Do not open the bonnet, do not lift the boot floor and do not touch or move any orange cabling. Orange is the industry marking for high voltage on every electric and hybrid car sold, and it carries several hundred volts of direct current whether or not the car appears to be off.
Call for recovery. Say clearly on the phone that it is an electric or hybrid car with a high-voltage warning, so the right vehicle and a trained operator are sent.
Do not let anyone tow it on a rope or with two wheels down. Turning the driven wheels spins the motor and generates current back into a system that has just declared a fault. Flatbed only, or with the driven axle lifted.
Take it to a garage with high-voltage qualified technicians. This is not a job for a general workshop, and a competent independent will tell you so.

Can you keep driving?

No. In most cases the car will not let you anyway, because the contactors have already opened and the drive system is dead. The reason for the flat answer is not that the car will explode — it almost certainly will not — but that the fault behind this lamp is usually a loss of electrical isolation, and the sensible response to that is distance and a professional, not a look under the bonnet. Recover it.

What causes it

An insulation or isolation fault, meaning the high-voltage system has lost its separation from the car body — the classic cause of this lamp and the reason it is treated so firmly
A broken high-voltage interlock loop, often from a connector disturbed during other work or damaged underneath by a kerb or a road obstruction
Water ingress into the battery pack or a high-voltage component, sometimes weeks after a deep flood
Impact damage to the pack, which sits along the floor of most EVs and is exposed to anything that grounds out
A failed contactor, inverter or converter
A crash severe enough to have fired the pyrotechnic high-voltage disconnect, which is the system working as designed

Does it fail an MOT?

No.

There is no MOT test of the high-voltage system, no insulation check and no defect recorded against this lamp. Testers are given safety guidance on working around electric and hybrid vehicles rather than a procedure for inspecting them, and a station is entitled to refuse to test a vehicle it considers unsafe to work on — a car showing an active high-voltage fault is a fair example. Get the fault repaired first, then present it.

Fault codes that turn this light on

The lamp tells you which system reported a problem. The code stored behind it names the check that failed, which is the difference between knowing something is wrong and knowing where to look. These are the ones that commonly sit behind this symbol.

P0AA6Hybrid Battery Voltage System Isolation Fault
P0A0AHigh Voltage System Interlock Circuit
P0A0BHigh Voltage System Interlock Circuit A Performance
P0A0CHigh Voltage System Interlock Circuit Low

Got a different code? Look it up — the index covers every standard OBD-II code.

Common questions

What does the red lightning bolt warning light mean on an electric car?: It is the high-voltage system warning, and it means the car has detected a fault in the part of itself that carries several hundred volts. Most often that is an isolation fault, where the high-voltage system has lost its electrical separation from the car body, or a break in the interlock loop that runs through every high-voltage connector. Stop as soon as it is safe, switch off, get out, and call for recovery. Do not open the bonnet or touch any orange cabling.
Is it dangerous to sit in an electric car with a high voltage warning?: Sitting in an undamaged car for the moment it takes to pull over and switch off is not itself dangerous, and the car isolates the battery automatically when it detects a serious fault. The reason the advice is to get out and stay out is that you cannot tell from the driver's seat whether the fault is a failed sensor or water in the battery pack. If there is any smell of burning, hissing, smoke or heat from underneath, get well away from the car and call 999.
Can an electric car be towed?: Not on a rope or a conventional tow, in almost every case. The driven wheels are connected to the motor, so towing spins it and generates current into a high-voltage system that may be exactly what has just failed, and many EVs also need their electronics live to release the parking brake. Recovery is on a flatbed, or with the driven axle lifted on dollies. Check the handbook, and tell the recovery operator on the phone that it is an electric car so they send the right vehicle.
Why should you never touch the orange cables in an electric car?: Orange is the agreed industry marking for high-voltage cabling on every electric and hybrid vehicle, and it carries hundreds of volts of direct current. Direct current at that level is more dangerous than mains alternating current in one important respect: it tends to cause a sustained muscular contraction rather than a shock that throws you off. The system also stays energised inside the pack even when the car looks and sounds completely dead. That is why manufacturers require specific training and insulated tools, and why the honest advice for a driver is to leave it entirely alone.

This is general guidance, not a diagnosis. Manufacturers draw the same system differently and reuse symbols for more than one function, so check the handbook for your own car before acting on anything here.

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