Short answer
The EV or hybrid system fault light means the high-voltage system has reported a fault and may cut power to protect itself. Pull over when it is safe, switch off and check the 12-volt battery, a common and cheap cause. Do not touch orange high-voltage cables, and have the car seen by an EV-qualified shop.
- Also shown as:
- Check hybrid system · Check EV system · Electrical system fault · Red car with exclamation mark
- What it looks like:
- A red car outline with an exclamation mark, or a text message such as “Check hybrid system”.
Is it safe to keep driving?
Pull over when it is safe. A high-voltage fault can shut the car down without warning; do not attempt DIY inspection of orange high-voltage cables.
Stop driving now if:
- The red system fault warning appears while you are driving — pull over at the first safe place.
- You see smoke, smell burning or hear hissing or popping from the battery area. Get everyone out, move away and call 911.
- The car has been in a crash or driven through deep water.
What causes the EV / hybrid system fault light?
Most common first. Symbols and meanings vary by manufacturer; your owner's manual has the definitive meaning for your model.
- 12-volt battery too low. EVs and hybrids still use an ordinary 12V battery to boot their systems. When it is weak, the car can throw alarming high-voltage warnings.
- Battery management fault. The system that monitors cell voltages and temperatures has found something out of range and limited power.
- Isolation fault. The car has detected that high-voltage circuits are leaking to the body, often from moisture or damaged insulation, and shuts down for safety.
- Battery or inverter cooling fault. A failed pump, fan or coolant leak lets the battery or power electronics overheat, so the car protects them.
What should you do right now?
- Check the 12V battery first — a flat 12V battery is a common, cheap cause of a scary-looking hybrid warning.
- Do not open or touch any orange high-voltage cable or component.
- Have the car seen by an EV-qualified shop; check for open recalls on the battery.
What does the fix usually involve?
A dealer or EV-qualified shop reads the high-voltage system codes with the manufacturer's tool. Fixes range from a 12V battery or a cooling pump to a software update or a battery module.
Battery repairs are often covered by the high-voltage battery warranty, and several EV models have had battery recalls — check both before paying.
How much does it cost to fix?
$150 – $15,000
A 12V battery at the low end; a high-voltage battery module at the high end — check the battery warranty first: most makers cover it for at least 8 years / 100,000 miles.
A typical range, not a quote. Actual cost depends on the car, the shop and the fault.
Common questions
Is it dangerous if my EV shows a high-voltage fault?
The car is designed to cut power and isolate the battery when it detects a fault. The danger is in touching high-voltage parts or ignoring signs of fire — smoke, hissing or a burning smell. In that case, get out and call 911.
Is the EV battery covered by a warranty?
Most manufacturers cover the high-voltage battery on EVs and hybrids sold in the US for at least 8 years or 100,000 miles, and some states require longer coverage. The terms differ by maker, so check your warranty booklet.
Check your car
Free VIN check: open NHTSA recalls, owner complaints and the safety rating for your exact car.