Dashboard warning lights: what each color means and what to do
Updated · Autofy
Dashboard warning lights: what each color means and what to do
A red warning light means danger or a serious fault: stop as soon as it's safe and switch the engine off (oil, temperature, brakes, battery). An amber light means a fault to get checked soon, but you can usually drive gently to a garage (engine, ABS, DPF, tire pressure). Green and blue lights simply show that a function is on (lights, cruise control). A flashing light is always more urgent than the same light glowing steadily.
The color code, one line each
Carmakers all follow the same logic, taken from international standards for vehicle symbols:
- Red: danger. Stop as soon as it's safe.
- Amber (or yellow): a fault. Get it checked soon, but the car can usually reach a garage.
- Green: a function is on. Dipped headlights, indicators, cruise control.
- Blue: high beam, and on some cars, a cold engine.
Color isn't the whole story. A flashing light is always more urgent than the same light glowing steadily: it signals a fault happening now, not one that has been stored.
Red lights: stop
| Light | What it means | The guide |
|---|---|---|
| Oil can | Oil pressure too low | Oil warning light |
| Thermometer in water | Engine overheating | Coolant warning light |
| Exclamation mark in a circle | Parking brake on, or brake fluid low | Brake warning light |
| Battery | The alternator has stopped charging | Battery warning light |
With an oil or temperature light, switching the engine off right away is the only good call: a few more minutes can be enough to wreck it.
Amber lights: garage soon
| Light | What it means | The guide |
|---|---|---|
| Engine outline | Ignition, fuel injection or emissions | Check engine light |
| ABS | Anti-lock braking disabled | ABS light |
| Seated person with airbag | Airbags or seatbelt pretensioners at fault | Airbag light |
| Particulate filter | DPF clogged (diesel, and recent petrol cars) | DPF light |
| Coil (diesel) | Glow plugs, or an engine fault if it flashes | Glow plug light |
| Tire with exclamation mark | A tire is under-inflated | Tire pressure light |
Everything lights up at startup: that's normal
When you turn the key, the lights come on for a second or two. That's the self-test: each one proves its circuit works. What matters is what stays on once the engine is running.
A light that never comes on, even during the self-test, isn't good news either: sometimes the bulb has been removed to hide a fault, a classic trick on used cars. Worth checking before you buy.
Warning lights and inspections
A light that stays on can fail a roadworthiness test. In France, an ABS or airbag light left on is classed as a major defect, with a mandatory re-test within two months. More in our inspection guide.
Keep a record of what lit up
A light that comes on and then goes off by itself tends to be forgotten, until it comes back for good. Writing down the date, the mileage and what you were doing saves your mechanic real time.
Autofy keeps that log for you: report the light in two taps, the app ranks it by severity and factors it into your car's health score until it's fixed.