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Know your car , Maintenance and tyres , Safety and breakdowns · Updated 2026-10-18

Dashboard warning lights: what the colours mean

A dashboard full of symbols can feel like a foreign language, yet it is the car's way of telling you something. Some lights are friendly reminders, others mean you should pull over at the next safe place. You do not need to memorise every symbol: knowing how the colours work and a handful of important lights will cover most situations.

The colour code

Almost every manufacturer follows the same traffic-light logic, so it helps to learn the colours first.

• Green or blue: a system is switched on and working, for example the lights or cruise control. No action needed.
• Yellow or orange: something needs attention soon. Often it is a fault or a reminder. You can usually keep driving, gently, but should get it checked.
• Red: a serious warning. It may mean danger to you or damage to the car. Stop as soon as it is safe and find out why.

Flashing usually raises the urgency. A light that is steady is a warning; the same light flashing is often an alarm.

Lights that call for an immediate stop

If one of these comes on while driving, look for a safe place, switch off the engine and read the manual.

• Oil pressure: usually an oil can symbol. It means the engine may not be getting enough lubrication. Running on can destroy an engine in a short time.
• Coolant temperature: often a thermometer in waves. The engine is overheating. Stop, let it cool and do not open the cooling system while it is hot.
• Brake system: a circle with an exclamation mark or the word brake. It can be as simple as the handbrake being on, or as serious as low brake fluid or a hydraulic fault. If the pedal feels odd, do not continue and call for help.
• Battery or charging: a battery symbol. The car is no longer charging the battery properly and will run down. You may have only a short time before it stops.
• Airbag or seatbelt: not an emergency stop, but it means the safety system may not work in a crash. Have it checked soon.

Lights that mean get it checked soon

• Engine management (check engine): an engine outline. It means the engine computer has stored a fault. Steady, the car often drives normally for a while. Flashing usually signals a more serious problem such as misfiring, and you should reduce speed and load and go to a workshop.
• ABS or stability control: the normal brakes still work, but the extra safety system may be off. See ABS, ESP and driver assists.
• Tyre pressure: one or more tyres are low. Check them as soon as you can. See tyre pressure and rotation.
• Particulate filter or exhaust system: common on diesels. It may ask for a longer drive at steady speed, or for a workshop visit.
• Low fuel or washer fluid: simple reminders, but running a tank empty can harm the fuel pump.

What to do when a light comes on

1. Stay calm and check the colour and whether it is steady or flashing.
2. Notice how the car behaves: noises, smells, smoke, loss of power or a strange pedal feel.
3. If the light is red or the car behaves badly, stop safely and switch off.
4. Look up the symbol in the owner's manual. The symbol set and the exact meaning differ between cars.
5. If you are unsure, do not guess. A workshop can read stored fault codes, and that usually tells much more than the light alone.

A light that comes on and goes off

Sometimes a warning appears for a few seconds and then disappears. That is not a reason to ignore it. The car may have stored the fault even though the light is out. Mention it at the next service, and write down when it happened and what you were doing. A logbook entry in My Garage is a handy place for that.

All lights on at start

When you turn the ignition on, most warning lights switch on briefly as a self-test, and then go out when the engine starts. If a light stays on after starting, it is reporting something. If a light you would expect to see during the self-test never appears, a bulb may have been removed or failed, which is worth knowing when you look at a used car. See how to inspect a used car.

Switching lights off is not fixing them

Clearing a fault code or disconnecting the battery can make a light vanish for a while, but the cause remains. Be careful with a seller whose car has just been reset, or whose warning bulb has been covered or removed. A car that shows no lights at all when the ignition is on deserves extra questions.

What to remember

• Red means stop safely, yellow means check soon, green or blue means a system is on.
• Flashing is more urgent than steady.
• Oil pressure, overheating, brake and charging warnings are not for ignoring.
• Your manual explains the symbols on your car.
• A light that went out may still have stored a fault, so mention it to a workshop.

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