Dashboard warning lights: pull over now, or book in soon?

Modern cars have a lot of warning lights, and the symbols vary from one make to another. Your owner’s manual has the full list for your car. As a rule of thumb, the colour tells you how urgent a light is:

• Red usually means stop as soon as it’s safe, or don’t drive until it’s been checked.
• Amber or yellow usually means something needs attention soon, but the car is generally OK to drive carefully to a workshop.
• Green or blue is just information, like your headlights or cruise control being on.

Pull over safely and switch off

Oil pressure (an oil can symbol, usually red). The engine may not be getting enough oil. Running an engine without oil pressure can damage it within minutes. Pull over when it’s safe, switch off, and don’t restart it until it’s been checked.

Engine temperature (a thermometer in liquid, usually red). The engine is overheating. Pull over, switch off and let it cool down. Don’t open the radiator or coolant cap while it’s hot: the coolant is under pressure and can scald.

Brake warning (usually a circle with an exclamation mark, in red). First check the handbrake is fully off. If it is and the light stays on, it can mean low brake fluid or a problem with the braking system. Don’t keep driving on it; have it checked before you go any further.

Flashing check engine light. A steady check engine light is usually less urgent (see below), but a flashing one often means the engine is misfiring badly. Continuing to drive can overheat and damage the catalytic converter. Slow down, avoid hard acceleration and get off the road as soon as it’s safe.

Book in soon

Steady check engine light (an engine outline, usually amber). Something the engine’s computer monitors is outside its normal range. It could be minor, like a faulty sensor, or an early sign of something bigger. If the car drives normally you can usually keep driving it, but book in to have the fault code read rather than waiting to see what happens.

Battery or charging light (a battery symbol). This usually means the battery isn’t being charged, often because of a problem with the alternator or its drive belt. The car may keep running for a while on battery power alone, then stop without much warning. Head somewhere safe and get it checked promptly.

ABS light (the letters ABS, usually amber). The anti-lock braking system has a fault. Your normal brakes should still work, but the anti-lock function may not, which matters most in an emergency stop or on a wet road. Leave extra distance to the car in front and book in.

Airbag light (a seated person with a circle in front of them). If this stays on, the airbags may not work in a crash. The car will drive normally, which is exactly why this one is easy to ignore. It shouldn’t be.

Tyre pressure light (a horseshoe shape with an exclamation mark, on cars that have tyre pressure monitoring). One or more tyres may be low. Check the pressures at the next service station and look for anything stuck in the tread. If the light comes back soon after, you may have a slow leak.

Lights that come on and then go out

When you first switch the ignition on, most warning lights come on briefly as a self-test, then go out. That’s normal. What matters is a light that stays on, or one that comes on while you’re driving. A light that comes and goes is still worth mentioning at your next visit, because intermittent faults are easier to track down when you know when they happen.

When in doubt

If a light comes on and you’re not sure what it means, check your owner’s manual or give us a call on 02 9000 0000. It’s always better to ask early than to find out later that a warning was serious.

And if a red light comes on at the same time as the car feels wrong, such as losing power, steaming, knocking, a burning smell or unusual noises, stop somewhere safe first and ask questions after.