Understanding warning lights

Regardless of how much you know about cars, you can't always tell if something's wrong. That's where dashboard warning lights come in.

When you switch your engine on, your car's instrument panel will light up, illuminating all your warning lights. This is to check the bulbs and circuits are working and to make sure there's no issue with their associated components.

Your warning lights will then switch off after three or four seconds. If any light stays on, or one comes on when you're driving, there's an issue.

Knowing what your dashboard warning lights mean can help you avoid your car breaking down or complete failure.

But what does each symbol mean and how important is it when a light comes on?

First things first, if one comes on while you're driving, stop in a safe place as soon as possible. A red warning light means it requires immediate attention; others allow you to carrying on driving and get to a garage so a professional can check out the problem.

Some warning lights are found on all cars, while others may be specific to your car so get used to yours by reading your handbook.

Here are the most important warning lights to look out for:

ECU / Engine warning light

ECU / Engine warning ligh

This is one of the more serious warning lights. Sometimes the light will be followed by some unusual symptoms such as a lack of power or the engine making strange noises, and other times your car will seem fine.

This warning light can sometimes come on due to something small like a faulty electrical sensor, but it can also indicate a larger mechanical issue. If this light does come on, get a professional to look at it straight away as driving around could cause further damage.

Brake system / brake fluid warning light

Brake system / brake fluid warning light

The braking system's one of your car's most important features so keep an eye out for this light. This light will stay on as long as your handbrake's on, but if it comes up at any other time, something could be wrong with the braking system.

If you don't know how to check the brake fluid level, check your handbook. If the brake fluid level's low, top it up to the MAX mark before driving off. If the fluid level's okay, and the light stays on, take your car to a garage straight away.

It's always a good idea to check your brake fluid every few weeks to make sure there aren't any leaks.

ABS warning light

ABS warning light

If your ABS (anti-lock braking system) comes on while you're driving, there could be a problem with the system. Get your ABS checked as soon as you can. Most cars should still be safe to drive without ABS, but this isn't the case for every make and model.

If your brake and ABS warning lights come on at the same time, stop as soon as you can in a safe place and make sure you use your brakes carefully, reduce your speed gradually and don't press the brake pedal suddenly. Once you've stopped, call a professional.

Oil pressure warning light

Oil pressure warning light

Your oil warning light will flash up if the oil temperature gets too high, the level's low or the oil pressure's too low. If it comes on while you're driving, stop in a safe place and check your oil level. Top it up if it's too low. Oil lubricates your engine so phone a professional if the warning light remains on even though the oil level's correct. Left unchecked this could result in total engine failure.

Battery charge warning light

Battery charge warning light

If this light doesn't come on at all or shows while you're driving, it could indicate one of three issues:

  • Faulty battery or starter terminal
  • An alternator failure
  • A broken or loose alternator drive belt

A broken drive belt's a serious problem so park up in a safe place as soon as possible, switch off your engine and call a professional.

Coolant warning light

Coolant warning light

Without coolant, your car can overheat and it could get so hot it would effectively 'weld' itself together. Running hot for too long can lead to total engine failure so if this light shows, stop your car immediately and check your coolant levels. Top up if you need to, but if your coolant level's fine, get your car seen to as it could be a sign of a larger problem.

Tyre pressure monitor warning light

Tyre pressure monitor warning light

Most modern cars are now fitted with tyre pressure monitoring systems. This warning light will show up if it senses your tyre pressures are low or you have a puncture. If it illuminates on your dashboard, check your tyres.

Airbag warning light

Airbag warning light

This car warning light indicates a faulty airbag. Not only could this result in the airbag not going off in a crash, it could also mean it goes off unexpectedly, potentially causing injury and an expensive repair bill. Make sure you and your passengers are safe by getting your car to a garage if this light shows.

Power steering / EPAS warning light

Power steering / EPAS warning light

This is another warning light that's most common in modern cars as the majority now have power steering. The power steering, or EPAS, warning light will turn on if there's something wrong with the steering system.

Another sign of a problem is if the steering goes heavy and more effort's required to make the car change direction, so get your car seen as soon as possible.

DPF / Diesel particulate filter warning light

DPF / Diesel particulate filter warning light

Most modern diesel cars are now fitted with a diesel particulate filter (DPF), which reduces emission by removing soot from exhaust gases. If there's a fault, this warning light will illuminate on your dashboard. You could be releasing more fumes and damaging your engine at the same time.

Routine car checks and maintenance can help reduce the risk of a warning light showing up on your dashboard.

All information is correct at time of publication. Hastings Direct cannot be held responsible for any misinformation displayed.

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