Skip advert
Advertisement
Tips and advice

Car dashboard warning lights: the complete guide

Your car uses illuminating dashboard symbols to warn you if there’s an issue. But what do they mean?

Many motorists, including us at Carbuyer, have been caught off guard by an unexpected warning light blinking into life on our car’s dashboard. If you’re reading this, chances are the same thing has happened to you and you’re likely wondering what the symbol means. While some car dashboard symbols are there to warn you about critical issues, such as engine temperature or oil pressure, not every light denotes a serious problem.

Advertisement - Article continues below

Every time you start your car, most, if not all, of your dashboard warning lights should illuminate for a brief moment. This allows you to check that they’re working, but most should disappear once the engine is running.

Before we dive into the meaning of each symbol, we should note the importance of dashboard warning light colours. Generally, warning lights are split into three groups. Blue and green lights mean that a system, such as the headlights, is turned on, and does not relate to a fault. An amber light indicates that there is an issue with the car and, whilst it may still be drivable, the issue should be investigated as soon as possible. A red warning light is the most serious and should be dealt with immediately. It’s best to stop as soon as it’s safe to do so, turn the engine off, then check the car’s manual for advice before continuing on with your journey.

Exhaust image Smoke from exhaust: what does exhaust smoke mean?

Some warning lights are used to draw your attention to something less serious, such as a door that’s not been closed properly or to let you know you’ll soon need to fill up with fuel. In modern hybrid and electric cars, a lack of engine noise means it’s often necessary to include a warning light telling you your car is on and ready to set off.

Advertisement - Article continues below
Skip advert
Advertisement
Skip advert
Advertisement - Article continues below

Even seemingly harmless issues can illuminate a dashboard warning light. One of the less urgent and easy-to-fix warnings that could flash up is the low windscreen washer fluid warning light. This is usually amber in colour, and although it’s not a serious mechanical fault, you shouldn’t ignore it – if something were to get on the windscreen and obscure your view of the road, it could be dangerous if you’re unable to wash it off quickly.

It goes without saying that much more serious issues, such as problems relating to the brakes, engine, oil or gearbox should be acknowledged as soon as possible, as a major mechanical failure whilst driving could put your life at risk. Pull over as soon as it’s safe to do so and wait for assistance to sort the issue before you continue your journey in these instances.

Most car warning lights are universal for all makes and models of cars, making them easier to recognise for any driver. Their location on or around the dashboard can vary, however, and we’d still recommend looking at your car’s handbook to double-check what they mean.

Read on to find out the most common and important dashboard warning lights you might come across in your car.

Engine warning light

The engine warning light, sometimes referred to as an engine management light or EML, illuminates when there is a potential problem with the engine. It looks like a stylised, old-fashioned engine and will illuminate either amber or red depending on your car and the severity of the issue. Even if your car sounds and feels normal to drive, it is very important to have your car checked as driving with an engine problem could lead to serious (and expensive) damage.

Advertisement - Article continues below
Skip advert
Advertisement
Skip advert
Advertisement - Article continues below

The EML can be triggered for many reasons, ranging from a fairly benign sensor issue to a complete engine failure, so a proper diagnosis is critical to prevent potential damage. Read our in-depth explainer to find out the most common causes of an EML.

Oil pressure warning light

The oil pressure light, shaped like an oil can, is one of the most serious dashboard warning lights, hence its red colour. Oil pressure is critical for allowing oil to circulate through your engine’s most vital moving components while it’s running. If there is an oil leak, too little (or too much) oil or an issue with the oil pump, serious damage can occur to the engine which will likely result in a big repair bill or even a write-off.

While you should never ignore any warning light, this one is especially important to heed; stop the engine immediately and consult the handbook. You may simply have to top up the oil to make the light go out, but there could equally be a much more serious issue that requires a garage to investigate.

Brake system warning light

The brake system warning light indicates another serious issue that will require urgent action. It will illuminate if you’ve accidentally set off with the handbrake still partially engaged – the light should vanish once the brake is fully released. Note that some cars may instead have the letter ‘P’ instead of an exclamation mark to represent that the parking brake is on. If this doesn’t solve the problem, or the warning light appears as you're driving along, pull over safely and call for roadside assistance or arrange for the car to be taken to a garage.

Advertisement - Article continues below
Skip advert
Advertisement
Skip advert
Advertisement - Article continues below

Potential causes of a brake system warning light include low level of brake fluid or a faulty pad wear sensor. However, it could also be a more serious issue with the braking system and you shouldn’t risk driving any further. It goes without saying that if the pedal feels spongy when you press it, or sinks all the way to the floor, then it’s easy to tell that a significant issue has occurred and the car should definitely not be driven.

Battery charge warning light

This warning light can indicate a number of things, all relating to the car’s battery and charging system. Modern cars have numerous complex electrical systems that may not function correctly unless the battery is charging. This can lead to failure of the headlights, power steering, brakes and even the engine itself.

The cause of the warning light may be as simple as a faulty battery that’ll need replacing. But it could also be due to a problem with the car’s wiring or, more seriously, a fault with its alternator or drive belt. Other signs of a failing battery could be dim headlights or an engine that’s reluctant to start. Most garages can check your car’s battery and charging system to identify what’s at fault, or you can test your battery yourself at home.

Temperature warning light

If you see the temperature warning light on at any time after start-up, then the engine is running too hot or there isn’t enough coolant (also called antifreeze) in the system. This may be due to a number of issues, all of which could leave you stranded in a cloud of steam. It could be that the car’s radiator is leaky, clogged or broken – you’ll likely see coolant dripping out if this is the case. It could also be due to a faulty water pump.

Advertisement - Article continues below
Skip advert
Advertisement
Skip advert
Advertisement - Article continues below

More serious is a blown head gasket, which can signal catastrophic failure if you don’t turn off the engine immediately. White smoke from the exhaust could be a sign of head gasket failure.

Some cars may use a blue temperature warning light as well. This light means that your engine is cold, so it should only appear when you are starting your car after it has been sitting for a while. The blue light isn’t one to worry about but it’s advisable not to push your engine too hard until it has disappeared.

In any event, if you notice this red light, stop the car immediately, as running hot for too long can lead to total engine failure. If your car is constantly overheating, it will need to be investigated by a garage.

Low-fuel warning light

This is fairly self-explanatory, but we’ll go through it anyway. This is a warning light that comes on when the amount of fuel in the tank has passed a certain level. It’ll usually come on when you’ve got around 50-70 miles of range, and is designed to give enough warning so you can find a fuel station. Running out of petrol won’t cause any mechanical damage, but stopping on the road due to running dry is an offence. If you run out of diesel, it’ll be necessary to bleed the air from the fuel lines and injectors before the engine will start properly. That means it’s more than simply topping up from a jerrycan.

Advertisement - Article continues below
Skip advert
Advertisement
Skip advert
Advertisement - Article continues below

If you’re using more fuel than you’d expect, it could mean that you have a fuel leak (check the ground under your car; especially your driveway or parking space), or your car’s on-board computer (ECU) is telling the engine to use more fuel than it needs. A garage will be able to check this for you.

Tyre-pressure sensor warning

Since 2014, it has been mandatory for manufacturers to fit tyre-pressure monitoring systems (TPMS) to their new cars in the EU. These clever systems monitor the amount of air in the tyres and can detect a drop in pressure.

If it does detect a drop, it will let the driver know by illuminating the tyre-pressure sensor warning light. This is important, because low tyre pressures can adversely affect braking and cornering and a sudden drop in pressure can cause a dangerous blow-out at high speed. If the TPMS system alerts you to low pressure, you’ll need to check and inflate the tyre. If it has an obvious puncture, you’ll need to change the wheel or use a puncture repair kit.

Traction-control warning light

You’ll most commonly see your car’s traction-control warning light when the wheels lose grip, usually in the rain or snow. It gives a visual indication that you’re close to the limit of grip. If it’s on constantly, it usually means it’s deactivated – either by a fault or by you switching the system off. If it’s the former, you’ll need to get the system checked, if it’s the latter, you should switch the system back on – check your car’s manual to find out how to do so.

Glow plug warning light (diesels only)

We won’t go into the technicalities of how a diesel engine works, but all you need to know is that they use glow plugs to heat up the combustion chambers before starting the car, allowing the fuel to go ‘bang’, thus creating a force to turn the wheels. The glow plug warning light will almost always illuminate before starting the car, but if it illuminates in normal running, it could indicate that something’s wrong with the plugs themselves or the systems and computers that control them. 

Advertisement - Article continues below
Skip advert
Advertisement
Skip advert
Advertisement - Article continues below

You may not notice anything wrong at first, but issues with glow plugs can cause combustion to occur slightly too early or too late (known as ‘knocking’). This likely won’t cause any damage to the engine, but it will make your engine sound a bit rough and not run as smoothly or efficiently as it should, resulting in a drop in fuel economy. You should take your car to a garage to investigate the issue.

Seatbelt warning light

These days, the vast majority of new cars come with a system to let you know if any of your passengers haven’t got their seatbelts fastened. There’ll usually be a light – as above – to tell you if this is the case.

Cars use pressure sensors in the seats and sensors in the seatbelts – so if there’s a certain amount of weight on a seat and the seatbelt isn’t secured, it’ll let you know. These warnings may be accompanied by an unusual noise, too.

Door/boot/bonnet warning lights

Like the seatbelt light, these lights don’t usually mean that there’s anything physically wrong with the car (unless the sensor that sends the signal to the light is itself faulty). Instead, they tell you that one of the openings – be it a door, boot or bonnet – is open.

Advertisement - Article continues below
Skip advert
Advertisement
Skip advert
Advertisement - Article continues below

This is often obvious if, for example, you’re putting the weekly shop into the boot or securing your children in the back seats. But these lights also tell you if a door, boot or bonnet hasn’t been shut properly and is only loosely closed, so they can be very useful.

Hybrid and electric vehicle warning lights

As electrified cars become ever more popular, they bring with them a new selection of warning lights to decipher. The following examples appear exclusively on hybrid and electric vehicles.

Ready to drive warning light

Unlike a standard petrol or diesel, a hybrid or electric vehicle will be virtually silent when starting up. To avoid any confusion, this light simply informs you that your car is ready to be driven, so there is no cause for concern.

Limited power warning light

Having a tortoise on the dashboard may look friendly but this warning light actually means that your vehicle is running on limited power. There are a number of faults that could be causing this lack of power and they vary in severity, but it can also indicate a very low charge in the battery, and is limiting your power to help you get to a safe place before energy runs out completely. It’s best to stop the car as soon as is safely possible and arrange for it to be taken to the garage for a diagnosis.

Battery charge level warning light

This light will appear if your battery is at a critically low level of charge. If you do not stop the vehicle soon, you could end up stranded. The best, and most obvious, course of action is to seek the nearest available charging point, whether this is at home or a public facility. 

Pedestrian alert system

Because electric and hybrid vehicles can be so quiet, especially at low speeds, it can be difficult for pedestrians to hear them approaching. In order to prevent any accidents, these vehicles are usually fitted with a system that emits a sound to alert pedestrians to your presence, without the aggression of using the horn. If this light stays illuminated, regardless of your speed, then there is a fault with this system. This will require a dealer visit in order to determine the problem.

Read our Top five engine management light causes and prevent your car from costly repairs.

Skip advert
Advertisement

Charlie writes and edits news, review and advice articles for Carbuyer, as well as publishing content to its social media platforms. He has also been a regular contributor to its sister titles Auto Express, DrivingElectric and evo. As well as being consumed by everything automotive, Charlie is a speaker of five languages and once lived in Chile, Siberia and the Czech Republic, returning to the UK to write about his life-long passion: cars.

Skip advert
Advertisement

Recommended

What is an IDP licence? International Driving Permits explained
holiday car
Tips and advice
12 Mar 2024

What is an IDP licence? International Driving Permits explained

Driving licence penalty points explained
motorway
Tips and advice
4 Mar 2024

Driving licence penalty points explained

Towing capacity, weights and limits guide
Towcar
Tips and advice
29 Feb 2024

Towing capacity, weights and limits guide

How to tow a car
towing eye
Tips and advice
29 Feb 2024

How to tow a car

Most Popular

Hot car deal: stylish Peugeot 2008 small SUV for £120 a month
Peugeot 2008 front quarter
Deals
12 Mar 2024

Hot car deal: stylish Peugeot 2008 small SUV for £120 a month

Best new car deals 2024: this week’s top car offers
Carbuyer best new car deals hero
Deals
15 Mar 2024

Best new car deals 2024: this week’s top car offers

Skoda Superb Estate review – a near-faultless, practical family car
Skoda Superb Estate Carbuyer drive
In-depth reviews
15 Mar 2024

Skoda Superb Estate review – a near-faultless, practical family car

Tips & advice

View All
Car dashboard warning lights: the complete guide
Car dashboard symbols and meanings
Tips and advice
19 Dec 2023

Car dashboard warning lights: the complete guide

Electric car charging stations: a complete guide
Public EV charge point
Tips and advice
11 Jan 2023

Electric car charging stations: a complete guide

PCP vs HP – which type of car finance is right for you?
PCP vs HP
Tips and advice
17 May 2022

PCP vs HP – which type of car finance is right for you?

Average speed cameras: how do they work?
Average speed cameras: how do they work?
Tips and advice
12 Apr 2023

Average speed cameras: how do they work?

Best cars

View All
Top 10 best car interiors
Peugeot 208 hatchback
Best cars
25 Jun 2021

Top 10 best car interiors

Top 10 best electric cars 2024
The best electric cars 2023
Best cars
2 Jan 2024

Top 10 best electric cars 2024

Top 10 best cheap-to-run cars 2024
The best cheap-to-run cars 2023
Best cars
2 Jan 2024

Top 10 best cheap-to-run cars 2024

The UK's top 10 fastest hot hatchbacks 2024
Fastest hot hatchbacks hero
Best cars
2 Jan 2024

The UK's top 10 fastest hot hatchbacks 2024