Car Warning Lights - What Do They Mean?

It can be alarming when a warning light flashes up on your car dashboard, but try not to panic. In this article we’re going to explore what the different car warning lights mean and explain why some of the most common may have appeared and what you should do if you see them.

Car warning lights usually appear in four possible colours depending on the type and severity of the warning. The whereabouts of the icons will differ from car to car, so use your car's user manual to familiarise yourself with the dashboard. The following infographic includes a list of the car warning lights that you may come across.

Car Dashboard warning lights explained

Red Dashboard Warning Lights

Indicate problems that require immediate attention. Anything unexpected that correlates with the engine, brakes or airbags should be checked over as a priority.

Battery warning

Battery warning

Brake system alert

Brake system alert

Hazard warning Light

Hazard warning

Oil Pressure warning

Oil pressure warning

Seat belt reminder

Seat beltreminder

Power steering warning

Power steering warning

Hand brake on

Hand brake on

Brake pads fault

Brake pads fault

Engine temperaturewarning

Doors open reminder

Security system fault

Security system fault

Transmission fault

Transmission fault

SRS fault

SRS fault

>Airbag switched off

Airbag switched off

Bonnet open reminder

Bonnet open reminder

Airbag fault alert

Airbag fault alert

Brake fluid low

Brake fluid low

High transmission oil

High transmission oil temperature

Boot open reminder

Amber Dashboard Warning Lights

Indicate that something should be monitored. Some icons may require attention as they have the potential to turn into major problems.

Washer fluid low indicator

Washer fluid low indicator

Check
                      engine light

Checkengine

Low fuel
                      warning light

Low fuelwarning

ESP fault
                      warning light

ESP fault warning

Due a service
                      indicator

Due a service indicator

Traction control system activated

Traction control system activated

Side airbag fault

Side airbag fault

Lane assist in operation

Lane assist in operation

Low oil level indicator

Low oil level indicator

Cruise control in operation

Cruise control in operation

Low on coolant

Low on coolant

Change in tyre pressure

Change in tyre pressure

Side airbag fault

Water in fuel (diesel)

Cruise control in operation

Glow plug indicator (diesel)

DPF replacement due

DPF replacement due

4x4 low gear mode

4x4 low gear mode

4x4 high gear mode

4x4 high gear mode

Catalytic converter warning

Catalytic converter warning

Child safety lock on

Child safety lock on

DPF replacement due

RBS hybrid fault

Traction control system deactivated

Traction control system deactivated

ABS warning light

ABS warning

Bulb failure

Bulb failure

Limited electric power indicator

Limited electric power indicator

Vehicle electric charging

Vehicle electric charging

Green (or blue) Dashboard warning lights

Notify you of certain information that shouldn't be ignored. For example, accidentally switching your high beams on can be hazardous if used in the wrong conditions.

Parking sensor in operation

Parking sensorin operation

ECO mode activated

ECO mode activated

Headlamps on

Headlamps on

Fog lights on

Fog lights on

Full beam lights on indicator

Full beam lightson indicator

Interior light on

Interior light on

Power steering warning

Coolant system too cold

Indicators on

Indicators on

Car ventilation indicator

Car ventilation indicator

Window wipers on

Windscreen wipers on

Automatic hand brake is on

Automatic hand brake on


                      Side lights are on

Side lights on

Electric vehicle mode activated

Electric vehiclemode activated

Electric car charging

Electric car charging

Stop/start system

Stop/start system

Please remember that this is a guide and dashboard lights are subject to change depending on the vehicle’s make and model. Check your vehicle’s user manual for dashboard specifics. If you’re concerned or see any warning lights that require attention, visit your nearest Halfords Autocentre.

Now we’re going to take a closer look at some of the more common car warning lights, what might have caused them to appear and what you should do if you see them. If you’re ever unsure and want a second opinion, let our fully trained technicians have a look with our full diagnostic check.

Red warning lights

Battery warning

Battery warning

The cause: If this light doesn't go out a few seconds after starting the engine, there could be a fault in your alternator, battery or electrical system. This means that your car isn't charging itself when driving, which could cause the battery to drain and the engine to eventually stop.

The solution: If this light comes on, you should turn off anything non-essential that uses the battery (e.g. heating, air conditioning, radio, charging devices, sat navs and heated seats). Don’t stop and turn off your engine straight away because your car may not start again. Instead, wait until you’re somewhere safe. You can then visit any Halfords Autocentre for a Free Battery Health Check.

Brake system alert

Brake system alert

The cause: If this light appears while you're driving, then you’ve probably left your handbrake on. If your handbrake is off but the light is still on, it may mean that you’re low on brake fluid or there’s a serious problem with your hydraulic brake system.

The solution: If you notice a difference in your brakes – for example, if they feel spongy or the pedal sinks to the floor – then pull over and call your breakdown service immediately. If the brakes feel normal, it's still recommended that you book in for a Free Brake Check at your local Halfords Autocentre.

Seat belt reminder

Seat belt reminder

The cause: You or a passenger are not wearing a seatbelt while the vehicle is in motion.

The solution: This is a simple problem to resolve, but also one of the most important. If this light comes on it essentially means someone in the car isn’t wearing a seatbelt. Please remember that all passengers, whether they're sat in the front or the back, are required to wear a seatbelt by law.

Power steering warning

Power steering warning

The cause: The most common reason for this indicator to appear is a lack of power steering fluid, but there also may be a more serious problem with the system.

The solution: Pull over, switch the engine off and check your power steering fluid levels. If the light remains illuminated, seek assistance as it may not be safe to continue driving.

If you've recently disconnected the battery, you'll need to reset the steering system. Turn your steering wheel fully left and then fully right before driving slowly for a short distance.

For added piece of mind, you can also take advantage of our free Steering Check, which is available at our Halfords Autocentres and

Engine temperature warning

Engine temperature warning

The cause: Your coolant level is low. Without coolant, the car will get too hot to function and this could cause damage to the engine, which can be very expensive to repair.

The solution: First, pull over to allow the engine to cool down. Next, check the coolant level of the tank under the bonnet. Be very careful when opening the lid on the coolant tank because you could be scalded by escaping steam if the engine is still hot.

If the coolant level is fine but the light comes back on, it could mean you have a leaky radiator or a more serious problem such as a blown head gasket. If this is the case, you need to get your car looked at straight away.

Doors open reminder

Doors open reminder

The cause: Either your boot, bonnet or one of the car doors hasn’t been shut properly.

The solution: Pull over and make sure that all your doors are firmly shut. If you have children in the back seats, it's a good idea to switch on the child safety locks to ensure they don't open the doors when the car is in motion.

Airbag fault alert

Airbag fault alert

The cause: There's a fault with one or more of your airbags.

The solution: If there’s a fault with your airbag, you should get this looked at by a mechanic straight away. If you don’t and then get into an accident, the airbag may not activate and this could leave you and your passengers without protection. Alternatively, it could be activated when you least expect it, causing injury.

Amber warning lights

Check engine

Check engine

The cause: A sensor has detected a problem with your engine. This light could indicate a number of things, from simple issues such as a fuel cap not being fastened correctly to wider problems with the engine or emissions system like a failed catalytic converter.

The solution: Even if your vehicle is not experiencing any other symptoms, it's best to get this checked with a diagnostic machine at a trusted garage to determine the problem. Our full Diagnostic Check is a great option as our experts will be able to identify any issues or faults and advise on repairs.

Change in tyre pressure

Change in tyre pressure

The cause: The tyre-pressure monitoring system has detected a drop in pressure.

The solution: You could have a puncture in one of your tyres or they may just need inflating. Your tyre pressures can affect your braking distance and handling, so it's best to stop and check your tyres and pump them up if necessary. If you notice a puncture, change the wheel or use sealant to stop the leak. Then visit your nearest Autocentre to get it repaired. We also offer a Free Tyre Check for added peace of mind.

Glow plug indicator

Glow plug indicator (diesel)

The cause: Your glow plugs, which are heating elements that help start your engine, are faulty.

The solution: It's normal for the warning light to appear for a second or two on start. However, if it stays on longer, visit your local Halfords Autocentre for a diagnostic check as you may require a replacement.

ABS warning light

ABS warning light

The cause: There’s a fault in your ABS braking system, which helps your car come to a stop in emergencies.

The solution: If the ABS braking system is working, you should feel the brake pedal pulsing when you brake hard. If it's not doing this, you need to get car checked out as soon as possible as your emergency braking may be affected.

If the ABS indicator is on and the brake warning light is showing, it could mean there is something seriously wrong with your brakes. We recommend booking in for a Free Brake Check at your local Halfords Autocentre where an expert can assess the system.

Limited electric power indicator

Limited electric power indicator

The cause: This will usually mean that you’re very close to running out of charge and depending on your vehicle, it may stop.

The solution: Your car will start to use up its stored supply of petrol or diesel but, if you have a plug-in hybrid, you may want to plug into an electrical charging point at your nearest charging station. Make sure you monitor the charge gauge to see how much power is remaining during your journey. If you're concerned about your Hybrid vehicle, visit your nearest Halfords Garage where our experts will be able to assist you.

Remember, if your dashboard symbols are illuminated then your car is trying to tell you something, so don't ignore it. Book in with our expert mechanics at your nearest Halfords Autocentre to get a diagnostic check or a service on your vehicle.

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