Car warning lights guide

It can be alarming when an engine 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, why they appear, and what you should do if you see them.

Car warning light symbols 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 warning lights on your dashboard. The following infographic includes a list of the car warning lights that you may come across.

Dashboard warning lights

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  Brake system alert  Hazard warning Light

             Battery warning                               Brake system alert                             Hazard warning 

Oil Pressure warning  Seat belt reminder  Power steering warning

        Oil pressure warning                        Seat belt reminder                         Power steering warning 

Hand brake on  Brake pads fault  
              Hand brake on                                   Brake pads fault                      Engine temperature warning 
 Security system fault   Transmission fault

        Doors open reminder                    Security system fault                         Transmission fault             

SRS fault  >Airbag switched off  Bonnet open reminder

                   SRS fault                                     Airbag switched off                        Bonnet open reminder     

Airbag fault alert  Brake fluid low  High transmission oil

             Airbag fault alert                                 Brake fluid low                   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  Check
                      engine light  Low fuel
                      warning light

    Washer fluid low indicator                       Check engine                                  Low fuel warning 

ESP fault
                      warning light   Due a service
                      indicator  Traction control system activated

          ESP fault warning                         Due a service indicator                Traction control system activated

Side airbag fault  Lane assist in operation  Low oil level indicator

            Side airbag fault                        Lane assist in operation                      Low oil level indicator 

Cruise control in operation  Low on coolant  Change in tyre pressure

    Cruise control in operation                     Low on coolant                          Change in tyre pressure 

Side airbag fault  Cruise control in operation  DPF replacement due

       Water in fuel (diesel)                 Glow plug indicator (diesel)                  DPF replacement due

4x4 low gear mode  4x4 high gear mode  Catalytic converter warning

         4x4 low gear mode                           4x4 high gear mode                      Catalytic converter warning

Child safety lock on  DPF replacement due  Traction control system deactivated

        Child safety lock on                              RBS hybrid fault               Traction control system deactivated

ABS warning light  Bulb failure  Limited electric power indicator

               ABS warning                                            Bulb failure                       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  ECO mode activated  Headlamps on

      Parking sensor in operation            ECO mode activated                             Headlamps on

Fog lights on  Full beam lights on indicator  Interior light on

               Fog lights on                        Full beam lights on indicator                     Interior light on   

Power steering warning  Indicators on  Car ventilation indicator

      Coolant system too cold                         Indicators on                            Car ventilation indicator

Window wipers on  Automatic hand brake is on  
                      Side lights are on

       Windscreen wipers on                 Automatic hand brake on                         Side light on 

Electric vehicle mode activated  Electric car charging  Stop/start system
 Electric vehicle mode activated         Electric car charging                         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.

Car warning light symbols

Now we’re going to take a closer look at some of the more common dashboard 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 on the dashboard

Battery warning light

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

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 a Free Brake Check at your local Halfords Autocentre.

Seat belt reminder light

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 sitting in the front or the back, are required to wear a seatbelt by law.

Power steering warning light

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: Pullover, 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 peace of mind, you can also take advantage of our Free Steering Check, which is available at our Halfords Autocentres.

Engine temperature warning light 

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 in 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.

Door open reminder light

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 light

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 on the dashboard

Check engine light

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.

Tyre pressure warning light

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. See our guide on tyre pressure warning lights here.

Diesel glow plug indicator light

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

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 your 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 a Free Brake Check at your local Halfords Autocentre where an expert can assess the system.

Limited electric power indicator light

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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