Car dashboard warning lights - what do they mean?
Modern cars are filled with electronics and packed with sensors to monitor how your vehicle is behaving.
It’s important to know what car dashboard warning lights mean because you might be able to avoid a car breakdown or full-on failure.
So here's what the different yellow and red warning lights on your dashboard mean, why they come on, how urgent the problem is and what you should do when you see them.
The warning lights on your dashboard follow a traffic light colour system:
Green: the system is working correctly or is currently in use
Yellow: something is not working correctly - take extra care and check it out as soon as possible
Red: there is a serious, and potentially dangerous problem - stop driving as soon as it is safe to do so
Click a warning light to learn more:
Bake Warning Light
Also known as the brake system warning light, parking brake warning light or brake fluid warning light.
If this red light remains on after you fully release the parking brake, or comes on when you’re driving, it may indicate that the brake fluid level is low. Unless you know how to check your brake fluid levels yourself, this will be one for the professionals.
If the ABS warning light is also illuminated this signals that the braking system has malfunctioned and your brakes may not work properly. In this case the Electronic Brake Force Distribution (EBD) warning light may also be illuminated.
Engine management light
Also known as the check engine or ECU warning light.
When the engine management light is illuminated it’s often accompanied by tell-tale signs that the engine is not working properly, such as a lack of power or stuttering as you press the accelerator.
This light could indicate a number of faults, from minor issues like a broken electrical sensor to a much larger mechanical issue, like a fault with your emission control system or catalytic converter.
Airbag warning light
Also known as the supplemental restraint system (SRS) warning light.
When this light goes red it means that at least one element of the airbag safety system is not working correctly: either the airbag system itself; the front passenger occupant classification system (which detects the front passenger’s weight and position in order to safely deploy the airbag); or the seat belt pretensioner system, which tightens the belt in the event of a crash.
Power steering warning light
Also known as the EPS or EPAS warning light.
This warning light indicates that there’s a problem with the power steering.
For electric powered systems, this problem could be as simple to fix as rebooting a computer. Find a safe place to stop and try turning the car off and back on again after 30 seconds. If the light stays on you should take your car to get checked as soon as possible.
Diesel particulate filter warning light
Also known as the DPF or exhaust particulate filter warning light.
If you have a diesel, one of these lights will come on if there is a problem with the exhaust particulate filter, which removes harmful soot from the exhaust gases to reduce emissions. It could indicate that the filter has become blocked with soot.
Engine temperature warning light
Also known as the coolant temperature warning light.
This light will come on when the engine is overheating. This could mean that coolant levels are running low, perhaps due to a leak in the system, or it could be a sign of a larger problem, like a head gasket failure.
Coolant levels warning light
Coolant fluid absorbs the heat from your engine and disperses it through the radiator to prevent your engine from overheating. This yellow warning light will come on when coolant levels are running low, to remind you to top them up.
Oil warning light
Also known as the low engine oil or low oil pressure light.
The oil warning light comes on when either the oil temperature gets too high or the oil level or pressure is too low. If the oil is not lubricating the engine effectively it could lead to expensive or even irreparable engine damage, so it’s important to act quickly.
Low tyre pressure warning light
Many Mercedes-Benz cars are now fitted with tyre pressure monitoring systems that will let you know when the pressure falls. This could happen over time or it could be because of a puncture.
Battery warning light
Also known as the battery charge light or battery charging system light.
If this light comes on when you’re driving it indicates that the battery is not charging. This could be due to a problem with your car’s electrical system and it could have several causes, such as a faulty alternator, faulty battery, bad electrical connection or damaged cabling.
Anti-lock brake system (ABS) warning light
ABS is an important safety feature that really comes into play when you need to make an abrupt stop, or in difficult driving conditions like icy roads.
Electronic stability problem (ESP) warning light
Also called Electronic Stability Control (ESC), this warning light indicates a problem with traction control. If it’s flashing it means the ESP system is intervening – for example, if you’re driving on a slippery road. If the light stays on it means the ESP system is not working properly.
The ESP light will light up with the word ‘OFF’ if the system has been deactivated, in which case you may have inadvertently turned it off.
To check, try stopping and restarting the engine. If the light remains on after restarting get it checked at a garage as the ESP system is an important safety feature.
Brake pad warning light
Also called the brake pad wear warning light, if this symbol shows up it means a sensor has detected your brake pads are too thin.