Every time you switch on your car, you’ll notice that your dashboard comes to life with an array of different lights and symbols. Whilst most warning lights are the same in all makes and models of cars, their exact locations on or around the dashboard will vary. It’s always best to have a look at your car’s handbook to get yourself familiar with what they all mean.
They can appear a little confusing, but there’s nothing to worry about because their job is to let you know that all the systems they represent around the car are in perfect working order. However, if you notice that one of these lights stays on, or switches on whilst you’re driving, then it could be cause for concern because it could indicate that there’s a problem.
The different lights symbolise different things. The blue, orange and green lights are the least serious, but if one illuminates whilst driving, it’s always best to pull over when you get the chance. You should stop your car as soon as it is safe to do so if a red warning light appears, these are the most serious. It’s best to check your car manufacturers handbook for information on what each symbol means, and what to do next.
Sometimes the problem is obvious and isn’t something that needs your immediate attention – for example, a light telling you that you’re low on screen wash which will go off as soon as you top it up. However, for most of the other lights, it’s best to have the problem checked out, especially if it’s a light related to a major component of the car, such as the brake system warning light of the oil warning light.
This guide will go through what the most important dashboard lights stand for and give you a better understanding of what the symbols could mean if you see them light up in your own car.
Engine Management Light:
Even if your car feels fine to drive, if you notice this warning light stay on, or light up whilst you’re driving, then it’s important that you get your car checked out as soon as possible. This light symbolizes a potential problem with your engine, and if you ignore it, you could be further damaging your engine, which could prove to be costly. It could very well be a minor issue or a faulty sensor, but caution is always best to prevent potential damage.
Here’s a list of the 5 most common possible triggers for the illumination of the Engine Management Light:
- Blocked diesel particulate filter or differential pressure sensor fault
- Ignition system fault
- Emissions system failure
- Loose petrol or diesel filler cap
- Mass airflow sensor
Brake System Warning Light:
If you see the brake system warning light on your dashboard, it could be as something as simple as you leaving the handbrake slightly on whilst pulling away, so be sure it’s fully released. It could also potentially be low brake fluid, or it could be that the brake pad sensor is faulty. However, if you have fully released the handbrake and that doesn’t fix the issue, or you find that the light comes back on as you’re driving, then your brakes need urgent attention so you will need to pull over in a safe location and arrange for your car to be taken to a garage. This light could potentially be a very serious problem with the braking system, and you shouldn’t take the risk. If the brake pedal feels spongy or sinks all the way to the floor when you press it, then this is a significant issue and the car should not be driven any further.
Oil Pressure Warning Light:
After the brake warning light, the oil pressure warning light is the next most serious warning light to look out for. A faulty pump, a leak, too little or even too much oil can cause damage to your engine; which could end up costing you thousands of pounds. This means that it’s important that you don’t ignore this light The oil pump keeps the engine oil circulating and maintains the oil pressure in the engine. If you see the oil pressure warning light illuminate, immediately stop the engine and take a look at the car’s handbook. It could be as simple as topping up the oil. However, if the light doesn’t go out after you’ve topped up the oil then it could be more serious, and you should take your car to a mechanic.
Temperature Warning Light:
If you see this light whilst driving, then it means that your car is running too hot, potentially because there isn’t enough coolant or antifreeze in the system. If the car’s radiator is broken or clogged up and is leaking coolant, you’ll likely be able to see fluid dripping from the radiator. The temperature warning light can also appear due to a faulty water pump. But most serious of all, it can light up if the car’s head gasket has blown. This can lead to critical engine failure if you don’t turn off the engine immediately.
If you ever see this light on your dashboard whilst driving, then it’s important that you switch off the car immediately, because running hot for too long will cause irreversible damage.
Battery Charge Warning Light:
The battery charge warning light relates to the car’s battery and charging system. If this light illuminates on your dashboard, it could mean a variety of issues. Without the battery and charging system providing the car with electricity you will find that the power steering, brake servos and the engine itself will all be affected. It can also be a significant problem during hours of darkness because a faulty battery can lead to your headlights failing.
Whilst the cause could be something as simple as a faulty battery, quite simply rectified with a replacement battery, it could also be a problem with the car’s wiring or something more serious like the alternator or the drive belt. Most garages are able to identify the fault by checking your car’s battery and charging system.
Tyre Pressure Sensor Warning Light:
In recent years it has become compulsory for car manufacturers to fit Tyre Pressure Monitoring Systems (TPMS) in all new cars so they are becoming increasingly more common. TPMS’ job is to monitor the amount of air in the tyres at all times and if a drop in pressure is detected, it will alert you to the problem through the tyre pressure warning light. This is essential for overall road safety because low tyre pressure can affect how a vehicle handles and the time in which it takes to stop when braking. If the pressure drops suddenly when travelling at high speed, then it can cause a catastrophic blow-out. If the TPMS system alerts you of an issue, then you’ll need to check your tyre pressure as soon as possible and inflate it to the correct pressure. If you suffer a puncture, then you’ll need to change the wheel to the spare, or use a puncture repair kit to get you to the nearest tyre specialist.
Glow-Plug Warning Light (Diesels Only):
Diesel engines differ from petrol engines in that they rely on heated air to ignite fuel rather than a spark. This means a diesel car doesn’t use spark plugs to make the air/fuel mixture react to get the engine to start but instead uses glow plugs to create heat. If the glow plug warning light illuminates whilst driving, either staying on or flashing, there could be an issue with the glow plugs themselves, or with the control module responsible for controlling them. If you notice your car struggling to start or there is a ‘knocking’ noise on ignition, this could be an indication that your glow plugs are failing. Failing glow plugs prevent the engine from running smoothly and efficiently, so if your diesel is struggling to start, or sounding a little rough, it may be time to have your glow plugs replaced.
Electronic Stability Programme Warning Light:
When your car is close to the limit of grip, most likely in snowy or icy conditions, when it’s raining or on lose, gravelly surfaces the electronic stability light will illuminate to warn you of the loss of traction. If your car has a button that lets you to partially or completely turn off the standard electronic safety system, it is not encouraged to do so on public roads. However, when taking part in professionally organised high-performance driving activities, such as on a closed airfield or race track, turning off the electronic stability programme can allow drivers to use their own skills, judgement and reflexes to manoeuvre the car more freely.
If this light is always illuminated then it could mean that it’s been deactivated, which could be a fault or you could have chosen to switch it off. If it’s a fault then you will need to get the car checked, and if you chose to switch the system off, then its advisable to switch it back on, particularly on public roads.
Low-Fuel Warning Light:
This warning light will come on when you have about 50-70 miles of range left in your tank and indicates that the fuel has gone below a certain level. Essentially, the low-fuel warning light is designed to give you adequate time and mileage to find a fuel station. Whilst running out of petrol won’t damage your car, if you run a diesel car dry, the fuel lines and injectors will need to be bled to get rid of the air to allow the engine to start properly. Stopping on the road because of an empty tank is considered an offence.
If you suspect your car has a fuel leak because it seems to be using more fuel than normal, this can usually be diagnosed by checking the ground under the car, particularly in areas where you’ve parked such as a driveway, garage, car park or on the side of the road. Alternatively, your car’s onboard computer – ECU – could be telling the engine to use more fuel than it needs. Either way, a garage will be able to rectify the problem for you.
Bonnet, Boot and Door Warning Lights:
These warning lights are designed to alert you that one of your doors; bonnet, boot, passenger door or driver’s door, is open. This light doesn’t mean that there’s anything physically wrong with the car but that a door may have only been loosely closed, rather than shut tight. If, after checking all the doors are securely closed, the warning light is still on, it could be a fault with the sensor.
Seatbelt Warning Light:
If there is a certain amount of weight on a seat and the seatbelt hasn’t been fastened, the seatbelt warning light will illuminate, and you may be subjected to an annoying binging noise. The majority of modern cars have pressure sensors located in the seats and in the belts themselves to let you know if your passengers haven’t ‘belted-up’. You must wear a seatbelt if there is one fitted, there are very few exceptions to this rule so typically if the seat has a belt, it should be worn. If you don’t and are stopped by the Police, you could be fined up to £500.