>Dashboard warning lights: A Complete Guide for Your Car
Dashboard warning lights: A Complete Guide for Your Car
It’s quite common for drivers to continue driving when the lights on their dashboards illuminate. The fear of large repair bills is enough to put a lot of drivers off taking their vehicle to a garage – even when they can pay for car repairs in instalments with Bumper.
However, failing to take action when your car is warning you of a problem can be a costly, and sometimes a dangerous decision.
In this guide, we’ll take you through what the mean of warning lights on your car dashboard for your vehicle and what you should do about them.
It’s important to remember that when you turn the ignition in your car the vehicle will run a check, illuminating all of the lights at once. If any of the lights stay on, this indicates there is a problem (with the exception of the brake light, which illuminates when the handbrake is engaged).
Check Engine Light
The Check Engine Light or Engine Management Light links to the Engine Control Unit and will be displayed if there is a problem with your engine’s performance.
The light can illuminate in different colours depending on how urgent the warning is:
Yellow, amber or orange – It is safe to continue driving for now, but it is advised you have your vehicle checked soon to keep your engine performing efficiently.
Flashing amber – It may be safe for you to drive for a short while, but you should book in with a qualified mechanic as soon as possible.
Red – This indicates a serious problem with one or more systems. You should stop your car when it is safe to do so and contact a breakdown service.
What has caused the light to illuminate?
The Engine Management Light and Engine Control Unit cover a variety of sensors all over the vehicle. This makes identifying the problem difficult.
Here are some common causes of the Check Engine Manage Light:
Problem with the catalytic converter
The catalytic convertor turns harmful carbon monoxide into carbon dioxide, but the system can sometimes become clogged in the process.
You can help prevent this by taking the car on longer journeys and taking it for a regular service.
A failure with this system will increase your emissions level, causing the check engine light to illuminate.
EGR valve failure
The Exhaust Gas Recirculation valve controls the amount of nitrogen oxide in the engine, helping to improve the car’s efficiency.
Exhaust gases are redirected back through the engine’s cylinders, which are then used again in the combustion process.
The valve can become stuck open or closed by a build-up of particles resulting in your check engine light illuminating.
It is recommended a qualified mechanic cleans the valve for you.
Faulty spark plugs
Spark plugs ignite the fuel in the combustion chamber.
If these were to fail, you would notice a decrease in your engine’s performance and increased stalling.
Spark plugs should be changed regularly and in accordance with your car’s manual.
Fuel Injector problems
The amount of fuel entering your vehicles combustion chamber is moderated by the fuel injector.
The injector can become clogged, resulting in lower performance.
Loose or faulty petrol cap
Driving with your car’s petrol cap open can increase your emission levels as fuel hydrocarbons leak out and pressure can be lost.
If the check engine light is illuminated, it would be a good idea to check your petrol cap is shut or if there is any damage. A faulty cap shouldn’t be too expensive to replace.
A Diesel Particulate Filter is fitted to the exhausts of diesel cars, removing harmful particles as exhaust gases are ejected.
However, these particles can build up over time. A large build up will trigger the Engine Control Unit to start a DPF regeneration process which burns more fuel, burning off the extra particles.
If the regeneration process fails, the check engine light will be illuminated, and you should seek the advice of a qualified mechanic.
Mass Airflow Sensor malfunction
The job of the Mass Airflow Sensor is to tell the Engine Control Unit how much fuel to add to the combustion chamber to match the air flowing through the engine. This ensures the vehicle runs efficiently.
A failure of this sensor would mean a poorer fuel economy and may cause your engine to stall.
The sensor sits behind the airflow filter in the engine which can result in incorrect readings.
You should have the filter replaced every 12 months or so to ensure it is working and fitted correctly.
Oxygen Sensor malfunction
The oxygen sensor measures the amount of unburnt oxygen emitted through the exhaust.
If this sensor fails there will be more fuel burnt than necessary, decreasing your car’s fuel efficiency.
What you should do if you the check engine light comes on
If the check engine light comes on, note the colour of the light.
If it is an orange or amber colour and you feel the car is performing as it should, you can continue your journey, but make sure you book in with a garage as soon as possible.
If the check engine light is red, you should find a safe place to stop and contact a breakdown service. It is not recommended you continue your journey.
ABS stands for anti-locking brake system. The ABS prevents your vehicle from skidding by quickly releasing and applying the brakes on the wheel.
If the ABS light comes on, your brakes may still work but the ABS might not engage, which may be a problem if you need to perform an emergency stop.
If the ABS and brake system light are on at the same time, then your vehicle is unsafe to drive.
If just the ABS light is illuminated, you should drive carefully and book in with a qualified mechanic as soon as possible.
If the battery light on your car illuminates and stays on, this indicates there is a problem with the car’s battery.
There are three reasons this could happen:
Damaged battery or cables
This is the most common reason. Over time the terminals on the battery can erode or the cables can become unplugged or damaged. If there is damage, the battery won’t be able to hold charge from the alternator. It’s likely your battery will need replacing.
The alternator creates the electrical charge that is stored in your battery. It powers the headlights, radio, heater and electrical windows. If the alternator fails, then no electricity will be generated and your car will eventually lose power and stop.
Broken alternator belt
A broken alternator belt can be a serious problem as the belt controls not only the alternator but the coolant pump and power steering. If the battery light stays on and the engine becomes hot or you find it hard to steer, you may have a problem with the alternator.
What should I do?
You should turn off unnecessary electrical systems such as the radio and headlights (if it is safe to do so).
If you are close to home or a garage you can continue to drive cautiously for a short distance until you can have your vehicle checked by a qualified mechanic.
If you are far from home, you should not continue to drive. If your power steering fails, you may find it difficult to drive.
It is important to note that once you turn your engine off a damaged battery may not have enough charge to turn it on again.
Tyre Pressure Sensor Light
The purpose of the Tyre Pressure Monitoring System is to alert you when the pressure is low.
Underinflated or overinflated tyres can result in tyre wear.
Overinflation results in decreased traction. This will result in premature wear at the centre of the tyre.
Underinflation will cause your car to feel sluggish, decrease your fuel economy, and create excessive heat build-up. This will result in in premature wear on both sides of the tyre.
If the light stays on, check the pressure using a gauge and adjust according to your car’s manual. If the light continues, you may have a puncture. It is recommended you have your tyres changed or repaired by a professional.
Traction Control Light
The Traction Control System is activated when your car detects one or more of the wheels has lost traction. This can happen in wet or icy conditions.
When traction is lost the engine transfers power from the wheels that are slipping to the wheels that have grip.
If the Traction Control Light is illuminated and stays on there is a problem with the system.
In some vehicles the light will illuminate when the system is engaged and go off when the vehicle regains traction (you can check this in your car’s manual).
If the light is on all the time, the system will be shut down and you should take the vehicle to be checked by a qualified mechanic.
You should take extra precaution whilst driving to the garage.
Brake System Light
Your brakes are without a doubt your car’s most important safety system.
If the brake light comes on and stays on when the hand brake is disengaged, there could be a problem with your brakes.
The most likely reason for this is low brake fluid. Using your owner’s manual for guidance, locate the brake fluid reservoir and top up if necessary to the correct amount.
Make sure to use the correct fluid for your engine. This can be found in the owner’s manual.
If the light remains on when the fluid is at the correct level, you may have a leak.
Press down on your brake. If it sinks slowly to the floor, check under your vehicle for any yellow liquid leaking out.
If there is no leak, you may have a problem with your brake pads. The warning light can stay on when brake pads are significantly worn.
Some cars have a separate light for worn brake pads that looks like this:
You should not drive any further with a brake fluid leak or worn brake pads. Carefully stop in a safe place and contact a breakdown service.
Read our blog on Brake pad replacement costs.
Oil Pressure Warning Light
There a are several reasons the Oil Pressure Warning light could be illuminated. Here are some common ones:
Your oil level is low
Oil lubricates the engine and all the moving parts working properly and helps the cooling and cleaning process.
If the oil is not kept at the correct level, you could cause costly damage to the engine.
Check under your car, if there is an oily patch underneath you will need to contact a qualified technician.
Increase your oil level by locating the dipstick. Remove the stick and wipe with a cloth.
Once wiped, replace the stick and pull it out again. You will be able to see the level of oil.
If you’re unsure on how to locate the dipstick or what the correct level of oil should be, this can be found in your car’s manual.
Your oil pump needs replacing
If the oil pump isn’t working the pressure will drop. This makes it hard for the oil to lubricate the moving parts in your engine. This may result in the engine making a loud noise whilst running.
Check your oil level, if it is fine and there is no sign of a leak the light may indicate a faulty pump.
You should not continue to drive with a faulty pump this could cause a lot of damage to your engine.
You have a faulty sensor
If your oil level is fine, there is no sign of a leak and your car sounds and is running normally it could be a faulty sensor.
It is not recommended that you drive your vehicle. You should contact a breakdown service.
Engine Temperature Warning Light
The Engine Temperature Warning light indicates your engine is overheating.
You should stop when it is safe to do so and check the coolant levels under the bonnet. Be careful when doing so, as the bonnet could be hot.
If you’re unsure how to locate the coolant tank you should consult your car’s manual.
Top the coolant up if necessary and wait at least 30 minutes for your engine to cool before continuing your journey.
Fuel Indicator Light
The fuel indicator light means your car is low on fuel and you should fill up your ank as soon as possible.
Can I drive with the light on?
It is not recommended you drive far with this light illuminated. You should keep your tank around a quarter full at least to keep the fuel pump lubricated.
If the fuel pump is continuously unlubricated for extended periods of time this can significantly reduce the pump’s life span. This can be expensive to replace.
How many miles can I go?
If you’re far away from your nearest garage you may have no choice but to drive with the fuel indicator light on.
How many miles you can travel differs greatly between makes and models of cars and other variables such as, tyre pressure, gear choice and road surface can have a big effect.
Here is a rough guide for popular models, taken from the RAC.
|Audi A3||43 miles|
|BMW 3 Series||44 miles|
|Ford Fiesta||37 miles|
|Ford Focus||41 miles|
|Mini Cooper||44 miles|
|Nissan Qashqai||43 miles|
|Vauxhall Astra||30 miles|
|Vauxhall Corsa||36 miles|
|Volkswagen Golf||44 miles|
|Volkswagen Polo||42 miles|
Tip: The arrow next to the light indicates which side of the vehicle your fuel cap is located.
Airbag and Seatbelt Light
Common causes for the airbag and seatbelt warning light illuminating are:
Interference with seatbelt sensor
If dirt has become stuck in the seatbelt catch this can cause the seatbelt to not lock properly or for the computer to think the seatbelt is not fastened.
Damaged wires under seat
The wires under the driver or passenger’s seat can be damaged by items being stored or trapped under them.
Damaged clock spring
The car’s clock spring allows the steering wheel to turn whilst maintaining the connection between the electrical system, horn, and airbag. If the clock spring is damaged this may result in the airbag and seatbelt light illuminating.
Car has already been in an accident
The car may have been in a small accident that wasn’t big enough to trigger the airbag but triggered the warned light. The light would need resetting.
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