We all noticed that when we turn on the car, a multitude of warning lights, of different colors, light up and once the engine starts, they go out. With this, the on-board computer tests the operation of all systems and notifies you that all is fine.
Problems arise when one or more indicators remain lit on board after starting the engine, which announces a malfunction of a system. In case of failure, one or more indicators may light up while driving.
We shall try to offer you a complete guide about the on board indicators of your car and to make you understand as well as possible what each one represents, because some can be absolutely trivial (like burning a light bulb or when you run out of windshield fluid) or out right worrying, such as the lack of brake fluid in the braking system.
Also in this article we will explain all the on-board indicators that you can find on most cars , from 2000 to 2018. If you want to read only about those from VW, navigate to the end of the article.
Read here about the 5 most important on board indicators
These indicators can light up in several different colors, the most serious problem being indicated by the color red. If a red light comes on in the dashboard, we recommend that you stop the car as soon as possible. Regarding the other range of colors, yellow, orange, blue or green, we also recommend that you stop the car and consult the car’s user manual but also visually inspect the car, maybe you can see the problem and thus fix it before you have to get it checked by a mechanic.
As i mentioned above, some lights report small issues that do not affect the functionality of the car, some cars have lights on the dashboard for low tire pressure or even lack of windshield fluid, so it would be ideal for you to read the car’s manual to get used to its features.
Keep in mind that red lights announce a serious problem. Let me give you a simple example. If the yellow oil warning light comes on board, it means that you need to get your car serviced or that the oil level has dropped, but not dangerously much. If the same light is illuminated in red, the problem could be serious. You may have a serious oil leak that, if left unchecked,will cause the car’s engine to stall.
The main, most important dashboard lights are the same for all car models; the only thing that might differ is their position on the board.
Here are some of the most important
The Check Engine light
Check Engine is definitely the best known warning light and rightly so. It notifies the driver that the engine is not running properly.
Most often it can be a minor problem, but when the Check Engine light appears on board it is recommended to take the car to your mechanic for detailed testing. This indicator light may come on due to many factors. Only an OBD2 tester will tell you what the problem really is.
There may be minor problems, a sensor that reads the data incorrectly and is sending incorrect parameters to the on-board computer, causing the computer to believe that the engine is not working properly , or there may be major problems, such as low compression in one of the pistons, a spark plug that no longer works properly or even a problem with the car’s gearbox.
There is no point in worrying too much until you test your car . Most of the time the problem arises from a faulty sensor that transmits inaccurate information to the ECU.
Oil pressure warning light
An engine without oil would take less than a few seconds to completely destroy itself. This light is therefore so important and tries to warn the driver that the engine does not have the required level of oil.
Therefore this light is quite important and it tells the driver that the engine does not have the required level of oil.
The engine may lose oil, may have a broken oil pump, may “waste” oil, all of which are problems that can lead to engine damage. If this warning light appears while driving, and if it is red you should stop the car right away.
Many times you may just need to top up the oil level. However, consider taking the car to a service center for a thorough investigation.
As I said, there are many reasons why the car may have started consuming or wasting oil. We are used to looking under our car for oil marks and if we don’t see them we think that everything is fine and that the car has no problems with the oil.
Cars may consume oil in excess when they have issues with gaskets, piston rings or turbines, so it’s worth taking a run for service for a small diagnosis.
Braking system warning light
When the brake light indicator appears, it is advisable to stop the vehicle. If you accidentally leave with the handbrake on, this sign will stay on board until you lower the brake lever to its normal position.
If the light is still on then you really have a problem. Pull the car to the right and call a tow truck to help you get to the nearest mechanic.
A problem with the braking system can be fatal. This warning light may indicate a lack of pressure in the braking system or may be a blocked caliper that simply stopped working.
Our advice, if the car does not slow down when you apply the foot brake, try to brake using the handbrake, because it has an auxiliary braking system, and also use the engine brake as aggressively as possible to slow down the car.
Battery warning light
This indicator light warns you that you have a problem with the car’s battery or alternator. Both are quite serious, because the power steering, abs and even the engine need electricity to work.
Potential defects can occur from a worn out battery, from an alternator that no longer works within the parameters or from a broken or defective accessory belt, belt that no longer spins the alternator. In any case, the repair is not very expensive and does not require much time.
If the car runs out of battery and the alternator does not work, it will basically stop running. If the alternator works and the battery is dead, you should reach a mechanic to get your car serviced, but if you stop the car, it will only start pushed or with cables.
Temperature warning light
Tells you that the engine is no longer cooled properly which might cause problems if you continue to travel this way.
An elevated temperature can occur due to lack of coolant, due to a broken radiator or a fan that no longer works. It can also announce a faulty water pump. No matter the reason you should either stop the car or find a mechanic as soon as possible.
Fuel warning light
Quite self explanatory, it appears on the dashboard when the fuel in the tank falls below a certain level set by each manufacturer.
In very rare cases this indicator lights up very quickly after refueling, the driver has the impression that the car consumes too much but in this case you might have a leaking tank. On some cars, if you refuel with the engine running, this warning light will stay on until you stop and restart the car.
TPMS control - Tire pressure
This warning light is quite rare on older cars, but on new ones it has become a standard feature. The indicator is connected to four sensors that monitor the air pressure in your car’s tires.
The warning light usually stays on even after you apply the correct pressure to all 4 tires. It is easily canceled from the on-board computer, where you have to confirm that you have inflated the tires.
Traction control
You will see this light flashing on board every time the tires on the drive axle lose traction. Basically, if the indicator is flickering lets you know you’re on the edge of traction. If the light is constantly on, it means that you have deactivated the traction control or this system is suffering a malfunction.
Many race cars will have this light constantly on since once the race mode is activated the ESP and traction control will automatically be deactivated.
Plug Control - only Diesel
Diesel engines, unlike gasoline engines, do not need a constant spark to ignite the fuel mixture. With one small exception, when the engine is cold, the fuel is ignited by means of incandescent spark plugs that heat the air in the combustion chamber up to 800 degrees Celsius.
Diesel engines self-ignite the fuel mixture due to their different diesel combustion properties and with the help of higher piston compression than gasoline engines.
When the engine is cold the spark plugs are needed. This warning light will not tell you which of the spark plugs are worn out. The car needs to be inspected by a mechanic.
Now that we’ve talked about those warning lights which should worry you, we’ll explain the rest of the lights you might see pop up on the dashboard once in a while. Not being numbered, we will explain the indicators shown in the picture above, from left to right, on each line.
- Adaptive Cruise Control - this light notifies the driver that adaptive navigation is on.
- Cruise Control - autopilot is turned on. The difference between 1 and 2 is that the ACC has an extra brake sensor, so the car automatically keeps its distance from the one in front and brakes and accelerates on its own.
- Lane Assist is on. The car is kept in its own lane with the help of the ACC sensor.
- The warning light indicates you need to press the brake pedal. Usually with automatic gearboxes.
- The light informs you that you have a problem with the car’s airbags or seat belt system.
- The hood is raised.
- The boot is open.
- The light indicates problems with the braking system.
- At least one door is open.
- The red light informs you that the engine cooling system has a serious problem.
- Low oil pressure.
- Ignition issues
- Problems with the Power steering system
- The light informs you that some passengers do not have the seat belt on
- Problems with central locking.
- Problems with the car battery or charging system.
- Problems with headlights or with the adaptive headlight system.
- Problems with adaptive shock absorbers.
- Problems with air suspension.
- Airbag control and seat belt system.
- Low level of windshield fluid.
- ABS control, problems with the ABS system.
- Gearbox problems.
- Break indicator worn out
- Brake pads must be replaced
- Lightbulb worn out
- Problems with the car’s hood system.
- Defective glow plugs. Applies only to diesel cars, the witness tells you that at least one incandescent spark plug no longer works.
- Problems with DPF or FAP on some cars. Applies only to diesel cars with a year of manufacture over 2009. The particulate filter is clogged and needs to be cleaned or regenerated.
- ESP light . Stability control no longer works or is disabled by the driver.
- Check-Engine light
- EPC indicator
- The light indicates low oil level.
- When this light appears, you may have problems adjusting the headlights.
- An error that only occurs in keyless cars, lets you know you don’t have the key in the car.
- The car’s fuel level is low.
- The light tells you to press the clutch pedal.
- Indicates problems with the windshield sensor, light and rain sensor.
- Fog lights are defective.
- The light let’s you know you have a problem with the rear spoiler of the car.
- Problems with the towing system.
- The TPMS light , is responsible for monitoring the tire pressure.
We continue the article with another list of on-board lights that will surely interest you.
- Problems with fog lights.
- Problems with the power steering system. In this case the steering wheel of the car will turn harder and in most cases you will hear noises like rubbing when you try to turn.
- Problems with fog stop / stops.
- Low windshield fluid level. Top up with windscreen fluid to cancel the warning light.
- the brake pads indicator. These must be changed when the warning light comes on. Be careful when changing them, inspect all brake pads. Some cars have wear sensors only on the front axle. When changing the brake pads, inspect all the brake discs.
- Cruise control on.
- Signaling
- Problems with rain sensors and automatic lights.
- The outside temperature is approaching the freezing point.
- You have new unread information about the status of the car.
- Problems with the diesel ignition system. At least one glow plug does not work. You will have problems starting in cold weather.
- Fog warning light
- Car key issues
- The key is not in the car or in the immediate vicinity.
- The car key no longer has a battery. It would be advisable to change it as soon as possible.
- If you have a braking sensor or ACC system, this light will tell you that you are too close to the car in front and you need to increase the distance.
- Press the clutch pedal
- Press the brake pedal
- Problems with the steering wheel immobilizer
- High beam on
- TPMS sensor, one of the tires, no longer has the proper pressure.
- Low beam on
- Problems with any of the car lights and beams
- Brake stop light issues
- Problems with the DPF or particulate filter. This indicator appears only on diesel cars.
- Car towing system error.
- Problems with the air suspension system.
- If you have Lane Assist, this light will tell you that you have exceeded your lane.
- Problem with car catalytic converter / catalyst.
- Do not have your seat belts fitted.
- The parking brake is applied. If it is not, it means that you have a problem with it.
- Car battery problem.
- Parking aid. It usually appears when another parking sensor is displayed.
- You need to overhaul the car.
- Adaptive headlights.
- Indicator showing the inclination of the headlamps.
- Rear spoiler problems.
- Problems with the car’s hood system.
- Airbag problems.
- Handbrake indicator
- This light will tell you that you have water in the fuel filter.
- At least one airbag is deactivated.
- You have a mechanical or electrical error.
- Low beam indicator
- Dirty air filters need to be replaced.
- The car is in ECO mode.
- Downhill help activated.
- The engine has a high temperature, pull to the right and stop the car.
- Problems with the ABS system, avoid sudden braking.
- Fuel filter problems.
- You have at least one door open.
- The hood is open.
- Low level of fuel
- Automatic gearbox transmission error. The problems can be various, from mechatronic, to clutches or torque converter.
- You have activated the speed limiter, you cannot exceed a certain preselected speed.
- Problems with car shock absorbers.
- Low oil pressure.
- Windshield defogger activated.
- The trunk is open.
- Stability control is turned on.
- Rain sensor.
- The car has engine problems. High level of emissions
- Rear defogger.
- Automatic wipers on.
We hope that in this article not only we have covered the most important on-board lights,but we have also offered you some tips on how to act when you encounter problems with the car, especially in cases where said problems are indicated by red lights on your dashboard.
Cars tend to evolve therefore so will the warning lights. We will try to update this article accordingly. The next set of warning lights we will be talking about are those you will find on the dashboard of a Volkswagen
As you can see, we did not number the lights so we will explain them one by one, from top to bottom, from left to right.
- Dashboard light that comes on when you put the hazard lights or choose to change direction.
- Autopilot on-board, the pilot is now active.
- This warning light informs you that you have a problem with the power steering system.
- The parking brake is applied, if the brake is not applied the warning light tells you that you have a problem with the braking system and it must be checked as soon as possible.
- Seat belt warning light .
- ECO mode is active.
- EPC on-board witness. Find out more about EPC.
Photo: expertecautomotive.com, midwesttransmission.net, dev.motoringresearch.com, goldeagle.com, bradleys-tow.com, youtube.com, bestride.com, yourmechanic.com
