From the heartbreak-inducing check engine light to a simple reminder to fasten your seat belt, there are quite a few lights on your dashboard that can appear more often than not. While they cause quite the stir once they light up, they do help you understand if anything is wrong with your vehicle and if need be, you can use a diagnostic device such as OBDeleven to discover the cause of the illumination in front of your eyes.
There are two types of lights: an ambient one and a red one. While the former means that something needs to be looked at, a red light means that you need to immediately stop and have your car towed to a specialist, as it is a safety hazard to you and other drivers on the road. For example, if a brake warning light, which is red, has shown up on your dashboard, it can mean that potentially your brake system has failed and can result in you not having any stopping power whatsoever, which is quite dangerous, to say the least. At the same time, you should check your car's user manual to ensure that the dashboard light is not potentially life threatening to you or your passengers.
At the same time, pretty much all of the lights show their faces once you start the car, checking whether the systems are running fine and dandy. If a light stays on, though, it might indicate an issue – a diesel car has the glow plug light that will stay on until it is okay for the engine to be started – and potentially, end your journey there and then without you being able to travel to your destination without a hunch.
Thus, for you to fully understand every warning light there is on the spectrum, we present to you the list and an explanation of the most common dashboard lights.
Check engine light
The doom and gloom of every car owner, the check engine light will never deliver good news to you, as it indicates that the engine control unit is having an issue and is potentially indicating that your car’s heart is not running smoothly. While there could be a wide variety of causes as to why the all-feared orange light has appeared on the dashboard, the only way to truly find out what has gone wrong will only be possible by running diagnostics.
That is due to the sheer number of various moving parts on an engine that could, for example, cause an engine misfire. It could be faulty spark plugs, the wiring of the spark plugs themselves, issues with glow plugs – a diesel engine exclusive – or a vacuum leak, and those are not the only potential causes of the issue. Whatever the case might be, blindly guessing can take a lot of time and money, which is why you should invest in a proper diagnostic device such as OBDeleven.
Oil pressure warning light
With oil being essential to run an engine, as it lubricates all of the metal parts inside of it, increasing not only its longevity but also efficiency, an oil pressure warning light is a serious issue that has to be dealt with as soon as possible.
The red light – indicating the hazard of the situation – will usually appear when your engine does not have enough oil. However, there might be cases when it could be a faulty sensor causing the issue or a faulty engine oil pump that is unable to deliver enough lubricant into the apparatus that drives a car. Still, since it is a red light, it’s best if you stop as soon as you see it on your dashboard to avoid any long-term damage to the engine, which could become a very costly adventure down the line.
Brake system warning light
Another system that is absolutely crucial to the safe operation of a car, is the brake system warning light can either mean that the parking brake is left on or in a scenario that hopefully has a happy ending, means that your braking system is no longer operational.
And since it is crucial to ensure your and others’ safety on the road, the light is red, indicating that you have to stop as soon as possible and have your car towed to a specialist for them to inspect it. They might need to only replace the brake pads or the issue could be much more serious, as a leaky braking system can leave you in a very precarious position on the road.
In any case, if your braking performance worsens, whether it would be a longer braking distance or vibration once you press the brake pedal, you should drive down to your local mechanic even before the brake system warning light comes on your dashboard.
Battery charge light
While a car battery is much larger than the average household battery that you would use in a TV remote, for example, it still has to be recharged. The battery charge light does indicate that there might be an issue with either the battery charging system or that the 12-volt battery has drained, hindering your ability to start the car. Another light that will turn red as soon as an issue is apparent, and another light that will turn on and stay on as you turn the key to start your car. However, if it does stay on once your engine is running, it does mean a problem can be found under your hood.
Once again, an OBD-II diagnostic device will help you out determine the exact issue, as the battery itself might be more than okay to use once you fix the alternator, for example. So, using something like OBDeleven might prevent you from buying a new 12-volt battery when you do not need one, saving you an expense you did not need to deal with in the first place.
Temperature warning light
All car manufacturers, in some shape or form, have chased the maximum efficiency of an Internal Combustion Engine (ICE) for over a century now. Even if the automotive industry is slowly shifting away from the ICE, and looking towards emissions-free transport that will include electric vehicles, temperature will continue playing a role. If your engine, even the battery, gets too hot, it either is operating inefficiently – consumes more fuel/burns more oil – or is unable to continue operating at all.
Similar to a situation where not enough oil is in the engine, a malfunctioning cooling system can result in significant engine damage that will make your heart sink once you have to repair issues that are now deep-rooted. Thus, reacting immediately and alleviating the overheating engine is crucial – with a trip to a mechanic guaranteed either way. But if the engine has been running hot for quite a while, the trip will not be as pleasant when compared to an excursion to fix the cause behind an overly warm engine.
Low-fuel warning light
Probably one of the most obvious warning lights out of the list, the orange low-fuel warning light is still an anxiety-inducing cautionary notice to fill your vehicle with the good old, refined oil to continue running. While there is not much to be said about the light itself, it can also be caused by a fuel level sensor that is no longer functional. If you just filled up with gas or diesel and the light is still on, a trip to the mechanic is very much due.
Tire Pressure Monitoring System (TPMS) light
With the number of sensors ever-growing on a car, the Tire Pressure Monitoring System (TPMS) was once a quirky gimmick seen on some French cars in the late-to-early 90s, as well as being an option on luxury vehicles. However, with the onset of new technologies and multiple tire-related crashes in the United States (US), the TPMS became mandatory in the 50-state country and the mid-2010s in the European Union (EU).
The system indicates that there is not enough air in your tires, which is not only a safety hazard but also increases the fuel consumption of your car. Nevertheless, the TPMS light can also turn on following a major temperature change towards the colder end, which can deflate the tire a little bit and set off the system. Nevertheless, always make sure that your tires have enough air in them, with the recommended levels of pressure typically found on a sticker placed on the driver’s side door jamb, to ensure the maximum level of road grip.
Traction control light
A scenario whereupon the traction control light would turn on is an atypical one, as it means that the traction control system is on and is trying to ensure that the car stays on the road in slippery conditions.
Typically, such a situation occurs during snowy or rainy weather, as you drive over an icy or rainy patch of the road, which causes you to lose traction. The system itself, despite its complexity, is fairly simply explainable. Once your tires get on a slippery surface, or one side of the is more slippery than the other, the system will automatically reduce the power delivered to the now-unstable tire to slow it down or use the Anti-lock Braking System (ABS) to specifically slow down that wheel to stabilize the car. Once the system “feels” that the car has stabilized, the light, which indicates that it is turned on, will switch off.
An option to turn off is available on most vehicles with the press of a button. However, the Volkswagen Arteon (2017 – 2020) does not have such an option, for example. You can turn off the stability control, which is called Electronic Stability Control (ESC) on the Arteon, with the help of OBDeleven One-Click App ESC off permanently.
Glow plug light
With a very fundamental difference in how petrol versus diesel engines start and operate, glow plugs help diesel engines when they are starting. They do have to warm up and that is why the dashboard light appears whenever you turn the key on a diesel engine. Once the light disappears, it is safe to start the engine, as the glow plugs have warmed up enough.
In the case that the glow plug lights turn on while you are driving or do not turn off once you turn the key, a diagnostic scan will help you determine whether you have a serious issue with a key system in your car. Typically, though, the light will start blinking to point you to a problem with your diesel-powered vehicle.
Seat belt warning light
As seat belts have become the foundation of safety in the automotive industry, a reminder to fasten them has only improved the chances of survival if a car does get into a precarious situation.
While the seat belt buckle could be faulty, wrongly indicating that the seat belt is not latched into its place, the scenario is quite unlikely. Still, there are cases whereupon you would need to disable the seat belt warning light, especially if your car is being prepared for track use and you are installing a five-point harness to ensure that your newly-built sportscar meets the safety requirements to race on a circuit. With OBDeleven, you can turn off the seat belt warning for some Volkswagen Group (VAG)-made cars, if you plan to do some mad skids in a controlled environment.
Door, boot, or bonnet warning light
The purpose of this dashboard light is to warn the driver that one of the doors on his car is open and that, affirmed by the red color of the light, they should immediately stop and check the state of that door before driving any further.
If all of the doors are closed, the problem could be related to the electrical circuits on the car, or the falsely-active light could point to an issue with any of the door switches or the latch in the boot. Nevertheless, always be mindful of your openings and make sure that you do not drive away with one of the gates to your car open.
Bulb failure light
Being a yellow/amber light means that the failure of one of the car’s bulbs is not an immediate safety threat to the driver or his passengers. At the same time, a vehicle’s lights can be used as reference points in the dark, or to indicate a turn at an intersection, which means that it can become a problem sooner rather than later.
Still, while newer vehicles typically indicate which light has gone out, the root of the issue might be in the fuse box, the electric circuit, or the control unit of the lights themselves. As such, before you rush in and buy a new light bulb for your front driver’s side light, make sure you run a diagnostic check with OBDeleven to eliminate the possibility of a control unit failure, for example.
ABS warning light
Sharing some similarities and even components with the traction control system, the Anti-lock Braking System (ABS) is the reason why you avoid a trip to the dentist once you apply a lot of force to the brake pedal, as well as from locking up – like Formula 1 cars do – and not being able to steer the car towards safety. While the system is not operational all the time and only turns on when it needs to ensure the safety of the vehicle’s occupants, its importance cannot be understated, evident by the fact that it is mandatory on all new modern cars.
The warning light, though, even if it is still safe to drive the vehicle once it turns on, indicates that there is an issue to be found in the ABS module, low levels in the fluid reservoir, speed sensors, or the system is turned off. Whatever the issue might be, having a properly working ABS can be the preventative factor from a serious injury in a worst-case scenario.
Airbag warning light
Another system that is designed as a preventative measure from additional injuries if everything goes south, the warning light is to warn the driver that something is not quite right with the airbags. Technically it will make no difference to the driving experience or feel ¬– it is a redundancy system – but resolving the issue immediately is a must to guarantee everyone’s safety.
Typically, the problem could lie in crash sensors, which detect an accident and deploy the airbags as well as the seat belt tensioners, or the car’s wiring. The Supplemental Restraint System (SRS) could also be experiencing issues and might not deploy properly and fire off only half of the airbags on the car, which is not ideal.
Nevertheless, similarly to the ABS, if the light turns on – visit your local dealership to resolve the issue as soon as possible.
History of dashboard lights
While dashboard lights, much like OBD-II ports, have become universal across car makers globally, that was not always the case, as car dashboards were very rudimentary and only included gauges. Showcasing speed, fuel level, revolutions per minute (RPM), battery voltage, and sometimes the time, they were treated as a space where designers could have fun and create something that they themselves would admire. Form preceded function, as even “knobs and ornamentation on steel dashboards caused facial injuries in collisions,” according to the National Museum of American History, and were changed as safety became more of a priority.
Padded dashboards were the first step toward a safer environment in the car, yet they still lacked information that could indicate, for example, a failure braking system. Tell-tale lights or Idiot lights were first explored by Hudson Motor Car Company – becoming a part of Chrysler eventually – in the 1930s when it introduced “a plastic instrument cluster adorned with a shooter-sized red glass jewel that lit up when there wasn’t enough current flowing through,” per the Popular Mechanics magazine from the 1980s. According to the magazine, covering various things related to the inner working of mechanical devices and machines, new panels were installed in the 1940s, which were mainly plastic and had an inherent structural weakness to them. By the end of the next decade, the various gauges found on instrument clusters on cars were eliminated, leaving only the most important data ¬– speed, RPM, and fuel – visible to the driver, as warning lights were adopted across the board. While some bohemians remained, the industry began to move towards full reliance on tell-tale lights to warn drivers of potential safety hazards.
Eventually, idiot lights were placed in the back seat, with them being used only when such a need arose on the same instrument cluster in front of the driver, enabling car manufacturers to design clusters that were mostly focused on the three, previously mentioned, gauges. However, most recently another trend has emerged, as manufacturers place more and more emphasis on central console-mounted screens. While car makers have little wiggle room in terms of what information they can omit from showcasing to the driver, the location of the engine check light or a low battery charge on an Electric Vehicle (EV) is seemingly up to the manufacturers themselves, as concept and production vehicles alike have begun to spur the new fad of drivers controlling everything on a screen where previously, the climate and radio controls were mounted.