Dashboard Warning Lights – If you see a warning light on your dashboard (or touch screen, or the car’s smartphone app…) that means something went wrong. But some warning lights are more intuitive than others, especially those that have been around for a long time.
New cars are more complicated than most of us would have imagined just a decade or two ago, and they’re changing every year, with bigger screens, more efficient powertrains and more technological integration. As more cars incorporate electrification and semi-autonomous driving advancements, traditional instrument lights and warnings will increasingly go by the wayside as new ones take their place, but it’s still important to know what they all mean.
Any new car on a dealer lot today, even the most basic, likely has an advanced safety system that consists of cameras and sensors tied into the car’s main computer network, though the complexity varies based on the car’s level of safety tech and driver-assistance technology. Combine that with a central infotainment system controlling a lot of the car’s functions, and any minor problem can turn into a major one.
A warning light on the dashboard or instrument cluster (or infotainment display, or smartphone app) means something went wrong. Some are more intuitive than others, even though the methodology and design of warning lights has stayed fairly consistent over the years.
A red light indicates a major problem or failure, and you should prepare to stop as soon as it’s safe to do so. A yellow or amber light calls your attention to a condition you should be aware of, such as the traction control system activating on a wet or slippery surface. A green, blue or white light means you’re using a feature, like the headlights or a particular safety feature.
Let’s take a look at these lights, keeping in mind that they may vary somewhat. If you aren’t familiar with the lights in your car, this is a good primer, but always have your owner’s manual at the ready.
Check Engine Light – Dashboard Warning Lights
Dashboard Warning Lights – The check engine light, or CEL for short, is one of the most common dashboard warning lights but also one of the least specific. That’s because the check engine light warns of any engine-related issue. This can include something as simple as a loose gas cap (which may have a warning light of its own), or a more serious issue like a misfire, knocking or a loss of compression, which could result in premature engine wear or failure, which may leave you stranded and will be expensive to fix.
The check engine light can be red or amber, and it typically features the outline of an engine, the words “service engine soon” or simply “check engine” in bold letters. Some owner’s manuals also refer to it as the malfunction indicator light, or MIL.
It is completely normal for the check engine light to illuminate momentarily when turning the key in the ignition, but it should disappear as soon as the vehicle is running. If not, the system is detecting an issue. Due to the potential for severe engine damage, we don’t recommend driving your vehicle if the check engine light is on. Call for a tow truck and have a repair shop diagnose and fix the issue.
Engine Coolant Temperature Light – Dashboard Warning Lights
Dashboard Warning Lights – The engine temperature light features ared thermometer. When illuminated, it indicates that the engine is overheating. This is a serious problem and it can result in catastrophic engine damage, so if you see this warning light, you should always pull over as soon as it’s safe to do so and turn off your vehicle. There are a number of issues that can cause the engine to overheat, such as a broken water pump, a stuck thermostat, a leak in the radiator or in one of the coolant hoses or a blown head gasket.
Transmission Fluid Temperature Light
The transmission temperature light is often depicted as a yellow or red thermometer surrounded by a gear, or with the words “AT OIL TEMP.” When illuminated, this light indicates that the transmission is overheating. As before, you should stop and turn off your vehicle when it’s safe to do so if you see this warning light. Common reasons for an overheating transmission include low fluid levels, worn internal components, high mileage or extended periods of heavy towing.
Engine Oil Pressure Light
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The engine oil pressure light is typically depicted as a red oil can, and it signifies that oil is not circulating properly through the engine. This is a major issue because insufficient oil pressure can cause an engine to wear prematurely or even seize up, and it’s another light that means you should pull over and turn off the vehicle as soon as you can. Common reasons for low oil pressure include low oil levels, a worn oil pump and other worn internal components. It’s a good idea to check the engine oil level regularly and change the oil at the manufacturer-specified intervals.
Engine Oil Change Light
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The oil change light does exactly what you’d expect: it indicates when the engine oil should be changed, based on mileage driven. Most modern vehicles require synthetic oil, which has allowed automakers to stretch oil change intervals from the traditional 3,000-mile limit to anywhere from 5,000 to 15,000 miles in some cases. You may see this indicator displayed as text instead of as a light, such as “Service Engine Soon” or “Oil Change Required.” Some automakers refer to this feature as the oil life indicator as well.
Battery Warning Light
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The battery indicator light is red and it features the outline of a battery with plus and minus symbols. When illuminated, this light indicates that the vehicle’s charging system isn’t functioning properly. The battery could be the issue, but the cause could also be a loose or corroded battery cable, a worn alternator, a broken accessory belt or another electrical fault in the system.
It’s completely normal to see this light turn on and then off when starting your vehicle. If the light turns on while you’re driving, though, you should pull over and stop as soon as it’s safe to do so. Otherwise, the engine will stall once the battery is completely drained, which may only take a few minutes.
EVs also have battery warning lights. A battery symbol with a lightning bolt means the battery’s charge level is low (this may also appear in plug-in hybrid vehicles) and a battery symbol with a temperature gauge means the battery is running hot, and the car should be pulled over and shut off as soon as it is safe to do so.
Tire Pressure Warning Light
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The tire pressure warning light is depicted as a yellow tire with an exclamation point in the middle. This warning light signifies that one of the vehicle’s tires is underinflated, and – in some modern vehicles – it can show the pressure of all four tires and indicate which is low.
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The tire pressure monitoring system (or TPMS) is responsible for activating this light. If it turns on while you’re driving, you should pull over and stop as soon as possible. Driving with a flat or underinflated tire is unsafe, as it can drastically alter the vehicle’s handling. Call for a tow truck if any tire is flat, or change the tire if your vehicle is equipped with a spare. If the tires are all still inflated, you should drive to the closest service station to check the pressures and add air if necessary.
Common reasons for this light to turn on include a puncture, a faulty tire pressure sensor or gradual loss of pressure due to seasonal temperature changes.
Reduced Engine Power Light
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Modern vehicles are equipped with a fail-safe system, or limp mode, that limits engine performance if a major fault is detected. This setup is designed to protect the engine, transmission and other driveline components from damage. The system triggers the engine light to turn on, and – in some vehicles – a “reduced engine power” readout may also illuminate.
While the vehicle may still be drivable, it’s best to pull over and stop due to the potential for damage. A faulty throttle position sensor is one of the most common reasons for this light to turn on.
Brake Warning Lights
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The brake warning light features a red circle with an exclamation point or “P” in the middle, or simply the text “BRAKE.” When illuminated, this light can indicate such things as routine notifications that your parking brake is engaged to warnings that there’s a fault in your braking system, such as a failing master cylinder. If you unexpectedly have a brake warning light come on, first pull off the road, then set and release your parking brake. If the light does not turn off, it’s time to call a tow truck before the system fully fails or more damage occurs.
It could be something as simple as a sticky parking brake, low brake fluid or worn brake pads. More serious issues, including problems with the master cylinder or the computers that handle your car’s braking system, may be the culprit.
ABS Warning Light
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The ABS light features a yellow or red circle with the letters “ABS” in the center, and it illuminates when a problem is detected with the anti-lock braking system or when the system is active. Generally, if it’s flashing while you’re braking, the system is functioning as intended. If it’s on constantly, there’s a problem with your anti-lock braking system.
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ABS improves braking performance on slippery roads by pulsing the brakes to prevent the wheels from locking up and skidding. The brakes should still function if this light comes on while driving, but emergency braking performance may be reduced. If you notice any changes to your braking response or pressure when this light comes on, pull over and stop. Common causes for this light to turn on include a faulty wheel speed sensor or an issue with the ABS controller.
Traction Control Warning Light
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The traction control system works hand in hand with the anti-lock braking system. It selectively applies the brakes to limit the wheels from slipping during acceleration, and it often engages when driving on icy and snowy roads, wet pavement, sand and gravel. The yellow traction control light – a car with two squiggly lines underneath – illuminates momentarily when the system is intervening. If the light stays on, however, that means there is a problem with the system and it may not operate properly. A faulty wheel speed sensor is one of the most common reasons for this light to turn on.
Stability Control Warning Light
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Electronic stability control, or ESC, is another aspect of the anti-lock braking system. Stability control works to keep the vehicle heading in its intended direction. It does this by monitoring wheel speed and steering inputs, and then applying the brakes as necessary to prevent sliding or spinning. Some vehicles have a dedicated “ESC” or “VSC” warning light that illuminates when the system is engaging and stays lit if there is a fault, but many vehicles don’t. In those instances, the traction control warning light turns on instead.
Power Steering Warning Light
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The power steering light features a red or yellow steering wheel icon, often with an exclamation point on the side. It illuminates when a problem is detected with the steering. If your vehicle is equipped with electric power steering (EPS), you’ll need to take it to a mechanic to get the issue diagnosed. If the car has hydraulic power steering, however, the light often means that the power steering fluid reservoir is low. Top it off and keep an eye out for leaks. Schedule a service appointment if this doesn’t fix the issue.
It is not safe to drive the vehicle if this light comes on, even if you don’t notice any problems right away, because a gradual or sudden lack of power steering assistance will make the car much harder to maneuver.
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Airbag Warning Light
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An illuminated airbag light indicates that there is a fault with the vehicle’s airbag system, which is often referred to as the supplemental restraint system (SRS). This indicator light typically features a red airbag icon, though in some vehicles it is replaced by “SRS” or “AIR BAG” text.
You should not drive your vehicle if this light turns on, because it means that the airbags may not deploy in the event of a crash and the seat-belt pretensioners may not tighten appropriately. Have a qualified repair shop diagnose and fix this problem.
Seatbelt Warning Light
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The seat-belt light does exactly what you’d expect: it features the outline of a person wearing a seat belt, and it stays illuminated until the driver of the vehicle buckles up. Some vehicles also monitor the front passenger seat with weight sensors in the seat that communicate with the car’s computer. If all occupants have buckled up and the light doesn’t turn off, this may mean there is a problem with the belt buckle sensor or one of the pressure sensors under the seat.
Automatic Shift Lock Light
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Modern automatic transmissions are equipped with a shift interlock, which prevents the vehicle from shifting out of park until the driver has pressed the brake pedal. In some vehicles, it can also prevent the engine from starting. This reduces the risk of the vehicle rolling away if the gear selector is pushed accidentally. The shift lock light features a green foot within a circle, and it turns on to show when the system is active.
Low Fuel Warning Light
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The low fuel light features an amber or red gas pump, and it illuminates when the fuel tank is almost out of gasoline or diesel fuel, depending on the type of vehicle. The fuel level required to trigger this warning light can vary from vehicle to vehicle, but it often indicates about one to two gallons of fuel remaining. Additionally, this light may turn on if the gas cap is loose.
Washer Fluid Warning Light
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The washer fluid light illuminates when a low level of windshield washer fluid is detected. This indicator light is typically yellow and it features a windshield icon. The same symbol is located on the cap of the washer fluid reservoir, so you can easily tell where to add the fluid. Most vehicles only have one washer fluid reservoir, even if there are rear windshield wipers with washers, and it’s usually found under the hood. In cars with rear washers, the washer fluid reservoir typically has a separate pump and hose that moves fluid to the rear glass.
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Engine Stop-Start Light
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Many modern vehicles are equipped with automatic stop-start systems that are designed to save fuel in stop-and-go city driving. These systems can shut the engine off when the vehicle is slowing to a stop and quickly turn the engine back on once the brake pedal is released. This reduces the amount of time the engine is idling when sitting in traffic.
The engine stop-start light is typically an “A” surrounded by a circular arrow, and it can indicate a few different things. It may illuminate in a green or blue color to show that the system is active, or in an amber color to show that the system has been disabled. An exclamation point next to this icon usually indicates a fault with the stop-start system.
Security Light
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The security light may turn on for a few reasons. It may illuminate and disable the ignition system if the incorrect key is inserted. The light may indicate a fault with the ignition if it illuminates while driving. The most common reason is to deter thieves. When the vehicle is parked and locked, it’s typical for the light to blink occasionally to indicate that the alarm system is armed. The design of this indicator light can vary, but it usually features the outline of a car with either a key or a padlock icon.
Glow Plug Light
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Diesel engines are equipped with glow plugs, which are designed to heat up the combustion chamber and assist with starting the engine when it’s cold. It takes a few seconds for glow plugs to sufficiently warm up the engine air temperature, and they shut off once it is hot enough.
The amber glow plug light – a squiggle with two loops – illuminates to show that the glow plugs are warming up. The light turns off once the engine is ready to start. If the glow plug light blinks or remains on, it indicates that there may be a problem with this system and the vehicle may be difficult to start.
DPF Light
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In addition to glow plugs, diesel vehicles are also equipped with a diesel particulate filter (DPF), which collects engine soot and ash as it travels through the exhaust. This filter improves emissions and reduces the amount of smoke coming from the tailpipe; however, it can become clogged over time.
The DPF light illuminates when the filter is blocked and requires cleaning or replacement. This warning light is usually amber in color, and the design often features a box filled with small circles or a puff of smoke passing through a line of circles.
DEF Light
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The diesel exhaust fluid light, or DEF light, is the third warning light that diesel vehicle owners should be aware of. This light looks very similar to the DPF light with the addition of two droplets to symbolize the fluid. The light turns on when a low level of diesel exhaust fluid is detected, often followed by text warnings to refill the DEF reservoir. This fluid is a mixture of urea and deionized water that is injected into the exhaust system to reduce nitrogen oxide emissions. Another common name for DEF is AdBlue.
You should refill the DEF tank as soon as possible when this light turns on. Otherwise, the engine could enter a reduced-power mode or stop altogether if the tank is fully empty.
Cruise Control Light
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The cruise control light typically features a speedometer icon, and it can indicate a few different things depending on the color. Green often means that the cruise control has been set. An amber or yellow light can indicate that cruise control is enabled but not set, or that there is a problem with the system. Refer to your owner’s manual for specific information about the cruise control system in your vehicle.
Adaptive Cruise Control Light
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Adaptive cruise control uses forward-facing cameras and sensors to maintain a set cruising speed and distance to the car ahead. When engaged, adaptive cruise control can slow the vehicle if the car ahead begins to slow. Conversely, it can return the vehicle to the desired cruising speed if the car ahead accelerates or merges into another lane.
There are a few common dashboard lights related to the adaptive cruise control system. You may see text that reads “ACC,” a speedometer icon with a car behind it, or a car with waves in front of it. These lights typically indicate that the system is enabled. A series of bars between two vehicle icons usually indicates the desired following distance to other cars. Refer to your owner’s manual for additional information about this system.
Forward Collision Warning Indicator
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If your car is equipped with forward collision warning, this light will let you know that the car needs your attention.When your car’s forward-collision warning system senses that you’re closing on the vehicle ahead of you too fast, you’ll see a dramatic flashing red or amber light screaming “Brake.” You’ll need to immediately brake to avoid a collision or reduce the severity of an inevitable crash. An audible warning usually accompanies the flashing light.
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Lane-Departure Warning Light
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As its name suggests, the lane-departure warning system alerts the driver if the vehicle is drifting out of its lane. Common alert methods include “LDW” or “LDA” warning lights, a symbol of a car veering out of a lane, audible beeping and – if bundled with lane keep assist – a tug at the steering wheel to correct the vehicle’s path.
Parking Assist Light
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If your vehicle is equipped with parking sensors, you might see a warning light with a “P” and a triangle separated by waves. This symbol may also be accompanied by audible beeping or a bird’s eye view of the vehicle. It indicates that either the front or rear bumpers are in close proximity to an object, but it may also indicate a potential issue with this system. Refer to your owner’s manual for additional info.
Blind-Spot Monitoring Light
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Blind-spot monitoring systems use sensors at the sides and rear of the vehicle to detect other cars that may be obstructed by the driver’s field of view. These systems typically alert the driver by illuminating an icon – two staggered cars separated by waves – in the side mirror on the side of the approaching vehicle. You may also see “BSM” or “BLIS” lights on the dashboard. These lights can indicate that the system is operating, but they can also indicate a potential issue. Again, refer to your owner’s manual for more detailed information.
Drowsiness Monitoring Light
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Driver-attention monitoring systems use a number of sensors to detect if the driver is paying attention to the road. Most systems look for telltale signs like constant steering wheel corrections and extended driving distances without a break, but some advanced systems can also monitor eye movements. These systems typically alert the driver by flashing a coffee cup symbol on the dashboard, as well an “attention assist” or “time for a break” message.
Master Warning Light
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Master caution warning lights, common to high-performance aircraft, are finding their way into today’s cars and trucks. The master warning light (or instrument panel message) tells you to check other systems for issues. For example, it may illuminate to tell you to check your tire pressure monitoring system or the vehicle’s maintenance status. In some cars, it will remain illuminated until the underlying issue is corrected.
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Fog Lamp Indicator
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The fog lamp indicator lets you know if your fog lamps are on or off. If it’s illuminated, they’re on; if not, they’re off. In most states, driving with your fog lights on is unlawful while traffic is approaching from the other direction.
Gearbox Warning
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A gearbox warning is similar to a transmission fluid temperature warning light and sometimes shares the same spot on the dashboard. It indicates a fault in the transmission or components. Its illumination can be caused by something as simple as low transmission fluid or a mechanical problem that’s much more serious. Ignoring a gearbox or transmission warning light can lead to potentially expensive repairs or a failure while in traffic.
Gas Cap Indicator
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Most cars don’t have a gas cap indicator light, but the first step in investigating a check engine light is ensuring the gas cap is present and properly tightened. A leading cause of check engine lights is a loose or missing fuel cap.
Some, but certainly not all, cars will alert you if your fuel door is open. Most electric vehicles will tell you if the charging port door is open.
High-beam Headlight Indicator
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A basic high-beam headlight indicator will light up blue when the high-beam headlights are on and turn off when you switch back to your low-beam headlights.
Automatic High-Beam Headlight Indicator
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In newer cars with automatic high-beam headlights, there will typically be an “A” next to the high-beam headlight indicator to show that the automatic high-beams are active. In many vehicles, the icon will change from white to blue when the automatic system switches from low to high beams.
Door/Trunk/Hood Open Warning
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Most vehicles on the road today have dashboard warnings that let you know if you have a door, trunk, hatch or hood ajar. Some let you know which one it is, while others let you sleuth it out yourself. It’s a good idea to check any opening that triggers a warning, even if you think it’s closed, because it may not be fully latched.
In some cars, the warning is a simple icon. In others, it’s a high-definition image of the vehicle with the relevant area illuminated.
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Electric Vehicle Dashboard Warnings
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Electric vehicles have several dashboard warnings and displays that cars with internal combustion engines don’t have. Some include charging status, range and time to charge. Since electric cars are nearly silent, a dash message or indicator will tell you when the vehicle is ready to move.
One of the most critical electric car indicator lights, as mentioned earlier, is a battery pack overheat warning. It’s a signal to park the vehicle outside, as the battery cooling system may have failed. Another EV-specific light worth noting is a symbol of a car with an exclamation point. This indicates a fault somewhere in the car’s electrical system, and you should get the vehicle serviced immediately if it comes on.
ECO Driving Indicators
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Two types of dashboard indicators indicate how economically you’re driving. The first just notes when you’ve set your vehicle dynamics system to its Eco mode, limiting the car’s performance to increase fuel efficiency. The second is an active indicator that monitors how you’re driving and lets you know when you’re driving in an economical manner. These systems may vary, particularly in cars that have more sophisticated Eco modes, and aren’t necessarily limited to EVs or hybrids.
Four-Wheel-Drive/All-Wheel-Drive Indicators
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If your vehicle is equipped with four- or all-wheel drive, you’ll have a few additional indicators on your dash. In vehicles with four-wheel drive, there will be an indicator that shows whether you’re in two-wheel drive, four-wheel drive high range or (if equipped with a two-speed transfer case) four-wheel drive low range. There may be additional indicators for locking differentials, hill descent control and other systems specifically for four-wheel drive or off-road driving modes.
Vehicles with all-wheel drive will have an indicator that warns you if there’s a fault with your drivetrain.
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