Smart Warning Lights

On this page you can find explanations of the warning lights you may be seeing in your Smart.

Smart Models

(click your model)

smart forfour

smart fortwo

Warning Lights Explained

Hybrid Service Warning

A spanner with a lightning bolt (or zig-zag) through it would suggest to you that your Smart's hybrid system needs servicing. This can be due to several factors such as mileage, age or that the system has detected a fault. Ideally, you will take the vehicle to a Smart mechanic as the hybrid systems are very specialized.

Power Steering Warning

If you see a red steering wheel with an exclamation point next to it appear then it is most likely an electric power-assisted steering issue. Try pulling over and resetting the car by switching it off completely and then starting it again. If the light continues after you restart the car then seek help from a trained mechanic or Smart dealership.

Security/Anti-Theft Warning

A simple red dot on the dashboard instrument cluster could represent the security/anti-theft system experiencing an error. This could be in any of the security systems such as the immobilizer or alarm (if fitted). If the light persists while driving then it definitely indicates a problem and requires being looked at by a trained mechanic.

Airbag Warning

A passenger with a large circle in front of them and illuminated red displayed on the dashboard is your Smart trying to tell you that there is an issue with one or all of the airbags. As soon as this comes on it is advised that you take the car to a trained mechanic or a Smart dealership.

Seat Belt Reminder

A picture of a passenger with a band across them displayed in front of a red light indicates that a passenger has not correctly attached their seatbelt. This system works by detecting a passenger based on the weight on a seat so if you have any shopping or luggage on a seat then that may be what's setting it off. An audio alert usually comes on too once the car is in motion.

Transmission Oil Overheat Warning

If you are being shown a red warning in the dashboard that looks like a thermometer in a wavy circle (or maybe flower petals) then your transmission oil is too hot. This can be caused by the oil maybe needing replacing as it's not doing its job properly or the transmission in your Smart being pushed too hard. Pull over as soon as possible to allow the oil to cool down before setting off again. If the problem continues then seek help from a trained mechanic or Smart dealership.

Engine Temperature Warning

If you see a collection of waves with a thermometer floating above displayed with a red backing light then your car is telling you the engine is too hot. The waves represent the coolant in the engine which is usually what is measured in terms of temperature. The cause behind this can vary from the engine being pushed too hard to a leak or malfunction. You must pull over and allow the engine to cool down, if the problem persists seek professional help from Smart or a trained mechanic.

Oil Temperature Warning

If you see an oil can with a thermometer floating above it then it is most likely your car telling you the oil in the engine is too hot. This indicator is typically only used for performance Smart models that expect the driver to push them hard. The cause behind this could be heavy acceleration or in worst cases a loss of oil. As it is a red light you must pull over and allow the engine to cool down. If it persists then seek help from a mechanic.

Brake Warning

This warning light may appear different depending upon the region that you have bought your Smart. In most territories, the brake warning light will appear simply as the text BRAKE, though in Canada it will appear as an exclamation point with brake pads surrounding a circle. The Canadian version is a bit confusing as that symbol also looks like a handbrake symbol for a lot of cars. In any case whatever region you are in and you see a red icon (especially the red brake warning) you need to pull over the car immediately. There could be all sorts of things wrong with the brakes including fluid pressure or even technological like brake assistance programs that may be faulty. Seek the assistance of an independent garage or Smart dealership if you see this icon.

Charging System Warning

This warning light is shaped like a battery (or a Lego brick) with a positive and negative symbol on each side and is a solid red color. If this light appears on your dashboard then it means that the battery is no longer being charged by the engine. As it is a red light this means you should pull over and stop driving the car as quickly as possible. A common cause for this problem is that the alternator has stopped working or the wires connecting it to your battery have come loose. Continuing to drive with a battery that may be near empty could lead to a serious accident as you may lose vital systems at any time. Seek the help of an independent mechanic or go to your local Smart dealer/garage.

Oil Pressure Warning

An Aladdin's lamp style icon in red with nothing around it on its own represents that the oil pressure in the engine is low. This can be caused by a leak leading to a rapid loss in oil from underneath your engine or the oil being burnt within your engine and pushed out of the exhaust. As this is a red warning light it is not advised that you continue to drive the vehicle until it goes out. Driving with a low oil pressure light on can cause serious damage to the engine as it will not be properly lubricated and could overheat and/or cause extensive wear.

Master Warning Light

A triangle warning symbol with an exclamation mark in the center is typically used to indicate that the car has detected a serious fault. If the warning comes on only for a few seconds then it could be your car telling you that you momentarily lost traction and the car was acting to fix this. If you find the warning light stays on even after restarting your car seek help from a Smart dealership or trained mechanic.

Adaptive Cruise Control Warning

A speedometer and car with an exclamation mark warning could be for the adaptive cruise control system reporting a fault. It may also be displayed using the letters "ACC" displayed in either a yellow or red illumination. This system uses radars and/or cameras to monitor the traffic in front of the car and adapt the speed to follow it. If this warning light has appeared then try restarting the car to see if it resists and if it persists seek a trained mechanic or Smart dealership.

Lane Sense Warning

If you are seeing a warning light that looks like a car straying over broken or solid lines then your car may be reporting that you are switching lanes. An audio alert may accompany the visual one and this system can only work if it can detect the lanes using a camera or other technology. Some Smart models can act on behalf of the driver and correct the car steering to make sure it stays in the middle of the current lane.

Forward Collision Detection Off

A warning light on the dashboard showing 2 cars with a star symbolizing a crash with the word "OFF" underneath would suggest that the forward collision detection system is turned off. If you have not turned off the system yourself then it is advised you visit a trained mechanic or Smart dealership to fix this safety feature.

Forward Collision Detection Warning

A warning showing 2 cars following each other with an exclamation point and arrow beneath one of them could be for the forward collision detection system. The system is trying to tell you that it has detected a situation where a potential collision may occur and is responding to it by adjusting the brakes, suspension and seatbelts. If you are seeing this warning light stick on persistently then seek the help of a trained mechanic or Smart dealership.

Key-Fob Detected Indicator

A symbol of a key surrounded by waves on your dashboard could be to let you know that the car's key-fob has been detected. If the car has a keyless system fitted then this indicator will let you know that you are now able to start your car. On the off chance that this doesn't display when your car keys are in the car then you may have a flat battery in the fob.

ABS Warning

This warning light is very obvious and will feature the letters "ABS" surrounded by a circle and some crudely drawn brake pads. The warning is to let you know that the ABS braking-assist system has malfunctioned yet the brakes could very well still work normally without the assistance. It's recommended that you seek the help of a trained mechanic or Smart dealership as soon as possible.

Stability/Traction Control Off

Much like the stability control (also known as traction control) warning symbol, this one features the word "OFF" underneath it to let you know that the system is turned off. Switching the stability control off in a car is not usually as simple as pressing a button by accident, it's common that you would have to hold down a button for several seconds. If you have not switched it off yourself then you may be experiencing a fault and need help from a trained mechanic.

Stability Control Warning

If the stability control has to kick in then you will most probably see an orange/yellow warning light showing a car with swirls below. Most of the time when this kicks in you will also hear an audio alarm to let you know that the car has intervened to restore traction. If you are not experiencing a lack of traction and the light is stuck on then your Smart is most likely experiencing a fault with the system. Seek help from a trained mechanic or Smart dealership if the warning light remains on constantly.

Low Fuel Indicator

If you have what looks like an old-fashioned fuel pump at a gas station symbol light up orange/yellow then you are most likely low on fuel. If this warning light appears even after you have filled up with fuel then seek help from your dealership or trained mechanic.

Low Washer Fluid Warning

A symbol showing a windscreen (or an open book) with a water fountain in the middle is trying to tell you that the washer fluid is low in your car. Topping up should be easy and under your bonnet is a cap that will have the same symbol to show where to put your washing fluid. If you have topped up and the light has not gone out (wait a few minutes) then seek professional help.

Loose Gas Cap Warning

If a strange symbol appears on your dashboard that appears to show a car with a chunk taken out of it with a screw hovering next to it then your gas cap may be loose. If you have checked your gas cap and it is correctly fastened then you may need to seek help from a trained mechanic who can check for other problems. A loose gas cap or a leak in that system can cause pressure issues on modern engines (especially those that are diesel-powered) which can cause the engine to act erratically.

Check Engine Light Warning

The dreaded check engine light can mean a lot of things for your Smart and can range from a simple fix to a major expense. The symbol may appear as either an icon with text in the middle or may appear without any text and be the outline of a sort of transmission. If you see this warning light come up then pull over and try to restart the engine, sometimes a wild fluctuation can set it off when there is no real problem. If the light is flashing instead of being a solid light then the problem is most likely fatal for the engine and requires you to switch it off as soon as possible. A mechanic will plug in an OBD2 reader to your dashboard to get a fault code and diagnose the issue further - you can also do this yourself with one bought cheaply.

Hybrid Power Limitation Warning

If you see a yellow/orange turtle in a circle on your dashboard then your Smart is trying to tell you that the hybrid system is low on power. This could be caused by the batteries being depleted due to heavy use but a more sinister reason could be battery damage. If this warning stays on for a longer time than it used to then it's probably best to get your car's hybrid system tested.

Electronic Throttle Control Warning

If you are shown a lightning symbol (zig-zag) between 2 bent lines you could be experiencing an issue with your electronic throttle control system. The easiest solution to fix this can be to pull over and restart the car, otherwise, it is best you visit a trained mechanic.

Tire Pressure Warning

Most Smart cars sold today have a tire pressure warning light fitted in the instrument cluster on the dashboard. As soon as the tire pressure drops this light will illuminate orange to indicate that you need to fix the problem. If the indicator is flashing it may mean that a rapid drop in pressure is detected and it is recommended that you pull over straight away. The drop in pressure could be caused by a leak from a puncture or wear and tear around the rim - even a rapid change in temperature can sometimes cause this too. Driving around on tires that are not correctly pumped up can be dangerous, affecting both braking and handling. The worst-case scenario is that the tire bursts (usually at the worst time possible like at higher speeds) and your car becomes uncontrollable. You need to either pump the tire up yourself or seek help from a trained professional from a tire shop or at Smart.

Auto Stop-Start Warning

If you experience a circle with an arrow and the letter "A" in the center or even an exclamation mark then this would suggest the auto stop-start system has experienced a fault. The easiest solution is to restart the car to see if the problem persists, if so seek professional help, though the car may function normally just without that economy feature.

Cruise Control Indicator

A green warning light showing a speedometer with an arrow pointing towards it suggests that the cruise control system is active. The symbol may also appear as yellow and maybe even with an icon indicating a car shape next to it.

High Beam Indicator

A blue (or sometimes yellow) semi-circle with straight lines coming out of the side indicates that the vehicle's full-beam lights are switched on. When you activate the main lights the full beam will also activate and produce a much stronger beam of light pointing forward. It is common (and law in some places) not to drive with these on when facing another road user. To turn these on and off it's usually the backward and forward motion of the stalk that the lights are on behind the steering wheel.

Fog Lamp Indicator

If you see a semi-circle next to a bunch of wavy lines then it would suggest that your fog lamps are turned on. When you activate your main lights these additional lights will be visible too in an attempt to help you see in foggy conditions. If you need to switch them off the control will most likely be near your steering wheel and lights.

Hybrid Ready Indicator

A green box with the word "READY" inside of it on a Smart dashboard most probably means that the hybrid system is ready to be used. The batteries will have sufficient charge to run the motors and allow the car to run in electric mode.

Brake Pad Warning Light

A yellow brake disc with an exclamation mark illuminated in yellow could be a sign that your brake pads are getting low. This is becoming more common in modern models and it should give you enough time to sort the problem out before the pads get dangerously thin.

Engine Coolant Warning

Powertrain/Drivetrain Warning

The drivetrain/powertrain of your Smart refers to mechanical parts that carry the power from the engine of your car to the wheels. This can include the transmission/gearbox, clutch, differentials, off-road equipment and axles (as well as many other parts and driving aids). A warning light showing here that won't disappear when you turn your car off and then on again is probably severe and may be dangerous to drive while illuminated.

Heads Up Display Warning

A warning light that appears on your Smart's dashboard that looks like a caterpillar or long tube with flashing lines coming from it could be related to the heads-up display. If you are not seeing an error also come up on your separate heads-up-display as well as this then there may be an issue with the system Check with a Smart mechanic or dealership to have them run diagnostics on your car and diagnose the problem.

Electronic Parking Brake Warning

The electronic parking brake replaces the handbrake in modern Smart models and is usually operated with a button rather than a stick near the gear shifter. It can also display as a yellow warning light with a "P" letter enclosed inside of it too. If a fault is detected with the system a warning that looks like brake pads around a circle featuring a lightning symbol inside will appear in red. As the driver feels less feedback from a digital system in comparison to the traditional handbrake system this warning is very important. Driving with this warning illuminated could be dangerous, seek help from your local Smart dealership.

Hood Ajar Warning

More severe than the trunk ajar warning, the hood ajar warning is extremely important not to ignore. Check the bonnet/hood on your Smart is not open still by opening it fully and closing it again with some force to ensure the mechanism locks. Driving with a loose bonnet/hood can be very dangerous as it could fly open at speed and take out your windscreen.

Trunk Ajar Warning

An outline of a car with the visual of a flap extending out from the right-hand side would suggest that your trunk is still open. Be sure to close the trunk on the car before driving as the warning get more severe and included audio alerts too. If your trunk is not open then you may have a problem with the sensor.

Engine Air Filter Warning

If your air filter is blocked then you need to get it changed for a new one - an easy and fairly low-cost procedure. Some modern Smart models can be fitted with a sensor that will warn you that it is getting blocked before it poses a problem. This warning light appears on your dashboard as a string of balls with what looks like a gust of wind blowing through it.

Water In Fuel Warning

Most diesel engine fuel filters can separate traces of water in the fuel before it can cause problems but if some still get through then you may see this warning. Water can prove fatal for engines and so your fuel filter can remove some of this and store it to be emptied later. If you check your car's owner's manual it should detail this process if you see this warning light that looks like a fuel pump next to water droplets or rain.

Glow Plug Warning

A warning light that is illuminated yellow that looks like a coil of wire or string represents the glow plug warming up. This is part of a diesel engine and helps it start from cold. It should only show briefly as it starts up once you turn on your ignition and should disappear quickly to suggest it has finished warming up. If the warning remains on your dashboard then there may be a problem with it and so you need to see a Smart mechanic.

Service Reminder

Some models are fitted with a service reminder that is triggered by a certain number of miles or months since it was last seen by a mechanic. It usually appears as a spanner with an exclamation mark passing through it. This is usually just a friendly reminder and not an indicator that something is wrong but best to get sorted soon to keep your car in peak condition.

Brake Override Warning

Pushing both the brake pedal and the accelerator pedal at the same time not only causes damage to the vehicle but can also cause an accident. In some cars, you can find a warning in the dashboard that tells you that you are pressing both pedals in order for you to understand and stop doing it. Some models even take care of the problem for you but you still need to alter your driving for safety reasons. If this warning light is flashing then there is a problem with the system itself and you need to get it sorted as soon as possible.

Adblue Warning

Adblue® is an additive used in some modern diesel engines to reduce the amount of pollution that it puts out. When it gets low you need to replenish it otherwise the engine may not start at all if it empties completely. The warning displays with the words Adblue or even just as a bottle that is emptying. You can purchase the Adblue® fluid from many different places including fuel/service stations.

Headlight/Taillight Out Warning

Some modern models are fitted with a warning system that displays if a headlight or taillight is out. This can be super useful as a light being out may not be easy to notice but can lead to safety issues quickly. The warning looks like a light bulb trapped inside a circle with two smaller semi-circles around it.

Immobiliser Warning

The immobilizer is a security component in your car that prevent thieves from hotwiring it. It disables the fuel pump power supply and it works by detecting your key inside of the car to enable it to start. If there is an issue with the unit then your car will most likely not start and display an icon that looks like a car with a large key inside of it. Seek the help of a trained Smart mechanic in order to diagnose the problem and fix it.

Air Suspsension Warning

Some models of cars (typically offroad-capable ones) are fitted with an air suspension system that allows it to be lowered or raised. Unfortunately, these systems have a lot of moving parts and rely on piping that is prone to get damaged. If you see a warning light that looks like the outline of a car with arrows pointing up and down then it may be related to the air suspension. The car can be dangerous to drive with a fault in it so seek the help of a trained mechanic.

Automatic Transmission Warning

An automatic transmission can make driving a car so much easier but is also a complex component. When it goes wrong it tends to go very wrong with expensive results. If you see what looks like a cog with an exclamation mark then your car may be telling you that it is detecting a fault in the gearbox. Get it checked out as soon as possible and try to avoid pushing it - or even driving at all if you don't fancy risking further damage.

Oil Service Warning

A yellow oil symbol (rather than the more severe red) can mean that you need to get the oil serviced (changed basically) and/or that the oil level has dropped. Some makes of modern cars display this as an actual message such as "oil service required" or "oil change required" on the dashboard. To sort this out you should get the oil changed and ideally have the oil filter replaced at the same time to get rid of the dirty contaminants that may remain in the system. If you are looking for a quick fix to get you by though you could just top the levels up to be sure but this isn't a long-term fix.

Models: 2