Car Warning Lights Explained

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With numerous warning lights flashing up on your dashboard, it can be difficult to work out which ones require immediate attention and which ones are simply informational.

Read on to find an explanation for the most common symbols that appear on most makes and models. We explain what each symbol means and what action you should take if they appear.

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Immediate attention

These warning symbols are typically the most severe and generally require immediate action to rectify. In some cases further driving could cause serious engine damage and/or risk of life.

Check engine light

Oil pressure warning

What it means: This indicator highlights a loss in oil pressure and suggests there isn’t enough oil in the engine. Without oil lubricating the engine, further driving could cause your engine to overheat and lead to severe damage.

Action required: Check your oil level and pressure as soon as possible.

Battery charge warning

What it means: The battery charge indicator suggests an issue with the vehicle’s electrical system. This is important since modern cars rely on electricity for the steering, brakes, lights and engine, and as such a fault with the electrics can be very serious.

Action required: If possible, drive to the nearest garage to get your vehicle checked when you see this warning light come on.

Engine temperature warning

What it means: When the engine temperature symbol appears, it means the temperature in the engine has exceeded normal limits. This could be because of issues with the coolant, fans, radiator or water pump and further driving could cause serious engine damage.

Action required: Check your coolant, fans and radiator.

Brake system warning

What it means: A fault in the braking system is a serious concern and could imply that complete failure is imminent. This warning light may show because of a fluid leak resulting in a loss of brake fluid, worn brake pads, faulty sensors or because the handbrake is still on.

Action required: When you see the brake system warning light turn on, immediately pull over when it’s safe to do so and perform some basic checks. If necessary, call for a tow to the nearest garage.

Trailer tow hitch

What it means: If the trailer tow hitch indicator comes on it means that either the trailer hitch is unlocked or there is an issue with the lighting system because the system has registered an additional load on the circuit. Commonly this can be triggered because of modifications to the lighting system i.e. the type of bulb has been changed or additional lights have been added.

Action required: Lock the trailer hitch or get your lighting system checked out.

Steering wheel lock

What it means: The steering wheel lock indicator means that the steering wheel has been locked and cannot be moved. This warning should only come on with the ignition off and the lock engaged.

Action required: If it comes on in a different situation, while it shouldn’t lock the wheel while driving, you should have your vehicle checked.

Power steering warning

What it means: Not to be confused with the steering lock indicator, the power steering warning light means that an issue with the power steering has been detected and has been turned off. Driving without electric power steering is not recommended and the system will continue to be disabled until fixed.

Action required: Get to the nearest garage as soon as possible. Call for assistance if necessary.

Seat belt indicator

What it means: This is a common dash light that means that one passenger doesn’t have their seat belt connected.

Action required: Ensure that all passengers have their seatbelts connected.

Master warning light

What it means: The master warning light usually comes on in conjunction with another warning light and highlights that one or more warning issues has been detected.

Action required: Try to find the issue yourself if it is obvious. If you fail to diagnose the cause of the master warning light yourself, it is recommended that you seek professional aid.

Distance warning

What it means: The distance warning signifies that the vehicle is too close to the vehicle in front, or that an obstacle is fast approaching.

Action required: Ensure you are driving a safe distance away from the vehicle in front.

Catalytic converter warning

What it means: If the catalytic converter warning light comes on, it means that it is overheating or not working properly.

Action required: Have your catalytic converter checked.

Airbag suspension

What it means: This warning light comes on when the front airbag has been disabled. If this warning light comes on, it means there is an issue with the airbag or seat belt system.

Action required: Stop driving when it is safe to do so and get your vehicle checked.

Air suspension

What it means: The air suspension warning light means there is an issue with the air suspension bags.

Action required: Driving while the air suspension light on is not advised, get your suspension checked as soon as possible.

Low fuel level

What it means: This symbol signifies that the vehicle is low on fuel and needs a refill.

Action required: Refuel the vehicle.

Bonnet open

What it means: The bonnet open symbol means that the vehicle’s bonnet is currently open and has not been closed properly.

Action required: Ensure the bonnet has been closed correctly.

Hazard lights on

What it means: This symbol signifies that the hazard lights are currently on.

Action required: Unless you have pulled over in an emergency and are causing a hazard, or there’s something wrong with your car which means you have to slow down, for example, you shouldn’t have your hazard lights on. Switch them off to avoid causing confusion among other drivers.

Parking brake light

What it means: This indicator signifies that the parking brake light is on.

Action required: N/A.

Door ajar

What it means: The door ajar warning light means that one or more doors are still open and didn’t close properly.

Action required: Ensure all doors are closed correctly before setting off on your journey.

Key fob battery low

What it means: This symbol signifies that the batteries in the key fob are low and should be changed.

Action required: Check which batteries are required for your key fob and change them for a new set.

Ignition switch warning

What it means: The ignition switch warning light comes on when an issue with the ignition system has been detected.

Action required: Clean out the keyhole and wipe the key, if that doesn’t fix the issue or the issue occurred while driving, have the vehicle checked out.

Forward Collision Warning

What it means: This symbol signifies that a potential collision has been detected.

Action required: Respond to the collision i.e. braking or avoiding.

Convertible roof warning light

What it means: The convertible roof warning light comes on when the roof is opening or closing. If it stays on continuously, the roof is not opened fully or a fault has been detected.

Action required: Open the roof fully if possible. If the roof is no longer functioning, you will need to get it checked out by a professional.

AdBlue tank is empty

What it means: This indicator means you are low on AdBlue exhaust fluid and it requires filling. If the tank empties, the engine will not restart until it has been refilled.

Action required: Refill your exhaust fluid, making sure it’s the right type for your car.

AdBlue malfunction

What it means: The AdBlue malfunction warning light means that an issue has been detected with the AdBlue system, or that the tank is not filled with the expected fluid.

Action required: Ensure the tank is filled with the correct fluid. If this doesn’t fix the issue, get your vehicle checked.

Water fluid filter warning

What it means: This symbol represents that the water fluid filter is full and needs to be drained.

Action required: On manual systems you should empty the filter. If your vehicle uses an automatic system it means there is an issue with the filter and it needs to be checked out as soon as possible.

Advisory issues

Warning lights

Warning lights which are amber/yellow tend to be for issues that require you to take some action to prevent potential extensive damage in the future.

Transmission temperature

What it means: Similar to the engine temperature warning light, the transmission temperature warning light indicates that the engine is exceeding normal operational limits.

Action required: Check your coolant, fans and radiator.

Traction control/electronic stability off

What it means: This symbol signifies that the vehicle’s traction control system has been turned off. Since modern vehicles usually allow the driver to turn the system on and off manually, this light will alert you to when you’ve turned it off by accident. If you didn’t accidentally turn it off, it means a fault has occurred which has turned off the system.

Action required: If you accidentally turned it off, turn it back on. If you didn’t accidentally turn it off, get your vehicle checked.

Traction control/electronic stability on

What it means: This symbol signifies that the vehicle’s traction control system has been turned on. If it remains on continuously, it could represent a fault in the traction control / electronic stability system.

Action required: Get your traction control / electronic stability checked.

Tyre pressure warning

What it means: The tyre pressure warning light comes on when the monitored pressure in one or more tyres is low.

Action required: Check the pressure in each tyre and look for punctures. If you don’t find a puncture simply inflate the tyres with low pressure. If you have a puncture, pull over when safe to do so and change the tyre if possible. Otherwise call for assistance.

Side airbag

What it means: If this symbol comes on, it means there is a fault with the side airbag.

Action required: Check to see if there is something interfering with the sensor by checking the passenger seatbelt isn’t unnecessarily engaged. Otherwise have your vehicle checked.

Service vehicle soon

What it means: This indicator comes on when a fault condition has been detected in an area of the vehicle systems, which requires professional servicing.

Action required: Get your vehicle checked at a manufacturer-approved garage before the recommended service interval date ends.

Security alert

What it means: If this light is on while the vehicle is running, it suggests an issue with the security system. However, otherwise it means the ignition switch is locked.

Action required: Get your security system and wiring checked.

Reduced power warning

What it means: The reduced power warning light means that the engine computer has detected an issue and reduced the performance of your vehicle in order to minimise / avoid damage to the engine.

Action required: Stop driving when it is safe to do so. If you have an OBD II scanner, scan your vehicle to pinpoint the issue. If not, have you vehicle scanned.

Press clutch pedal

What it means: This indicator is asking you to push the clutch.

Action required: Press the clutch before moving the gearknob out of park.

Powertrain fault

What it means: The powertrain fault light comes on when an issue has been detected with the AWD (all-wheel drive) or powertrain.

Action required: If this light comes on, you should consult a mechanic when possible.

Overdrive light

What it means: This indicator means that the overdrive system has been manually turned off.

Action required: If you didn’t mean to turn the overdrive system off, turn it back on.

Oil change reminder

What it means: The oil change reminder comes on when the oil has passed its expiry date and needs replacing.

Action required: Check your oil level by removing the dipstick, wiping it clean and inserting it back into the filter. If the oil is too low, top it up using a product which is suitable for your vehicle. If the oil level is sufficient but the light remains on, there might be a problem with your car’s electrics. In this case, take your car to a garage at the earliest opportunity.

Gas/fuel cap

What it means: Most likely to come on after refueling, the gas/fuel cap warning light indicates that the cap hasn’t been tightened securely or has become loose.

Action required: Ensure that the cap is tightened securely before setting off.

ESP/traction control fault

What it means: If this symbol becomes lit, it means that a fault with the electronic stability/traction control has been detected.

Action required: Have your ESP (electronic stability programme) checked.

Child safety lock

What it means: This symbol simply means that the child lock is on.

Action required: N/A

Lamp out

What it means: The lamp out warning light highlights that there is an exterior light that is not working correctly.

Action required: Find the defective light if possible and get it replaced. Otherwise get your lights checked.

Headlight range control

What it means: If this symbol becomes lit, it means there is an issue with the headlight range control system.

Action required: It is safe to drive without headlight range control as long as your headlights are still working correctly. You will need to get your headlights checked by a professional in order to rectify the control issue.

Check engine light

What it means: If the check engine light stays on continuously after starting the engine, it means the diagnostic systems have found an issue that needs to be investigated.

Action required: Have your engine checked as soon as possible.

Brake fluid warning

What it means: The brake fluid warning light simply means that brake fluid levels are low.

Action required: Top up your brake fluid with the correct product for your vehicle model.

Brake pad warning

What it means: This warning light represents that the brake pads are wearing and/or are worn out.

Action required: Have the brakes replaced. If you recently had them replaced, this could mean there is an issue with the sensor, in which case you should have them checked by a mechanic.

Brake lights warning

What it means: The brake light warning light means that there is an issue with one of the brake lights.

Action required: Check all the brake lights and have the defective bulbs replaced.

Automatic gearbox warning

What it means: This indicator signifies an issue with the gearbox or transmission.

Action required: Have your gearbox inspected as soon as possible.

ABS (anti-lock braking system) issue

What it means: The ABS warning light implies there may be a fault in the ABS system.

Action required: Although an issue with the ABS might not affect the functionality of the brakes, it is not advised that you continue to drive as your vehicle will not handle correctly under heavy braking. Have your brake system and ABS inspected.

AWD (all-wheel drive) issue

What it means: Similar to the above, the AWD light comes on when there is an issue with the AWD system. If the light blinks it could mean the AWD has overheated

Action required: If the light is blinking, pull over when safe to do so and wait for the light to turn off. If the light isn’t blinking / doesn’t turn off, have your AWD inspected.

Airbag deactivated

What it means: Unless you have manually deactivated the airbag on your car for carrying a rear-facing child seat in the front, you shouldn’t see a warning light for the airbag. If you do, this could potentially mean it’s having problems deploying or even that there’s an issue with the seatbelts.

Action required: If the light is showing and you haven’t deactivated the airbag, consider taking the car to a garage to be checked.

Adaptive suspension dampers

What it means: There is an issue with your adaptive suspension dampers.

Action required: When the adaptive suspension damper warning light comes on, it means action is required and you should contact an authorised repairer immediately.

4WD (four-wheel drive) lock indicator

What it means: This indicator means that the 4WD lock mode has been enabled.

Action required: If you don’t need 4WD capabilities, turn 4WD off.

Exterior light fault

What it means: This symbol signifies that a change in light voltage has been detected, normally meaning that one of the bulbs have gone in any of the exterior lights. Finding the culprit can be challenging however, as nowadays modern cars use exterior lights in door mirrors, handle, rear number plates etc.

Action required:  Find the defective light if possible and get it replaced. Otherwise get your lights checked.

Adaptive light suspension

What it means: The adaptive light system light simply means that adaptive lighting has been enabled.

Action required: N/A

Rear fog lights

What it means: Similar to the Front Fog Lights indicator, this symbol signifies that the rear fog lights are currently on.

Action required: N/A

Rain and light sensor

What it means: This symbol represents an issue with the rain and light sensor system which could prevent the wipers and headlights from switching on automatically.

Action required: Turn on wipers and headlights manually as required. Get your sensor checked when convenient to rectify the issue.

Windshield defrost

What it means: This symbol signifies that the windshield defrost is currently on.

Action required: N/A

Washer fluid reminder

What it means: The washer fluid reminder means that washer fluid levels low and need topping up.

Action required: Refill washer fluid to avoid driving with a dirty/obscured windscreen.

Rear window defrost

What it means: This symbol signifies that the rear windshield defrost is currently on.

Action required: N/A

Key not in vehicle

What it means: This symbol signifies that the key is not in the car.

Action required: The engine may not start/restart if the key is not located. If the batteries of the key fob have died, there should be an alternative to keyless ignition in your make and model of vehicle. Replace batteries if necessary.

Car on ramp

What it means: This warning light means that the vehicle is currently on ramp/jack.

Action required: Drive cautiously while you’re on these types of surfaces, paying special attention to your gear selection if you’re in a manual car.

Rear spoiler warning

What it means: This symbol signifies an issue with the rear spoiler.

Action required: While the car is safe to drive at normal speeds, you might run into issues at higher speeds if the spoiler isn’t up. Call a mechanic to schedule necessary repairs to the spoiler.

Lane departure warning

What it means: The lane departure warning means that the vehicle has been detected to be leaving its current lane without signalling that it is turning.

Action required: Depending on the level of autonomy in your vehicle, it may automatically steer you back into line if it detects your car leaves its lane. However, you’ll need to add steering input straight away in order to take back control of the vehicle.

Hill descent control (HDC)

What it means: The hill descent control light comes on when the system has been enabled.

Action required: When this driving mode is selected, the car will have enhanced automatic braking. You will only have to use the throttle to accelerate and decelerate on slopes. Be sure to check how to use HDC on your model as its functions differ depending on your vehicle.

Cruise control

What it means: When cruise control is activated, this indicator comes on.

Action required: Enable cruise control on A-roads and motorways where there’s less stopping/turning in order to stay safe.

Automatic windscreen wipers

What it means: When the windscreen wipers are on in automatic mode, this warning light comes on.

Action required: You will usually be able to set a frequency and speed for automatic wipers, so ensure this is at a safe level which doesn’t intervene with your view of the road.

Glow plug indicator

What it means: The glow plug indicator means that the glow plugs are warming up and the engine shouldn’t be started until the indicator turns off. If the indicator starts to flash, it means there is an issue with the glow plugs.

Action required: Get your vehicle checked at the earliest opportunity.

Fuel filter warning

What it means: If the fuel filter warning light comes on, it means that the filter is full and needs emptying. Failure to empty the filter could lead to engine damage.

Action required: On manual systems you should empty the filter. If your vehicle uses an automatic system it means there is an issue with the filter and it needs to be checked out as soon as possible.

Exhaust fluid

What it means: This symbol signifies that the exhaust fluid level is low and needs filling.

Action required: Refill your exhaust fluid with the correct product for your vehicle.

Informational

These symbols aren’t intended to warn you about an issue, as such. However, they will tell you important information about your car’s functions that should be heeded, otherwise not doing so could potentially cause an issue.

fog lights

Press brake pedal

What it means: This indicator is asking you to push the brakes.

Action required: This only applies to automatic vehicles. You’ll need to press the brakes before shifting out of Park mode and going to Drive.

Information warning light

What it means: This symbol represents that a new message is stored in the information display and will remain until read.

Action required: Read the message.

Icy road warning light

What it means: This light turns on when outside air temperatures begin to hit freezing and pre-warns you of potentially deteriorating road conditions.

Action required: Remember to make smooth gear changes, steering inputs and braking when its icy to avoid skidding. Usually a higher gear is best to aid grip on this type of surface. It’s also recommended that you increase your distance from the car in front tenfold if there is ice on the road.

Electric park brake

What it means: This symbol means that the brake is engaged or there’s a malfunction with the brake.

Action required: Ensure that the brake isn’t unnecessarily engaged first. If that doesn’t fix the issue, top up your brake fluid. If that still hasn’t resolved the issue, get your brake system checked.

Clogged air filter

What it means: This warning light means there is an issue with the engine’s air filter and that reduced or sub-optimal airflow is being received by the engine.

Action required: The air filter should be inspected as soon as possible to prevent issues occuring in the engine.

Low beam indicator

What it means: This symbol signifies that the headlights are currently on at low beam.

Action required: Unless there’s no oncoming traffic on the other side of the road, or the road ahead is clear of other cars, you should keep your low beam at night time/when visibility is poor.

High beam indicator

What it means: This symbol signifies that the headlights are currently on at high beam.

Action required: High beam should only be used when the road ahead is clear of other cars, to avoid dazzling other drivers.

Front fog lights

What it means: This symbol signifies that the front fog lights are currently on.

Action required: Fog lights are recommended in conditions where visibility drops below 100 metres (or 328 feet).

Auto high beam

What it means: This symbol represents that the lighting system has automatically put on the high beam headlights.

Action required: Remember to switch automatic high beam off when you no longer need this function.

Side light indicator

What it means: Perhaps the most common dash symbol, the side light indicator means that the headlights have been switched on.

Action required: If your car is an older model, it may not turn the lights off automatically when you lock it. However, it should beep to warn you if headlights have been left on. Be sure to start the car and switch them off in order to save your battery running out.

Fan

What it means: This symbol signifies that the internal fan/air conditioning is currently on.

Action required: N/A

Signal indicators

What it means: The signal indicators warning light means that one of the turn signals has been used.

Action required: Regularly check your vehicle to ensure that the left and right turn signals are working.

Recirculated cabin air

What it means: The recirculated cabin air warning light means that the ventilation systems are recirculating air from within the vehicle.

Action required: N/A

Parking with park assist

What it means: This symbol signifies that the vehicle is currently parking with park assist.

Action required: Be sure to check in your manufacturer handbook how to use the park assist properly and safely.

Lane assist

What it means: This symbol signifies that lane assist has been enabled and is working.

Action required: Remember that lane assist in its most basic form will still require you to steer the car in order to keep it within the lines. However, be sure to check how to use this system for your model of vehicle, if it’s equipped with it.

Eco driving indicator

What it means: The eco driving indicator simply means that the eco driving system has been enabled.

Action required: Depending on your driving style, you shouldn’t leave eco mode selected all the time. For example, throttle inputs tend to be less responsive in this mode, meaning it won’t be suitable for high-speed motorway journeys.

Brake hold indicator

What it means: This symbol signifies that the brake hold is working correctly.

Action required: N/A

Blind spot indicator

What it means: The blind spot indicator turns on when a vehicle or obstacle has been detected in one of the vehicle’s blind spots.

Action required: Like other advanced driver assistance systems such as lane assist, blind spot indicators are there to help you perform regular mirror checks. However, this shouldn’t stop you from making other observations while you’re driving.

Automatic emergency braking (AEB)

What it means: The AEB indicator turns on when AEB has been turned off, or when the sensor isn’t working properly.

Action required: If you’ve not turned it off and it’s a sensor issue, get it checked out as soon as possible as AEB is a lifesaving safety feature.

Adaptive cruise control

What it means: Similar to the cruise control indicator, the adaptive cruise control indicator comes on when adaptive cruise control is in use.

Action required: Just like ordinary cruise control, you should only activate this feature on roads which require you to maintain a constant speed without needing to stop or turn regularly.

Winter mode

What it means: The winter mode indicator enables you to set off in second and even third gear to avoid the torque-heavy first gear which can cause tyres to spin in ice and snow.

Action required: Only use this mode when the conditions require it, otherwise you will likely stall the car.

Start/stop warning

What it means: The start/stop warning light means that the start/stop system has been engaged and that the engine has been turned off.

Action required: N/A

Speed limiter

What it means: The speed limiter warning light comes on when the speed limiter has been engaged.

Action required: This function differs to cruise control because it doesn’t allow you to maintain the speed limit you set. Only use this feature in areas where it’s safe to do so, such as those with a lots of speed cameras.

Seat temperature

What it means: This indicator signifies that the airflow has been diverted to the front side windows and footwell.

Action required: N/A

Now that you’re clued up as to what all those pesky warning lights mean, why not consider a brand-new vehicle from Moneyshake? Configure yours now to benefit from the full manufacturer warranty throughout the duration of your contract.

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