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Car dashboard lights – what they mean
11 October 2017
Award-winning motoring expert Quentin Willson guides you around the modern car dashboard – what the icons mean and what to do when they light up.
11/10/2017
312
car dashboard lights – what they mean
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Dynamic stability control (DSC)
This warning light flashes quickly if road conditions are slippery and the DSC has automatically switched on. If it’s on all the time, there’s a fault with the system that requires investigation.
Anti-lock braking (ABS)
The anti-lock braking system is designed to stop the wheels locking up and skidding on hard braking. This light appears if the system is active in emergency braking. If it illuminates permanently, there’s a safety issue with the brakes that needs fixing.
Air suspension warning
When this light illuminates, there’s a leak in the air suspension accumulators or pipework that could eventually sink the car to the ground. Leave your car for long periods and the air suspension may gradually discharge, but should return to normal when the engine restarts.
Lane departure warning
A warning light indicating that the car is crossing road lane markings due to driver fatigue or inattention. Sometimes accompanied by an electronic vibration warning through the seat or steering wheel.
Auto windscreen wiping
Comes on when the driver sets the wipers to automatic mode and then the built-in rain sensor detects rain on the glass and operates the wipers.
All-wheel drive
This is used on 4X4s to show that you’ve selected the four-wheel-drive system. Don’t drive at speed on tarmac with this light on as you could overheat the gearbox and front and rear axles.
Brake pad warning
Take this light seriously as it shows that your disc pads are worn down beyond a safe level and need replacing – pronto.
Cabin recirculating air
Press this button if you don’t want outside fumes to enter the car’s interior. It’s particularly useful if you’re stuck in traffic, to avoid breathing in diesel smoke.
Catalytic convertor warning
Warning light that shows a fault with your exhaust catalytic convertor. Only used on petrol cars and could also point to a problem with an oxygen sensor. Faulty catalytic convertors and sensors could eventually cause damage to your engine, lead your car to fail its MoT and increase fuel consumption.
Cruise control on
This shows that the cruise-control system is active. Since switching on the cruise control accidentally by nudging the button on the steering wheel is quite easy, don’t ignore this light. Your car could accelerate when you don’t expect it to.
Diesel particulate filter (DPF)
DPFs are fitted to modern diesels to reduce soot emissions, but they can clog up if you do a lot of in-town driving. If the DPF light comes on, you’ll need to ‘purge’ the filter by driving at 70mph for 20 minutes to burn off the excess ash and carbon.
Direct-shift gearbox (DSG)/gearbox warning
This light means your automatic gearbox (especially semi-automatic DSGs) has a fault or has overheated. DSG gearbox fluids and filters need changing every 40,000 miles.
Electronic stability program (ESP)
A warning light that briefly flashes on to indicate that your ESP has switched itself on automatically because the car has begun to slide or lose grip. If the ESP light is on permanently, this means there’s a fault with the system that needs fixing urgently.
Electronic power-assisted steering (EPAS)
Most new cars now have electronic rather than hydraulic power-assisted steering and the EPAS light will warn if there’s a fault with the electric motor or wiring. If this light is illuminated all the time, you’ll also feel that the steering also becomes heavy.
Eco driving
Lots of cars have eco driving modes that help to save fuel by adjusting engine and gearbox speeds. This is usually a green or yellow display light but there may also be an ECO button on the dash or steering wheel to manually switch the system on or off.
Fuel filter warning
This light tells you that your fuel filter is contaminated with water. You’d also feel a difference in engine smoothness such as rough running or a lumpy idle. Replace the fuel filter immediately.
Glow plug/engine warning
Mainly used on diesel engines to indicate the glow plugs that pre-heat the cylinders are working. This only normally flashes on for a few seconds before the engine fires up – but if it’s on permanently this means one (or all) of the glow plugs are faulty. Some car brands also use this symbol as an engine problem light.
Hill descent control
Only fitted to 4X4s, particularly Land Rovers, to indicate that the car can be slowly driven down a very steep gradient without touching any of the pedals. Shouldn’t be illuminated in normal road use.
Ice warning
Really useful warning light that detects freezing road temperatures. Tiny sensors on the front bumper measure the ambient air to warn the driver of the possibility of ice on the road ahead.
Key fob battery
Shows that the battery in your electronic key fob needs replacing. Once the battery goes flat, you may have problems opening, locking or starting your car. Dealers can replace the battery but there are lots of tutorials on YouTube to show how to do it for a few pounds. Replace the key fob battery every year.
Press clutch pedal
A safety warning light to tell you that you need to press the clutch pedal first to be able to start the car.
Press brake pedal
Some car brands use a similar system to the one above but use pressing the brake pedal as a safety system before the car will start.
Adaptive cruise control
The latest cruise-control systems slow the car down if you’re too close to the vehicle in front. You can switch this on and off manually. The warning light shows the adaptive cruise is active and your distance between other vehicles will be automatically controlled.
Stop start function
Button that automatically shuts the engine down at junctions or in traffic queues. Annoying system that keeps stopping the engine when you’re stationary – but saves fuel and emissions.
Speed limiter
Shows the car’s speed limiter has been set at a certain speed. Handy if you don’t want to inadvertently break any limits.
Tyre pressure monitor
Lights up if any of the tyres have lost air pressure. Means you don’t have to check them manually with a pressure gauge. Unreliable, complicated and the sensors need replacing every few years.
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Dynamic stability control (DSC)
This warning light flashes quickly if road conditions are slippery and the DSC has automatically switched on. If it’s on all the time, there’s a fault with the system that requires investigation.
Anti-lock braking (ABS)
The anti-lock braking system is designed to stop the wheels locking up and skidding on hard braking. This light appears if the system is active in emergency braking. If it illuminates permanently, there’s a safety issue with the brakes that needs fixing.
Air suspension warning
When this light illuminates, there’s a leak in the air suspension accumulators or pipework that could eventually sink the car to the ground. Leave your car for long periods and the air suspension may gradually discharge, but should return to normal when the engine restarts.
Lane departure warning
A warning light indicating that the car is crossing road lane markings due to driver fatigue or inattention. Sometimes accompanied by an electronic vibration warning through the seat or steering wheel.
Auto windscreen wiping
Comes on when the driver sets the wipers to automatic mode and then the built-in rain sensor detects rain on the glass and operates the wipers.
All-wheel drive
This is used on 4X4s to show that you’ve selected the four-wheel-drive system. Don’t drive at speed on tarmac with this light on as you could overheat the gearbox and front and rear axles.
Brake pad warning
Take this light seriously as it shows that your disc pads are worn down beyond a safe level and need replacing – pronto.
Cabin recirculating air
Press this button if you don’t want outside fumes to enter the car’s interior. It’s particularly useful if you’re stuck in traffic, to avoid breathing in diesel smoke.
Catalytic convertor warning
Warning light that shows a fault with your exhaust catalytic convertor. Only used on petrol cars and could also point to a problem with an oxygen sensor. Faulty catalytic convertors and sensors could eventually cause damage to your engine, lead your car to fail its MoT and increase fuel consumption.
Cruise control on
This shows that the cruise-control system is active. Since switching on the cruise control accidentally by nudging the button on the steering wheel is quite easy, don’t ignore this light. Your car could accelerate when you don’t expect it to.
Diesel particulate filter (DPF)
DPFs are fitted to modern diesels to reduce soot emissions, but they can clog up if you do a lot of in-town driving. If the DPF light comes on, you’ll need to ‘purge’ the filter by driving at 70mph for 20 minutes to burn off the excess ash and carbon.
Direct-shift gearbox (DSG)/gearbox warning
This light means your automatic gearbox (especially semi-automatic DSGs) has a fault or has overheated. DSG gearbox fluids and filters need changing every 40,000 miles.
Electronic stability program (ESP)
A warning light that briefly flashes on to indicate that your ESP has switched itself on automatically because the car has begun to slide or lose grip. If the ESP light is on permanently, this means there’s a fault with the system that needs fixing urgently.
Electronic power-assisted steering (EPAS)
Most new cars now have electronic rather than hydraulic power-assisted steering and the EPAS light will warn if there’s a fault with the electric motor or wiring. If this light is illuminated all the time, you’ll also feel that the steering also becomes heavy.
Eco driving
Lots of cars have eco driving modes that help to save fuel by adjusting engine and gearbox speeds. This is usually a green or yellow display light but there may also be an ECO button on the dash or steering wheel to manually switch the system on or off.
Fuel filter warning
This light tells you that your fuel filter is contaminated with water. You’d also feel a difference in engine smoothness such as rough running or a lumpy idle. Replace the fuel filter immediately.
Glow plug/engine warning
Mainly used on diesel engines to indicate the glow plugs that pre-heat the cylinders are working. This only normally flashes on for a few seconds before the engine fires up – but if it’s on permanently this means one (or all) of the glow plugs are faulty. Some car brands also use this symbol as an engine problem light.
Hill descent control
Only fitted to 4X4s, particularly Land Rovers, to indicate that the car can be slowly driven down a very steep gradient without touching any of the pedals. Shouldn’t be illuminated in normal road use.
Ice warning
Really useful warning light that detects freezing road temperatures. Tiny sensors on the front bumper measure the ambient air to warn the driver of the possibility of ice on the road ahead.
Key fob battery
Shows that the battery in your electronic key fob needs replacing. Once the battery goes flat, you may have problems opening, locking or starting your car. Dealers can replace the battery but there are lots of tutorials on YouTube to show how to do it for a few pounds. Replace the key fob battery every year.
Press clutch pedal
A safety warning light to tell you that you need to press the clutch pedal first to be able to start the car.
Press brake pedal
Some car brands use a similar system to the one above but use pressing the brake pedal as a safety system before the car will start.
Adaptive cruise control
The latest cruise-control systems slow the car down if you’re too close to the vehicle in front. You can switch this on and off manually. The warning light shows the adaptive cruise is active and your distance between other vehicles will be automatically controlled.
Stop start function
Button that automatically shuts the engine down at junctions or in traffic queues. Annoying system that keeps stopping the engine when you’re stationary – but saves fuel and emissions.
Speed limiter
Shows the car’s speed limiter has been set at a certain speed. Handy if you don’t want to inadvertently break any limits.
Tyre pressure monitor
Lights up if any of the tyres have lost air pressure. Means you don’t have to check them manually with a pressure gauge. Unreliable, complicated and the sensors need replacing every few years.
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The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.
