Dashboard warning lights serve as crucial indicators of your vehicle's health and safety, often prompting quick action to prevent potential issues or breakdowns on the road. Understanding these warning lights and their meanings can empower drivers to respond effectively. From the ubiquitous check engine light that signals a range of potential engine problems to indicators for low tire pressure, oil pressure, or battery charge, each symbol conveys vital information about your car's condition. This blog aims to demystify the most common dashboard warning lights, providing clarity on what they signify, how to interpret them, and the essential steps every driver should take when they illuminate. Whether you're a seasoned driver or new to the road, knowing how to respond to these alerts can make all the difference in maintaining your vehicle's performance and safety.
Whilst you should take all of the warning lights on the dashboard seriously, some are far more common than others and require a simple fix, here we look at the most common dashboard symbols, what they mean and what you should do about it. Follow this link for our complete list of ALL
Dash Warning Lights.
Fuel Warning Light
Severity: 1/10
Advice: Re-fuel at earliest opportunity at your nearest petrol station.
It’s little surprise that the most common dash warning light you are likely to see is the fuel warning light. Simply put, you’re low on fuel and recommended to refuel at the next available opportunity. On average a car will cover anything from 300-500 miles on a single tank of fuel, so you’ll likely see this light frequently. Whilst all cars vary, you are likely to have between 10-50 miles of range left in the fuel tank.
Traction Control Warning Light
Severity: 2/10
Advice: Adjust driving style to suit conditions.
It’s not uncommon to see the traction control light on the dashboard, particularly in a car you are not familiar with, ie a rental car. Most modern cars have a traction control system that detects any loss of traction the car may experience and implement electronically controlled adjustments to ensure safe control of the car is resumed. This can include reducing / cutting throttle input to more sophisticated systems that can apply the brake to individual wheels of the car where necessary. Traction control systems have many different names and abilities with an array of acronyms to match such as PASM (Porsche Active Stability Management), ESC (Electronic Stability Control), DSC (Dynamic Stability Control) and many more. If you see the light illuminate or flash it means that the system has been activated for your safety. Depending on the conditions or type of driving, you may see it more or less, for example, it’s not uncommon to see this warning symbol if driving in winter / snowy conditions where the tyres are likely to lose drip. Driving with winter tyres can significantly aid traction here.
Seatbelt Warning Light
Severity: 10/10
Advice: Always wear your seatbelt, the driver of the car is responsible for ensuring passengers are wearing their seatbelts before driving.
Whilst we all know that we should wear a seatbelt at all times (legally required and common sense), modern cars have sensors in the seats to detect if it is occupied and whether the seatbelt for that seat has been secured. Handy for knowing if the kids in the back have secured their seatbelts before setting off. It’s not entirely fool proof however, a heavy shopping bag placed on a seat can fool the system into thinking there is a person on the seat and unless you put the shopping on the floor, or belt it up, the light will stay on and likely you’ll receive an audible beeping warning sound. Another minor gripe is that for very basic manoeuvres such as moving the car into a garage will result in the seat belt light and beeping being activated if you didn’t secure your seatbelt.
Door(s) Open Light
Severity: 1/10
Advice: Check all doors / boot are closed properly
This light simple means that a door or doors to the car is not closed properly, you should check all doors are closed properly before setting off.
Tyre Pressure Warning Light
Severity: 5/10
Advice: Check all tyres when safe to do so for obvious puncture and seek advice / re-inflate
Many modern cars now have pressure sensors in the wheels to determine if the systems detect a change in the tyre pressure. Getting a puncture in a rental car can be a real pain, in any car in fact as it can severely affect your journey and be potentially quite an expensive fix. Before the days of tyre pressure warning lights, you might notice a puncture if the car started to pull to one side indicating that a tyre was deflating (or flat), or if completely punctured you would certainly feel and hear the ‘thudding’ of a wheel with no tyre pressure over any bump in the road. By this time, you could easily damage a wheel, which in itself could be an expensive fix. Tyre pressure warning lights aim to give maximum notice to prevent damage to the wheel and possibly the tyre. Car tyres can be repaired, depending on the location of a puncture (sidewall / shoulder damage usually requires a new tyre) if the puncture is detected early enough. If you see the tyre pressure warning light on a rental car, it’s recommended you stop as soon as is safe to do so and manually check tyres for low pressure as it may not be obvious. You may need to call the rental agent for breakdown assistance, or visit the local tyre shop / repair centre for advice. Tyre pressure warning lights can illuminate without a puncture however, tyre pressures can vary depending on driving conditions and ambient temperatures. In extreme heat, tyre pressures can increase by as much as 3-4 psi which could trigger the sensor.
Fog Light
Severity: 2/10
Advice: Check fog lights are switched off when not required
All cars are fitted with rear fog lights as standard and many have front fog lights also. Fog lights are simply much brighter lights to be used only in very low visibility circumstances (not darkness), such as fog or very heavy rain. As fog lights used in normal conditions can be hazardous to other drivers (they can be very dazzling), when the fog lights are in use they will be displayed on the dash. It’s very important that you turn off the fog lights when conditions improve as using fog lights when not required can result in an on the spot fine in certain countries.
Cruise Control Light
Severity: 1/10
Advice: Reactivate system when desired
This light indicated that the cars traction control system is in operation. Any contact with the brake pedal, throttle or clutch will usually disable the system and return full control to the driver.
Engine Temperature Warning Light
Severity: 7/10
Advice: Seek professional advice / breakdown assistance
Car engines, by their very nature generate an awful lot of heat (from combustion) and as such require a complex coolant system to maintain safe operating temperatures. The engine temperature waring light signifies that the safe operating window has been exceeded (over heated) and requires attention. You can check the coolant level of the car, however be very careful checking this on a hot engine as removing the radiator / expansion tank cap whilst hot / under pressure could be very dangerous and scald. You should stop the car as soon as is safe to do and switch off the engine and allow it to cool. Unfortunately, the engine temperature warning light is often the sign of a major fault (head gasket failure), however you could be lucky that just a minor leak to a hose in the coolant system has occurred and resulted in low coolant levels. It is essential that you stop the engine to prevent over heating as soon as safe / practical to do so to prevent further damage.
Washer Fluid Warning Light
Severity: 1/10
Advice: Refill washer fluid
Simply put, the washer fluid is low or empty and should be re-filled. Whilst generally not a major issue, the ability to clean the cars windscreen can be vital in poor conditions to ensure a clear view of the road. Whilst refilling with specific washer fluid (which has added cleaning / antifreeze properties) is recommended, if you are caught short clean water will suffice. You’re unlikely to see this light in a rental car as the rental agent should check fluids before releasing the car, however it’s usually a very simple fix.
Brake Warning Light
Severity: 9/10
Advice: Seek professional advice / breakdown assistance
This light signifies a fault in the braking system. As one of the cars primary safety features it requires immediate attention. It could indicate an issue with the physical components of the system such as worn brake pads / discs / drums or the brake fluid levels, or it could signify an issue with the braking system software.
Glow Plug (diesel cars only)
Severity: 3/10
Advice: Seek advice / repair of system
Diesel cars require the fuel to be pre-warmed before it will ignite and glow plugs perform this task. When the ignition is started on a diesel, the glow plug light will illuminate to show this automated task is being performed. You’ll likely not notice this as it takes a split second, however should the light remain on, it signifies an issue with the system that may cause issues with the car starting from cold in future. If it’s a rental car, you should report the fault to the rental agent for repair / replacement.
Traction Control Fault Light
Severity: 7/10
Advice: Schedule maintenance to have the TC system inspected / repaired. Drive with caution.
As covered above, the traction control system on a car is a vital safety feature and whilst it’s not uncommon to see its light activated when driving in difficult conditions (wet / icy), you shouldn’t see the fault light, this indicates that a vital safety feature of the car has malfunctioned.
Oil Pressure Warning Light
Severity: 7/10
Advice: Check engine oil level
It’s reasonably unlikely that you’ll see the oil pressure warning light on a rental car as the cars are invariably low mileage / new cars that *should* have very few mechanical concerns. The oil pressure warning light will illuminate if the systems detect low oil pressure which could indicate a major issue with the engine. However it may simply indicate that the engine oil level is a little low. It was considered that by the time the oil pressure warning light came on, the damage could have been done to the engine, however that is not necessarily the case. You should stop the car when safe to do so and check the engine oil level. If it’s a rental car, you’ll likely need to call the rental agent for assistance.
Engine Warning Light
Severity: 8/10
Advice: Seek professional advice / breakdown assistance
Much like the engine oil warning light, you’re unlikely to see the general engine warning light in a rental car, however if you do, it’s likely to signify a major engine issue which requires attention that likely requires professional diagnosis.
Antilock Brake Warning Light
Severity: 9/10
Advice: Seek professional advice / breakdown assistance
The antilock brake warning light will illuminate should the cars systems detect any issues with the ABS system. ABS systems were introduced to mass production cars from the 1980’s and have undoubtedly saved many lives. The ABS system optimises the amount of brake force distributed to each wheel to maximise effective braking force without skidding which significantly reduced braking distances. A fault in the ABS system should be investigated immediately as it’s a vital safety feature of the modern car.
Airbag Warning Light
Severity: 9/10
Advice: Seek professional advice / breakdown assistance
The airbag warning light signifies an issue with one or more of the cars airbags, or indeed the system as a whole. Airbags are deployed in the event of an accident and dependant on the point of impact, may deploy in a different location of the car to offer maximum protection to the occupants. It’s obviously a critical safety feature and any fault to the system should be investigated / diagnosed and rectified immediately. If a rental car, contact the rental agent immediately and request assistance.
Whether you are driving your own car, or see one of these dash lights in a
rental car from Heathrow Airport, knowing when they mean and what you need to do could save you not only time, but a hefty repair bill.