Complete Guide to Dashboard Warning Lights & Car Diagnostics

Ever been panicked by a dashboard warning light flashing up whilst driving? Warning lights can be triggered for a range of reasons, so it can be difficult knowing how to react and when to get a car diagnostic. 

At ATS, we conducted a study to investigate how well Brits understand dashboard warning lights. Our recent survey shows that the majority of Brits cannot identify a number of lights correctly, while 16% ignore their dashboard warning lights altogether. The most prevalent region for this was Wales, with 21% of Brits in Wales admitting to ignoring their warning lights. We also found that Brits who didn’t regularly service their car were less likely to be able to correctly identify their car’s warning lights. 

The Different Dashboard Warning Lights and their Meanings

Dashboard warning lights alert you to a fault or problem with your car, from tyre pressure loss to brake failure.

What are the Different Dashboard Warning Lights for Petrol and Diesel Cars?

Dashboard lights differ depending on if you’re driving a petrol, diesel, hybrid or electric car. First, let’s look at warning lights for petrol or diesel cars.

Check Engine 

This light warns of a potential problem with the engine and can signal a range of issues, such as a misfiring engine. It’s very important to get a car diagnostic to identify the problem as soon as possible. 

Engine Cooling Warning

The engine cooling warning light tells you that the engine temperature is getting too high, so you should stop the car as soon as safely possible. This sign also tends to indicate that your coolant levels are running low, so you should check these and refill if necessary.

If the light turns red, it shows your engine is overheating, so you should leave your car off for at least 30 minutes to allow your engine cool down. If you get this warning light on your dashboard frequently, you should get your engine checked.

According to our recent study, the engine cooling light is the warning light that the most Brits didn’t know, as 80% were unable to identify it. If you ignore this warning light or leave the problem untreated, you are allowing your engine to overheat. This is a serious safety risk and can lead to permanent engine damage. 

Oil Pressure Warning 

This signals a problem with your car’s oil pressure, which could cause serious damage to the engine. 

Brake System Warning 

If you see your brake system warning light come on, you should first check your handbrake is fully released. If the light remains on once you’ve released your handbrake, this could alert you to a more serious problem with your brakes and you should pull over as soon as possible. Don’t risk driving with faulty brakes.

According to our recent survey, 57% of Brits didn’t realise they were being warned about their brake system, with 37% believing it was the ABS warning light. Being unable to identify the brake system warning light could have serious consequences, including having to replace your brakes, which cost £250 on average, or even your entire car in the case that faulty brakes lead to a serious accident. 

Battery Warning 

According to our survey, 54% of Brits can identify this warning light. However, 39% of participants would respond to this light by replacing their battery when they didn’t need to. If you see this sign pop up on your dashboard, you should always have your battery checked by a professional to avoid having to buy a new battery unnecessarily. 

Brake Pad Warning Light 

This light tells you that a sensor in your brakes has detected that one of your brake pads is worn. 

According to our study, 61% are unable to identify this light and 47% believed it to be a brake light fault instead, while 14% thought it signalled cruise control was activated. 

Ignoring or wrongly identifying this light can be very dangerous, as driving with overly worn brake pads may can inhibit your ability to stop. If you see this sign, you should pull over as soon as you can safely do so and call for assistance.

Tyre Pressure Sensor Warning

This light is your Tyre Pressure Monitoring System (TPMS) signalling a drop in pressure or potentially a puncture in one or more of your tyres. You should check this as soon as possible.

Our research showed that 54% of Brits could identify the tyre pressure warning light correctly. However, new car drivers were less successful, with 65% of participants with a car up to 1 year old being unable to identify this warning sign. When you get a new car, you should always take some time to get to know the dashboard warning lights and how you should respond if they flash up on your dashboard. 

Low Fuel Warning 

A familiar signal to most drivers, this light means you’re running low on fuel. It will usually appear when you’ve got a range of about 50-70 miles left in the tank. It’s a good reminder to fill up before you run out. 

Electronic Stability Problem (ESP) Warning 

This light will flash when your car is losing traction or driving on a slippery surface, to indicate your ESP system is working. If the light is on constantly (not flashing), your ESP isn’t working properly. This is likely a fault in the system and should be checked by a professional. You can book a check up with your local ATS centre. 

Seatbelt Warning 

This light alerts you that someone in the car doesn’t have their seatbelt fastened. In most cars, this will be accompanied by an audible warning, such as beeping. Pressure sensors in the seats determine if someone is seated, so heavy objects on passenger seats may also trigger it. 

Door/Boot/Bonnet Warning

These lights signal that either a door, boot or bonnet are open. Pull over and make sure whatever is being signalled is properly closed. 

What are the Different Dashboard Warning Lights for Electric and Hybrid Cars?

Although many of the above lights are also in electric and hybrid cars, there are various warning lights exclusive to hybrid and electric cars. Now let’s look at the warning lights exclusive to electric and hybrid cars and what they mean. 

Ready to Drive 

As electric cars and hybrids can be silent when starting up, this light indicates that the car is ready to drive. 

Limited Power Warning

This light signals your EV is running on limited power. It’s often accompanied by a message informing you what’s wrong. 

Battery Charge Level Warning

This tells you that your battery is critically low. Find the nearest charging point to avoid getting stranded. 

Pedestrian Alert System

Because EVs and hybrids are so quiet, this pedestrian-alert warning light will flash up on your dashboard and make a loud noise to warn approaching pedestrians that may not have heard the car. 

What is a Car Diagnostic?

What is Checked in a Car Diagnostic Test?  

A car diagnostic will analyse various parts of vehicle, specifically any problems with your:

• Engine
• Transmission and responsiveness
• Brake responsiveness
• Fuel tank
• Oil tank 
• Exhaust system 
• Major components (signs of wear or damage)