Worrying warning light or fault code appeared on your dashboard?

Gilmar Motors use the latest state-of-the-art car diagnostic test equipment to help troubleshoot system warnings and check engine lights to identify issues early before a possible component failure occurs.

Our diagnostic equipment checks for faults with engine management, electrical systems, lights, emissions, tyres and more to quickly identify any potentially costly problems.

Our trained technicians can then assist with advising you of any recommended repairs to fix the problem, reset the engine management or warning light and prevent further damage in the future.

The standard diagnostic check can take up to 1 hour. However, if additional time is required to complete the diagnostic check, we will contact you for approval to proceed.

What is ‘car diagnostics’?

All modern cars contain on-board computers that monitor or control things like emissions levels, engine temperature and even windscreen wipers. When things go wrong, these computers produce error codes which can only be read with vehicle diagnostics equipment. You may see a warning light on your dashboard, but these only give a small part of the full picture.

Our car diagnostic check picks up these errors and identifies what they mean, so component failures can be prevented before they lead to further damage or expensive repairs.

Now we’re going to take a closer look at some of the more common car warning lights, what might have caused them to appear and what you should do if you see them. If you’re ever unsure and want a second opinion, let our fully trained technicians have a look with our full diagnostic check.

Red warning lights


Battery warning

The cause: If this light doesn’t go out a few seconds after starting the engine, there could be a fault in your alternator, battery or electrical system. This means that your car isn’t charging itself when driving, which could cause the battery to drain and the engine to eventually stop.

The solution: If this light comes on, you should turn off anything non-essential that uses the battery (e.g. heating, air conditioning, radio, charging devices, sat navs and heated seats). Don’t stop and turn off your engine straight away because your car may not start again. Instead, wait until you’re somewhere safe.

Brake system alert

The cause: If this light appears while you’re driving, then you’ve probably left your handbrake on. If your handbrake is off but the light is still on, it may mean that you’re low on brake fluid or there’s a serious problem with your hydraulic brake system.

The solution: If you notice a difference in your brakes – for example, if they feel spongy or the pedal sinks to the floor – then pull over and call your breakdown service immediately. If the brakes feel normal it is still recommended to have them checked.

Seat belt reminder

The cause: You or a passenger are not wearing a seatbelt while the vehicle is in motion.

The solution: This is a simple problem to resolve, but also one of the most important. If this light comes on it essentially means someone in the car isn’t wearing a seatbelt. Please remember that all passengers, whether they’re sat in the front or the back, are required to wear a seatbelt by law.

Power steering warning

The cause: The most common reason for this indicator to appear is a lack of power steering fluid, but there also may be a more serious problem with the system.

The solution: Pull over, switch the engine off and check your power steering fluid levels. If the light remains illuminated, seek assistance as it may not be safe to continue driving.

If you’ve recently disconnected the battery, you’ll need to reset the steering system. Turn your steering wheel fully left and then fully right before driving slowly for a short while.

Engine temperature warning

The cause: Your coolant level is low. Without coolant, the car will get too hot to function and this could cause damage to the engine, which can be very expensive to repair.

The solution: First, pull over to allow the engine to cool down. Next, check the coolant level of the tank under the bonnet. Be very careful when opening the lid on the coolant tank because you could be scalded by escaping steam if the engine is still hot.

If the coolant level is fine but the light comes back on, it could mean you have a leaky radiator or a more serious problem such as a blown head gasket. If this is the case, you need to get your car looked at straight away.

Doors open reminder

The cause: Either your boot, bonnet or one of the car doors hasn’t been shut properly.

The solution: Pull over and make sure that all your doors are firmly shut. If you have children in the back seats, it’s a good idea to switch on the child safety locks to ensure they don’t open the doors when the car is in motion.

Airbag fault alert

The cause: There’s a fault with one or more of your airbags.

The solution: If there’s a fault with your airbag, you should get this looked at by a mechanic straight away. If you don’t and then get into an accident, the airbag may not activate and this could leave you and your passengers without protection. Alternatively, it could be activated when you least expect it, causing injury.

Amber warning lights


Check engine

The cause: A sensor has detected a problem with your engine. This light could indicate a number of things, from simple issues such as a fuel cap not being fastened correctly to wider problems with the engine or emissions system like a failed catalytic converter.

The solution: Even if your vehicle is not experiencing any other symptoms, it’s best to get this checked with a diagnostic machine at a trusted garage to determine the problem. Our full Diagnostic Check is a great option as our experts will be able to identify any issues or faults and advise on repairs.

Change in tyre pressure

The cause: The tyre-pressure monitoring system has detected a drop in pressure.

The solution: You could have a puncture in one of your tyres or they may just need inflating. Your tyre pressures can affect your braking distance and handling, so it’s best to stop and check your tyres and pump them up if necessary. If you notice a puncture, change the wheel or use sealant to stop the leak.

Glow plug indicator (diesel)

The cause: Your glow plugs, which are heating elements that help start your engine, are faulty.

The solution: It’s normal for the warning light to appear for a second or two on start. However, if it stays on longer.

ABS warning light

The cause: There’s a fault in your ABS braking system, which helps your car come to a stop in emergencies.

The solution: If the ABS braking system is working, you should feel the brake pedal pulsing when you brake hard. If it’s not doing this, you need to get car checked out as soon as possible as your emergency braking may be affected.

If the ABS indicator is on and the brake warning light is showing, it could mean there is something seriously wrong with your brakes.

Limited electric power indicator

The cause: This will usually mean that you’re very close to running out of charge and depending on your vehicle, it may stop.

The solution: Your car will start to use up its stored supply of petrol or diesel but, if you have a plug-in hybrid, you may want to plug into an electrical charging point at your nearest charging station. Make sure you monitor the charge gauge to see how much power is remaining during your journey.

Remember, if your dashboard symbols are illuminated then your car is trying to tell you something, so don’t ignore it.

Our initial diagnostic check is £60 plus VAT for the first hour. If our technicians require further time then one of our team will contact you to discuss this.

Use our booking form to arrange an appointment with Surrey based Gilmar Motors.