Most drivers would of experienced an unknown light on their dash at some point in their driving career and quite often it fills you with dread when the light comes on, partially because you don’t know what the light means and partially because it can signal an expensive and timely repair. As soon as a light appears it is advised to get your car checked as soon as possible, the earlier you catch an issue the higher chance you have of repairing it at it’s cheapest and stopping any damage occuring else where.
Depending on the model car there is a range of lights you may see which would indicate a problem, the most common lights would be the Engine Check Light (known as MIL formally), ABS/Brakes, Airbags, DPF and Traction Control. Some cars, mainly modern cars will now combine or replace the light(s) with messages on a display giving more accurate information to the driver.
This light can cover virtually any aspect of the car and can often appear in conjunction with another light, for example if a wheel speed sensor is to fail you will get the MIL for the faulty sensor, but you would also get the ABS light to show the ABS system isn’t functioning either. The MIL light can come on for either a intermittent or permament issue so it’s always advised to check it out as soon as possible.
Some common causes of a MIL light would be;
> Engine misfire (plugs, leads, injectors)
> Sensor issues (O2/Lambda, Mass Airflow/MAF)
> Solenoids (Throttle Body, EGR Valve)
> Cooling system (thermostats, sensors)
> Exhaust system (catalytic converter, sensors, leaks)
> and much more!
The ABS light will appear when you have an issue that causes the braking or ABS system to malfunction, go into safe mode or simply not function at all, normally this light will appear in conjunction with the MIL.
Some common causes of a ABS light would be;
> Faulty ABS Unit (failed unit, electrical issues)
> Faulty wheel speed (wheel speed sensor, hub pickup ring)
> Faulty speedomoter sensor
> and many more
When your airbag light is on, chances are the airbags will not work so it is important to get checked out as soon as possible. On some vehicles the airbag light will illuminate if you have disabled passenger airbags, so always check that first.
Some common causes of a Airbag light would be;
> Faulty airbag module (electrical, high resistance)
> Airbag controller (faulty, electrical issue)
> Impact sensors
> Clockspring
> and many more
The traction control light is normally illuminated to show that you have the traction control turned off, if you cannot get the light to go out or its accompanied by any other light then chances are theres a fundamental problem with a component that the traction control relies on such as a wheel speed sesnor.
Most modern diesels are fitted with a DPF filter on the exhaust, as you drive the car they clog up and normally will regenerate themselfs without you knowing to burn off the particles that are clogging it. However, if you don’t take the car on long drives this automatic regeneration doesn’t have time to run and the DPF clogs causing this light. Refer to your owners handbook on how to regenerate the DPF, if this doesn’t work then it will need to be checked and regenerated at a garage, or worse case a new DPF.
Some cars will have an extra braking light to the ABS to warn of low brake pads or similar issues, refer to the handbook
Most cars will have a battery light to indicate when there is an issue with the cars electrical/charging system
This light would indicate one or more tyres is under/over inflated or there is an issue with the TPMS system
A light to say you need more screenwash in your car
So the next time you see a mysterious light on your dash, never be embarassed to ask for advise and get it checked out. Most garages will carry some form of diagnostic equipment, here at Whatlington Garage we carry a range of dealer level diagnostic equipment for most makes of cars to enable us to find the fault causing the light. If you have a mysterious light, or would like some advise just give us a call on 01424 870 307.
