The Anatomy of Healthy Cars: A Service and Repair Blog

Illuminated Check Engine Light: 3 Possible Causes

by Brittany Marshall

When you get into your car and turn the key in the ignition, you may notice that your dashboard lights up like a Christmas tree. After a second or two, the lights should turn off. From then on, the lights will only be illuminated when individual systems within the car are in operation or if a component on your vehicle has malfunctioned. One light you need to pay particular attention to is the check engine light.

The check engine light is usually yellow in colour and is shaped like the outline of an engine block. If you are unsure of what the light looks like or you are struggling to locate it on your dashboard, you should check your car's drivers manual. 

The check engine light is activated by your car's central computer when it receives information of a fault in the form of a diagnostic trouble code. A number of problems can trigger this diagnostic trouble code. Below are three possible triggers of the check engine light.

Faulty Oxygen Sensors

The oxygen sensor in your car monitors the rate at which oxygen passes through the engine and exhaust system on your vehicle. The amount of oxygen in the engine and exhaust gas must be checked to ensure that the correct ratio of fuel and air is fed to the engine. Over time, the oxygen sensors in your car can fail. When they fail, the onboard computer will no longer be able to calculate the correct fuel and air mix and will illuminate the check engine light to alert you to the problem.

Loose Petrol Cap

Many modern cars have a sensor which is built into the fuel cap. If you refuel your car and fail to reinsert the petrol cap correctly, the check engine light will light up. Driving around with a loose petrol cap is dangerous as it allows gasoline fumes to escape, creating a fire risk.

Faulty Catalytic Converter

The catalytic converter is responsible for converting harmful carbon monoxide fumes into carbon dioxide. Over time, the converter can become increasingly inefficient which results in higher temperatures and reduced fuel economy. The catalytic converter is linked to your car's computer and will trigger the check engine light if it begins to fail.

If you have any concerns about the condition of your vehicle, you should contact an auto servicing and repair shop today. A trained mechanic will be able to carry out a full inspection of your car.