How to Understand Your Vehicle's "Check Engine" Light

A modern-day car is a technological masterpiece, that's been designed to be as efficient and comfortable as possible, while making as little impact on the environment as it can and maintaining its value in the marketplace. While this technology is generally a good idea for the average car owner, it comes with its drawbacks as well. Principally, it's very difficult for the average "do-it-yourself" motorist to work on their vehicle, simply due to its complexity. What happens, therefore, if the ubiquitous "check engine light" illuminates on your vehicle's dashboard?

Modern-Day Complexity

In years gone by, the check engine light was typically linked to a problem with the engine's compression, timing or temperature. However, these days the light is managed by the vehicle's ECU or brain and can be the harbinger of hundreds of potential issues. Even though the light may prompt you to get your car serviced, the issue could just as easily be within the transmission or an electronic circuit. 

The modern-day car relies on dozens of different sensors and most of these are wired to the same circuit as the check engine light. These sensors may determine whether the combustion mixture is correct, if the exhaust gases are within legal parameters, where the crankshaft is in relation to the camshaft and even whether the throttle pedal is open or closed. A blip within the electrical current can often cause the light to illuminate.

Decoding the Problem

You can begin to narrow down the problem by picking up a special code reader from your auto-parts specialist. This tool can then be plugged in to the computer and will then display a specific code according to the exact problem. You may have to refer to your owner's manual to see where the receptacle is, but in many vehicles it is within the driver or passenger footwell and may be underneath the carpet.

Taking Action

Once you have the code, you can go online and determine what it refers to. In some more complicated situations, however, the code may just be an entry-level warning that will prompt other codes and further investigation. If you're lucky, you may find that the code refers to something that you can do yourself, but otherwise you will need to take the vehicle into a trained mechanic for further advice.

One thing that you should never do, however, is simply ignore the light as it could relate to a fairly serious issue. In this case, early intervention may save you some money.