Few things strike fear into the heart of the average car owner more than that terrifying yellow light. It goes by many names, including the check engine light (CEL) or malfunction indicator light (MIL). Whatever the case, everyone knows that it spells trouble (or at least a costly repair) once it appears on the dash. While a check engine light's sudden appearance is certainly not good news, it often doesn't warrant the anxiety and stress that it can induce in many people. In fact, an illuminated check engine light often indicates a fairly minor problem, especially if there are no other apparent systems.
What It Really Means
Your car's check engine light is, in most cases, more of a caution flag than an immediate warning. While there are many warning lights (such as the low oil pressure light) which require immediate attention, the check engine light is simply telling you that something is amiss and that you should take action when possible. In particular, your check engine light is indicating that one or several systems in your car has thrown a trouble code. The severity of these trouble codes can vary, but they generally indicate that one or more sensors are reporting data to your car's computer that indicates a problem with how your car is currently running.
Is It an Emergency?
While you should never ignore a check light engine, it is not necessary to immediately turn your car off and pull to the side of the road if you are not currently experiencing any other symptoms. If your car throws a check engine light, then it is a good idea to have it checked out as soon as you can. Many auto parts stores offer check engine light services for free, and this is often a perfectly good first step.
Understanding Trouble Codes
Once you have your vehicle's codes read, you will be in a much better position to decide whether you need to take immediate action. In many cases, the stored code will tell you exactly what the problem is. This will often be emissions related, as the underlying system was originally designed for the purpose of emissions testing. In some cases, your car may have a large number of stored codes. This can often be caused by unrelated problems such as vacuum leaks which in turn cause several sensors to report erroneous data. In these cases, you will need to take your vehicle to a qualified mechanic for a more in-depth diagnosis.
Once you understand why your car displays a check engine light and what the codes mean, you will be better prepared to deal with them as they come up.