Things to Know About a Vehicle with the Check Engine Light On - Service Information at Capitol Chevrolet

The check engine light (also known as the malfunction indicator lamp) is a mystery to many. Some freak out if it lights up, while others ignore it entirely in hopes that it'll go away on its own. The best reaction usually lies somewhere between these two extremes. At Capitol Chevrolet, we want to provide you with important information about your Chevy, and this includes knowing what to do when this light turns on. Learn more about the check engine light below.

Illuminated check engine light

4. What a Check Engine Light Means

Modern vehicles use computers to control a wide number of functions, from making sure the ignition timing is accurate to regulating the mixture of fuel and air injected into the engine. As minor issues arise, such as an improper air/fuel ratio, the computer will adjust to correct the issue. A check engine light means that there's a computer-regulated problem in the engine that the computer can't correct. In particular, the malfunction in the engine could affect the emissions system. Since there are many things that could cause the light to turn on, it serves not so much as a precise indicator of what the problem is, but rather a way to notify you that there is an issue that needs to be addressed. Though the light may not be accompanied by immediately noticeable symptoms, it's likely that there will at least be a decrease in power and efficiency.

A person using a code reader

3. Things That Could Cause the Check Engine Light To Illuminate

There are a number of reasons a check engine light could turn on in your Chevy. One or more faulty oxygen sensors or a failing catalytic converter could trigger the light, as well as making your exhaust more toxic and decreasing vehicle efficiency. The mass airflow sensor or EVAP system could also have a problem, or the fuel injectors or spark plugs could require replacement. As you can see, the light covers a wide variety of possibilities from all around the vehicle, which means that further investigation is required.

2. What To Do if the Light Turns On

The first steps you need to take depend on whether the light is flashing or not. If the light is solid, that usually means that there's not an immediate emergency, which means that you don't need to pull over right away. Our recommendation is to park somewhere, remove the gas cap, and screw it back in tightly. Then, start your car again. A loose gas cap can cause the check engine light to illuminate, so it's always best to check that first. If that doesn't solve the problem, schedule a service appointment as soon as possible. If the light is flashing, our advice changes. A flashing check engine light usually means that the engine is undergoing severe misfires. This can dump unburned fuel into the exhaust system, which may in turn damage the catalytic converter. Replacing this component is expensive, so it's best to pull over as soon as it's safe to do so, turn off your engine, and call for a tow.

Person screwing in a fuel cap

1. Reading the Code

When the computer registers a problem that triggers the check engine light, it stores a code in its memory that points to the cause. This code can be read by a code reader. If you bring your car to the dealership with a check engine light that's on, the first thing the technicians will do is hook it up to a code reader. Code readers are also available for purchase. Since all vehicles since the mid-1990s have a standardized code system, OBD-II, your buddy's code reader will likely be able to tell what's wrong with your car. But reading the code is just the beginning.

The code is not a detailed description of the problem; it simply points you in the right direction. When technicians read the code, they'll know where to start investigating, but it will take more work to make an actual diagnosis. After that, they'll be able to make a repair.