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See the Light: What To Do When Your Check Engine Light Turns On

Check Engine Light


It’s Friday night. You’re in your car. As you pull up to a stoplight, you check your hair in the rearview mirror: perfection. Reaching into your center console, you grab a stick of gum in an effort to make sure your breath is as pure as your intentions. It’s date night, the first date in fact. You had a good feeling as you left your house, but the proverbial butterflies have found their way into your stomach and you’re questioning everything at this point. Did I wear the right shirt? Should I bring up my impressive pog collection, or is that too ironic? Do I know what ironic means? You beg the powers that be to give you a sign, any sign. Perfectly on queue, a light goes on. Is it God? No. It’s your car. More specifically, it’s your check engine light. One of the rare instances in which a situation is made clear,  although entirely to your dismay. Unfortunately, date night is going to have to take a rain check, but it’s not necessarily the end of the world.

In its most basic sense, the check engine light turns on when your vehicle’s computer system has detected an issue. In a broader sense, depending on the year, make, and model of your car, it could mean one of literally hundreds of things. However, before you run to your local auto shop and hand over the money you had intended for dinner and a movie, be sure to run your own “diagnostics” test.

Check the Gas Cap

Check to ensure that the gas cap on your car is fully on, and not cracked, as a drop in compression within the gas tank can result in activating the check engine light. If you are more mechanically minded, you may also want to check oil levels, belts, and hoses, as any one of these elements can also trigger the light if they are low or out of place.

Gas Cap

Check the Oxygen Sensor

So you’ve taken a look at all of the above possibilities and the light persists. That’s ok, just take a breath. And while you’re breathing, remember that, like yourself, a car needs its own oxygen. A vehicle’s oxygen sensor monitors the balance between fuel burned and relative oxygen levels within the engine. Over time, oil ash covers this sensor and limits its ability to change the mixture of fuel and oxygen. This sensor can go out or become faulty in its operation, causing a significant decrease in your miles-per-gallon as well as increasing your vehicle’s emissions. This issue needs to be addressed as quickly as possible, as it can lead to serious damage in the vehicle’s catalytic converter. Having your oxygen sensor replaced can cost around $200 at your local shop, but if you are familiar with where the sensor is on your car, the procedure is as simple as unclipping the old sensor and replacing it with a new one.

Check the Airflow Sensor

Similar to the oxygen sensor, your check engine light can turn on when dealing with a failed airflow sensor. The purpose of the airflow sensor is to communicate with your car’s computer to add the correct amount of fuel based on the air that is coming through the engine. A failing airflow sensor can result in decreased mileage, increased emissions, and in some events, can cause the car to stall. While, in theory, you can drive for anywhere from a few weeks to a few months with a broken mass airflow sensor, you will absolutely notice your car stalling more frequently and your gas mileage will go down significantly over time. This is another simple fix where the cost is mostly relative to the parts needed, but it is still recommended that a professional handle the issue.

Check the Spark Plugs

The check engine light can also turn on in the event of failed spark plugs. The purpose of the spark plug is to seal the combustion chamber and ultimately initiates combustion in your engine. You’ll notice a jolt in the acceleration of your car when spark plugs misfire.  This is another cheap and easy replacement that should be addressed right away. Cars manufactured before 1996 should be replaced every 25,000-30,000 miles, as where newer vehicles can last up to 100,000 miles.

Spark Plug

Call the Mechanic

If you have waited too long and failed to keep your vehicle on a regular maintenance schedule, first you should roll up a newspaper and smack yourself on the nose.  After a few minutes of reflection, consider that you need to take care of your wheels. Another possible check engine issue is a failing catalytic converter. This issue needs to be addressed right away, as prolonged use without repair could result in terrible mileage, increased emissions, and the possible untimely death of the vehicle as a whole. On average, replacing the catalytic converter will cost around $2,000 and it is highly recommended that the repair be handled by an experienced mechanic.

There are literally hundreds of reasons a check engine light could go on, each with their own unique set of fixes and frustrations. Regardless of the cause, the answer is simple. Take care of it, right away. Ensuring that you are keeping your vehicle on a regular schedule of maintenance can help in avoiding further issues down the road, which means that next time you make plans for dinner and a movie, it won’t mean popcorn and infomercials at the local mechanic.

Do you have any Check Engine Light stories? Let us know in the comments below!

Caroline Rex

She's a graphic designer by trade, but loves writing blog posts on the side. As a closet car fanatic, Caroline enjoy sprinkling knowledge about the unique ins and outs of the underdogs of the auto world. #neonsruletheworld

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