Why is My Check Engine Light On?

Why is My Check Engine Light On?
Why is My Check Engine Light On?

It happened—one of several “worst-nightmare” scenarios for a car owner, right behind a flat on your way to an appointment and the whatchamacallit getting stuck in the domaflutchie: Your car’s check engine light is coming on. Following these helpful tips will tell you what to do when that Check Engine light appears.

Seeing a “Check Engine” light on your dashboard is alarming and frustrating. That pesky little light is meant to warn you of a problem; but what the problem is can be a mystery. Somewhere inside the complex workings of your vehicle, something triggered it. When this happens, you’ll need to take your car to the shop to have the problem diagnosed. Here are a few things you can do immediately after seeing the “Service Engine Soon” light for the first time.

“Check Engine” = Check out

If the Check Engine light turns on and you start noticing problems with your car’s performance, take it to a service shop right away. A yellow Check Engine light indicates that a problem exists, but it’s not very urgent. A red or blinking Check Engine light means the problem requires immediate attention. It could be a problem related to your car’s emissions system or a costly repair like needing a new catalytic converter. In all likelihood it’ll take time for your mechanic to troubleshoot the problem. But they should tell you how long they think it’ll take and how much it’ll cost.

The Gas Gap

Check your gas cap. A missing or faulty gas cap can turn a Check Engine light on. The pressure inside your gas tank is thrown off when the gas cap is off, defective,  or not secured properly. Sometimes the seal around the cap goes bad. To your car’s on-board diagnostic (OBD) system, a change in pressure could indicate an emissions leak, and the light is triggered to alert you to the problem. Replace the missing cap or tighten the existing one to see if the problem goes away. Give it a day. If the light stays on, head to the repair shop or dealership.

Crack the Code

You can get an inexpensive code reader in an auto parts store. If you’re a do-it-yourselfer, it may be worth picking one up. At the same time that your car’s Check Engine light triggers, a code is stored in the computer’s memory. The code reader will enable you to pull the code to find out the precise cause.

Workarounds Beware!

Take Check Engine lights seriously. Sometimes our tendency is just to want them to go away and think that they will. It’s coming on for the reason it was designed for — to warn you about a problem. But some make the mistake of thinking that if they clear it out, their problem is solved. Wrong. One popular method: run out a car’s battery, which drains all the current from the capacitor. Doing this also wipes out the data stored in your car’s computer, making it tougher to diagnose the problem later.

Is It All Good in the Hood?

Open the hood and look for leaking hoses, frayed wires, cracked or missing belts, and anything unusual. Carefully and closely inspect the spark plug wires. If they’re cracked or otherwise showing signs of serious wear and tear, your plugs may be misfiring. If you get a Check Engine light along with slight jolts while accelerating, the spark plugs could likely be to blame. This is a quick, easy, inexpensive fix: replace the old wires. To avoid the problem, replace plugs on older cars every 25- 35,000 miles. On newer cars, replace roughly at every 100,000 miles.

Be Proactive — With a Pro

If you can’t solve your Check Engine light issue on your own, don’t let it slide. Something made it come on, and ignoring the problem is guaranteed to result in an even costlier repair. At the shop, a mechanic will use a diagnostic computer or an electronic scan tool to pull the code that caused the light to come on. The shop’s diagnostic may discover issues with one of the following components:

The mass airflow sensor, or MAF sensor, calculates the amount of air coming into the engine so the computer can add the right amount of fuel. A faulty MAF could trigger the Check Engine light. It can also cause a car to experience impaired gas mileage, increased emissions, or frequent stalling. Avoid this problem by changing your air filter on a regular basis.

There are 2-4 oxygen sensors in the typical vehicle. This sensor analyzes the amount of oxygen in a vehicle’s exhaust to determine how much fuel has been burned. Gas mileage is seriously compromised when it malfunctions. Emissions usually increase, too. If you wait and ignore the light, it could worsen into a problem with the catalytic converter.

The catalytic converter converts carbon monoxide (CO) and other compounds into ones that are safe for the environment. If it stops functioning properly, your gas mileage will suffer and your car may accelerate more and more slowly.

Although it’s only natural to look at a Check Engine light with dread, remember:  It’s there for a reason. If you ignore it, things will go from bad to worse.

Check with Your Tech—at Quality Automotive.

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