Why Is the Check Engine Light On
Driving is one of those things that works best when you don’t have to worry about how things work. You have something to look out for on the road without worrying about what’s going on under the hood. But one day you’re driving home minding your own business and your check engine light comes on with no warning or explanation. What are you doing?
As Yalopnik pointed out , the check engine light is one of the most annoying and confusing warnings around. It is just light and no information tells you what the problem is. This is a baby crying without explanation, but here are some steps you can take to find out on your own before heading to a mechanic for an expensive repair.
Do it first
First of all, is the indicator flashing or on continuously? According to Consumer Reports, blinking can indicate an emergency . If the indicator flashes, stop, turn off the car and get help.
Constant light means there is no immediate cause for alarm, but you should check it out anyway. Head to an auto parts store and ask them for a diagnostic to find the reason why the engine light comes on. Call ahead and make sure they can handle your make and model, as some vehicles have dedicated computers. Once you’re there, they’ll plug a small computer under your dashboard and read a code that says what happened. (You can also purchase your own code reader, known as an OBD II reader .)
Overall, five common problems can cause the check engine light to come on, and some are easy to fix on your own. Let’s take a look at the most common problems.
Your oxygen sensor needs to be replaced
The oxygen sensor is the part that monitors the unburned oxygen from the exhaust gases. This helps keep track of how much fuel is burned. A faulty sensor means that it does not transmit correct data to the computer and causes a decrease in fuel consumption. Most cars have two to four oxygen sensors; the code you get from the scanner will tell you which one needs to be replaced.
What is causing this
Over time, the sensor becomes covered in oil ash, which reduces the sensor’s ability to change the oxygen / fuel mixture. A faulty sensor not only reduces fuel consumption, but also increases emissions.
What are you supposed to do
Failure to replace a broken oxygen sensor can eventually lead to catalytic converter failure, which can cost over $ 2,000. Delivery of the car to the store will cost you about $ 200, depending on the car. However, the oxygen sensor is easy to replace on many vehicles and is usually detailed in the owner’s manual. If you know where the sensor is, you only need to disconnect the old sensor and replace it with a new one. Regardless of how you approach it, fix it right away.
Your gas cap is loose or faulty.
You wouldn’t think the gas cap is that important, but it is. When it loosens or cracks, fuel vapors will escape and can destroy the entire fuel system. This results in lower fuel consumption and higher emissions.
What is causing this
If you get an error message pointing to the gas cap, it means that fuel vapor is leaking from your cap. This means that it is either cracked or simply not tightened well enough.
What are you supposed to do
If your car doesn’t jerk or jerk when the check engine light comes on, the first thing you should check is the gas cap. Pull, tighten, and inspect the cover to see if it is cracked. Continue driving and see if the engine light goes off. Alternatively, you can buy a gas tank for a few dollars online or from an auto parts store. All you have to do is remove the old one and screw on the new one. If you have already made it to the store, you can replace it. Although it is not dangerous for the car, it is best to take care of it right away to reduce fuel consumption.
You need to replace the catalytic converter
The catalytic converter works to reduce exhaust gases. It converts carbon monoxide and other harmful substances into harmless compounds. If your catalytic converter fails, you will notice a decrease in gas mileage or your car will not move faster when you hit the gas.
What is causing this
Catalytic converters should not fail if you do regular maintenance. The main cause of the failure has to do with other items on this list, including a broken oxygen sensor or damaged spark plugs (we’ll get back to those in a second). When it fails, it stops converting carbon monoxide into less harmful emissions.
What are you supposed to do
If your catalytic converter fails completely, you will ultimately be unable to keep the vehicle running. Your gas mileage will also be dire, so try to fix it as soon as possible. Unfortunately, a new catalytic converter can cost you a couple thousand dollars and you can’t do it yourself unless you become an experienced mechanic.
You need a new MAF sensor
The mass air flow sensor tells the car computer to top up the required amount of fuel, depending on the amount of air entering the engine. A defective one can increase emissions, cause the vehicle to stall and reduce gas mileage.
What is causing this
Most MAF sensors fail due to an improperly installed (or never replaced) air filter. You should replace the air filter at least once a year to prevent damage to the air flow sensor.
What are you supposed to do
In theory, you could drive for weeks or even months with a broken MAF sensor. You will notice a decrease in gas mileage, and over time, the car will start to stall severely. In the store, the replacement cost is between $ 200 and $ 300 depending on the vehicle, but this is usually the cost of the parts because the job is relatively easy. It’s not that hard to do it yourself, but the process is quick enough that you can let the mechanic take over the project if the sensor doesn’t become a problem.
You need new spark plugs and wires
The spark plug insulates the combustion chamber and provides a gap through which the spark can jump and cause combustion in your engine. When the spark plugs fail, the spark plugs misfire. When this happens, you will feel a slight jolt in the acceleration of your vehicle.
What is causing this
Most spark plugs in vehicles prior to 1996 should be replaced every 25,000-30,000 miles. Newer ones can last up to 100,000 miles. However, candles fail over time, and there is nothing you can do about it.
What are you supposed to do
Replace them immediately. It’s simple, cheap, and will make your car perform better. If your spark plugs are out of order and you’re headed to an auto parts store, you can easily replace them by following the video above. Since this is part of your vehicle’s regular maintenance, spark plugs are usually easily accessible through the hood of your vehicle. It’s simple enough, I’ve seen people do it several times in an auto parts parking lot.
There are many other options for checking your engine, but the five above are the most common and a good place to start.
This story was originally published in 2012 and has been updated with new information on November 9, 2020 as per Lifehacker’s style guidelines.