How to Reset Check Engine Light?

Check Engine Light on for once gives you the stomach butterflies everyone dreads. Because you are never sure what this thing wants you to do: get your whole engine replaced at the earliest or simply keep driving and wait for it to turn off by itself!

You must have seen your check engine light turning on by as little an incidence as getting your vehicle washed. There is nothing to worry about in this case if it happens now and then with your car, and it turns off in one or two days. But you need to keep in mind a few things if the light turns on suddenly while driving or after you get back from the repair shop.

In this article, we will discuss everything you need to know about the check engine light. What turns it on? How serious is the matter? And how to reset the check engine light?

What Does the Check Engine Light mean?

The malfunction indicator light, commonly known as the check engine light, signals a discrepancy in the range of emissions or preventative maintenance service. The engine control computer produces this signal, which uses various inputs and sensors to get the required information.

When the input readings from the engine fall out of the normal range, the check engine light turns on. The system tries to compensate for the difference, and if successful, the light is turned off. Otherwise, you see it on till you catch and correct the malfunction.

What Could Cause the Check Engine Light to Turn On?

Here we have the probable causes for the Check Engine Light turning on. And then, we will proceed to the ways you can use to reset your check engine light. The reason may be as simple as a gas cap left loose or as weighty as an important engine sensor failing its function.

1. Loose Gas Cap

Let's start easy. A loose gas cap can turn on the check engine light. This is the most common reason that people complain about the check engine light turning on. Tighten it enough to create a vacuum seal every time you fill your car.

2. Malfunctioning Mass Flow or Oxygen Sensors

Remember, we talked about the sensors, inputs, and normal range emissions. Your vehicle's engine makes sure the right amount of air mixes with the fuel. For that, it has mass flow sensors.

When these sensors fail to respond, or the ratio gets disturbed, the car's check engine light turns on.

The same is the case with the oxygen sensor. This malfunction is the second on the list of most common reasons for the check engine light in action. This happens while driving when the unburned oxygen in the automobile exhaust falls out of the normal range.

In these cases, it is important to get your car run through the hands of a professional car repair. Mass flow sensor failure is the reason why your vehicle might stall or delay the pickup. And when the oxygen sensor fails, the unburned oxygen can damage the other engine parts if too little or too much. More importantly, these two sensors are a bit costly to get replaced. So, you must get them repaired soon if the check engine turns on due to any of these.

3. Spark Plug

Worn-out spark plugs cause the engine's performance to drop, and this drop can be recorded on the onboard computer. This can cause the Check Engine Light to come on. Make sure you change sure spark plugs after every 100000 miles.

Check this link if you want to know how to identify worn-out and good spark plugs.

Although it is very unlikely to happen, it is still a possibility. Over time, catalytic converters get clogged and hinder the exhaust gases from passing through them. When this happens, it puts pressure on the engine and thus causes power loss. The computer can record this power loss and cause the Check Engine Light to come 'On.'

Spotting a bad catalytic converter is easy. If there is a rotten-egg-like smell coming from the exhaust pipe area and your Check Engine Light is on, it is the catalytic converter creating a mess. Replace your catalytic converter as soon as possible. We know it can be expensive, but your car cannot run without it.

Check Engine Light 'ON' may be minor, but not Negligible.

Most people ignore their Check Engine Lights and thus find themselves waiting on a highway for the next car to pass by. Check engine light can indicate a small problem as well as a major problem with the engine performance.

If the Check Engine Light is not dealt with responsibly, new major issues may arise. How will the engine report them to you when it is on already, and you deal with it like a no-problem?

First things first, is the check engine light illuminating or flashing? A flashing one demands a flashing action. But the illuminating one is no less a matter of concern either. Continue driving regardless until you get to run your vehicle through a professional check.

Your vehicle is going to fail the emissions test on state inspection. And this can be bad!

Thirdly, if you see your check engine light on, be prepared for the consequences of the chain reaction that has now started inside your engine. For instance, the failure of an oxygen sensor drastically affects the fuel economy and can damage the neighboring engine components.

So, it is necessary to always get the Check Engine Light reset.

How to Reset the Check Engine Light?

Whether your vehicle is the latest in the market or an old one, the reasons for the check engine light turning on a stay more or less the same, and so do the ways to reset or turn it off.

Here are the universally known methods to reset your Check Engine Light that use minimum tech jargon and tools.

1. Just Drive Your Car and Wait for It to Go Off by Itself

When you see that your Check Engine Light, don't freak out. Like yeah, do take notice, but don't panic at the very moment!        

Just wait a day or two for it to go off automatically. The onboard computer will figure out what the problem is and might solve it. Most probably, it is the fuel to air ratio which the computer adjusts automatically.

The computers in a vehicle are programmed to ensure that the Check Engine Light is not turned on purposeless. They reset the default settings a couple of times. The light should go off if everything is alright.

If the light remains on for more than three days, try the methods below.

2. Turn the Car On and Off in Succession

Some car models automatically reset the error codes if turned on and off three to four times in succession. You don't need to start the engine, just put the key in the ignition and turn it on and off at one-second intervals. After that, drive off for a couple of minutes and check if the light has gone.

3. Disconnect and Connect the Battery

You'll probably need some tools for this task. Open up the hood and unscrew the positive terminal of the battery using an appropriate numbered wrench. Make sure the disconnected wire is away from the battery terminal as it might touch the terminal due to flexibility and cause sparking.

After 15 minutes of leaving the battery disconnected, turn the ignition on and off three times in succession. This will clear the system memory and any previous read errors.

Screw up the battery terminal and start the car. Wait a minute, and the light should be gone.

Check out this link on how to tell the positive and negative of a car battery?

4. OBD Code Reader

For this, you'll need an OBD (Onboard diagnostic) reader and some common tools. These readers are inexpensive to buy but do a lot of work. They help clear the erroneous data from the vehicle's computer. Follow the instructions below precisely:

1. Simply plug your reader in the OBD port in your vehicle. The OBD port is mostly found under the dash area on the driver's side. Some cars might require you to remove the fuse box to find the OBD port. The fuse box is also located underside the dashboard area on the driver's side.

2. Once connected successfully, press the 'ENTER' button on the meter.

3. The system scanning will begin, and a list of error codes will appear on the LCD screen. Note down the error codes to gather more information on them from the manual or the web.

4. After scrolling down the list to the last, you will find an option to erase the data. Or you might have a physical button on your OBD reader. Press this button and check if the Check Engine Light has gone.


Q: Why did my check engine light suddenly come 'ON' when I changed some fuses?

A: There can only be the following possibilities:

1. You might have used the fuse with the wrong value. Every component in the car requires a specific fuse, and only that fuse must be used.

2. The fuse you replaced went bad just after replacing and caused a system in your vehicle to stop functioning.

The easiest way to clear out this problem is to use an OBD meter. It will enlist all the error codes, which can then be looked up in the manual book to locate the faulty fuse or the one that needs replacing.

Q: Does the check engine light a reminder for the car maintenance session?

A: The check engine light is not designed to tell the driver when and where maintenance is required. It will simply tell you that something is wrong with the engine's performance. Never wait for the check engine light to come on before you take your vehicle for maintenance. Regularly change the air and oil filter, replace engine oil, and change spark plugs after 100000 miles of driving.

Q: Should I keep driving when the Check Engine Light comes on?

A: There is no need to just stop the car the moment you see the Check Engine Light. But yes, keep driving for a while to see if it goes off or not. In fact, give it at least three days and if it stays on, use the hacks above to reset your check engine light.

Q: I have tried all the methods above, but my Check Engine Light is not going off. What do I do?

A: The above guide deals with almost all probable causes of the indicator turning on. And it should fix any problems you are having with your Check Engine Light. But the guide only caters to resetting the light when there is no apparent engine malfunction. But if it fails to do so, take your car to a garage and consult a professional mechanic.

Final Thoughts

Dealing with the check engine light is an important part of vehicle maintenance and enjoying its maximum efficiency. Because it is not just the light, it is the underlying malfunction that is asking you to address!

The ways mentioned above to reset the check engine light is applicable when you maintain your vehicle and feel nothing abnormal while driving. If that's the case, your car needs an urgent visit to the car repair. 

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