How to Turn Off Check Engine Light with Scanner? Our Guide

When you are observing the check engine light on the dashboard in your car, it means something is wrong with one of the engine systems. In most cases, it's all about bad readings of some sensors but modern vehicles have wider opportunities for self-diagnosis, so things may vary. The natural desire of any driver is to turn off the check engine light using a simple and cheap scanner.

Check engine light highlights

• Common reasons:vast choice of different problems
• How to fix:read the codes to narrow down the issue
• Possible consequences:depends on the actual culprit
• Priority level:Medium
• Can you drive?Carefully
• DIY repair:Impossible
• Repair price range:$150-$1,000

Some common reasons why the check engine light is on

It's really hard to make a full list of problems that can trigger the check engine light in your vehicle. I've tried to find a comprehensive list to cite here, in this article, but it appeared that in different brands, models, and generations of cars, these lights turn on because of different reasons.

So, we'll only speak about the most common things that can trigger the scariest warning light in your car. Now, I want to comfort you a little - this warning light doesn't mean that your engine is done or is about to die. It's most likely connected to one or several sensors that send bad or no readings to the ECU.

Here are some of the most common examples of such problems:

• oxygen sensor goes mad and sends wrong readings;
• the engine misfires heavily;
• problem with the efficiency of the catalytic converter;
• throttle sensor problem;
• spark plugs or ignition coils issues;
• wrong fuel pressure on injectors;
• damage of the ECU;
• problems with the alternator or battery.

We can continue but other problems seem too specific to mention them here. Thankfully, car manufacturers provide each vehicle with a diagnostics slot. In most cases, it's OBD 2. You may use a cheap code scanner to connect to this slot and quickly get all the error codes.

If the check engine light is on, there is an error code in the ECU and you can read it. Once you know the code, you are only left to check it in the manual or online. In most cases, you will get a full answer to your question. But sometimes, codes may be misleading and, in this case, you will most likely need to go to a professional car mechanic.

Can you just turn off the check engine light with a scanner?

The check engine light may appear on the dash of your car in that case only if there is an error code in the ECU. So, if you clear that error code, the light will immediately go off. It still doesn't mean that you have already solved the problem. But let's deal with this step by step.

So, yes, you can clear the check engine light with just a scanner. But not every type of scanner. You will need some scanner and software that allow you to clear the codes and communicate with your ECU. Fortunately, even the cheapest scanners allow this, you will just need some good software (not necessarily expensive, it may even be free).

Here's what you do to turn off the check engine light with the scanner:

• connect your scanner to the OBD II slot (or another diagnostics slot in your vehicle);
• turn on the ignition in your vehicle to let ECU work;
• read the code and make sure it's not something urgent and serious;
• go to the menu in the software you are using for scanning the vehicle;
• find the option "clear error codes" or it may also be called differently but mean the same;
• apply this option and wait till the operation is completed;
• then disconnect the scanner from the OBD II port and turn off the ignition.

This is a relatively simple explanation of what you can do to turn off the check engine light if you only have a code scanner. You will not do any harm to your vehicle by launching a code-clearing program.

But you should also understand that this is not the repair. This is just the clearing of codes that may reappear in a minute or in a day depending on what errors the car was telling you about. Let's see why this won't work out well.

Clearing the codes - why doesn't it work?

Well, the error code is not the initial problem that turns on the check engine light in your vehicle. It's just something that tells you about the initial problems. So, in most cases, by clearing the code from the ECU, you will only temporarily turn off the check engine light. When the initial issue appears again, the warning light will go on the dash.

We can't say that this will happen every time. For example, your engine misfired because of bad fuel and the check engine light was on. You cleared the code and then bought good fuel and the engine stopped misfiring, so the code will not reappear and the warning light will stay off.

But in most cases, here's what happens:

• you clear the code and the check engine light goes off;
• then you start the engine and the initial problem is still there;
• after some time (it may be a minute or a week), the problem sends the same code to the ECU;
• this means that the check engine light will appear again;
• you may again use the scanner and put it off but it won't work for a long time.

So, in most cases, you can turn off the check engine light with a scanner but you will not want to do that regularly because it basically doesn't make sense. It only takes your time and puts the vehicle at risk of developing problems.

We believe the best option to get the check engine light off the dashboard is to repair your car after understanding the meaning of the code. This way, you will work with the initial reason for this problem, but not with the warning light itself.

Repairing your car to get rid of the check engine light

So, the proper repair will start with the reading of the code. The error code will tell you quite a lot about the problems and will sometimes just point you at the module or unit that needs replacement.

But codes may also be misleading. For example, a dying battery may not supply some of the electronic units of your vehicle with proper voltage and this will trigger some exotic error code that has no proper explanation. But the initial problem is in the battery that just fails to deliver over 12V.

Here's how you should repair your vehicle:

• read the code with the scanner and google it to see which unit triggers the code;
• check if you can replace the failed unit by yourself or if you need some help;
• arrange the visit to the repair shop if needed;
• make sure you are installing high-quality parts, better chose OEM parts for this;
• after you are done, turn the ignition on, keep it on for 10-15 seconds, and then start the engine;
• wait for about 5 minutes, you may also need to drive the car to let it see the new unit;
• check if the warning light is still on.

If the light is off, congratulations - you've just repaired your vehicle. If the light is on, use your scanner again and see if the code is different now. If you can't manage to deal with the code, just let professionals diagnose and repair your car. This will help you avoid issues and quickly cope with the warning light.

If this is the coil or plug or something like that, you will be able to use other methods I've described in this blog to check the failing unit. But if it's about some complicated system, better avoid DIY repairs and go to the professionals at once.

Will the warning light go off by itself after repair?

In most cases, after you repair your vehicle, it will need some time to see that everything is OK now. After that, the check engine light will go off. But, in some cases, the ECU remembers the code for a long time and can show the annoying light to you every time you start the car.

If this is the case, you may reset or clear the codes with the scanner as I described earlier in this article. Use this method to clear the codes and then see if the light reappears on the dashboard. If it does, then most likely, you didn't succeed in dealing with the initial problem and the vehicle needs some more inspections and repairs.