Check Engine Light: What is it? How To Turn It Off With An OBD2 Scanner?

1,346 Views Updated: 05 Jul 2018
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Check Engine Light: What is it? How To Turn It Off With An OBD2 Scanner?

It can be a source of a headache when your car’s Check Engine light starts glowing on the dashboard. You probably have no idea what it means or how you should respond to it.    
What you know for sure is that the warning is annoying, you want to be rid of it.    

What Is The Check Engine Light?

Officially known as the Malfunction Indicator Lamp (MIL), the Check Engine light belongs to your car’s diagnostic system. It is the engine's computer trying to tell you that something is wrong.   

All cars come pre-installed with computers to manage and oversee vehicle performance. They help regulate things ignition timing, engine speed, and automatic gear transmission.    
When the computer finds a problem engine's electronic system that it can't fix, the warning indicator light comes on. Depending on the car manufacturer, the light is yellow, amber, or orange.    
The light may be labeled “check engine”, “check”, “check powertrain” or simply display the image of an engine alone.    

Not only does the computer turn on the Check Engine light, it stores a diagnostic trouble code that indicates the source of the trouble to its memory.  

The information in the code can be accessed by using an automotive diagnostic scanner, or other electronic scan tools.   
On some rare occasions, the Check Engine light may come on even though nothing is wrong with the car. This could be due to changes to the weather or other trivial factors. The light usually goes off by itself after a while.

Reasons Why The Check Engine Light May Be On

There are a number of reasons why the Check Engine light might pop up or start flashing. The light is there to warn you about an issue that needs to be checked out.   
Below are the most common problems that can cause a Check Engine light to come on. 

1. Failure of Oxygen Sensor

An oxygen sensor is the part that measures the amount of unburnt oxygen left in the exhaust system. It sends data to the car's computer, which uses it to regulate the mixture of fuel and air going into the cylinders.   

A faulty sensor is usually caused by oil Ash which reduces the sensor’s ability. It costs less than $200 to replace one.    
Most cars have more than one oxygen sensor, so your car will continue running with a faulty one. However, it will burn more fuel than needed, and cause bad emissions.    
If a faulty oxygen sensor is not replaced, it can eventually damage your spark plugs and catalytic converter. The latter will cost more than ten times what it takes to replace an oxygen sensor.

2. Loose Gas Cap

The gas cap plays an important role in a car's fuel delivery system. It helps seal the system, and prevent gasoline vapor or fumes from leaking out. It also helps regulate pressure within the tank.    
If your Check Engine light was triggered by a gas cap, it means the cap is either broken or loose.    
To correct it, you can pull over and tighten the gas cap, and see if the Check Engine light goes off. If broken, you can buy a new gas cap for $5-$10 at an auto parts store and replace it.

3. Failure of Catalytic Converter

The catalytic converter is part of the car's exhaust system. It helps to convert harmful carbon monoxide into carbon dioxide which harmless to the environment.    
Catalytic converters are low maintained parts. They don't fail as long as you perform regular maintenance like oil changes, replacing spark plugs and oxygen sensors when bad.    
Discolored emissions and strange noises coming from the exhaust indicate a problem with the catalytic converter.    
Failure to replace it leads to reduced performance, bad gas mileage, and overheating. The price of a replacement is around $2000 dollars.

4. Old Spark Plugs and Wires

The spark plugs ignite the mixture of fuel and air in the cylinders to initiate combustion. The spark plug wires deliver the electricity generated by the ignition coils to the spark plugs.    
After thousands of miles, spark plugs experience wear, and begin to fail. This can cause the plugs to misfire leading to reduced acceleration and gas mileage.    
It can also clog the catalytic converter, damage oxygen sensors, and ignition coils, forcing the engine to shut down completely.  
Spark plugs and wires are very cheap and easy to change.

5. Mass Airflow Sensor Failure

The mass airflow sensor oversees the amount of air entering the engine and tells the computer how much fuel to mix. Without it, the car cannot adjust to changes in altitude.    
It's failure can be caused by air filter that has not been replaced in a long time or one that is improperly installed.    
A faulty sensor can lead to reduced performance, trouble starting, and lack of control over the throttle pedal. It costs between $100-200 to replace.

Is It Safe To Drive A Car With The Check Engine Light On

When the Check Engine light comes on after you just had your tank filled, you probably failed to replace gas cap properly. If it still stays on after you screw back on correctly, you can continue driving.    
In most instances, the problems being announced by the Check Engine light would hardly affect your car’s mobility immediately. It is completely safe to drive your car for a while until you get it checked out.    
It just means that you're going to need a repair sometime down the road. Do not ignore the light for too long as this might lead to damage of other parts and costly repairs.    

What To Do About A Check Engine Light

There are two ways you can deal with the nuisance of a Check Engine Light: using an OBD2 scan tool or visit the mechanic.

How to Turn The Check Engine Light Off With An OBD2 Scanner

This is a kind of OBD2 cheap automotive scanner that can be connected to your car’s universal connector just below the steering column to access the trouble code stored in the computer's memory.
When you connect your OBD2 scanner into the car’s port, put your key in the on position, making sure not to start the engine, then press down on the scan button of your OBD2 reader and wait while it scans for codes.    
After it is done scanning, it will send you a list of codes or one single code, which you should write down.    
You can Google what the codes mean and find out the trouble with your car.   
Once you know what the problem is or after fixing it, reconnect the OBD scanner, then press down on the button that reads “erase.” This will reset the scanner and turn off the car’s Check Engine light.
It’s easy to find the Best OBD2 Scanners Reviews on   

Visit A Mechanic

A visit to an auto repair shop will find you a mechanic to diagnose the problem and repair it which will cause the Check Engine light to go off.

The Bottom Line 

Knowing what the Check Engine light indicates is the first step on the road to fixing the issue.    
Now you can find the right OBD2 scanner that works best for your vehicle, budget, and diagnostic needs depending on the features you require.

Posted by: Stephan321 Posts: (12) Opinions: (0) Points: 160 Rank: 804

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