The check engine light is a very useful feature because it keeps you on your feet. You’re informed as soon as there is a problem and can react immediately. This often protects your car from long term damage.
However, sometimes the check engine light turns off by itself without you having to do anything. This does happen but it by no means is an indicator of the problem being solved. In fact, it just means your car passed some internally regulated tests. But we’ll talk more about that later on.
So can check engine light turn itself off? Yes, it absolutely can. If possible, you should still visit a mechanic or check the light code and try to figure out why it turned on in the first place.
Why Does The Check Engine Light Turn On?
To understand why the check engine light can turn itself off, you need to know why it turns on in the first place.
Your car is always running tests on itself. These include both continuous and non-continuous monitors. The former includes things like engine timing and misfires while the latter includes things like air-fuel ratio and the EVAP system.
The check engine light turns on if your car fails any two tests in a row. This is why you’ve probably heard mechanics or car fans talk about ‘two trip monitors’ when discussing this light.
Why Does The Check Engine Light Turn Off By Itself?
After failing two tests, the car continues to run tests. If the light turns off, this means that at some point the car passed the tests it had previously failed three times. While this can mean that the car is alright, you should still consult a mechanic.
It is always best to know what went wrong. Even if it was a temporary problem or a glitch, there is the possibility that it was a precursor to a much bigger problem. Or perhaps, it was an indicator of an issue somewhere else in the engine. Either way, it is always better to be safe rather than sorry.
For a while after the light has turned off, technicians can see which test your car failed and why the light was on.
What If The Light Doesn’t Turn Off By Itself?
If the light doesn’t turn off, you need to investigate the root of the problem. Take a look at your transmission, engine, and generally just pay attention to the way your car is driving. Go to a mechanic if you can find a serious issue.
However, if nothing seems to be wrong with these areas, your car probably failed a test involving a non-evasive sensor. Alternatively, there might be a mechanical failure. In such cases, it is okay to keep driving your car. You’ll reach a mechanic without furthering the damage.
The only thing you should not do is ignore the light. Doing so is incredibly dangerous not only for your car, but also for you, everyone in your car, and the people driving around you.
The Five Most Common Problems That Trigger A Check Engine Light
If you’re choosing to self diagnose your car, this list will be helpful because it outlines the most common problems that turn a check engine light on.
Oxygen Sensor Failure
A car’s oxygen sensor keeps track of the unburnt oxygen in its exhaust system. The information it collects is sent to the car’s computer. There, the air and fuel sent to the cylinders is monitored.
Your engine will continue working correctly even if this sensor isn’t working properly. However, in the long term, it will affect your spark plugs and catalytic converter. Both will affect your car’s performance.
Loose Fuel Cap
A loose fuel cap is one of the most common reasons why the check engine light turns on. It is an integral part of any car’s fuel delivery system since it stops the backflow of gasoline fumes. Moreover, it maintains your engine’s pressure.
If your check engine light turns on soon after you’ve filled your tank, you should stop at the side of a road and make sure the cap isn’t loose. Sometimes people find that the cap isn’t on their car at all and has fallen off.
Either way, this problem is easy to fix and won’t cost a lot. If this is the reason your light turned on, it won’t turn off until you fix the issue.
Catalytic Converter Failure
The catalytic converter turns carbon monoxide into carbon dioxide and makes your car more environmentally friendly. It is easy to fix and can be replaced without much hassle.
Even if this isn’t the problem you are dealing with, you should take certains steps to prevent it from ever happening. For instance, change your oil and be on the lookout for strange sounds or fumes coming out from the converter.
Spark Plug Issues
A malfunctioning coil always triggers the check engine light. You should know that cars that burn diesel don’t have coils. So if you own a vehicle like that, this isn’t an issue you need to be worried about.
You can change your own spark plugs. The process is fairly simple, however, you can go to a mechanic if you want to.
Mass Airflow Sensor Failure
The mass airflow sensor or the MAF takes note of how much air is going into the engine. It’s a crucial feature for people who travel through changing altitudes.
It’s very easy to figure out if you’re dealing with an MAF failure. The throttle pedal will suddenly change positions, you’ll have trouble starting your car, and you’ll notice a rough idle.
The check engine light can protect your car from a lot of damage and you from a lot of expenses. Sometimes it can turn off by itself but you shouldn’t ignore it in the hopes that it will do so.
As soon as you notice that it has turned on, stop driving, investigate your car, and if there are no obvious issues, drive to a mechanic. Otherwise, call one to your location. Stay safe!