Can check engine light turn off by itself? Let’s find out

Owning a car is impressive but comes with a lot of responsibilities. First, you need to understand the essential parts, and signals vehicles give when there is a mechanical problem. Vehicles do not talk, so you need to comprehend what they signal.

Though mechanical problems arise from different parts of a car, external parts never show a signal on display at all.

Therefore, where you should primarily pay attention to signals are the interior parts that might prove pretty hard to interpret without some mechanical knowledge.

Engine signal is the most common. It appears as an engine symbol on display referred to as the check engine light. When the check engine light appears, it signals a problem detection in the engine.

Therefore, you need to react and get the mechanic to find and solve the issue.

Unfortunately, most people ignore the signal and go on with their business simply because the vehicle never came to a halt. This poses a long-term damage threat to your car.

If the engine is not immediately checked, the problem continues spreading and result in a more costly issue.

However, after a while, the check engine light might turn off by itself without any mechanical intervention. But, that does not necessarily mean the problem is solved. It implies that your vehicle only got through some internally controlled tests.

So can the check engine light go off by itself? Yes, it surely can. However, you should visit your mechanic to find out the cause of the light in the first place.

What Triggers the Check Engine Light to Turn on?

Getting the root of a problem is the first step to solving it. Therefore, knowing the source of the check engine light will let you know why it turned off by itself.

It runs some tests on itself when the car is running, including both the non-continuous and continuous monitors. The continuous test includes misfires and engine timing, while the non-continuous include the EVAP system and air-fuel ratio.

If the car fails any two tests subsequently, the check engine light turns on immediately. It means there is a problem in the engine that needs to be checked. If you have been keen with your mechanic or car fanatics, you have probably heard them talk about ” two trip monitors.” They always refer to the two tests the car failed, leading to the light.

Why does the Check Engine Light Turn off by itself?

If you are the kind of a person who ignores the car signals, most likely you have seen the check engine light go off by itself. Did you ask yourself why even though you never took it for a checkup? Here is why.

Even after failing the two tests, the car does not stop carrying out tests on itself. It continues, and if it passes the tests it had formerly failed, the check engine light goes off. Though this will suggest the car is fine, it would be wise to ask your mechanic.

Sometimes, the light might turn off after passing the test, but the engine could be having a bigger mechanical problem somewhere else. Therefore, taking the car for a checkup would be the best precaution. After all, you don’t want to incur high costs in the future.

In other situations, the Electronic Control Unit (ECU) simply reads the signals wrong, this might be by mistake, or it can signal the ECU has some issues that need a deep check, especially if the error light alternates on and off often

Most Common Problems that make a check Engine Light turn on and then off

Replacing the fuel

If you fill the car with fuel from other gas stations, or with a low-quality one, you will notice that the check engine light goes on and then will go off if you refill the car with the same fuel as before.

This happens often, maybe because of the additives that mislead the ECU triggering the Check Engine Light to go on when using other fuel than before, especially diesel.

Simply adding the same fuel before the last refilling will fix the problem. In other situations, you’ll need to use a scanner either to see if other issues occur or to delete the error.

Catalytic Converter Issues

If the catalytic converter fails, the car fuel undergoes incomplete combustion emitting strange fumes. There are situations when the catalytic converter has fluctuations in its functionality working as it should and not working, triggering the check engine light to lit and then to go off.

Oxygen Sensor Problems

Being in strong relation with the catalytic converter, the O2 sensor can cause similar effects in behavior to the converter having moments when it works ok and other situations when it doesn’t, making the check engine light have times when it’s on and then to go off on its own.

If the oxygen sensor fails, your car continues to work, but if not taken care of soon, it affects the catalytic converter, the spark plugs, and the car’s performance.

Spark Plug Problems

If your car uses diesel, you are free from this problem. Spark plug problems are significant issues that make the check engine light turn on. Sometimes, tighten the plug to take care of the problem.

All the above problems can later make the check engine light turn off by itself but still require checking to prevent further damage to the engine.

Do Errors Still Stay in the ECU after the Check Engine light goes off on its own?

Some problems remain in the ECU after the light goes off on its own, while some are solved. Even if some problems are solved, it is better to visit your mechanic and find the reason since the light might indicate another problem.

Can you drive the car even if the Check Engine Light goes off by itself?

Yes, you can continue driving the car, but to avoid extensive damage to the engine, you should take it for a checkup. Moreover, it is good to prevent future and long-term damages.

Should I Check the Errors that Initially Triggered the Check Engine Light even if it has Disappeared after a While?

As I said before, a check engine light implies a mechanical problem, and the best thing to do is understand the problem even if the check engine is turned off by itself. Some problems are never solved completely.

Also, the light might have been signaling another problem that could be more significant if not cared for. So, yes, you should check the initial errors.


Various issues make your car turn on the check engine light signaling a problem in the engine. The most common problems include spark plug, loose fuel cap, catalytic converter failure, mass airflow sensor failure, and oxygen sensor failure.

Surprisingly, these problems can be easily solved, and some, like loose fuel caps, can be avoided.

Check engine light can turn off by itself if your car passes the two tests it had initially failed three times. However, this should not stop you from taking the car for a checkup or driving it.

Finally, it is better to get some basic knowledge about vehicles. With some knowledge, you can detect some common problems and solve them.

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