Why does the check engine light suddenly go off?
When the check engine light comes on, it lets you know that something is wrong with your vehicle. In most cases, the light won’t go off until you fix the problem. So should you worry if your check engine light goes off on its own?
Before you panic, read on for possible causes. Not only will we look at the most likely causes, but we’ll also tell you what to do next. At the end of the article, we’ll answer your most important question about the Check Engine Light:
Why does the Check Engine Light go off on its own?
The Check Engine Light may go off on its own once you fix the issue that caused it. The system continually runs self-diagnostic tests to check for further errors. The light may turn off from the dashboard when a simple problem is fixed.
When you start your car, it runs a self-diagnostic test. If the system doesn’t pass two tests at the same time, the Check Engine Light will come on. Depending on the code set, it may also turn off automatically once the problem is fixed.
Common reasons why the Check Engine Light turns off by itself
It’s not normal for the light to turn off by itself, but there are a few possible causes.
- You may have replaced a loose or broken gas cap, or you may have refueled while the engine was running.
- You may need to correct the air-fuel mixture ratio.
- You may have intermittent wiring issues or sporadic engine problems.
Let’s take a closer look at these options based on what we’ve seen as professional mechanics.
1. A loose or bad fuel cap
Leaking fuel cap
The fuel cap is designed to prevent contaminants from entering the fuel system. A loose gas cap will send a warning to the computer and turn on the check engine light.
Tightening the fuel cap after the warning light comes on may cause the warning light to reset automatically after a diagnostic check. Replacing a damaged or broken fuel cap with a new one may also cause it to turn off automatically.
2. Refueling with the engine running
Refueling your car
There are several reasons why it’s best to stop your car before refueling: Not only does having the engine running increase the risk of fire, it can also cause other problems.
If you fill up your gas tank with gas while the engine is running, the sensor will continue to measure the pressure. Because of this, drivers may notice that the check engine light on the dashboard comes on when the engine is running after refueling.
However, the opposite can also be true: if there’s some kind of problem with the sensor and filling the tank temporarily solves the problem, the light may also go out.
3. The mixture is slightly too rich or lean
The balance of air and fuel in the combustion chamber must be perfect. If this air-fuel balance is even slightly disturbed, the check engine light may turn on temporarily.
As soon as the balance is restored to normal, the light will turn off automatically. But in most cases, these imbalances may require repair with a filter or sensor. Once the repairs are complete, you may need to reset the error code.
4. Intermittent wiring issues
Damaged car wiring
Let’s say you have a small wiring issue that’s causing intermittent power outages. In this case, sometimes the wires connect, and sometimes they don’t. In this case, a strong connection can cause the lights to go out on their own. Miswiring can cause big problems later on, so it’s important to track down any electrical issues.
5. Intermittent engine part problems
The same goes for temporary problems. For example, if a pump or sensor fails for a minute and then repairs itself, the check engine light may not stay on. This is less likely than other causes. Once parts start to fail, it usually gets worse. Additionally, not all error codes can be reset automatically, especially serious ones.
What to do if the Check Engine Light goes off on its own?You may think that it’s okay to ignore the problem if the Check Engine Light goes off, but this is not recommended. At some point something went wrong and the light came on, it’s best to find out what’s going on before it becomes a bigger problem.
Here are some recommended steps:
1. Read Error Codes
When a vehicle experiences a fault, a diagnostic trouble code (DTC) is set in the computer. You can read these codes with a compatible scanner to see what’s going on. If you don’t have a code scanner, many auto parts stores will also read the codes for free. The problem is that these codes aren’t that easy to understand. Even if you know what the code means, there are often multiple fixes, so a diagnosis is required. We recommend using our online error code library first.
2. Fix the problem
Once you know what’s wrong, it’s time to fix it. Some repairs are simple, such as: B. Replacing the fuel cap. If you can do the repair yourself, you can avoid the labor costs of a professional and save a lot of money. Of course, you may need to allow yourself a little extra time when repairing your car yourself, especially if you don’t have advanced tools or equipment. If you’re not confident in your ability to perform the repair, skip to step 4.
3. Resetting the Error Codes
Once the repairs are complete, you will need to reset the codes. If the light comes on again, you may need to drive the car a bit until the self-diagnostic system detects a difference. If the light doesn’t reset, or you don’t want to wait, you can reset the codes yourself. Just use a compatible code scanner to reset the system.
4. Get Help from a Professional
There are plenty of reasons to believe you might be able to fix the problem yourself. You don’t necessarily need to have the same experience as us to fix your car.
However, if it seems like too much work or you’re not sure what steps to take next, contact a professional mechanic. You don’t want to ignore the problem and let it get worse.
Is it safe to drive with the check engine light on? If the Check Engine Light stays on, you may be able to continue driving. Depending on the problem, you may have to wait a little while for repairs to be completed. The only way to be sure is to check for codes to determine what the problem is first.
However, there are two disadvantages to driving with the Check Engine Light on. First, you don’t know if another problem will develop during this time. If something serious happened, you wouldn’t notice because the light wouldn’t be able to come back on. Secondly, it could cause further damage in the long run if the problem causes more wear and tear. For example, continuing to drive with bad spark plugs could damage your catalytic converter, an expensive repair you want to avoid.
On the other hand, if the check engine light is flashing, you have a serious problem on your hands. Do not continue driving if this light is flashing. Fix the problem or have your car towed to a repair shop.
Is a check engine light that comes on and off a serious problem? In most cases, there’s nothing to worry about. If the light goes off on its own, the problem is probably resolved. However, it never hurts to check the codes to find out what the problem was, especially if it’s intermittent so you can resolve it before it becomes a more serious issue.
Why is the Check Engine Light off but the code is still there?A record of the code will remain in the computer until you reset it.If the error isn’t severe enough to turn on the Check Engine Light, we may be able to read the code.
How many miles do I need to drive to reset the check engine light?The light may go off after repairs because the system runs a self-test when you turn on the vehicle. In other cases, it may expire after not driving a certain distance specified by the manufacturer. An easier solution is to use a compatible code scanner to reset the system and light. How long does it take for the Check Engine Light to go off?
This depends on the car you’re driving and what caused the light to come on. In some cases, one ignition cycle is enough to turn off the light after a self-test. In other cases, you may need to drive a certain distance or successfully complete a certain number of cycles. The best solution is to use a compatible code reader to turn off the light and reset the system.
The first sign of the Check Engine Light coming on can be heartbreaking for anyone. When the light goes off again on its own, you can breathe a sigh of relief. Before you get too excited, remember something that caused this light in the first place. An error or malfunction occurred that caused the computer to issue a warning.
Rather than ignoring these warnings, it’s best to run a diagnostic. Even if the light isn’t on, your car may need repairs to keep running smoothly in the future. Taking good care of your car today will help it serve you well tomorrow.