Are you experiencing a problem where the check engine light does not illuminate when the key is turned on? If there is a problem, how will you know? This situation occurs for a variety of reasons, and there are some things you can do to prevent it.
An ignition switch fuse has blown, or the bulb has burned out, a faulty oxygen sensor has failed, an ECU fuse has blown, or the ECU has been damaged.
There are three types of check engine lights: yellow, orange, and amber. A flashing light indicates that something serious is going on, such as a misfire, which causes the catalytic converter to overheat quickly.
When you do not see the check engine light, it means everything is going well. It is possible, however, that the warning light may have burned out on your dashboard if it used to display the check engine light but now fails to do so.
You can learn more about these issues in detail by reading this article. Additionally, we will discuss how each of these problems should be addressed.
Troubleshooting The No Check Engine Light When the Key Is In On Position
The next section of this article will explore some of the most common causes of the check engine light not coming on when the ignition is turned on. In some cases, you can fix the problem yourself, while in others, a mechanic may be required.
An engine light inspection should be performed by a professional mechanic if you have this problem. A scanner will be connected, and he will read the ECU codes to diagnose the problem.
There are different codes for different types of problems. There is a mechanic who knows what to do in each case and will fix the problem. Now that we have that out of the way let’s examine what typically sets off the check engine light.
1. ECU That Has Been Damaged
The ECU is an essential component of your engine that performs a variety of functions. Damage to this component will prevent the check engine light from coming on. An ECU that is damaged will also prevent you from driving your vehicle properly.
It’s possible that the ECU is damaged if the check engine light doesn’t come on and the car won’t start. It is only possible to solve this problem by replacing the ECU. Although replacing the ECU is expensive, you have no other choice if you want your engine to function properly.
2. A Blown Fuse In The ECU
A blown ECU fuse will prevent the ECU from getting power, and the check engine light will not illuminate. It is also possible for the wiring to get loose between the connectors, which can also lead to a problem.
For the check engine light to work again, you must replace the ECU fuse. In order to ensure that your battery works properly, you should make sure it is fully charged.
3. Oxygen Sensor Malfunction
Sensors are connected to the ECU in many ways. Sensors such as Fuel Pressure sensors, Battery Current sensors, Oxygen sensors, etc., are included in these systems. Failure of any of these sensors will cause the check engine light to illuminate.
It is possible that the oxygen sensor is causing the problem since it is more likely to fail than the other sensors. It should be possible to fix the problem by replacing the faulty oxygen sensor. A mechanic can diagnose the problem, or you can get a scanner yourself if you don’t know which sensor is the problem.
The oxygen sensor is usually screwed onto the exhaust system. The electrical wire connected to the sensor should be disconnected. Replace the old sensor with the new one by unscrewing it.
4. Burned Out Bulb
With time, check engine light bulbs can become damaged. As long as this is the issue, all is well with your car. However, the check engine light isn’t working because the bulb is damaged.
There is a need to replace the bulb. It is an easy job for anyone to replace a bulb on their own. To access the information cluster, you must first remove the radio and dashboard.
Replacement of the bulb can either be done by you or by a mechanic. You should seek the advice of a mechanic if you are unsure of how to put the parts back together without damaging them.
5. Blown Ignition Switch Fuse
Located inside the battery compartment of your vehicle is a fuse known as the ignition switch fuse. Whenever the ECU is exposed to an unacceptable electrical charge, this fuse blows.
As a result, the check engine light will not illuminate because the ECU will stop working. Before buying the other expensive components that could cause the same issue, you should check this first.
If this is the problem, you need to replace the fuse. Fuse replacements for ignition switches are very inexpensive and easy to do. Changing the fuse is as easy as taking out the old one and replacing it with a new one.
How Does The ECU Work?
ECUs, or Engine Control Units, are your engine’s brains. Fuel and air are proportioned correctly in your engine so that it runs smoothly. As well as alerting you when your car is having problems, it also lets you know if there is a problem.
Is It Possible To Turn Off A Check Engine Light?
Remove the bulb from the information cluster to disable the check engine light. It is important not to disable the CEL because it is there for a good reason.
Even After I Turn My Car Off, Why Does My Engine Light Remain On?
Depending on the ECU, it may take a little while for the car to shut off after you have turned it off. Therefore, it’s important to have your vehicle checked if the light remains on after you’ve turned off the engine.
Does The Check Engine Light Come On When You Turn The Key?
Whenever your information cluster is functioning properly, all of the lights should illuminate. However, if your car is in good condition, the check engine light will go out.
What Is The Best Way To Manually Reset My Check Engine Light?
To reset your check engine light, follow these steps:
- Pop the hood of your car after turning off the engine.
- The negative battery terminal can be found on the car battery.
- A positive battery terminal is red, while a negative battery terminal is black.
- Make sure the negative terminal of the battery is disconnected and left for a few minutes.
- You should now be able to turn off your check engine light by connecting it again.
If the underlying problem that is causing the check engine light to come on hasn’t been resolved, this is only a temporary solution. You must resolve the issue that causes the check engine light to illuminate. That’s a fact you can’t avoid.
The Bottom Line
A car’s key in the on position does not cause a check engine light to come on. So before you go out shopping for parts, have a professional mechanic read the error codes.
Regardless of what the check engine light says, it would be best if you never ignored it. It tells you something about your engine and other components of your vehicle. Another possibility is a loose gas cap, which indicates a leak in the emissions system. Check if the gas cap is loose if you still see the light turned on.