Check Engine Light but No Code Is Showing | Causes & Solutions

When driving your car, one important signal you’ll take note of in the dashboard is the check engine sign. This sign can indicate several big issues that can occur, and you need to be wary of them by checking the accompanying code. However, sometimes you can have a check engine light but no code.

What does this mean? This issue can arise for a few reasons, and we’ll be looking at why it occurs and what you can do to take care of this problem.

Check Engine Light but No Code Is Showing

What Is the Check Engine Light?

The check engine light or sometimes alternatively known as the malfunction indicator lamp, is an indicator located on the dash or instrument panel of most cars. This indicator would light up to indicate several things, such as your engine requiring maintenance or that your engine has a massive fault. Due to the dangers engine faults can possess, having a computerized detection system to alert drivers of them is incredibly helpful.

To properly understand the issue, the check engine warning light is accompanied by a code. Some cars allow you to read the code on its, but others can require the use of a code scanner. By understanding the code, you can pinpoint the issue and quickly address it.

Possible Reasons For No Code Showing With Check Engine Light

Possible Reasons For No Code Showing With Check Engine Light

Now let’s explore the reasons why a code doesn’t show up. There is a multitude of reasons like faulty scan tools, failed emissions tests, failure of internal engine components, and software issues. Let’s get to know them.

1. Broken Or Wrong Code Reader

As we’ve mentioned before, often, a code reader is used to obtain the code that helps you understand what’s wrong with the engine computer. Sometimes the reason why no code shows up is that you’re using the wrong code reader. 

Several different models of ODB readers see use. Sometimes, in the case of an older model being used, it might be compatible with the particular alert system. As a result, it cannot read the code and show it to you. It is worth checking out with different code readers and having a newer code reader on hand.

The other possibility is that the code reader is broken or damaged. Although most of the code readers are durable and resilient, some cheaper ones might wear out over time and be unable to pick up readings or show the code.

2. Software Problems

For trouble codes that appear on the instrument panel, there can be problems with the software, which may cause the code to not show up. It is hard to tell if it’s a problem with the software or not without properly inspecting the car and engine control module (ECU). 

If you see that the display of your instrument panel is giving you trouble or you notice bugs in it, you might want to get your vehicle inspected. For an older car, these problems may become more frequent, requiring you to. Problems with the software can sometimes result in false alarms, which is why you should consider regular inspection of your car’s electronics.

3. Electrical Malfunction

Due to the electrical circuitry involved in operating the check engine light, sometimes it can end up being fused or shorted. As a result, the engine warning light might end up being turned on permanently, but no appropriate trouble codes pop up. Electrical shorts aren’t very common but can spiral into a big issue if left unchecked. 

If the check engine light persists for a long time, then it might be because of an electrical short and not something wrong with the engine itself. Also, contaminated ports or user error can also cause the warning light.

Another thing to note is that there can be a chance that a fuse has been blown. 

Fuses are protective devices, but once they have been blown they need to be replaced for the circuit to work properly again. A blown fuse can sometimes be the reason why you don’t get any indication for a trouble code.

What Is An OBDII Code Scanner?

It means On-Board Diagnostics II. An OBDII code scanner or reader is a device that you can connect to the OBD port of your car (often located in the dashboard, behind the steering wheel). When connected, you can use the device to get code readings or access other information. 

The obd2 scanner is commonly used due to being more advanced and having better features. With the use of an OBDII code scanner, troubleshooting the issues of your car becomes easier.

How To Solve Check Engine Light With No Codes Issue?

Finally, let’s look at what we can do about no trouble codes appearing with your check engine light. Some solutions include:

Check The Code Scanner Or Reader

As we’ve mentioned before, one reason why no trouble code appears if you’re checking with a scanner is that the scanner is not operating properly. Check the scanner to see if it’s broken or not.

Also, make sure to use an up-to-date scanner. Old scanners might have compatibility issues and might not be able to read or show the trouble code. Newer scanners have better compatibility and are generally better supported. Also, some of the OEM codes of manufacturers can’t be read by some scanners, which also can cause the issue. You should go to an auto parts store for car maintenance or the car dealer, where they will read the codes most probably for free.

Check The Port

Sometimes your ODB port may present an issue. A contaminated or damaged port might prevent the proper connection from being established, and as a result, the scan tools might not properly pick up the signals. So they won’t be able to show the error code.

You can attempt to check and fix the ODB port for damage, but usually, you will need to replace it with a new one.

Check The Fuse

Locating and replacing the fuse can open fix this issue. You will need to find the fuse box for your car and then locate the required fuse. Consult an instruction manual to help you better locate this fuse.

If it is burnt, you will need to replace it. Some cars come with spare fuses for situations like this. Otherwise, you will need to buy a proper replacement fuse. Fuses are considerably cheap.

Repair The Electrical Circuitry

If the other three solutions don’t work, it can be safe to assume that something is wrong with the electrical circuitry in your car. If you do not have experience working with electrical circuits and devices, you should immediately consult an expert to inspect your car. There can be several other issues present due to malfunctioning circuitry, and it is important to get a full inspection to identify and fix these issues.


So if you happen to have a check engine light but no code, there can be a multitude of reasons as to why this can happen. It is important to go through the possibilities and if you happen to be lost, contact an expert or known mechanic to take a look at your car. 

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