If your check engine light is flashing but your scanning tool can’t pull any fault codes, this guide is for you. Codes usually accompany the engine warning light and get logged into your car computer. So, what does it mean when you can’t find any codes?
Check engine light flashing but no codes usually happen when you use the wrong OBD II scanner or one that’s incompatible with your car model. A blown fuse or electrical short in the car system could also cause the light to come on for no reason.
Read the following detailed guide to discover more details about your check engine light coming on but no fault codes are stored in your car and what to do to fix this issue.
Why your check engine light flash but no codes
Whenever the dreaded check engine light comes on, you look forward to getting those codes pulled to help you understand what problem you’re dealing with.
But sometimes the code reader may pull nothing—not a single trouble code!
As we have just said above, this is most likely to happen if you’re using the wrong code scanner that’s cheap and outdated. Or the device isn’t compatible with your specific car model, making it impossible to retrieve the error codes.
But one thing to keep in mind is that the check engine usually comes on to alert you that there’s an issue with your car engine. If it comes flashing, it means the issue is even more critical and requires immediate action.
Below, we take a closer look at the most common reasons for the check engine light to flash but no codes:
You’re using the wrong code scanner
One of the most common reasons why you’re not pulling any codes is that you could be using the wrong scanner. The scanning tools vary from model to model.
You’ll find cheap models that are only programmed for reading the most basic codes but are limited when it comes to giving you everything you need with the transmission or emission systems.
Also, the local auto parts shop giving you a free check engine light diagnostic test may be using cheap scanning devices that won’t pull the codes.
Try using a mode advanced OBD II scanner model or have your mechanic do the scan for you (of course, at a cost). They usually have more enhanced scanners capable of pulling even those “hidden codes” from your car computer.
It could be a simple user error
If your code scanner can’t seem to pull any codes and the check engine light is on, you may have done something wrong during the scanning process.
You may think that a scanning tool is too simple a tool for you to mess up when using…but human is to error, right?
Consider going through the scanning tool user manual and checking the instructions on how to use it. Then, follow these instructions and see if the device will pull the fault codes this time.
A blown fuse could be the culprit
The engine control unit (ECU), engine control module (EC), and power train control module (PCM) run off a fuse, similar to the other electrical devices in your car.
If this fuse blows, the just may not get to the required component and the engine warning light will come on, even though there’s no fault.
Is the OBD II port clogged?
A contaminated OBD II port could also be causing connection issues between your car computer and the scan devices. This will make it hard to retrieve the fault codes.
Take a closer look at the port and get rid of any debris or dust that might be contaminating the connector. Try hooking up the scanner again and see if it works this time.
Think an electrical short in the system
An electrical short can also cause the check engine light to come on when there’s nothing wrong with the engine. When there’s a short in the system, it may be causing the power to jump to the light, forcing it to come on.
You can check if this is the issue behind the engine light on and no codes by turning your key into the ON position without starting the engine. If the light doesn’t go off after a few seconds, then the system might be experiencing an electrical short!
How to fix check engine light comes on but no codes?
To fix the issue of the check engine light flashing but no codes, you’d want to look into the all potential causes describe above.
Start by looking at your code scanner. Make sure you’re using the right model for your car that’s capable of reading multiple codes. or the unit could be defective and outdated. Try hooking it to another car and see if it works fine.
You may also want to look for a more advanced scanner to see if it will stand a chance of pulling those trouble codes from your car.
Next, inspect the port where you hook the scanning tool. Remove any dust and debris that may be clogging up the connection. Compressed air may help clean the port.
You should inspect your car for a blown fuse. For this part, you may want to consult your car user manual to understand the layout of the fuses and how to access them. Check if the fuse running ECU, ECM, and PCM is blown and replace it with a new one.
If none of the above fixes seem to work, you may be left with no other option but to get a professional to inspect your car.
If you’re unable to check for electrical shorts in your car system, take it to an auto repair shop to have an expert do it for you.
What if check engine light flashes then stops but there are no codes?
Another issue you may experience is the check engine light coming on and flashing, and then going off on its own. And when they hook up a scanner, it pulls no codes.
A blinking engine light indicates that your car engine is most likely experiencing a misfire. You may be using a cheap or outdated code scanner that’s not capable of pulling the fault codes.
The light coming on and then going off after a while could also mean that the misfire is clearing itself before it sets a hard diagnostic trouble code. While this is rare, some vehicle systems are capable of doing this.
In such a case, it may only be a matter of time before the engine warning light starts flashing continuality without going off again. Our advice is not to ignore the flashing check engine light that comes and then goes off on its own.
Just pull over your car and have it towed to an expert to have it diagnosed for the underlying issue causing the misfire before it becomes catastrophic.
Can check engine light come on and nothing be wrong?
Yes, the check engine light can come on when there’s nothing wrong with your car. Generally, when the check engine light shows up, there’s definitely something going on with your car engine. The reason can be critical or minor.
If the CEL pops on while you’re driving your car, just pay attention to how your car is behaving. Do you hear any unusual sounds? Do you experience any surging or shaking? How about a steering and brake check?
If nothing seems wrong with your car, then you can continue driving it until you get to a mechanic.
The light may also come on due to a minor issue such as a loose gas cap (especially after fueling your car) or due to something serious like a cat converter that needs to be inspected.
Whether the case is minor or serious, we always suggest having your car checked. Even if your car seems to be running fine, don’t ignore the CEL forever, or it may grow into a more severe problem that requires expensive repair costs or even parts replacement!
Is it OK to drive with flashing check engine light but no codes?
A flashing check engine light is generally caused by an engine misfire which is a result of bad spark plugs or faulty ignition coils.
If your car is flashing, we don’t recommend you to continue driving it ad you could cause further damage to the engine. Instead, you should have a mechanic carry a check engine light diagnostic test to find out what’s causing the misfire.
Assuming your “flashing check engine light but no codes” problem isn’t caused by one of the issues we discussed above, then your mechanic will have an easy time retrieving the code to help them discover the source of the warning light.
And if you can’t pull the codes, a professional mechanic may have a more advanced scanner that will pull the codes and find out if the check engine light came on due to an issue with the engine system or not.If your check engine light is flashing but no codes appear, it could be a sign of a serious problem with your car’s engine. However, before jumping to conclusions, it’s essential to check other possible causes that might trigger this issue. For instance, a flashing key on position or car sputtering could also be contributing factors. To learn more about these potential causes, check out our articles on flashing key on position and car sputtering. These articles provide an in-depth look at the common causes and possible solutions for these issues, so you can take the necessary steps to keep your vehicle running smoothly.
Frequently Asked Questions:
Your car not throwing codes could be linked to a variety of issues such as using the wrong code scanner, a blown fuse, a clogged OBD II port, or an electrical short in the car system. A simple user error when using the scanning tool to retrieve the error codes can also cause the scanning tool to return no codes.
If your check engine light is on but everything is running fine, it could be a false check engine light alarm. If you try scanning and the code reader returns a nonsense code or nothing at all, it’s possible that a computer error might have triggered the warning light. The CEL may also come on and your car still runs fine while there’s indeed an underlying problem. For instance, a loose gas cap can trigger the engine warning light to come on but your car still runs fine.
Yes, the check engine light can come on for no reason. In such a case, the car computer that turned on the check engine light could be malfunctioning itself. The best way to be sure about the source of the CEL is to run a diagnostic test. The codes pulled will tell you if the light was a false alarm and whether your car ECM is having issues.
Plugging in your scanner but not pulling any codes while the check engine is clearly on and flashing can happen due to a number of reasons we have discussed in the above guide. These include using the wrong type of OBD II scanner or using an outdated model, connecting your scanner to a contaminated port, a blown fuse for the car computer system, electrical short in the car system, or user errors.
The Flashing check engine light usually means something is wrong with your car engine and requires your immediate attention. If you don’t get any codes, we suggest using a better-quality scanner to see if it helps pull the codes. If that doesn’t work, take your car to a mechanic for a check engine light diagnostic test to find out what issues your engine is experiencing and fix them early on before they turn catastrophic.