Disconnecting the battery is one proven method of making the check engine light go away. However, this method doesn’t always work and you may still see the light after you hook up the battery again.
So, why is check engine light still on after disconnecting battery? The check engine light is still on after disconnecting the battery because the underlying problem causing the light to illuminate hasn’t been fixed.
This article has more information on why you can still see the check engine light even after disconnecting and reconnecting the battery, and what to do to reset the light.
Why check engine light is still on after disconnecting battery
If the CEL (check engine light) doesn’t go away after disconnecting the battery, it means that the underlying problem hasn’t been solved yet.
Disconnecting your car battery may or may not clear the error codes in your onboard computer. So, you might see that light is still on after you hook up your battery again. The trick usually works for minor issues like if the light is on because of a loose gas cap.
However, if the underlying issue is more serious, e.g. a faulty oxygen sensor, catalytic converter issues, or problem with the engine, then the chances of the light resetting as a result of disconnecting the battery are pretty low. It could make the problem even worse.
For the method to work, you also want to ensure you do it correctly. The process is pretty simple and involves three key steps below:
Step 1. Assuming you have already located the battery location under the hood, use a wrench to disconnect the negative cable (it’s usually covered by a black cap) from the battery terminal.
Step 2. Next, press and hold the horn for approx. 30 seconds or try switching on the vehicle lights. This will help completely drain any electricity left in the capacitor.
Step 3. Leave the battery disconnected for about 15 minutes to give the vehicle system sufficient time to reset. After the wait time is over, reconnect the cable back to the negative terminal of the battery and ensure you tighten them in place.
If you follow these steps, the error codes will be cleared, and the check engine light will be reset.
If that doesn’t work, then it means a more serious issue is affecting your vehicle or your car decides to keep the error code anyway.
In this case, you’d want to take your vehicle to your mechanic. They’ll use a scanning tool to pull out the error codes on your vehicle and determine the real issue causing the engine light.
How long will check engine light stay off after disconnecting battery?
If the issue that made the engine light come on was minor, then the light will not come on again.
If the light comes on after some time or right after you reconnect the battery, then it’s clear your car has a serious problem that needs your immediate action.
We advise you to have your car looked at by a mechanic as soon as possible.
A professional mechanic will use the necessary tools to diagnose the car issue and offer you a definitive solution that resets the check engine light.
Will a bad battery cause your engine light to come on?
Yes, a bad battery can also be responsible for the check engine light on your dashboard. As you already know, the battery is tasked with supplying the electrical power needed to run your vehicle.
In addition to that, it helps control and stabilizes the system voltage. Proper voltage input is key for the vehicle computer.
If the battery is dying and fading, it will deliver low voltage. Your car computer will receive low voltage and promptly report an error code for the same, resulting in an engine light showing up!
Thus, when diagnosing the cause of the engine light on your car, you should have the battery tested as well to ensure it is in good condition.
Do you have to disconnect both battery terminals to reset the check engine light?
NO! You only need to disconnect the NEGATIVE battery cable to reset the check engine light.
Leave the cable disconnected for at least 15 minutes to allow your vehicle systems enough time to reset.
Hook up the cable to the car battery and if the issue is resolved, the check engine will not be popping up anymore.
If not done correctly, this method might not help clear the error codes and reset the engine light.
Before you disconnect the battery, keep in mind that this method will clear out memory for the radio and all the other onboard components.
How do you reset check engine light without disconnecting battery push start?
If the battery disconnection method doesn’t work, you can try other methods of resetting the engine light on your vehicle.
Mark you; we don’t always recommend the battery disconnection method because it ends up resetting your vehicle’s onboard computer and clears the codes.
Use an OBD II scanner
One such method involves using an OBD2 scanner. This helpful tool will diagnose your vehicle and pull all the error codes which you can then decode to understand what problem your car has.
You can then proceed to solve the issue or get a new replacement if you’re dealing with a faulty part. Afterward, you can erase the error code using the scanning tool and the light will clear up.
Turn your car on and off
The other trick of resetting the check engine light without disconnecting the battery involves tuning your car on and off.
Simply turn on your car for one sec and leave it for another 1-2 seconds. Do this 3 times in a row.
And when you turn your car on for the 4th time, the CEL should have cleared. This method has a higher chance of success, though it may not work for all types of vehicles.
Hire a mechanic
If you can’t reset the engine light yourself, then you should consider having a professional do it for you. Whether it’s your mechanic or dealership, these professionals have the necessary tools for diagnosing your vehicle and fixing the issue correctly so it doesn’t show up again.
Sometimes the best way to reset the light is to let it go off on its own. If you try all these methods and nothing works, and your car is operating smoothly, it could only be a matter of time before the light clears on its own.
Can you drive with the check engine light on?
The answer is yes and no as it depends on the situation. If the engine light is on but your car is running fine, then it may be safe to drive your car.
However, in a situation where the light is on and your car is showing problems, you may want to avoid operating the car until the underlying issue has been resolved.
Instead, consider taking your car to a mechanic to check it out., They’ll be able to tell what the problem your car is facing is and whether you should drive it with the light on or not.If you’re experiencing a check engine light after disconnecting the battery, there could be several reasons behind it. One possible cause is a glitch in the computer system, which can cause the check engine light to come on. However, if the check engine light persists after reconnecting the battery, you may want to consider other causes, such as issues with the sensors or other parts of the engine. Our articles on troubleshooting check engine light issues can provide valuable insights into the problem. For example, if you experience a check engine light after repairing your vehicle, our article on after repair may be helpful. This article covers common causes and solutions for check engine light issues that arise after repairing your vehicle. Similarly, if you’re experiencing a check engine light after changing your air filter, you may want to read our article on after air filter change. This article discusses potential causes and solutions for check engine light issues that arise after changing your air filter. Take a look at these articles for expert advice on diagnosing and fixing check engine light issues.
1. Does unplugging battery clear check engine light?
Yes, unplugging the battery and then reconnecting it again after a few minutes can help clear the check engine light if it came on due to minor issues like a loose or faulty gas cap. However, this trick won’t work if the underlying issue is more serious and you might be left with no option but to have a professional diagnose your vehicle and make the light go away.
2. Why did my check engine light come on after I changed my battery?
If the check engine light comes on after changing your battery, you’d want to check things. Start by ensuring you’ve replaced the right type of battery for your car. Ensure the battery is properly connected to the car and the battery terminals are clean. You should also check that the battery cables are clean, tight, and dry. If all these things check out, then the new battery isn’t the problem.
3. How long do you leave battery disconnected to reset check engine light?
You should disconnect your battery for at least 15 minutes to reset the check engine light. This will give the vehicle systems an adequate amount of time to reset, and in the process clear the error code and the engine light.
A check engine light coming on can be frustrating and disconnecting the battery is one way to clear it out. However, this trick doesn’t always work and you may still see the light after hooking up your battery. You can also try other methods we have discussed in the above guide to help reset the check engine light.
If none of these methods, take your car to a mechanic or dealership. They’ll check the error codes for you and diagnose your car based on what the code says, helping clear the engine check light.