Will Disconnecting Battery Reset Check Engine Light

Having a check engine warning light on the dashboard can be very traumatizing especially if the light is blinking. It can cause you to lose focus when driving as you would be wondering what could have caused the light to come on.

So, how do you make this check engine light go away? will disconnecting the battery reset the check engine light?

Yes, disconnecting the battery for around 15 to 20 minutes can reset the car’s system and cause the check engine light to go away if the problem that caused the light is fixed. If the problem is not fixed, the light will come back on again after a few miles.

What is a Check Engine Light?

The check engine light is the most dreaded warning light that comes on in any car. It is a sign that something is wrong somewhere in the engine and what makes it worse is that the problem could be several things so you don’t exactly know what is wrong until you start checking.

This warning light usually comes on when the car’s computer has been sent a message by the onboard diagnostic system about a malfunction somewhere in any one of the numerous systems.

When the check engine light comes on, the problem is either from the emission system, the car ignition system, the fuel system, or the exhaust system. It must be something that has to do with the engine.

Causes of Check Engine Light Warning

The check engine light can come on for several different reasons, they are:

1. Loosely Covered Fuel Tank

The check light can come on because of a loosely covered gas tank. This is because when the fuel tank is not properly covered, the fuel system considers it an abnormality. So it sends a message to the main computer system which triggers the check light.

2. Spark Plug

The problem could also be from the spark plug so one of the first places you should check is the spark plug. You could just quickly try to clean the spark plugs and fix it back to know if that’s what triggered the check light.

3. Faulty Oxygen Sensor

The oxygen sensor measures the amount of oxygen that hasn’t been burned and is left in the exhaust system of the car.

When the oxygen sensor is faulty, it is not measuring the unburned oxygen which is considered an irregularity and it is then reported to the car’s main computer which causes the check engine light to come on.

4. Faulty Mass Airflow Sensor

The mass airflow sensor regulates the amount is air that mixes with the fuel to aid proper combustion. When the mass airflow sensor is bad, combustion is not done right because the air going in for combustion isn’t regulated.

So it sends a message to the main computer which generates a code that will allow the check engine light to come on.

5. Faulty Catalytic Converter

The catalytic converter is a very important and expensive part of the vehicle’s exhaust system. It converts the toxic air that is being released from the engine into the exhaust system into less toxic gases.

When it’s faulty, toxic air can get into the car which can be very dangerous and harmful to everyone in the car. This is why the exhaust system sends a message to the onboard system which triggers the check engine light to come on.

6. Alarm Installation

If the alarm of your car was just installed and the check light comes on, it could be that the alarm wasn’t properly installed or maybe the product that was gotten isn’t compatible with your vehicle.

Will Disconnecting Battery Reset Check Engine Light?

Disconnecting the battery may or may not reset the check engine light, it all depends on why the light came on.

If the check engine light came on as a result of a fault or something even more serious, disconnecting the battery would do you no good.

The light may go off once you restart the car but after a while, the lights will come on again because the fault hasn’t been rectified and the affected system keeps generating trouble codes that turn the lights on.

Which Battery Terminal Do You Take Off to Reset the Check Engine Light?

While trying to reset the check engine light by resetting it, you should be careful about which one goes off first so that the systems can be properly reset.

The negative battery terminal which is usually colored black with a minus (-) sign on it should be taken off. The positive battery terminal which is usually red doesn’t have to be removed to reset the battery.

All you have to do is disconnect the negative terminal and reconnect it to reset the check engine light.

How Long Do You Disconnect Battery to Reset the Check Engine Light?

After the negative terminal has been disconnected, you should wait for about 15-20 minutes so that the car’s systems can completely clear all the error codes before you reconnect the battery.

When the battery has finally been reconnected, the error codes would have cleared and the check engine light would have been restored.

You should disconnect the negative which has the (-) sign to reset the check engine warning light. You don’t have to remove both positive and negative. Only the negative, when disconnected for 15 to 20 minutes can do the job.

Note that I have personally disconnected my battery for 5 minutes and it did not clear the warning light. But to be on the safer side, you should leave the battery disconnected for at least 15 minutes.

Other Ways to Reset Check Engine Light

Asides from disconnecting the battery and waiting for the systems to reboot before reconnecting the battery, there are other ways by which the check engine light can be reset.

One of the other ways the check engine light can be reset is by using an OBD2 scanner and code reader to clear the trouble codes that have been generated by the car’s system.

You could also keep driving and wait till the engine check light goes off by itself.

The last method is by turning your engines off and on four times in a row. This also works sometimes in resetting the check engine light


Ultimately, the check engine light should not be ignored whenever it comes on and if after resetting it, the light comes back on after a short distance, find what is causing the light to come, and fix it before resetting it again, otherwise, the light will keep coming back on.