UniEnergy Technologies Battery » 5 Steps To Reset Idle After Replacing Battery

5 Steps To Reset Idle After Replacing Battery

Your car is one possession that will need attention from time to time, given its service to you. And you might find the need to change your batteries either from a dead one or a damaged one to a new one.

But most times, the car must be accustomed to its new battery to work perfectly, which requires you to reset the idle. The idle reset procedure is often needed in cars with an electronic throttle body built in recent years. And unlike the conventional throttle body that connects the computer with the throttle with a cable having an IAC (Idle air control valve), the connection in an electronic car is, you know… electronic.

So what do you do to reset your idle after replacing your battery? Often, you may not know how to go about this, and bringing your car to its standard functionality will get frustrating. No need to fret; resetting the idle is a process called idle relearn that although it may seem complicated, it takes minimal time, less effort, and relatively easy steps.

Common signs that show you need to reset your idle is when the idle becomes too high or too low after replacing the battery. Your car’s computer needs time and effort to start working with the new change. This article will focus on answering vital questions on idle relearn and how to reset your idle after replacing your battery.

What is idle relearn?

Idle relearn, also called throttle body relearn, is a process of getting your car to achieve its required idle speed after a battery disconnection, replacement, a disconnection in battery cables, and the battery dying and throttle body replacement.

When you notice your car’s idle is not normal, you must know it is time to let your computer relearn the idle and work like it usually would. Again, you do not need an expert for this procedure, so you do not need to get worked on it. As we go on, we’ll provide a step-by-step guide to getting out of this situation.

What is idle relearn?

Is an idle reset necessary?

In most modern cars, no physical cable connects the throttle body and the accelerator pedal. Instead, the vehicle uses ETB, an electronic throttle body with a plate, motor, and sensors. This throttle synchronizes airflow in the engine, including the idle speed. In its idling process, the throttle receives a signal from the car, which relays the appropriate speed for the idle depending on the engine’s temperature and the pressure on the accelerator pedal. This information determines the control of the throttle plate and how it is programmed. So, when you disconnect your battery and put in a new one, the computer loses its memory and thus loses connection with the throttle, and the plate gets displaced. Since the computer communicates with the ETB every time, you will need to have some procedures done to reset the idle. Fortunately, the idle is made to auto-relearn by itself, but it will need your help for the process to be done appropriately.

How to reset the idle after replacing the battery

Many cars do not have a manual for idle relearn, so you’re left to help yourself out. This article is a chance to get your idle to work normally again.

And although different cars have a unique idle relearning procedure, there are specific basic methods that will keep you. Follow these few simple steps to reset the idle.

Step one

The first step in resetting your car idle is warming it up. This enables the car’s auto to relearn the amount of airflow that is required for your vehicle when you drive, thus, taking a step to make sure the throttle plate is in the correct position.

Therefore, warm the car by driving it for around 5-7 minutes and get ready to start the procedure. Note that warming your vehicle is optional, so you can decide to do or not do it. But this step indeed makes the relearning process easier.

Step two

Ensure the car’s engine is turned off and the hand brake is pulled up. Insert the key into the ignition, turn it off, and then turn it on. Turn it back off and on again, making that action performed twice. It is essential to do this before starting the car entirely.

How to reset the idle after replacing the battery

Step three

You can start the car and release the hand break with your legs on the pedal. The car is now expected to do its part of the work.

Step four

Leave the car idle for a few minutes to learn its idle speed gradually. Keep fixated on the RPM to see if there’s a number adding up. If it is, then it’s an indication that the computer is in the process of attaining the proper airflow and communicating efficiently with the computer.

Note: keep A/Cs, radio, and other electronic devices off so your car can focus on the task. Besides, the A/C may cause wrong relearning from the computer.

Step five

Once the process is done, you should check if the idle is working as usual. Next, turn the car’s accessories like fans and A/Cs on and notice how the idle works with them. If the idle level is still not correct after this, you will need to repeat the relearning process. Make sure you follow the steps judiciously.

Pro tip: some car models require a scan tool to reset them, while others need to follow these idle relearning procedures. After this process, you must check the proper idle reset for your car’s model if your car still doesn’t work correctly.

Resetting your car engine after replacing the battery

You might think you only have to worry about the idle, but resetting the car’s computer (ECU) is just as crucial as resetting the idle, especially when you get a check engine light. In most occasions, after changing the battery, you will need to reconnect and make some things work correctly again. The best bet is resetting the computer, which controls most things. Here’s how to change the car computer manually:

Resetting your car engine after replacing the battery

1. Remove the positive terminal of the battery

This is the first step if you’re resetting your computer. First, use a perfect size wrench to unloosen the bolt that holds the battery clamp. Then remove the terminal once it’s free and lay the cable aside.

2. Leave the battery for a while

After you have removed the battery’s terminal, let it sit out for about five minutes. This will help shut out all the car’s devices, like the radio, and let the computer go off since there is no power.

3. Reconnect the battery terminal

Once the 5 minutes is completed, reconnect the cable to the positive terminal tightly. The system and device will come back on.

4. Start the car

Since all the systems are turned back on, start the car and check if the check engine light is still on. If it isn’t, then the process is complete.

5. Test drive the car

You may test drive the car for a few minutes or leave it running to meet its operating temperature.

Resetting the computer with the OBD diagnostic tool

Get an OBD scanner

If this method doesn’t work, and you keep seeing the check engine light, then you should consider using a diagnostic tool, an OBD scanner. The OBD scanner works by reading and removing errors in data and memory in your car system, thereby eliminating the check engine light error. Using the OBD scanner is a relatively easy and sure process that will take you very little time to complete and ensure that your computer works. So, how can you go about this?

1. Get an OBD scanner

You can get an OBD scanner online or in any hardware store nearby. A good scanner might be expensive, but it’s worth it if you want your car to work correctly again. In addition, these scanners come with more options that make diagnosis much more straightforward and can be readily available as an app on your mobile devices, improving accessibility.

2. Connect the OBD scanner to your car

You can find the port for the tool beneath the steering wheel. Insert it, launch the app on your mobile device, and then scan the computer for error codes. The app will show you codes on your computer if there are any, which is the cause of your computer’s malfunctioning. Erase them and turn off your car to turn it back on. Then, insert the tool and check for error codes again. Usually, you shouldn’t find any, but if you do, you will need to take your car to a repair shop to run a complete diagnosis.


Many things come with changing your car battery, more than you know. And if you do not take care, a lackadaisical approach towards it may cost you your vehicle’s good health and, of course, your money.

In this article, we discussed how to reset the idle after replacing your battery and touched on how to reset your car’s ECU. These vital things are vital to ensuring your vehicle has a healthy system. And the steps above will guide you through the process of idle relearning and reconnecting your computer. First, however, contact an expert immediately if there are any problems.

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