How Long to Leave Battery Disconnected to Reset Car Computer

Last Updated on April 23, 2023 by Ryan

The amount of time you should leave the car battery disconnected to reset the computer will depend on the make and model of your vehicle. Generally, a minimum of 30 minutes is sufficient for most cars. In some cases it can take up to an hour to fully reset the car computer.

It’s important not to rush this process as it could lead to other issues with your vehicle that may require more extensive repairs. After disconnecting the battery, wait at least half an hour before reconnecting and starting up your engine again so that all systems have time to properly reset and reboot correctly.

If you’re looking to reset your car’s computer, one of the most effective ways is to disconnect the battery. However, it’s important to make sure you leave it disconnected for long enough in order to get a successful reset. Experts recommend leaving the battery disconnected for at least 10 minutes before reconnecting – this gives the computer time to completely shut down and restart as needed.

Be sure not to leave it off any longer than necessary though as this could lead to more issues with your car’s systems!

Fastest Way To Reset A Vehicles Computer, Check Engine Light & Clear Codes

Does Disconnecting a Car Battery Reset the Computer?

The answer to this question is yes, disconnecting a car battery can reset the computer. Disconnecting a car battery will cause all of the stored data in the vehicle’s computer to be erased. This includes any codes that had been previously stored, as well as any faults or diagnostic codes that were detected by the on-board diagnostics system (OBD).

It should be noted, however, that some vehicles may require additional steps in order to completely reset their computers after a battery disconnection. For example, many vehicles require an ignition cycle (turning the key from “off” to “on” and back again) after reconnecting the battery in order for certain components such as oil change reminders and clock settings to be re-calibrated.

How Long Does It Take for a Car Computer to Reset Itself?

It typically takes anywhere from 10 to 30 minutes for a car computer to reset itself, depending on the make and model of vehicle. During the process, all settings are returned to their original manufacturer defaults and any stored data is cleared from memory. The process also includes running diagnostic tests, which can take longer if there are any issues with the system that need to be addressed.

After it has been successfully reset, your car’s computer should be ready for normal operation again without any further input or configuration necessary.

How Long Do You Hold Battery Cables Together to Reset Computer?

When resetting a computer, it is important to make sure that you hold the battery cables together for at least 15 seconds in order to allow enough time for the system to be completely reset. This can vary depending on the type of computer and its components, but as a general rule of thumb it is recommended that you keep them connected for around 15-20 seconds before releasing them. After this time has passed, your computer should be properly reset and ready to use.

How Do I Reset My Ecu After I Disconnect the Battery?

If you have recently disconnected your car’s battery, it is important to reset the ECU (Engine Control Unit). Resetting the ECU will clear all stored diagnostic trouble codes and data. To reset the ECU, begin by disconnecting the negative cable from your car’s battery for at least 10 minutes.

After reconnecting the negative cable, press down on both brake pedals and turn on the ignition switch without starting up your engine. You may need to hold this position until all warning lights appear on your dashboard before releasing them. The next step is to turn off the ignition switch and wait a few seconds before restarting it and turning on accessories like radio or air conditioning unit.

This process should help reset your vehicle’s ECU but if you are still having issues with performance after completing these steps, then it might be time to take a trip to an auto repair shop for further diagnosis of any underlying issues causing this problem.

How Long to Leave Battery Disconnected to Reset Car Computer


Will Touching Battery Cables Together to Reset Computer?

No, you should never touch battery cables together to reset a computer. Doing so can create an electrical spark which can cause damage to both your computer and the battery itself. It is always best to consult a professional if you need help troubleshooting or resetting your device.

How to Reset Car Computer Without Disconnecting Battery

If you need to reset your car computer without disconnecting the battery, you can use a special tool called an OBD-II scanner. This is a device that connects to your car’s onboard diagnostic port and allows you to access information about your vehicle. You can then reset any trouble codes or settings from within the scanner interface.

It’s important to note that this process may require some technical knowledge in order to be successful so it is best left in the hands of a professional mechanic if possible.

How Long Does It Take for a Car Computer to Reset

When resetting a car computer, it usually takes anywhere from 10 minutes to an hour for the process to be completed. The length of time is determined by the complexity and size of your vehicle’s system as well as any other programs or updates that need to be installed. It is important to follow all instructions given in order for the reset process to be successful and take less time than expected.


In conclusion, resetting a car computer can be accomplished in several different ways. Disconnecting the battery is one of the most straightforward and cost-effective methods available to drivers. However, it’s important to note that you should leave your battery disconnected for at least 30 minutes or longer before reconnecting it so that the reset process has time to take effect properly.

Once this step is completed, you should be able to start your vehicle with no further issues.


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