How do you reset an ECU on a 2012 Kia Optima?

To reset the ECU on a 2012 Kia Optima, you can disconnect the negative battery terminal and leave it disconnected for about 10-15 minutes. This allows the ECU to clear any stored data and reset itself. After reconnecting the battery, you may need to drive the vehicle for a short period to allow the ECU to relearn its settings. Always consult your owner's manual for specific instructions related to your vehicle.