How do you reset the ecu on a Hyundai Santa Fe 24i?

To reset the ECU on a Hyundai Santa Fe 24i, disconnect the negative battery terminal and leave it disconnected for about 15 minutes. This allows the ECU to discharge and reset. After reconnecting the battery, start the vehicle and let it idle for a few minutes to allow the ECU to recalibrate. Optionally, you can also drive the vehicle for a short distance to help the ECU relearn the engine parameters.