DTC U012D-00: Lost Communication With Generator Control Module: General Description
WARNING: This page is about a different car, the 2021 Kia Seltos. However, it is still accessible from the selected car via links, so may be relevant.
Alternator in which there is a communication regulator in order to compensate current loss resulting from repetitive starting. The alternator is duty controlled as current control by ECM/PCM with the battery voltage, current, temperature information from battery sensor. The more electrical load, the higher duty output.