DTC B1603-00: CAN Bus OFF (B-CAN): 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.
The IBU-BCM is responsible for monitoring and controlling body electrical systems. The IBU-BCM uses B-CAN to communicate with other modules to receive required data and transmit needed data.