DTC B251F-00: High Mounted Stop Lamp Short To Ground: 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.
Once the Body Control Module (BCM) receives stop lamp switch working signal, it sends the signal to the ICU using CAN communication. The ICU turns on the stop lamp.