DTC B2801-00: MM CAN Signal Line Error: General Description
WARNING: This page is about a different car, the 2024 Kia Forte. However, it is still accessible from the selected car via links, so may be relevant.
The CAN communication consists of a twisted pair of network wires. One line is CAN low line and the other line is CAN high line. The CAN lines pass through the head unit (AVN or audio) and AMP modules. This allows the Telematics Unit (TMU) to communicate with each module. Through MM-CAN, TMU is communicating with head unit to make a display and sound in the vehicle.