K-Bus System

The K-Bus system utilized in a serial communication network. It uses a the wire color white/red/yellow (white wire/red stripe/yellow tracer). The body bus (K-Bus) is responsible for the data exchange of telegrams that are required throughout the system. For instance, if the BC1 and IHKA have to communicate, they exchange information via the K-Bus.

The K-Bus system is divided into two segments named K-Bus I and K-Bus II. These "two" buses are essentially the same bus spliced inside the BC1.

K-Bus communication occurs at 9600 bits per second. The K-Bus switches between 0-12 volts (High/Low) and has a low impedance, making it resistant to electromagnetic interference. Most users are active on the bus when the ignition is switched to KLR.

Fig 1: K-Bus System Function

Courtesy of BMW OF NORTH AMERICA, INC.

The K-Bus network enters sleep mode 60 seconds after the ignition is switched off. While in sleep mode the K-Bus rests at 12 volts.

The BC1 is the Main Controller, supplying power and establishing message sequencing.

Fig 2: K-Bus System Function

Courtesy of BMW OF NORTH AMERICA, INC.