Bus System Overview

Fig 1: Identifying Vehicle With I And K-Bus Control Unit

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 2: Identifying Vehicle With K-Bus Control Unit

Courtesy of BMW OF NORTH AMERICA, INC.

The I/K-Bus consists of a single copper wire. The wire color of the I and K-Bus is uniform throughout the vehicle with: I-Bus WS/GR/GE and the K-Bus WS/RT/GE (Note: 2001 E39s with base Kombi have changed K-Bus wire color to the same as the I-Bus, WS/GR/GE).

Due to the linear structure of the network, the I/K-Bus is available for other modules in the event of a disconnected or failed control unit. Just as the CAN-Bus, this is referred to as a "Tree" structure with each control unit occupying a branch. The I/K-Bus provides the diagnostic connection to the control units located on those busses (except IKE/KOMBI).

Always refer to the to determine the exact wiring configuration and color for a specific model.