The LCM is the Main (master) Controller of the I-Bus.On E38 and E39/E53 High version vehicles: If the bus line is quiet for more than 60 seconds, all of the control modules will go into Sleep Mode.Ĭontrol units that provide the I/K-Bus operating voltage (Master controllers) are: (9600, 8E1).Īny device can start sending when the bus is idle, but if it discovers that the line is pulled low without doing it itself, it has to abort. The I/K-Bus is always active when terminal R (Ignition) is switched on. Serial communications on the bus are 9.6Kbps, 8 data bits, Even parity, and 1 stop bit. This is the reverse of many digital signals where the normal voltage is 0V and is raised high (Vmax which in this case is Vbatt or +12v) to send a bit. The bus’ physical layer is an open collector setup – pulled high (+12v) by the bus and pulled low by the talker. This means that the normal voltage on the wire while the bus is idle is +12V (the battery voltage, or Vbatt). A bit is transmitted by pulling low or shorting the bus with the ground momentarily. – MRS, Multiple-restraint system (Airbag module) – SM, Seat Memory, 1x Driver and 1x Passenger – MM, Mirror memory, 1x Driver and 1x Passenger On the BMW E46, the following control units are on the I/K-Bus: The most informative being the one named “IBUSInsideDRAFTREV5.pdf”. Most of the information in this article comes directly from the PDF files in the resources & downloads section (Under the “K-Bus Structure” and “Resources” folders). Both of these bus systems are technically identical, the only difference is their use by model. From this point forward they will be referred to as the I/K-Bus and differences will be pointed out separately.

Models without Navigation or IKE will use the K-Bus only. The K-Bus was added to the E38 along with the I-Bus. With the introduction of the E38, the I-Bus is now referred to as the instrumentation bus. The E31 version of the I-Bus was used for body electronics and driver information systems. The I-Bus is known as the “Instrumentation-Bus” and the K-Bus is the “Karosserie-Bus” – Karosserie is German for “Body”. Initially the I-Bus was introduced on the E31 as the information bus. The I/K buses handle information/multimedia peripherals.

Since the K-bus has available only one single line yet it transmits data in both directions, data are transmitted in half-duplex mode – it is possible to only transmit or receive at any one time. In other words, it is a way for devices within the car to communicate with each other. The K-bus is a serial communications bus in which all connected control units can send as well as receive information over a single wire.

The K-Bus is a standard bus protocol for BMW car electronics. *** Project: Arduino & BMW K/I-Bus Interface ***

Using navcoder with usb to serial