Documentation for the I/K-Bus protocol found in BMW vehicles from 1989 to 2013.

This documentation covers the common functions of the I-Bus and K-Bus.

P-Bus, and M-Bus are not covered. D-Bus is also not discussed, although it may be added in the future.

This is an ongoing project, and the documentation will be expanded as time allows.

This documentation should not be considered authoritative. While great care, and effort has been taken in creating it, if you choose to use it, you do so at your own risk.

1. Applicable Models
2. Glossary
3. Device Index
   1. K/I-Bus
   2. D-Bus
4. Command Index
5. Features
   1. Sensors
   2. OBC
   3. Redundant Data Storage
   4. Controls
   5. Radio
   6. Telephone
   7. Navigation
   8. Lighting
   9. Body

This protocol applies to the bus system in the models listed below.

MINI and Range Rover (early L322) implementations are not discussed.

K-Bus was added to the E38 along with the I-Bus. Models without Navigation or IKE will use the K-Bus only. Both of these bus systems are technically identical, the only difference is their use by model.

The D-Bus was introduced as TXD (and RXD) in 1987. The term D-Bus was adopted with the introduction of the E38 in 1995, however it is still referred to as TXD in the ETM [electrical troubleshooting manual].

All modules in the vehicle are not connected directly to the D-Bus, some systems are connected through a gateway such as the IKE or cluster. The gateway handles all diagnostic “traffic” and routes the necessary information to the correct bus system.

On vehicles equipped with an I-Bus (E38, E39, E53 High) messages to be sent back and forth between the K-Bus and I-Bus have to be transferred via a Gateway. This Gateway is the IKE. The IKE determines by the address of the message recipient whether the message needs to be passed along to the other bus.

I-Bus was introduced on the E31 as the information bus. The E31 version of the I-Bus was used for body electronics and driver information systems. With the introduction of the E38, the I-Bus is now referred to as the **instrument bus **.

The M-Bus is used exclusively in the climate control systems for the control of the “smart:” stepper motors. These stepper motors are used to control various air distribution flaps.

The M-Bus was introduced on the E38 climate control system (IHKA). The M-Bus was also installed on subsequent models equipped with IHKA and IHKR.

The P-Bus is a single wire serial communications bus that is used exclusively on vehicle that are equipped with ZKE III. These vehicles are the E38, E39 and E53.

The P-Bus provides the Central Body Electronics system with a low speed bus for use by the General Module (GM) to control various functions.

• 8-bit addressing (256 unique addressess).
• Multicast, and broadcast addresses.
• Addresses are preassigned, and static.
• All buses are within the 8-bit scope, i.e. an address is unique across the I, K, and D buses.
• Variants of a device will have the same address, e.g. the address 0x80 is used by the low cluster (KOMBI), high clusters (IKE, IKI).
• The adress pool is shared by all models that utilise this bus system. An address is rarely reallocated even if the originally allocated device is not applicable to a new model.

The shared address space might suggest it's possible to communicate with D-Bus devices from the K/I-Bus, however that's not the case. This is purely a function of diagnostics, in which all devices must be addressable from the D-Bus.

1. 0x10 Ignition Request
2. 0x11 Ignition
3. 0x12 Sensors Request
4. 0x13 Sensors
5. 0x16 Odometer Request
6. 0x17 Odometer
7. 0x19 Temperature
8. 0x1d Temperature Request

1. 0x14 Language & Region Request
2. 0x15 Language & Region
3. 0x24 Property Text: IKE
4. 0x2a OBC Status
5. 0x40 OBC Input
6. 0x41 OBC Control
7. 0x42 Remote Control

1. 0x53 Redundant Data Request
2. 0x54 Redundant Data
3. 0x55 Replicate Data

1. 0x20 MID Button: Telephone
2. 0x31 BMBT/MID Menu Button
3. 0x32 MFL Volume
4. 0x3b MFL Buttons
5. 0x32 BMBT Volume Dial
6. 0x48 BMBT Buttons
7. 0x47 BMBT "Soft" Buttons (i.e. INFO)
8. 0x49 Navigation Dial
9. 0x57 Cluster Buttons

1. 0x23 Title Text: Radio
2. 0x36 Radio EQ
3. 0x37 Radio Tone/Select
4. 0x39 CDC Status
5. 0x4a BMBT Tape/LED Control
6. 0xd4 NG-Radio Station List

1. 0x02 Announce: Telephone
2. 0x2b Telephone LEDs
3. 0x2c Telephone Status
4. 0x2d Telephone Direct Dial
5. 0x21 Menu Text: Telephone
6. 0x23 Title Text: Telephone
7. 0x24 Property Text: Telephone
8. 0xa5 Body Text: Telephone
9. 0xa6 SMS Icon

1. Default
2. Pin-Code
3. Dial
4. Last Numbers
5. Directory
6. Top 8
7. Info
8. Bluetooth Pairing
9. SMS Index
10. SMS Message
11. SOS/Emergency

1. 0x02 Announce: BMBT
2. 0x02 Announce: GT
3. 0x02 Announce: Nav.
4. 0x1f GPS Time
5. 0x4f Monitor Control
6. 0xaa Navigation Control
7. 0xab Navigation View Status

1. 0xa2 Telematics Coordinates
2. 0xa4 Telematics Location

1. 0x59 Light Sensor Status
2. 0x5a Cluster Indicators Request
3. 0x5b Cluster Indicators

1. 0x76 Visual Indicators
2. 0x79 Door/Lid Status Request
3. 0x7a Door/Lid Status