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The BlueBus module supports multiple BMW display units, automatically detecting and adapting to your vehicle’s configuration. This guide covers the supported displays and their specific features.

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Supported display units

BlueBus supports four main display unit types, each with different capabilities:

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Board Monitor (Navigation)

I-Bus Address: 0xF0The BMBT is BMW’s full-color graphical navigation display, providing the most comprehensive BlueBus interface.

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Features

  • Full graphical menu system
  • Metadata display (artist, title, album)
  • Album artwork support
  • Configuration menus
  • Telephone interface with caller ID
  • On-Board Computer data display
  • Multiple screen layouts

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Supported models

  • 16:9 wide-screen models
  • 4:3 standard models
  • MK2, MK3, and MK4 navigation systems
BlueBus automatically detects your navigation system version:
  • MK I (GT MKI): Basic graphical interface
  • MK II (GT MKII): Enhanced UI
  • MK III (GT MKIII): Improved menu system
  • MK III New UI (GT MKIII_NEW_UI): Version 40+ with updated interface
  • MK IV (GT MKIV): Latest navigation system
  • MK IV Static (GT MKIV_STATIC): Version 40+ with static screen support
The navigation version is detected via diagnostic identity requests (I-Bus command 0x0C to address 0x3B).
The BlueBus adjusts menu rendering based on your navigation version to ensure optimal compatibility.

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Display detection

The BlueBus automatically detects which display units are present on the I-Bus by monitoring traffic: 
typedef struct IBusModuleStatus_t {
    uint8_t BMBT: 1;    // Board Monitor detected
    uint8_t MID: 1;     // Multi-Info Display detected
    uint8_t RAD: 1;     // Radio detected
    // ... other modules
} IBusModuleStatus_t;
Detection occurs by observing module status responses (I-Bus command 0x02) and other traffic from each module.

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UI mode configuration

The BlueBus can be manually configured for specific UI modes via EEPROM settings:
ModeValueDescription
CD530x01Business CD radio only
BMBT0x02Board Monitor only
MID0x03Multi-Info Display only
MID_BMBT0x04Both MID and BMBT
MIR0x05Multi-Info Radio
IRIS0x06Integrated Radio Information System
In most cases, you don’t need to manually configure the UI mode. The BlueBus will auto-detect your display configuration.

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Display-specific features

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Metadata display

Each display type shows Bluetooth audio metadata differently: BMBT: Full metadata with separate fields
  • Title area for track name
  • Index area for artist
  • Zone area for album
  • Album artwork (if available)
MID: Scrolling single line
  • Format: “Artist - Title”
  • Maximum 24 characters visible at once
CD53: Truncated display
  • Shows first 11 characters of title
  • No artist/album information

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Telephone display

Hands-free telephony display varies by unit: BMBT: Full telephone interface
  • Caller ID with name and number
  • Call duration timer
  • Signal strength indicator
  • On-call status icons
  • Menu-driven interface
MID: Limited telephone display
  • Caller number (up to 24 characters)
  • Basic call status
  • Telephone mode icons
CD53: Minimal telephone support
  • Status indicators only
  • No caller ID display

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On-Board Computer data

The BMBT can display vehicle data from the instrument cluster:
  • Coolant temperature
  • Ambient temperature
  • Oil temperature
  • Vehicle range
  • GPS date/time (if navigation equipped)
OBC data is retrieved from the IKE (Instrument Cluster Electronics, I-Bus address 0x80) via sensor requests (command 0x12/0x13).

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Button mapping

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BMBT buttons

The BlueBus responds to these BMBT button presses:
ButtonCodeFunction
Next0x00Next track
Previous0x10Previous track
Play/Pause0x14Toggle playback
Mode0x23Change mode
Knob0x05Menu navigation
Tel Press0x08Answer call
Tel Hold0x48Voice command
Number 1-6VariousPreset/playlist selection

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MID buttons

MID button events are sent via command 0x31:
ButtonFunction
Tel LeftPrevious menu item
Tel RightNext menu item
ModeSelect/confirm

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Radio controls

All display types support basic radio controls:
  • Seek up/down: Track navigation
  • CD button: Activate BlueBus (CD changer mode)
  • Volume: Adjust volume (when BlueBus is active)

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Display troubleshooting

Symptoms: Radio doesn’t show CD changer optionSolutions:
  1. Verify I-Bus connection (pin 2 on CD changer connector)
  2. Check that module is announcing itself (CDC announce, command 0x02)
  3. Press CD button on radio to activate CD changer mode
  4. Verify ignition status is detected (IKE command 0x11)
Symptoms: Track changes but no artist/title shownSolutions:
  1. Verify Bluetooth metadata is being received (check with phone)
  2. Confirm display type is correctly detected
  3. For MID: Check that radio is in CD mode
  4. For BMBT: Verify GT version detection is correct
Symptoms: Strange characters or corrupt displaySolutions:
  1. Check I-Bus signal integrity
  2. Verify ground connection is solid
  3. Update BlueBus firmware to latest version
  4. Check for I-Bus interference from other devices
Symptoms: Pressing buttons has no effectSolutions:
  1. Verify module is in correct mode (CD changer active)
  2. Check that BMBT/MID is detected on I-Bus
  3. Monitor I-Bus for button press messages (command 0x48 for BMBT)
  4. Ensure BlueBus is not in configuration menu mode

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Next steps

After confirming your display unit is working:
  1. Configure menu system preferences
  2. Set up audio settings for optimal sound
  3. If using BMBT, explore the comfort features
  4. Configure telephony settings for hands-free calling

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