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BlueBus integrates deeply with your BMW’s I-Bus systems to provide enhanced features beyond basic Bluetooth connectivity. These integrations leverage existing vehicle modules and data sources.

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On-Board Computer (OBC) data

BlueBus can display various vehicle sensor data on the vehicle’s screens by monitoring I-Bus messages from the Instrument Cluster Electronics (IKE).

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Temperature monitoring

The system monitors and displays multiple temperature sensors: Coolant temperature:
  • Source: IKE temperature update message (IBUS_CMD_IKE_TEMP_UPDATE)
  • Storage: ibus.coolantTemperature (firmware/application/lib/ibus.c:391)
  • Range: 0-127°C (values above 0x7F are ignored)
  • Event: IBUS_SENSOR_VALUE_COOLANT_TEMP
Ambient temperature:
  • Source: IKE temperature update message
  • Storage: ibus.ambientTemperature (signed char)
  • Range: -60°C to +60°C
  • Event: IBUS_SENSOR_VALUE_AMBIENT_TEMP
Oil temperature:
  • Source: Light Control Module I/O diagnostics (E38/E39/E52/E53 only)
  • Calculation: Logarithmic formula based on sensor voltage
  • Offset varies by LCM variant: 310 (standard) or 510 (LCM_IV)
  • Formula: 67.2529 * log(rawTemp) + offset (firmware/application/lib/ibus.c:556)
  • Event: IBUS_SENSOR_VALUE_OIL_TEMP
You can configure which temperature is displayed:
  • CONFIG_SETTING_TEMP_COOLANT (0x01) - Coolant temperature
  • CONFIG_SETTING_TEMP_AMBIENT (0x02) - Outside air temperature
  • CONFIG_SETTING_TEMP_OIL (0x03) - Engine oil temperature
Temperature units (Celsius/Fahrenheit) are also configurable:
  • CONFIG_SETTING_TEMP_CELSIUS (0x00)
  • CONFIG_SETTING_TEMP_FAHRENHEIT (0x01)

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Vehicle range

BlueBus monitors the vehicle’s calculated range from the IKE:
  • Parsed from OBC text messages (IBUS_IKE_OBC_PROPERTY_RANGE)
  • Format: “123 KM” or “123 MLS”
  • Storage: ibus.vehicleRange (uint16_t)
  • Parsing: Extracts numeric value, ignores ”---” invalid readings
  • Event: IBUS_SENSOR_VALUE_VEHICLE_RANGE
Code reference: firmware/application/lib/ibus.c:482-497

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Speed and RPM data

The system receives real-time speed and RPM updates:
  • Source: IBUS_CMD_IKE_SPEED_RPM_UPDATE (0x18)
  • Event: IBUS_EVENT_IKE_SPEED_RPM_UPDATE
  • Used for speed-dependent features like auto-lock

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Gear position

Automatic transmission gear position is monitored:
  • Source: IKE sensor response (IBUS_CMD_IKE_SENSOR_RESP)
  • Storage: ibus.gearPosition (4-bit value)
  • Event: IBUS_SENSOR_VALUE_GEAR_POS
Gear positions defined in firmware/application/lib/ibus.h:533-542:
  • IBUS_IKE_GEAR_PARK (0x0B)
  • IBUS_IKE_GEAR_REVERSE (0x01)
  • IBUS_IKE_GEAR_NEUTRAL (0x07)
  • IBUS_IKE_GEAR_FIRST through IBUS_IKE_GEAR_SIXTH

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GPS time synchronization

For vehicles equipped with factory navigation, BlueBus can synchronize the vehicle’s clock with GPS time.

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GPS time reception

BlueBus monitors GPS time broadcasts from the navigation system: 
// Navigation GPS time message
IBUS_NAV_CMD_GPSTIME (0x1F)
The GPS time data is parsed from the navigation module (firmware/application/lib/ibus.c:633):
  • Hour: BCD format at IBUS_PKT_DB2
  • Minute: BCD format at IBUS_PKT_DB3
  • Day: BCD format at IBUS_PKT_DB4
  • Month: BCD format at IBUS_PKT_DB6
  • Year: BCD format at IBUS_PKT_DB7 and IBUS_PKT_DB8
BlueBus automatically adjusts for the GPS week rollover issue by adding 1024 weeks (in seconds) to the epoch calculation: epoch + (1024 * 604800) (firmware/application/lib/ibus.c:643).

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Time synchronization modes

The CONFIG_SETTING_AUTO_TIME setting controls automatic time synchronization:
GPS synchronization (CONFIG_SETTING_AUTO_TIME_GPS, bit 1):
  • Synchronize from factory navigation GPS
  • Automatic correction for GPS week rollover
  • Requires navigation system (IBUS_DEVICE_NAVE)
Phone synchronization (CONFIG_SETTING_AUTO_TIME_PHONE, bit 0):
  • Get time from connected Bluetooth phone
  • Useful for vehicles without navigation
Daylight Saving Time (CONFIG_SETTING_AUTO_TIME_DST, bit 2):
  • Automatic DST adjustment
  • Timezone offset configuration (CONFIG_SETTING_AUTO_TIME_TZ)
Multiple sources can be enabled simultaneously, with GPS taking priority when available.

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Timezone configuration

The system supports 32 different timezone offsets (CONFIG_TIMEZONE_COUNT):
  • Stored as index: ConfigGetTimeOffsetIndex() / ConfigSetTimeOffsetIndex()
  • Actual offset: ConfigGetTimeOffset() / ConfigSetTimeOffset() (int16_t minutes)
  • DST flag: ConfigGetTimeDST() / ConfigSetTimeDST()

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Park Distance Control integration

BlueBus integrates with the factory PDC (Park Distance Control) system to provide visual feedback.

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PDC sensor monitoring

The system monitors eight PDC sensors: Front sensors:
  • frontLeft (ibus.pdc.frontLeft)
  • frontCenterLeft (ibus.pdc.frontCenterLeft)
  • frontCenterRight (ibus.pdc.frontCenterRight)
  • frontRight (ibus.pdc.frontRight)
Rear sensors:
  • rearLeft (ibus.pdc.rearLeft)
  • rearCenterLeft (ibus.pdc.rearCenterLeft)
  • rearCenterRight (ibus.pdc.rearCenterRight)
  • rearRight (ibus.pdc.rearRight)
Sensor values are received via IBUS_CMD_PDC_SENSOR_RESPONSE (0xA0) messages from the PDC module at address 0x60. Invalid/no-obstacle readings return 0xFF (firmware/application/lib/ibus.c:684).

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PDC status tracking

The PDC status structure (IBUSPDCStatus_t) tracks: 
uint8_t status;        // IBUS_PDC_STATUS_ACTIVE or INACTIVE
uint8_t isUpdated;     // Whether data changed since last reading
uint8_t checksum;      // For detecting data changes
PDC activation is detected from:
  • IBUS_CMD_PDC_STATUS (0x07) - PDC active broadcast
  • Bit 0 of 10th data byte in sensor response - PDC enabled flag

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Visual PDC display

BlueBus can display PDC information in multiple locations:
Cluster display (CONFIG_SETTING_PDC_CLUSTER, 0x01):
  • Shows PDC warnings in instrument cluster
  • Uses IKE check control display
Radio display (CONFIG_SETTING_PDC_RADIO, 0x02):
  • Shows PDC information on radio/navigation screen
  • Graphical representation on BMBT
Both displays (CONFIG_SETTING_PDC_BOTH, 0x03):
  • Simultaneous display on cluster and radio
  • Maximum visibility
Disable visual PDC entirely by setting CONFIG_SETTING_VISUAL_PDC to OFF.

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Light module integration

BlueBus monitors the Light Control Module (LCM) for various sensor data.

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LCM variants

The system auto-detects and supports eight LCM variants:
  • IBUS_LM_LME38 (E38)
  • IBUS_LM_LCM (E39 early)
  • IBUS_LM_LCM_A (E39 mid)
  • IBUS_LM_LCM_II (E39 late/E46/E53)
  • IBUS_LM_LCM_III (E46 facelift)
  • IBUS_LM_LCM_IV (E83/E85/E86)
  • IBUS_LM_LSZ (E6x)
  • IBUS_LM_LSZ_2 (E6x facelift)
Detection via diagnostic response: IBusGetLMVariant() (firmware/application/lib/ibus.c:1381)

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Light sensor data

BlueBus monitors LCM sensor voltages: Dimmer (58G) voltage:
  • ibus.lmDimmerVoltage
  • Controls automatic display brightness
Photosensor voltage (LSZ only):
  • ibus.lmPhotoVoltage
  • Ambient light detection
Load sensors (Xenon-equipped vehicles):
  • ibus.lmLoadFrontVoltage
  • ibus.lmLoadRearVoltage
  • Headlight self-leveling
All values retrieved from LCM I/O status (0x0B diagnostic job). For vehicles with factory navigation, additional features are available: Automatic map zoom based on vehicle speed:
  • CONFIG_SETTING_NAV_MAP_DEFAULT - Manual zoom control
  • CONFIG_SETTING_NAV_MAP_SPEED_20 - Auto-zoom at 20 km/h
  • CONFIG_SETTING_NAV_MAP_SPEED_30 - Auto-zoom at 30 km/h
  • CONFIG_SETTING_NAV_MAP_SPEED_50 - Auto-zoom at 50 km/h
  • CONFIG_SETTING_NAV_MAP_TIME_5 - Zoom change every 5 seconds
  • CONFIG_SETTING_NAV_MAP_TIME_10 - Zoom change every 10 seconds
Implemented using IBUS_SES_CMD_NAV_CTRL with IBUS_SES_DATA_NAV_CTRL_SETZOOM. BlueBus can send commands to the navigation system: 
IBusCommandSESShowMap()        // Display map screen
IBusCommandSESSetMapZoom()     // Set zoom level (8 levels)
IBusCommandSESRouteFuel()      // Show route fuel consumption  
IBusCommandSESSilentNavigation() // Mute navigation announcements

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Silent navigation mode

The CONFIG_SETTING_NAV_SILENT bit (0b10000000) in the NAV setting enables silent navigation mode, preventing voice guidance from interrupting audio playback.

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Vehicle type detection

BlueBus auto-detects the vehicle platform:
  • IBUS_VEHICLE_TYPE_E38_E39_E52_E53 (0x01)
  • IBUS_VEHICLE_TYPE_E46 (0x02)
  • IBUS_VEHICLE_TYPE_E8X (0x03)
  • IBUS_VEHICLE_TYPE_R50 (0x04)
Detection via IKE vehicle config response (IBUS_CMD_IKE_RESP_VEHICLE_CONFIG). Vehicle type affects:
  • Oil temperature calculation offset
  • Feature availability
  • UI rendering
  • Module compatibility checks

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