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Home >> Mercedes Benz >> 2008 >> C 230 (204.052) (CANADA) V6-2.5L (272.921) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Navigation System >> Description and Operation >> GF82.85-P-0015AZ Navigation 20 Function

GF82.85-P-0015AZ Navigation 20 Function




GF82.85-P-0015AZ Navigation 20 Function
MODEL 204
Navigation 20 retrofit (Universal Media Interface)





A1 Instrument cluster
A2 Radio (with code (510) Audio 20 with CD changer or with code (523) MB Audio 20 radio)
A2/23 GPS antenna (retrofit)
A40/8 Audio/COMAND display
A40/9 Audio/COMAND control panel
H4/27 Center instrument panel speaker
N10/1 Front SAM control unit with fuse and relay module
N30/4 Electronic Stability Program control unit
N40/3 Sound system amplifier control unit (with code (810) Sound system)
N80 Steering column module control unit
N125/2 Navigation 20 control unit (retrofit)
N135 Steering wheel electronics
S110 Left multifunction steering wheel button group
S111 Right multifunction steering wheel button group
X18/72 Navigation 20 electrical connector (retrofit)
CAN A Telematics CAN
CAN B Interior CAN
CAN E Chassis CAN
LIN E1 Steering LIN
LVDS Low voltage differential signal
MOST Media Oriented System Transport

Function requirements for navigation 20, general
^ Radio is switched on.

Navigation 20, general
The navigation 20 system is an extension of the audio system for vehicles with code (510) Audio 20 with CD changer or code (523) MB Audio 20 radio. The navigation 20 system is also referred to as "Universal Media Interface". The audio system of the navigation 20 has the following additional functions:
^ Navigation
^ iPod, Universal Serial Bus (USB) and AUX interface (except vehicles with code (518) Media interface as of 1.3.2011)
^ Bluetooth(R) audio (generation 1)
In vehicles with code (518) Media interface as of 1.3.2011, the navigation 20 electrical connector is installed as a USB interface that is exclusively used by Service (to update the map data or the software).
The function scope depends on the generation (device generation) and the version (software version). Generation and version are shown in the service mode on the Audio/COMAND display. Service mode is activated when the "Back" button (A40/9s2), the "Delete" button (A40/9s12) and the Audio/COMAND controller (A40/9s11) are pressed simultaneously for approx. 3 s while the "iPod" menu is active.





Screen display in service mode, shown on version v1.5 (generation 1)

The relevant version information is shown in the control field (main area) of the Audio/ COMAND display in the second text line (SW) front (left).
The generation can be detected based on the third text line (HW). In generation 1 devices, the hardware level is displayed without a slash.





Screen display in service mode, shown on version 2.2.4 (generation 2)

In generation 2 devices, the hardware level is displayed with a slash.
The diagnosis values are shown in the "Diagnosis" or "Diagnostic" menu. This is the only diagnosis option in generation 1 devices. Starting with generation 2, the navigation 20 control unit can be diagnosed via Xentry Diagnostics.
The navigation 20 system is operated with the Audio/COMAND control panel. The Audio/COMAND control panel transmits the control signals to the navigation 20 control unit via telematics CAN.
The navigation 20 control unit transmits the signals for the displays on the Audio/COMAND display via an LVDS line to the Audio/COMAND display.
The control signals of the Audio/COMAND control panel for the radio are forwarded by the navigation 20 control unit to the radio via telematics CAN.
The display signals of the radio for the Audio/COMAND display are also forwarded via the navigation 20 control unit to the Audio/COMAND display. To do this, LVDS lines are used.

Additional function requirements for navigation
^ "Delete" button on Audio/COMAND control panel was pressed and held.

Navigation
The navigation module is integrated into the navigation 20 control unit. The navigation system includes the following functions:
^ Position finding
^ Route planning and route guidance
^ Representation of navigation maps and visual driving instructions
^ Acoustic driving recommendations
^ Receiving and observing Traffic Message Channel (TMC) messages

Position finding
The navigation 20 control unit determines the location of the vehicle with the help of the Global Positioning Systems (GPS) and at the same time through evaluation of the wheel speeds (basic position finding). As a result, position finding is also possible even if no GPS signals are received.
Since GPS operates in the gigahertz (GHz) range (microwaves) and the signals are weak, reception interference can occur as a result of the following events:
- Atmospheric interference, e.g. inclement weather, water vapor, fog
- Multi-path reception due to signal reflections, e.g. from building walls
- Signal blocking, e.g. in built-up areas, in tunnels, from high buildings or trees
The GPS satellites permanently transmit time and position data (longitude and latitude). The accuracy of the position finding and the actual calculation is essentially based on the measurement of the runtimes of the signals transmitted synchronously by the various satellites. The navigation 20 control unit receives the GPS signals via a direct line from the GPS antenna.
For basic position finding, the navigation 20 control unit evaluates the wheel speeds. The navigation 20 control unit receives the wheel speeds via the following route:
- Electronic Stability Program control unit
- Chassis CAN
- Front SAM control unit with fuse and relay module
- Interior CAN

Route planning and route guidance
The route settings are specified via the "Navi" menu in the function bar on the Audio/COMAND display. In the "Mode" submenu, the following route options and avoidance options can be selected:
- Short route, fast route, economical route, scenic route (as of version v1.4.0)
- Freeways, toll roads, ferries and (up to version v1.4.0) avoid U-turns
The avoidance options are only ignored, if alternative route guidance involves major detours or if there are no other roads.
Additionally, "Observe traffic situation" can be selected in the "Mode" submenu. In this case, the disruptions to traffic relayed by the TMC are avoided automatically, if an alternative route saves time.
The route destination is input via the "Destination" menu in the function bar on the Audio/COMAND display. The following options are available to do this:
- ADDRESS INPUT
- Via a map (can be selected under address input) (as of version v1.4.0)
- From memory
- From recent destinations
- From points of interests
As of version V0.8.0, it is also possible to enter a destination using a 7-digit ZIP code for Great Britain.
Addresses are input with the Audio/COMAND controller via the character bar on the Audio/COMAND display.
After completing the destination input with "Start", the route is calculated and route guidance is active.
An intermediate destination can be entered during active route guidance. The intermediate destination is input via the "Destination" menu in the function bar on the Audio/COMAND display. The following options are available to do this:
- Select from points of interests
- Enter manually
When an intermediate destination is entered, it can also be deleted again via the "Destination" menu.

Representation of navigation maps and visual driving instructions
The Audio 20 control unit transmits the map data and the other display signals to the Audio/COMAND display via an LVDS line.
The full screen map view shows (from left top to right bottom) following display elements as a maximum:
- Maximum vehicle speed
- Freeway sign (as of version v1.4.0)
- Direction indicator
- Map display
- Upper information field
- Lane display
- Lower information field
The display elements maximum speed, freeway sign and lane display can be activated and deactivated in the "Navi" menu under "Map display".
Settings for display and assignment of information fields (top and bottom) can be changed in the "Navi" menu under "Configuration".
Settings for the map display are changed in the "Navi" menu under "Map display". The following settings are possible for example: Orientation towards North (two-dimensional), orientation in the driving direction (three-dimensional), automatic map zoom, freeway information (as of version v1.4.0), display of driving maneuvers, points of interests or one-way streets.
The map display can be changed with the Audio/COMAND controller:
- When it is turned, the map section becomes smaller or larger (zoom).
- When it is pressed (longer), a position cross is activated that can be used to move the map section in any direction (pressing the "Back" button resets the display of the current position).
- When it is moved up or down, the viewing angle is changed (only with orientation in driving direction).
As long as the navigation function is active, the Audio/ COMAND display is only available for navigation. Further messages (e.g. incoming calls) are only displayed in the instrument cluster.
As of version v1.4.0, when crossing a country's border, the country information of the current country you are entering is automatically shown for approx. 10 s on the Audio/COMAND display.

Acoustic driving recommendations
The navigation 20 control unit outputs the navigation announcements over the center instrument panel speaker. The language for the navigation announcements is specified in the navigation menu under "Navi", "Configuration" and "Voice output".
The volume of the navigation announcements is set by pressing the full screen map view of the Audio/COMAND controller. During the subsequent repetition of the last navigation announcement, a volume bar appears on the Audio/COMAND display and the volume can be adjusted by turning the Audio/COMAND controller.
It is also possible to repeat the last navigation announcement by pressing the voice control system On button (S111s4) on the multifunction steering wheel and in the navigation menu by selecting the "Ear" symbol in the function bar.
By pressing it for a long period of time, the navigation announcements are muted in both cases.
If the navigation announcements were muted, it is possible to cancel muting by pressing the voice control system On button for a long period of time or by starting a new route guidance, but not through an ignition change (engine off and engine on).
The navigation 20 control unit receives the actuation of the voice control system On button from the instrument cluster via interior CAN.

Receiving and observing Traffic Message Channel (TMC) messages
The navigation 20 control unit receives the TMC traffic messages from the GPS antenna via a direct line. To display the messages, "TMC" is selected in the function bar of the navigation menu.
In vehicles with software releases between version v1.4.0 and version v2.2.4, the "TMC" menu can only be selected, if TMC traffic information service messages are present.
While route guidance is active, a route-specific list of disruptions to traffic on the remaining route is shown.
While route guidance is inactive, a total list of all relayed disruptions to traffic is shown.
By selecting an entry, additional information on the respective disruption to traffic is shown.
"Monitor traffic situation" can be selected in the navigation menu under "Navi" and "Mode". In this case, disruptions to traffic relayed via the TMC are evaluated by the navigation module of the navigation 20 control unit and avoided automatically, if an alternative route saves time.
If no TMC message is present for a disruption to traffic, the corresponding stretch can also be blocked manually. To do this, "Traffic jam ahead" is selected in the navigation menu under "Navi", the length is specified by selecting "Less" or "More" and then "Start" is selected. The navigation 20 control unit then calculates an alternative route.

Additional function requirements for iPod, Universal Serial Bus (USB) and AUX interface (except vehicles with code (518) Media interface as of 1.3.2011)
^ An iPod, USB device or AUX device is connected to the navigation 20 electrical connector in the glove compartment.
^ The "Disc" menu on the radio is activated.

iPod, universal serial bus (USB) and AUX interface (except vehicles with code (518) Media interface as of 1.3.2011)
If you change to the AUX menu while the "Disc" menu is active, connected iPods, USB or AUX devices can be selected as an audio source. On USB devices, only mp3 files can be played back. AUX devices are operated on the AUX device itself. USB devices and iPods are operated with the Audio/COMAND control panel.
Operation via the left multifunction steering wheel button group or right multifunction steering wheel button group is possible, when the "Audio" menu in the instrument cluster is activated.
When the audio source iPod or USB is activated, the "iPod" or "USB" menu in the function bar of the Audio/COMAND display provides access to different selection lists, e.g. the following:
- Artists
- Albums
- Random tracks
The navigation 20 control unit forwards the audio signals to the radio via a direct line.
The radio receives the audio signals via the AUX input. Accordingly, the AUX jack electrical connector (X39/45) installed as standard in vehicles with navigation 20 is not operational.
In vehicles with code (810) Sound system, the radio forwards the audio signals to the sound system amplifier control unit via MOST.
The sound system amplifier control unit (with code (810) Sound system) or the radio (except code (810) Sound system) outputs the audio signals over the vehicle's speaker system.
In vehicles except code (810) Sound system, the retrofitted center instrument panel speaker is not generally used to output audio signals, but only for the voice output of the navigation system. More detailed information on the speaker system is available in the "Speaker output function" document.
As of circuit 15R ON (ignition key position 2), the battery of the connected iPod or USB device is charged.

Additional function requirements for Bluetooth(R) audio (generation 1)
^ "Audio streaming" is activated on the radio via the "Disc" and "AUX" menus.

Bluetooth(R) audio (generation 1)
The navigation 20 control unit can receive Bluetooth(R) audio signals from external devices via an integrated Bluetooth(R) module.
To do this, the external device must support the Bluetooth(R) Profile Audio Video Remote Control Profile (AVRCP) and the Advanced Audio Distribution Profile (A2DP).
Bluetooth(R) audio is divided into the following subfunctions:
^ Search for devices and authorization
^ Select authorized device
^ Operation

Search for devices and authorization
The following options are available to authorize a Bluetooth(R) audio source:
^ Authorization via navigation 20 control unit
^ External authorization
Following authorization, the playback of the audio files of the external device starts automatically.

Authorization via navigation 20 control unit
Once the external device has been switched to "visible" in Bluetooth(R) mode, "Search for BT devices" can be selected in the "Audio streaming" menu. Once the desired device has been found, it can be selected and authorized by entering or confirming the Personal Identification Number (PIN).

External authorization
"Device visible" is selected in the "Audio streaming" menu. The navigation 20 control unit is available for approx. 5 min to establish a Bluetooth(R) connection. From the external device, Bluetooth(R) devices must now be searched and the navigation 20 control unit authorized.

Select authorized device
Once the external device has been switched to "visible" in Bluetooth(R) mode, it can selected from the list of "Connected devices" in the "Audio streaming" menu. The automatic playback of the audio files of the external device will then start automatically.

Operation
By sliding the Audio/COMAND controller to the right, the next track is played back. By sliding the Audio/COMAND controller to the left, the previous track is played back or the current track is repeated (if the current track has already been played back for more than 5 s).
These control options can also be used by pressing the + and - button, setting of specific functions and volume control (S111s1) or by turning the Audio/COMAND controller.
For the operation with "Audio streaming", the Audio/COMAND display in the playing field (main area) and not in the function bar must be active.

Software and map update
In service mode, the navigation 20 system can be updated via the USB connector of the navigation 20 electrical connector. Service mode is activated when the "Back" button, the "Delete" button and the Audio/COMAND controller are pressed simultaneously for approx. 3 s while the "iPod" menu is active.
In vehicles with code (518) Media interface as of 1.3.2011, a navigation 20 electrical connector is also installed as a USB interface in the glove compartment; it is exclusively used to update software and map data.




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