Front central operating unit, component description - GF54.21-P-4500SX

MODEL 221.0 /1, 216.3 up to Model Year 8

Shown on model 221 up to 31.12.05

Fig 1: Identifying Front Central Operating Unit

Courtesy of MERCEDES-BENZ USA

Location

The front central operating unit is located under the COMAND controller unit (A40/3) on the center console between the front seats.

Task

The front central operating unit takes over the task of a Man Machine Interface (MMI) between the COMAND display (A40/8) and the user. The user's commands are recorded via the operation of the following buttons and controllers integrated in the front central operating unit as well as via the movement of the integral turn/push control (A40/9s11):

Volume control (A40/9r1)
Disc/radio quick select button (A40/9s1)
"Back" button (A40/9s2)
Hazard warning system button (A40/9s3)
Multicontour seat quick select button (A40/9s4), with code (409) left/right front multicontour seats or with code (432) left and right dynamic multicontour seat
Telephone/navigation quick select button (A40/9s5), with code (386) Preinstallation for telephone "Handy", UPCI system and code (527) COMAND APS with single DVD drive (with navigation) or with code (388) Telephone "Handy", UPCI system and code (527) COMAND APS [Auto pilot system] with single DVD drive (with navigation) or with code (494) USA version or code (498) Japan version, with code (387) Preinstallation for telephone "Handy", UPCI system, USA/Canada or with code (389) Mobile phone preinstallation with universal interface, USA/Canada
Button "ON" (A40/9s6)
Mute button (A40/9s7)
Transmission modes button (A40/9s8)
Head restraint folding button (A40/9s9)
Freely programmable button (A40/9s10)

Actuation of the buttons and rotary push-button is converted into Controller Area Network (data bus/CAN bus) (CAN) messages by the electronics of the front central operating unit and placed on the telematics CAN.

The COMAND controller unit reads in these CAN messages and places them on the central CAN. The central gateway control unit (N93) reads in these CAN messages and passes them on to the respective control units via the following CANs:

Front end CAN
Chassis CAN
Interior CAN

The hazard warning system button and the freely programmable button are only integrated in the front central operating unit and are read in by the upper control panel control unit (N72/1).

Design, shown on model 221

Fig 2: Identifying Design Of Front Central Operating Unit

Courtesy of MERCEDES-BENZ USA

Function

Volume control

Via the volume control the user can adjust the volume of the audio sources and Telematics sources, with code (386) Preinstallation for telephone "Handy", UPCI system, with code (388) Telephone "Handy", UPCI system, with code (494) USA version, with code (498) Japan version, with code (387) Preinstallation for telephone "Handy", UPCI system, USA/Canada or with code (389) Mobile phone preinstallation with universal interface, USA/Canada.

Disc/radio quick select button

By pressing the disc/radio quick select button the "CD" submenu or the "DVD-A" submenu is displayed to the user on the COMAND display, depending on which submenu was activated last "Last Mode". When the disc/radio quick select button is pressed for a second time the "Radio" submenu is displayed to the driver on the COMAND display.

Each further operation of the disc/radio quick select button switches over between the "CD" submenu or the "DVD-A" submenu and the "Radio" submenu

Button "Back"

By pressing the "back" briefly the current "menu" or "submenu" is closed on the COMAND display and a change is made to the preceding "menu" or "submenu".

By pressing the "back" button for more than 3 s all the "submenus" on the COMAND display are closed. The basic screen of the "menu" selected previously appears on the COMAND display.

Hazard warning system button

By pressing the hazard warning system button once the following components are actuated by the rear SAM control unit with fuse and relay module (N10/2):

Left turn signal lamp (E1e5)
Right turn signal lamp (E2e5)
Left turn signal lamp (E3e1)
Right turn signal lamp (E4e1)
Left outside mirror turn signal lamp (E6/5)
Right outside mirror turn signal lamp (E6/6)

By pressing the hazard warning system button again the actuation is interrupted by the rear SAM control unit with fuse and relay module again

The hazard warning system button is only integrated in the front central operating unit. The upper control panel control unit reads in the signal from the hazard warning system button and places the actuation as CAN messages on the interior CAN.

Multicontour seat quick select button, with code (409) Left/right front multicontour seats or with code (432) Left and right dynamic multicontour seat

By pressing the multicontour seat quick select button the "multicontour seat adjustment" submenu is displayed to the driver in the COMAND display.

Telephone/navigation quick select button, with code (386) Preinstallation for telephone "Handy", UPCI system and code (527) COMAND APS with single DVD drive (with navigation) or with code (388) Telephone "Handy", UPCI system and code (527) COMAND APS with single DVD drive (with navigation) or with code (c4) USA version or code (498) Japan version, with Code (387) Preinstallation for telephone "Handy", UPCI system, USA/Canada or with code (389) Mobile phone preinstallation with universal interface, USA/Canada

By pressing the telephone/navigation quick select button once the "Telematics (Tel)" menu is displayed to the driver in the COMAND display.

When the telephone/navigation quick select button the "Navi" menu is displayed to the driver in the COMAND display.

Each further actuation of the telephone/navigation quick select button switches between the "Telematics (Tel)" menu and the "Navi" menu.

Button "ON"

The COMAND display is switched on or off by pressing the "ON" button.

Mute button

The driver can mute the respective audio speakers fitted to the vehicle by pressing the mute button.

Transmission modes button

On vehicles except code (494) USA version, the user can choose between the following 3 transmission modes by pressing the transmission modes button:

Sport (S)
Comfort (C)
Manual (M)

On vehicles with code (494) USA version, the user can choose between the following 2 transmission modes by pressing the transmission modes button:

Sport (S)
Comfort (C)

Head restraint folding button

By pressing the head restraint folding button for less than 1 s the user can fold down the head restraints of the two outer rear seats as per an automatic run. By pressing the head restraint folding button for more than 1 s the user can put up the head restraints of the two outer rear seats again as per an automatic run.

So that the head restraints can be folded up or down on model 221, the positions of the head restraints must be stored in the rear seats control unit (N25/6). On model 216 the head restraints are controlled via the rear SAM control unit with fuse and relay module (N10/2).

On model 221 the head restraints of the center rear seat can only be folded down on vehicles except code (406) Rear multicontour seat, putting up take place manually.

Freely programmable button

The freely programmable button can be assigned by the user with one of the following functions:

Rear screen
The rear roller blind function on model 221.1 is fitted as standard equipment and on model 221.0 with code (540) Electric rear window roller blind or with code (498) Japan version or on model 216 with code (540) Electric rear window roller blind or with code (498) Japan version or with code (494) USA version
COMAND display OFF
Activate data protection
Towing sensor, with code (551) Anti-theft alarm system (ATA [EDW]), with code (494) USA version or with code (498) Japan version
Interior protection, with code (882) Interior monitoring (with ATA [EDW] only)
Repetition of route recommendation

For special vehicles the freely programmable button can be assigned with a two-way radio connection. This cannot be configured by the driver.

The freely programmable button is only integrated in the front central operating unit. The upper control panel control unit reads in the freely programmable button and places the actuation as a CAN message on the interior CAN.

Rotary push-button

With the turn/push control the user can control the individual menus of the user-relevant operation/information windows as well as the display of video picture information of the following systems on the COMAND display:

Navigation, with code (527) COMAND APS with single DVD disk drive (with navigation), with code (494) USA version or with code (498) Japan version.
Audio (e.g. radio, audio CD or DVD, MP3 or auxiliary (AUX)).
Telematics (e.g. telephone, SMS, address book), with code (386) Preinstallation for telephone "Handy", UPCI system, with code (388) Telephone "Handy", UPCI system, with code (494) USA version, with code (498) Japan version, with code (387) Preinstallation for telephone "Handy", UPCI system, USA/Canada or with code (389) Mobile phone preinstallation with universal interface, USA/Canada.
Video (TV, DVD video or AUX)
The TV function is available as standard equipment on vehicles with code (498) Japan version otherwise the TV function is available with code (863) Digital/analog TV tuner. The DVD video function is available as standard equipment on vehicles except code (494) USA version.
Vehicle (e.g. locator lighting, rear roller blind)
The rear roller blind function on model 221.1 is fitted as standard equipment and on model 221.0 with code (540) Electric rear window roller blind or with code (498) Japan version or on model 216 with code (540) Electric rear window roller blind or with code (498) Japan version or with code (494) USA version

Schematic representation

Fig 3: Identifying Schematic Representation Of Rotary Push-button

Courtesy of MERCEDES-BENZ USA

MOVEMENTS OF POSITION INDICATOR (CURSOR) ON COMAND DISPLAY VIA TURN/PUSH CONTROL

Movement at turn/push control	Movement of cursor
Rotate clockwise	The cursor moves to the right, or downward in vertical menus (exception: slider).
Turn counterclockwise	The cursor moves to the left or upwards in vertical menus (exception: slider).
Push forward	The cursor moves upward.
Push backward	The cursor moves downward.
Push left	The cursor moves to the left.
Push right	The cursor moves to the right.
Press down vertically	A selected menu or submenu is activated.

Step spacing

The rotary movement of the turn/push control is recorded in the following 2 grids of different fineness:

12 steps per revolution
32 steps per revolution

The low-resolution spacing (12 steps per revolution) is mainly used for selecting menus. The high-resolution spacing (32 steps per revolution) is used for selecting and moving within long lists. The turn/push control is blocked at the end of a selection list, i.e. when the bottom end of a selection list is reached, the Turn/push control can no longer be turned clockwise.