GF54.30-P-3043LE Comfort Displays, Function

GF54.30-P-3043LE Comfort Displays, Function
- as of model year 09

General function requirements
^ Instrument cluster (A1) activated

Comfort displays in general
The comfort displays provide a fast overview of the information, which is not required to operate the vehicle
The comfort display function is made up of the following subfunctions:
^ Function sequence for displaying outside temperature
^ Function sequence for displaying the time
^ Function sequence for display of Night View Assist (for code (610) Night View Assist)
^ Function sequence for illumination of instrument cluster

Function sequence for displaying outside temperature
The outside temperature value is defined through the resistance value of the outside temperature indicator temperature sensor (B14). The front SAM control unit with fuse and relay module (N10/1) directly reads in the resistance value of the outside temperature indicator temperature sensor, calculates the outside temperature (T) from it in °C and transmits a corresponding signal via the interior CAN (CAN B), central gateway control unit (N93) and central (CAN F) to the instrument cluster. The instrument cluster receives the signal and actuates the outside temperature indicator (A1p4) accordingly.
The outside temperature is displayed according to the country coding in either °C or °F.

In order to determine a correct outside temperature value, the following parameters must also be taken into account:
- Vehicle speed (falsification of value by airstream)
- Coolant temperature (falsification of value through radiant heat)

The vehicle speed is calculated on the basis of the wheel speeds. The wheel speeds are recorded by the following components:
- Left front rpm sensor (L6/1)
- Right front rpm sensor (L6/2)
- Left rear rpm sensor (L6/3)
- Right rear rpm sensor (L6/4)

The ESP control unit (N47-5) reads in the rpm sensor signals and sends these via chassis CAN, central gateway control unit and central CAN to the instrument cluster.
The instrument cluster receives the signals from the rpm sensors and calculates the current vehicle speed.

The coolant temperature is recorded by the coolant temperature sensor (B11/4). The CDI control unit (N3/9) (for diesel engine) or the ME-SFI [ME] control unit (N3/10) (for gasoline engine) reads in the coolant temperature sensor signal, calculates the coolant temperature and transmits the corresponding value via the chassis CAN.

The central gateway control unit passes this value on to the instrument cluster via the central CAN. The coolant temperature values have an influence on the outside temperature indicator as follows:
- Coolant temperature T < 60 °C The current outside temperature value is always displayed.
- Coolant temperature T > 60 °C and circuit 61 On At a vehicle speed of v < 20 km/h (12 mph), the outside temperature display only changes if the measured outside temperature value decreases.
At vehicle speeds of v = 20 to 45 km/h, rising outside temperatures are displayed after a delay period of t = 3 min. At vehicle speeds of v > 45 km/h rising outside temperatures are displayed after a delay period of t = 90 s.
- Coolant temperature T > 60 °C and circuit 61 OFF
A delay period (maximum t = 2 h) prevents any apparent outside temperature increase due to engine waste heat from being displayed. A rise in display value is not permitted during this delay period.

With circuit 15 Off, the last measured coolant temperature value is stored and displayed when reactivated. The display range is between -40 °C and +85 °C or between -40 °F and +185 °F. The display appears in the lower range of the multifunction display (A1p13).

The EZS control unit (N73) transmits the status of circuit 15 via the chassis CAN (CAN E), central gateway control unit and central CAN to the instrument cluster

If the instrument cluster receives implausible or no values at all from the temperature sensor for the outside temperature indicator, then the display of outside temperature is controlled as if the coolant temperature were T > 60 °C.
For vehicles with code (833) Great Britain version, the digital additional speedometer is displayed permanently instead of the outside temperature.

Function sequence for displaying the time
The time is shown on the analog clock (A70/1). The time is adjusted via the COMAND controller unit (A40/3). When adjusting, the instrument cluster reads in the signals directly via the central CAN.

For vehicles with code (527) COMAND APS with single DVD drive (with navigation) or code (529) HIGH Class Japan or code (530) COMAND APS USA (with navigation) the time synchronizes itself automatically via the Global Positioning System (GPS) signal received by the COMAND controller unit.
Manual adjustment of the time is only possible here if automatic synchronization is switched off on the instrument cluster. After updating the time stored in the instrument cluster, the instrument cluster transmits a corresponding signal via the central CAN, central gateway control unit and interior CAN to the upper control panel control unit (N72/1).
The upper control panel control unit actuates the analog clock via the instrument panel-LIN (LIN 1).

Additional function requirements for Night View Assist
^ Night View Assist active

Function sequence for display of Night View Assist
By pressing the Night View Assist button (S1s9) the display of Night View Assist camera (B84/2) pictures on the multifunction display is requested. The upper control panel control unit reads in the status of the Night View Assist button via the instrument panel LIN and transmits this on the interior CAN. The central gateway control unit relays this via the central CAN to the instrument cluster and, up to 31.5.09 via the chassis CAN to the ESP control unit and via the vehicle dynamics CAN (CAN H) to the Night View Assist control unit (N101), or as of 1.6.09 via the chassis CAN to the Night View Assist control unit.
The instrument cluster replaces the standard display of the electronic speedometer (A1p8) with the bar graph display with video image.
The Night View Assist control unit transmits the video images from the Night View Assist camera via the low voltage differential signal (LVDS) line to the instrument cluster.

The pictures from the Night View Assist camera are now shown in the multifunction display. Extremely bright image areas that blind the driver are suppressed. As a consequence, the driver is able to perceive the contents of the rest of the picture (e.g. obstacles, pedestrians or cyclists).
The light spread is processed in the Night View Assist control unit.

Instrument cluster illumination function sequence
The following events activate the background illumination of the multifunction display and the scale illumination of the instrument cluster:
- Unlocking the vehicle with the transmitter key (A8/1)
- Open or close driver door
- Change in status "Transmitter key inserted"
- Switching on the standing lights
- Circuit 15R switch on
- Pressing the OK button (S110s6)
- Pressing the "Back" and VCS Off button (S110s4)
- Pressing the electric parking brake switch (S76/15)

If the scale illumination of the instrument cluster has been activated and no further action takes place, the instrument cluster switches off the scale illumination after a time interval of t = 30 s has passed. If a fault message is displayed, this time interval extends to t = 120 s.

The central locking status and the status of circuit 15R are transmitted by the EZS control unit via the chassis CAN, central gateway control unit and central CAN to the instrument cluster.
The left door control unit (N69/1) (model 216) or the front left door control unit (N69/1) (model 221) transmits the driver door status via the interior CAN, central gateway control unit and central CAN to the instrument cluster.
The front SAM control unit transmits the standing lights activation status via the interior CAN, central gateway control unit and central CAN to the instrument cluster.

The status of the left multifunction steering wheel button group (S110) is transmitted by the steering column tube module (N80) via the steering LIN (LIN E1), chassis CAN, central gateway control unit and central CAN to the instrument cluster.
The electric parking brake controller unit (A13) transmits the electric parking brake switch status via the front end CAN (CAN G), central gateway control unit and central CAN to the instrument cluster.
The instrument cluster lighting is automatically adjusted to the light conditions of the interior compartment according to the signals from the right brightness sensor (A1b2) and left brightness sensor (A1b3).
Depending on light exposure, the instrument cluster controls the lighting between P = 80 and 100 % of the maximum brightness.

If the rain/light sensor (B38/2) transmits the "darkness detected" status, the instrument cluster switches automatically into night mode. The brightness then amounts to approx. 50 % of day mode. As soon as the rain/light sensor transmits the "Day" status, the instrument cluster regulates the lighting again to between P = 80 % and 100 % of the maximum brightness.
The overhead control panel control unit (N70) reads in the rain/ light sensor signal and sends this via the interior CAN, central gateway control unit and central CAN to the instrument cluster. The instrument illumination brightness can also be changed individually by using the switch and controls illumination/Night View Assist display brightness control (S6/2r1), provided that the exterior lighting is turned on.