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

GF54.30-P-3043RIT Comfort Displays, Function
- with CODE (P99) Special model "AMG Black Series"

General function requirements
^ Instrument cluster (A1) activated

General convenience display function sequence
The comfort displays function provides a fast overview of all supplemental information, which however is not required for operation of the vehicle.

The convenience display function consists of the following subfunctions:
^ Function sequence for displaying outside temperature
^ Function sequence for displaying the time
^ Instrument cluster illumination function sequence
^ Function sequence for an upshift recommendation

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 driver SAM control unit with fuse and relay module (N10/10) reads it in directly, calculates the outside temperature and then sends a corresponding signal over the interior CAN (CAN B) to the instrument cluster.
The outside temperature is shown in the left multifunction display (A1p13).
In order to compute the correct outside temperature value, the following parameters must also be taken into account:
- Vehicle speed (falsification of value through 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, SPS [PML] and BAS control unit (N47-5) reads in the signals of the rpm sensors directly and forwards them over the engine compartment CAN (CAN C) to the instrument cluster. The instrument cluster calculates the current vehicle speed.

The coolant temperature is recorded by the coolant temperature sensor (B11/4). The ME-SFI [ME] control unit (N3/10) reads in the signal of the coolant temperature sensor, uses it to calculate the coolant temperature and then sends the corresponding value over the engine compartment-CAN to the instrument cluster.

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 vehicle speeds of v < 20 km/h the display is only changed when the measured outside temperature value drops. At vehicle speeds of v = 20 and 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.
If the vehicle speed signal is faulty, rising outside temperatures are shown every t = 10 min in an attenuated manner.
- Coolant temperature T > 60 °C and circuit 61 OFF:
A maximum delay period of t = 1 h serves to ensure that any apparent increase in outside temperature because of engine waste heat is not displayed. A rise in display value is not permitted during this delay period.
- Coolant temperature T < 60 °C and circuit 61 OFF:
If the coolant temperature drops below a value of T = 60 °C, the delay period does not apply. Increasing temperatures are then displayed again. The display range is between -40 and +85 °C

If the instrument cluster receives implausible or no values at all from the coolant temperature sensor, then the display of outside temperature is controlled as were the coolant temperature T > 60 °C.

Function sequence for displaying the time
The time (24 hour military format) is displayed digitally via the electronic clock (A70) located in the center console. The time is automatically synchronized by the receiving Global Positioning System (GPS) signal.
The COMAND operating, display and controller unit (A40/3) sends the required data over the interior CAN to the instrument cluster. The instrument cluster routes the data over the local interconnect network (LIN) to the electronic clock.

Instrument cluster illumination function sequence
The illumination is switched on automatically when the instrument cluster is activated.
If the instrument cluster is activated by opening the driver door, the illumination is switched off again after t = 30 s. If an active warning is displayed, the run-on time is extended by an additional t = 2 min. The brightness is automatically adjusted to suit the lighting conditions in the interior compartment by brightness sensors in the instrument cluster.

Depending on the light falling on the brightness sensors, the instrument cluster automatically regulates the lighting in a range between 80 and 100 % of the maximum brightness. The brightness can also be changed individually by turning the instrument illumination brightness control and reset button (A1r1) if the exterior lights are switched on. If the rain/light sensor (B38/2) detects "darkness", the instrument cluster switches automatically to "Night" mode. The brightness is then approx. 50 % of the "Day" mode and it can also be adjusted using the instrument illumination brightness control. The rain/light sensor data are read in by the overhead control panel control unit (N70) and sent to the interior CAN. When the exterior lights are switched off, only the brightness of the left multifunction display and right multifunction display (A1p15) is automatically adapted by the brightness sensors. Manual adjustment via the brightness control is not possible in this case.

Function sequence for an upshift recommendation
If the engine speed and engine load reach a specified level, a gearshift recommendation is displayed on the upshift recommendation lamp (A1e69).
Three yellow LEDs and one red LED are integrated into the upshift recommendation lamp. When the red LED lights up a shift should be made, as otherwise the engine speed is restricted by the engine management. The light-emitting diodes are actuated in accordance with the engine speed to match the gear.

The ME-SFI [ME] control unit evaluates the respective load and speed information and forwards corresponding data over the engine compartment CAN to the instrument cluster.
The instrument cluster evaluates the data, compares them with the current vehicle speed and actuates the upshift recommendation lamp accordingly.