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

MODEL 453.0 (except 453.091), 453.3 (except 453.391), 453.4 (except 453.491) with CODE K35 (Instrument cluster with monochrome display) 

MODEL 453.0 (except 453.091), 453.3 (except 453.391), 453.4 (except 453.491) with CODE K36 (Instrument cluster with color 8.9 cm (3.5") display) 

Function requirements, general 

• 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 includes the following subfunctions:

• Function sequence for displaying outside temperature 
• Function sequence for displaying the time 
• Function sequence for frost warning 
• Function sequence for brightness control of instrument cluster, only with CODE K36 (Instrument cluster with color 8.9 cm (3.5") display) 

Function sequence for displaying outside temperature 

The outside temperature is detected by the outside temperature sensor (M21/2b1). The instrument cluster (A1) reads in the signal from the outside temperature sensor directly and uses it to calculate the outside temperature.

The outside temperature is shown in the multifunction display (A1p13) of the instrument cluster in either °C or °F according to the country coding. The following parameters must also be taken into account to determine a correct value of outside temperature:

• Vehicle speed (falsification of value through air stream)
• Coolant temperature (falsification of value through radiant heat)

The vehicle speed is calculated on the basis of the wheel speeds.

The Electronic Stability Program control unit (N30/4) sends information on the wheel speeds over the interior CAN (CAN B) to the instrument cluster.

The ME-SFI control unit (N3/10) sends information on the coolant temperature via the interior CAN to the instrument cluster.

The display's response pattern varies as temperature rises, according to coolant temperature and engine running time:

• Coolant temperature T = < 60°C. When the instrument cluster is activated, the current outside temperature is always displayed.
• Coolant temperature T = > 60°C. When the instrument cluster is activated, increasing temperature values are displayed with a slight delay.

The display range for the outside temperature is between T = -40 and +63°C or between T = -40 and +146 °F, with instrument cluster with color 8.9 cm (3.5") display.

The display range for the outside temperature is between T = -39 and +60°C or between T = -38 and +140 °F, with CODE K35 (Instrument cluster with monochrome display).

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

Function sequence for displaying the time 

The time is shown in the multifunction display and, in vehicles with code V31 (Additional instruments (Cockpit clock and tachometer)) and in the clock (A15p3).

For vehicles with additional instruments (Cockpit clock and tachometer), the instrument cluster sends the request to adjust the analog clock over the additional instruments-LIN (LIN B22) to the clock.

In vehicles with code 535 *smart Media System(, the time displayed by the instrument cluster is always synchronized with the time known to the smart Radio Multimedia Navigator (A40/3).

The Smart Radio Multimedia Navigator sends the current time via the telematics CAN (CAN A), the audio gateway control unit (N93/1) and the interior CAN to the instrument cluster (time synchronization). The instrument cluster adopts this and, in vehicles with additional instruments, actuates the clock over the additional instruments LIN.

Manual adjustment of time, only in combination with code 537 *smart Audio System(

For vehicles with multifunction steering wheel, the time can be manually adjusted using the left multifunction steering wheel button group (S110) and for vehicles without multifunction steering wheel, over the menu guidance button group (S4/5). For vehicles with multifunction steering wheel, the audio gateway control unit (N93/1) receives the signals from the multifunction steering wheel button group over the steering wheel clock spring contact (A45/1) and then sends them over the interior CAN to the instrument cluster. For vehicles without multifunction steering wheel, the menu guidance button group (S4/5) sends the signals straight to the instrument cluster.

Function sequence for frost warning 

To determine the temperature value, the instrument cluster uses the outside temperature value obtained directly from the outside temperature sensor.

If the outside temperature drops below the threshold value of T = 3°C, an ice crystal symbol appears in the multifunction display as a frost warning. This symbol flashes for t = 60 s to inform the driver that the road may be icy. At the same time the current outside temperature is shown in the multifunction display. If after the warning period the outside temperature is still below the threshold value of

T = 3°C, the ice crystal symbol is actuated continuously.

As soon as the outside temperature reaches a value of T = 3°C, the ice crystal symbol goes out again.

The outside temperature shown in the multifunction display remains visible until another display is selected by pressing the left button.

Function sequence for instrument cluster brightness control only for instrument cluster with color 8.9 cm (3.5") display 

After activating the instrument cluster, the brightness level can be regulated using the left multifunction steering wheel button group through the menu levels in the instrument cluster's multifunction display. The menu "Settings" and the submenu item "Ambient illumination" offers 5 settings.

	Electrical function schematic of instrument cluster, comfort display		PE54.30-P-2056-97BBA
	Overview of system components, instrument cluster (IC) component description		GF54.30-P-9996KJ