Comfort Displays, Function - GF54.30-S-3043TRF

Model 447 

With Code XM0 (Facelift) 

Function requirements in general 

• Instrument cluster (IC) control unit (A1/1) activated

Comfort displays in general 

The comfort displays provide a quick overview of the following information:

• Function sequence for displaying outside temperature 
• Function sequence for displaying the time 
• Function sequence for scale illumination of instrument cluster (IC) control unit 

Function sequence for displaying outside temperature 

The outside temperature is detected by the outside temperature sensor (B14). It is displayed in the display (A1/1p13) of the instrument cluster (IC) control unit in °C or °F depending on the country coding.

Model 447.8 or model 448.8 

The signal acquisition and actuation module (SAM) control unit (N10/1) directly reads in the signals from the outside temperature sensor and calculates the outside temperature. It sends this over the interior CAN (CAN B), the electronic ignition lock (EZS) control unit (N73), the chassis CAN (CAN E), the central gateway (N93/4) and the user interface CAN (CAN HMI) to the instrument cluster (IC) control unit.

Model 447.6/7 or model 448.7 

The signal acquisition and actuation module (SAM) control unit directly reads in the signals from the outside temperature sensor and calculates the outside temperature. It sends this over the interior CAN, the electronic ignition lock (EZS) control unit and the chassis CAN to the instrument cluster (IC) control unit.

The following parameters must be considered in addition so that the actual outside temperature is displayed:

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

Model 447.8 or model 448.8 

The Electronic Stability Program (ESP) control unit (N30/4) uses the wheel speeds to calculate the vehicle speed. It sends this over the chassis CAN, the central gateway and the user interface CAN to the instrument cluster (IC) control unit.

The CDI control unit or the ME control unit sends information on the coolant temperature over the chassis CAN, the central gateway and the user interface CAN to the instrument cluster (IC) control unit.

Model 447.6/7 or model 448.7 

The Electronic Stability Program (ESP) control unit calculates the vehicle speed from the wheel speeds and sends this over the chassis CAN to the instrument cluster (IC) control unit.

The CDI control unit or the ME control unit sends information on the coolant temperature over the chassis CAN to the instrument cluster (IC) control unit.

The coolant temperature values exert the following influence on the outside temperature display:

• Coolant temperature < 60°C:

  The current outside temperature value is displayed.

• Coolant temperature > 60°C and "Engine running" signal or "Drivetrain operational" signal set:

  At vehicle speeds of < 20 km/h (with vehicle deceleration), the outside temperature display is only changed if the measured outside temperature value drops. At vehicle speeds of 20 to 45 km/h, rising outside temperatures are displayed after a delay period of 3 min.

  At vehicle speeds of > 45 km/h, rising outside temperatures are displayed after a delay period of 90 s.

  If the speed signal is erroneous, rising outside temperatures are shown in an attenuated manner every 10 minutes.

  Model 447.8 or model 448.8 

  The CDI control unit or the ME control unit sends the "Engine running" or "Drivetrain operational" signal over the chassis CAN, the central gateway and the user interface CAN to the instrument cluster (IC) control unit.

  Model 447.6/7 or model 448.7 

  The CDI control unit or the ME control unit sends the "Engine running" or "Drivetrain operational" signal over the chassis CAN to the instrument cluster (IC) control unit.

• Coolant temperature > 60°C and "Engine running" signal or "Drivetrain operational" signal not set:

  A delay period of maximum 1 h prevents an apparent increase in outside temperature from being displayed that is caused by heat dissipated from the engine. A rise in display value is not permitted during this delay period. At "circuit 15OFF" the last measured outside temperature value is stored and then displayed when the circuit is reactivated.

  If the outside temperature has dropped below the stored value upon expiration of the delay period, the currently measured outside temperature is displayed after 8 seconds. The display range for the outside temperature is -40 to 85°C or -40 to 185°F.

  Model 447.8 or model 448.8 

  The electronic ignition lock (EZS) control unit sends the status of terminal 15 over the chassis CAN, the central gateway and the user interface CAN to the instrument cluster (IC) control unit.

  Model 447.6/7 or model 448.7 

  The electronic ignition lock (EZS) control unit sends the status of terminal 15 over the chassis CAN to the instrument cluster (IC) control unit.

  If the instrument cluster (IC) control unit receives implausible values or no values at all for coolant temperature, a coolant temperature of > 60°C is accepted.

Function sequence for displaying the time 

The time is shown in the digital clock (A1/1p6) in the multifunction display of the instrument cluster (IC) control unit.

Model 447.8 or model 448.8 

The time is synchronized with the radio (Audio/COMAND) (N87/6). The radio (Audio/COMAND) receives global positioning system (GPS) signals, evaluates them and sends information on the time to the instrument cluster (IC) control unit via the user interface CAN.

Model 447.6/7 or model 448.7 

The time synchronizes itself to the radio (Audio) (N87/2). The radio (Audio) receives GPS signals, evaluates these and transmits information on the time via the interior CAN to the instrument cluster (IC) control unit.

Function sequence for scale illumination of instrument cluster (IC) control unit 

The scale illumination is switched on when the instrument cluster (IC) control unit is activated. The brightness is automatically adapted to the ambient brightness (day/night) by the instrument cluster (IC) control unit.

Model 447.8 or model 448.8 

When it is dark, the brightness can also be adjusted by operating the instrument lighting brightness control (S1/2r1) in the lighting switch (S1/2). The signal acquisition and actuation module (SAM) control unit directly reads in the signals from the instrument lighting brightness control. It sends this over the interior CAN, the central gateway and the user interface CAN to the instrument cluster (IC) control unit. The instrument cluster (IC) control unit controls the brightness of all display elements accordingly.

Model 447.6/7 or model 448.7 without CODE JK3 (Instrument cluster with pixelmatrix display) 

In darkness, the brightness can also be changed by pressing the following buttons on the instrument cluster (IC) control unit:

• Instrument, switch and controls illumination button, bright (A1/1s3)
• Instrument, switch and controls illumination button, dark (A1/1s4)

	Electrical function schematic for instrument cluster (IC) control unit, comfort functions display	Model 448.8 except code XM0 (Facelift)	PE54.30-S-2072-97VDA
		Model 448.7 except code XM0 (Facelift)	PE54.30-S-2072-97VDB
		Model 448.7 except code XM0 (Facelift)	PE54.30-S-2072-97TRA
		Model 447.6/7 except code XM0 (Facelift)	PE54.30-S-2072-97TRB
	Overview of system components of instrument cluster (IC) control unit	Except code ME0 (Electric motor 85 kW) and except code ME4 (Electric motor 145 kW)	GF54.30-S-9989TRF