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Home >> Mercedes Benz >> 2021 >> S560 4Matic >> Repair and Diagnosis >> Electrical >> Gauges >> Electrical System, Equipment & Instruments - 217 Chassis (2 Of 8) >> Basic Knowledge >> Comfort Displays, Function - GF54.30-P-3043LF

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

Model 217, 222 

Function requirements in general 

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 

The outside temperature is detected by the outside temperature sensor (B14).

The front SAM control unit (N10/6) reads in the signals of outside temperature sensor directly, calculates the outside temperature and sends this to the instrument cluster via interior CAN (CAN B), electronic ignition lock control unit (N73) and user interface CAN (CAN HMI). The outside temperature is displayed in the instrument cluster in °C or °F, in accordance with the country coding.

The following parameters must also be taken into account to determine a correct value of outside temperature:

The vehicle speed is calculated on the basis of the wheel speeds. The Electronic Stability Program control unit (N30/4) transmits the information about the wheel speed over the suspension FlexRay (Flex E), the electronic ignition lock control unit and the user interface CAN to the instrument cluster.

The CDI control unit (N3/9) (with diesel engine) or the ME-SFI control unit (N3/10) (with gasoline engine) transmits information about coolant temperature via the engine CAN (CAN C), the powertrain control unit (N127), the chassis FlexRay, the electronic ignition lock control unit and the user interface 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 shown.

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

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

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

The CDI control unit (with diesel engine) or the ME-SFI [ME] control unit (with gasoline engine) sends the "Engine running" or "Drivetrain operational" signal over the engine CAN, powertrain control unit, chassis FlexRay, electronic ignition lock control unit and the user interface CAN to the instrument cluster.

IMPORTANT If the vehicle speed signal is faulty, rising outside temperatures are shown in an attenuated manner every t = 10 minutes.

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

A delay period of maximum t = 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.

With circuit 15 OFF, the last measured outside temperature value is stored and then displayed when the circuit is reactivated.

If, in the meantime, the measured outside temperature has dropped below the stored value, the currently measured temperature is displayed after t = 8 seconds. The display range for the outside temperature lies between T = -40 and +85°C or between T = -40 and +185°F.

The circuit 15 status is sent by the electronic ignition lock control unit over the user interface CAN to the instrument cluster.

Function sequence for displaying the time 

The time is shown by the analog clock (A70/1) in the center console. The time always synchronizes with the head unit (A26/17) (as of 01.06.2017 (model 222) or 01.12.2017 (model 217)) or the COMAND controller unit (A40/3) (up to 31.05.2017 (model 222) or 30.11.2017 (model 217)). The head unit (as of 01.06.2017 (model 222) or 01.12.2017 (model 217)) or the COMAND controller unit (up to 31.05.2017 (model 222) or 30.11.2017 (model 217)) transmits a signal to the instrument cluster via the user interface CAN and a signal to the front SAM control unit via the user interface CAN, electronic ignition lock control unit and interior CAN. The front SAM control unit actuates the analog clock via the instrument panel LIN (LIN 1).

Additional function requirements for instrument cluster brightness control 

Function sequence for instrument cluster brightness control 

The brightness is automatically adapted to the brightness conditions (day/night) when the instrument cluster is activated. Up to 31.05.2017 (model 222) or 30.11.2017 (model 217), the brightness can also be changed in darkness by actuating the instrument lighting brightness control (S6/2r1) in the center instrument panel button group (S6/2). The status of the instrument illumination brightness control is read in by the front SAM control unit over the instrument panel LIN, and forwarded over the interior CAN, electronic ignition lock control unit and the user interface CAN to the instrument cluster.

  Electrical function schematic of instrument cluster, comfort display   PE54.30-P-2056-97SEA
  Overview of system components, instrument cluster (IC) component description Model 217, 222
up to model year 2018		 GF54.30-P-9996LF 
    Model 217, 222
as of model year 2018		 GF54.30-P-9996LFM 
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