Comfort displays, function - GF54.30-P-3043FQ
MODEL 218
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 scale illumination of instrument cluster
Function sequence for displaying outside temperature
The outside temperature is detected by the outside temperature sensor (B14). The front SAM control unit with fuse and relay module (N10/1) reads in the signal from the outside temperature sensor directly, uses this signal to calculate the outside temperature and sends the outside temperature via the interior CAN (CAN B) to the instrument cluster.
The display of the outside temperature corresponds to the country coding in °C or °F in the multifunction display (A1p13).
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 from the wheel speed.
The Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS, or without engine 157) or the Premium Electronic Stability Program control unit (N30/7) (with code (233) DISTRONIC PLUS or with engine 157) sends information on the wheel speed to the instrument cluster via chassis CAN (CAN E) up to 28.02.2013, or to the instrument cluster via chassis CAN 1 (CAN E1), the front SAM control unit with fuse and relay module (N10/1) and chassis CAN 2 (CAN E2) as of 01.03.2013.
The CDI control unit (N3/9) (with diesel engine) or the ME-SFI control unit (N3/10) (with gasoline engine) sends information about coolant temperature to the instrument cluster over the chassis CAN up to 28.02.2013, or over chassis CAN 1, front SAM control unit and chassis CAN 2 as of 01.03.2013.
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 "Drive train 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 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.
The CDI control unit or ME-SFI control unit sends the "Engine running" or "Drivetrain operational" signal up to 28.02.2013 over the chassis CAN to the instrument cluster or as of 01.03.2013 to the instrument cluster over the chassis CAN 1, front SAM control unit and chassis CAN 2.
- Coolant temperature T > 60 °C and "Engine running" or "Drive train 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 is between T = -40 and +85 °C or between T = -40 and +185 °F.
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 by the analog clock (A70/1).
The time can either by entered manually in the system settings or is automatically updated by the GPS data (up to 31.08.2014 with code (511) Audio 50 APS incl. DVD changer or code (525) Radio MB Audio 50 APS or code (512) COMAND APS incl. DVD changer or code (527) COMAND APS with Single DVD drive (with navigation) or code (509) navigation module and as of 01.09.2014 with code (522) Radio Audio 20 and code (357) SD map navigation or code (531) COMAND APS). The radio (A2) (up to 31.08.2014 with code (523) Radio MB Audio 20 or code (510) Audio 20 incl. CD changer or code (526) COMAND with single DVD drive (without navigation) or code (528) COMAND incl. DVD changer and as of 01.09.2014 with code (505) Radio 20 NTG5 without navigation capability or code (522) Radio Audio 20), the Radio with Auto Pilot System (A2/56) (up to 31.08.2014 with code (511) Audio 50 APS incl. DVD changer or code (525) Radio MB Audio 50 APS) or the COMAND controller unit (A40/3) (up to 31.08.2014 with code (512) COMAND APS incl. DVD changer or code (527) COMAND APS with Single DVD drive (with navigation), as of 01.09.2014 with code (531) COMAND APS) sends information on the time to the instrument cluster via interior CAN (time synchronization). The instrument cluster accepts this and sends it over the interior CAN to the front SAM control unit. The front SAM control unit actuates the analog clock over the instrument panel LIN (LIN 1) accordingly.
Function sequence for scale illumination of instrument cluster
The scale illumination of the instrument cluster is switched on by switching on the standing light (circuit 58) (except with engine 157) or circuit 15R.
The front SAM control unit sends the status of the standing lights actuation (circuit 58) over the interior CAN to the instrument cluster. The electronic ignition lock control unit sends the status of circuit 15 over the chassis CAN to the instrument cluster.
The instrument cluster receives this information and switches on the scale illumination.
The brightness is automatically adjusted to suit the lighting conditions in the vehicle interior by a phototransistor integrated in the instrument cluster.
If the instrument cluster was activated by the driver door being opened, it only switches on the default screen of the multifunction display. This switches off again after t = 40 s. If an active warning is displayed, this run-on time extends to t = 120 s.
If the ambient illumination function is activated using the instrument cluster, this is automatically switched on when the vehicle is unlocked by radio or infrared. This causes the "standing lights actuation active" status (circuit 58 ON) to be set, thereby also activating the scale illumination of the instrument cluster. If the driver door is then opened, the ambient illumination goes off. The "Standing lights actuation active" status (circuit 58 ON) is canceled and the instrument cluster deactivates the scale illumination.
| Electrical function schematic of instrument cluster, comfort display | MODEL 218 up to model year 2014 | PE54.30-P-2056-97XAA |
| MODEL 218 as of model year 2014 | PE54.30-P-2056-97XAB | |
| Overview of system components, instrument cluster (IC) component description | GF54.30-P-9996FQ |