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Comfort displays, function - GF54.30-P-3043FL

MODEL 212 

Function requirements, 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 defined by the resistance value of 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 outside temperature is displayed in the multifunction display (A1p13) in °C or °F, depending on 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 wheel speeds are recorded by the following components:

The Electronic Stability Program control unit (N30/4) (model 212 (except 212.074/075/076/077/092/095/098/274/275/276/277/292/298) except CODE 233 (DISTRONIC PLUS)), the regenerative braking system control unit (N30/6) (model 212.095/098/298) or the Premium Electronic Stability Program control unit (N30/7) (model 212 (except 212.095/098/298) with CODE 233 (DISTRONIC PLUS), model 212.074/075/076/077/092/274/275/276/277/292) reads in the signals from the rpm sensors directly and sends these signals to the instrument cluster up to 28.02.2013 via the chassis CAN (CAN E) or as of 01.03.2013 via chassis CAN 1 (CAN E1), the front SAM control unit and chassis CAN 2 (CAN E2).

The coolant temperature is recorded by the coolant temperature sensor (B11/4). The CDI control unit (N3/9) (with diesel engine) or the ME-SFI control unit (N3/10) (with gasoline engine) reads in the signal from the coolant temperature sensor directly, uses this signal to calculate the coolant temperature and sends the temperature up to 28.02.2013 via the chassis CAN or as of 01.03.2013 via chassis CAN 1, the front SAM control unit and chassis CAN 2.

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 (12 mph) (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 "engine running" or "drivetrain operational" signal is sent to the instrument cluster by the CDI control unit (with diesel engine) or the ME-SFI control unit (with gasoline engine) up to 28.02.2013 via the chassis CAN or as of 01.03.2013 via chassis CAN 1, the front SAM control unit and chassis CAN 2.

IMPORTANT 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 "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 is between T = -40 and +85 °C or between T = -40 and +185 □.

IMPORTANT The circuit 15 status is sent by the electronic ignition lock control unit (N73) over the interior CAN to the instrument cluster.

Function sequence for displaying the time 

The time is displayed up to 28.02.2013 on the analog clock (A1p9) in the instrument cluster or as of 01.03.2013 on the analog clock (A70/1) in the middle of the instrument panel.

The time can be set either manually using the left multifunction steering wheel button group (S110) and the right multifunction steering wheel button group (S111) (vehicles up to 31.05.2012 with CODE 523 (MB Audio 20 radio) or CODE 510 (Audio 20 with CD changer)) or entered in the system settings (except vehicles up to 31.05.2012 with CODE 523 (MB Audio 20 radio) or CODE 510 (Audio 20 with CD changer)) or is updated automatically via the received GPS data (with CODE 511 (Audio 50 APS incl. DVD changer) or CODE 525 (MB Audio 50 APS radio)) or CODE 512 (COMAND APS incl. DVD changer) or CODE 527 (COMAND APS with single DVD drive (with navigation)) or CODE 531 (COMAND APS)).

The signals of the multifunction steering wheel button groups are read in by the steering wheel electronics (N135) and transmitted via the steering LIN (LIN E1) to the steering column tube module control unit (N80). The steering column tube module control unit sends the signals to the instrument cluster up to 28.02.2013 via the chassis CAN or as of 01.03.2013 via chassis CAN 1, the front SAM control unit and chassis CAN 2.

The radio (with CODE 523 (MB Audio 20 radio) or CODE 510 (Audio 20 with CD changer) or CODE 505 (20 NTG5 radio without navigation capability) or CODE 522 (Audio 20 radio)) or the radio with auto pilot system (A2/56) (with CODE 511 (Audio 50 APS incl. DVD changer) or CODE 525 (MB Audio 50 APS radio)) or the COMAND controller unit (A40/3) (with CODE 512 (COMAND APS incl. DVD changer) or CODE 526 (COMAND with single DVD drive (without navigation)) or CODE 527 (COMAND APS with single DVD driver (with navigation)) or CODE 528 (COMAND incl. DVD changer) or CODE 531 (COMAND APS)) sends information on the time via the interior CAN to the instrument cluster (time synchronization).

On vehicles as of 01.03.2013, the instrument cluster sends the request to set the analog clock via the interior CAN to the front SAM control unit. The front SAM control unit then actuates the analog clock via the instrument panel LIN (LIN 1).

Additional function requirements for scale illumination of instrument cluster 

Function sequence for scale illumination of instrument cluster 

On vehicles up to 28.02.2013 and on vehicles as of 01.03.2013 with CODE 954 (Avantgarde), switching on the standing lights or circuit 15R causes the scale illumination of the instrument cluster to be switched on.

On vehicles as of 01.03.2013 except CODE 954 (Avantgarde), the background illumination of the multifunction display and the scale illumination of the instrument cluster are always activated irrespective of the status of the standing lights.

The "Standing lights actuation active" status" is transmitted by the front SAM control unit via the interior CAN to the instrument cluster.

The electronic ignition lock control unit sends the circuit 15R ON status via the interior CAN to the instrument cluster. The instrument cluster receives these signals 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. The brightness can also be personalized by actuating the brightness control instrument illumination (A1r1).

IMPORTANT If the instrument cluster is activated by opening the driver door, it simply switches on the multifunction display lighting. This switches off again after t = 30 s. If an active warning is displayed, this run-on time extends to t = 120 s.

IMPORTANT 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 "Standing lights actuation active" status to be set, which also activates scale illumination of the instrument cluster. If the driver door is then opened, the ambient illumination goes off. "Standing lights actuation active" status is canceled, and the instrument cluster deactivates the scale illumination.

  Electrical function schematic of instrument cluster, comfort display MODEL 212 up to model year 2014 PE54.30-P-2056-97DAA
MODEL 212 as of model year 2014 PE54.30-P-2056-97DAB
  Overview of system components, instrument cluster (IC) component description   GF54.30-P-9996FL 
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