GF54.30-P-3043CW Comfort Displays, Function
GF54.30-P-3043CW Comfort Displays, Function
- up to model year 08
Function requirements:
^ Instrument cluster (A1) activated
Function sequence, comfort display, general
The comfort display is comprised of several subfunctions. These are:
^ Ambient temperature display
^ Time display
^ Illumination of instrument cluster
^ Gearshift recommendation (on model 204.006 with engine 646.811 and model 204.044 with engine 271.910 and manual transmission)
Function sequence, outside temperature indicator
The outside temperature is recorded by the outside temperature sensor (B14), read in by the front SAM control unit with fuse and relay module (N10/1) and forwarded to the instrument cluster via interior CAN.
In order to determine a correct value of outside temperature, the following parameters must also be taken into account:
- Vehicle speed (distortion of value by the airstream)
- Coolant temperature (distortion of the value by radiant heat)
^ Speed: The wheel speeds determined by the rpm sensors (L6/1, L6/2, L6/3 and L6/4) are read in by the Electronic Stability Program control unit (N30/4) and sent via chassis CAN to the instrument cluster.
The instrument cluster receives the values and calculates the current speed from them.
^ Coolant temperature:
The coolant temperature sensor (B11/4) is read by the ME-SFI control unit (N3/10) (gasoline engines) or the CDI control unit (N3/9) (diesel engines) and sent via chassis CAN to the instrument cluster.
^ Engine running time:
The engine running time is determined internally in the instrument cluster via a timer.
The display is shown as follows depending on the values:
^ Coolant temperature T < 60 °C:
The current outside temperature value is always displayed.
^ Coolant temperature T > 60 °C and circuit 61 On:
If the speed is decreasing and it falls below v = 20 km/h, the display only changes if the measured outside temperature value decreases.
At speeds between v = 20 km/h and v = 45 km/h, rising outside temperatures are displayed after a delay period of t = 3 min.
At speeds > 45 km/h, rising outside temperatures are displayed after a delay period of t = 90 s.
If the vehicle speed signal is faulty, increasing temperatures are displayed every t = 10 min in a buffered manner.
^ Coolant temperature T > 60 °C and circuit 61 Off:
A delay period (max.. t = 1 h) prevents that an apparent increased outside temperature is displayed due to heat dissipated from the engine. A rise in display value is not permitted during this delay period.
With circuit 15 OFF, the last measured 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 temperature currently measured is displayed after t = 8 seconds.
If the outside temperature rises above the stored value, the outside temperature currently measured is displayed after the situations described below.
The outside temperature is displayed
^ in the outside temperature indicator (A1p4)
(without code (442) Comfort multifunction steering wheel) or
^ in the multifunction display (A1p13)
(with code (442) Comfort multifunction steering wheel)
The display range is between -40 °C and +85 °C or between -40 °F and +185 °F
If the instrument cluster receives implausible or no values at all from the outside temperature sensor, then the display of outside temperature controlled as were the coolant temperature T > 60 °C.
Function sequence, time display
The time is digitally displayed in:
^ the digital clock (A1p6) (without code (442) Comfort multifunction steering wheel)
^ the multifunction display
On vehicles without navigation the time can only be adjusted manually using the left multifunction steering wheel button group (S110) and the right multifunction steering wheel button group (S111). The signals are read in by the steering column module control unit (N80) over the steering LIN and then transmitted over the chassis CAN to the instrument cluster.
In (United States of America) (CDN) and (Japan) vehicles with navigation installed, the time can and be set using the multifunction steering wheel button group, or it synchronizes (if set to do so in the instrument cluster) with the installed audio components. On ECE vehicles with navigation installed, the time always synchronizes with the installed audio components.
Function sequence, instrument cluster illumination
The illumination is switched on automatically when the instrument cluster is activated.
If the instrument cluster is activated via the opening of the driver's door, the illumination switches off again after t = 30 s. If an active warning is displayed then the run-on time extends by a further t = minutes.
The brightness is automatically adapted to the interior brightness conditions by the brightness sensor (A1b1). Depending on the light intensity on the brightness sensor the instrument cluster automatically adjusts the lighting in a range between 80% and 100% of the maximum brightness.
The brightness can also be changed individually by turning the instrument illumination brightness control (A1r1) when the exterior lights are switched on.
Function sequence, gearshift recommendation
If the engine speed and the engine load reach a predefined level, a gearshift recommendation will be shown in the travel distance display (A1p7) (without code (442) Comfort multifunction steering wheel) or in the multifunction display. The display consists of an arrow indicating a recommended upshift or downshift plus the number of the recommended gear (e.g. "Up-arrow 3").
In making the recommendation, the ME-SFI control unit (N3/10) (gasoline engines) or CDI control unit (N3/9) (diesel engines) evaluates the engine load and rpm information and compares it against the current vehicle speed.
The vehicle speed signal is sent to the ME-SFI control unit or CDI control unit from the instrument cluster via the chassis CAN. The request to display the gearshift recommendation is sent from the ME-SFI control unit or CDI control unit via the chassis CAN to the instrument cluster.
