GF54.30-P-3041CA Display Operating Conditions, Function

GF54.30-P-3041CA Display Operating Conditions, Function
MODEL 207.3/ 4

Function requirements, general
^ Circuit 15 ON
The circuit 15 status is sent by the electronic ignition lock control unit (N73) over the chassis CAN (CAN E) to the instrument cluster (A1).

Display operating conditions, general
The operating conditions display provides the driver with permanent information about the current operating conditions of the vehicle.
The display operating conditions function includes the following subfunctions:
^ Display of speed function sequence
^ Display of engine speed function sequence
^ Display of coolant temperature function sequence
^ Display of travel distance function sequence
^ Display of fuel quantity function sequence
^ Gear and transmission mode display function sequence (with transmission 722)
^ Function sequence for "ECO" display (with code (B03) ECO start/stop function)
^ Display of transport mode function sequence (as of 1.6.12)

Additional function requirements for display of speed
^ Vehicle speed v > 0 km/h

Display of speed function sequence
The vehicle speed is calculated on the basis of the wheel speeds.
The wheel speeds are recorded by the following components:
- Left front axle rpm sensor (L6/1)
- Right front axle rpm sensor (L6/2)
- Left rear axle rpm sensor (L6/3)
- Right rear axle rpm sensor (L6/4)
The Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS) or the Premium Electronic Stability Program control unit (N30/7) (with code (233) DISTRONIC PLUS) reads in the signals of the rpm sensors and transmits these via the chassis CAN to the instrument cluster.
The instrument cluster calculates the current vehicle speed, compares it against an internally stored speedometer characteristic, and then actuates the speedometer (A1p8) to match by way of a stepper motor.

Additional function requirements for display of engine speed
^ "Engine running" or "drive train operational" signal on

Display of engine speed function sequence
The engine rpm is recorded by the crankshaft position sensor (L5) (engine 651 without code (B03) ECO start/stop function) or by the crankshaft Hall sensor (B70) (engine 271, 272, 273, 276, 278, 642, engine 651 with code (B03) ECO start/stop function). The CDI control unit (N3/9) (for diesel engine) or the ME-SFI [ME] control unit (N3/10) (for gasoline engine) reads in the signals of the crankshaft position sensor or the crankshaft Hall sensor, uses them to calculate the engine speed, and then sends a corresponding value over the chassis CAN to the instrument cluster.
The instrument cluster receives the value for the engine speed and actuates the tachometer (A1p5) accordingly by way of a stepper motor.

Display of coolant temperature function sequence
The coolant temperature is recorded by the coolant temperature sensor (B11/4). The CDI control unit imports the signal of the coolant temperature sensor, uses it to calculate the coolant temperature and then sends the corresponding value via the chassis CAN to the instrument cluster.
The instrument cluster receives the value for the coolant temperature and actuates the coolant temperature display (A1p1) accordingly by way of a stepper motor.
The coolant temperature gauge is actuated via a correction characteristic. This correction characteristic defines the following four temperature ranges in which the coolant temperature display is actuated in different ways:
- T = 0 to 80 °C
The actual coolant temperature is shown.
This is only displayed as of T greater than or equal to 40 °C.
- T = 80 °C to 115 °C:
The coolant temperature display pointer is actuated constantly to a value of T = 90 °C.
- T = 115 °C to 120 °C:
The coolant temperature display pointer is actuated constantly to a value of T = 95 °C.
- T = 120 to 130 °C (start of red warning range)
The actual coolant temperature is displayed.
When a coolant temperature of T > 130 °C is reached, the coolant temperature warning lamp (A1e54) is also permanently actuated and a warning message is issued via the multifunction display (A1p13).
When a faulty combustion engine fan motor and air conditioning with integrated closed-loop control (M4/7) is detected the actual coolant temperature in the coolant temperature gauge is displayed. The coolant temperature warning lamp is also actuated.
If the instrument cluster does not receive any value for the coolant temperature, it actuates the coolant temperature warning lamp.
The coolant temperature display is not actuated.

Display of travel distance function sequence
The travel distance display includes the following subfunctions:
^ Determination of travel distance function sequence
^ Display of main odometer reading function sequence
^ Display of trip distance function sequence
^ Storage of counter readings function sequence

Determination of travel distance function sequence
The instrument cluster calculates the travel distance from the signals received from the rpm sensors taking the tire circumference into consideration.
The tire size is coded via the diagnostics tester.

Display of main odometer reading function sequence
The total distance display is shown in the multifunction display.
The maximum displayed counter reading of the main odometer reading is 999.999.
The display then overflows to 0. However, the actual kilometer reading continues to be stored internally in the instrument cluster.

Display of trip distance function sequence
The trip distance is shown in the multifunction display. The maximum displayed counter reading of the trip distance is 9999.9.
If this value is reached, the figure returns to 0.

Storage of counter readings function sequence
The main odometer reading is saved continuously to the nonvolatile part of the instrument cluster's internal memory. This memory guarantees the retention of the counter reading for at least five years even when the on-board electrical system battery (G1) is disconnected.
The current reading of the trip odometer is likewise stored in the nonvolatile memory of the instrument cluster.

Display of fuel quantity function sequence
The level of the fuel tank is recorded by the left fuel level indicator sensor (B4/1) and right fuel level indicator sensor (B4/2). The rear SAM control unit with fuse and relay module (N10/2) reads in the fuel level indicator sensor signals and forwards them over the interior CAN (CAN B) to the instrument cluster. The instrument cluster receives the signals for the fuel level indicator sensor, calculates them and then actuates the fuel level indicator (A1p2) to match by means of a stepper motor.
If the reserve range has been reached (approx. 12.5 % of maximum tank capacity), the instrument cluster actuates the fuel reserve warning lamp (A1e4). A corresponding message is shown on the multifunction display.
The reserve range is defined by comparing the measured fill level against a stored tank characteristic.
If the reserve range drops to approx. 50 %, a gas station symbol in the form of a gasoline pump is shown in the Range menu instead of the distance reading.

Display characteristics of fuel level indicator:
- After switching on circuit 15, the current fill level is displayed. In the process the pointer runs up in a buffered manner.
- After an engine start the display value for t = 4 s is updated every t = 0.8 s, to maintain a value below the full on-board electrical system voltage. After this time, or as soon as the vehicle starts off, the display is updated with a delay.
- When circuit 15 is switched off, the fuel level indicator pointer moves gradually back to zero.
A firmly attached fuel level sensor is detected by comparing any change in the fill level of the fuel tank with the calculated composite mileage. If the fill level drops faster over a specific distance than is technically feasible based on the composite mileage, the fuel level indicator sensor is deemed to be defective and a corresponding message issued on the multifunction display.

Function sequence, gear display and transmission mode display (with transmission 722)
The gear and transmission mode display is realized on the instrument cluster's multifunction display.
Gear indicator:
The information required for the gear indicator is supplied by the electronic selector lever module control unit (N15/5) on the drive train CAN (CAN C).

Transmission mode display:
The information required for the transmission mode display is supplied on vehicles with transmission 722.6 by the electronic transmission control control unit (N15/3) or on vehicles with transmission 722.9 by fully integrated transmission control unit (Y3/8n4) on the drive train CAN.
The CDI control unit or ME-SFI [ME] control unit forwards this information to the instrument cluster via the chassis CAN. The current gear and the current transmission mode are shown in the multifunction display.

Function sequence for "ECO" display (with code (B03) ECO start/stop function)
The automatic engine start/stop is automatically activated following each change of ignition, and it can be activated or deactivated by pressing the ECO start/stop function button (N72/1s50) in the UCP control unit (N72/1).
The status of the button for the ECO start/stop function is read in by the upper control panel control unit and via the instrument panel LIN (LIN 1) passed on to front SAM control unit with fuse and relay module (N10/1).
The front SAM control unit transmits the status via the chassis CAN to the ME-SFI control unit or CDI control unit.
If the function requirements are fulfilled, the driver is notified of the automatic engine start/stop readiness by the "ECO" symbol in the instrument cluster's multifunction display.
The request for this is transmitted by the ME-SFI control unit or CDI control unit via the chassis CAN to the IC.
If the ME-SFI control unit or CDI control unit establishes in driving mode by means of the currently applying parameters, that it is possible for the engine to stop automatically, however no neutral was engaged, the gearshift recommendation "->" is output in the multifunction display.

Display of transport mode function sequence (as of 1.6.12)
The transport mode is activated in the production plant at the end of the production process, and it sets the overall vehicle into a defined special condition (e.g. governed speed or restricted exterior light functions).
The transport mode remains active on its way from the production plant to the dealers and company-owned sales and service outlets around the world up to the so-called delivery inspection and the final handover to the end customers.
When the transport mode is active the multifunction display shows the corresponding message.
Detailed information on the operating state of the transport mode is given in the separate function description for energy management.