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

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

Function requirements, general
^ Instrument cluster (A1) activated

Display operating conditions function sequence
The display of operating conditions provides the driver with permanent information about the current operating conditions of the vehicle. The Display operating conditions function is comprised of the following partial functions:
^ Speed display function sequence
^ Display of engine speed function sequence
^ Display of coolant temperature function sequence
^ Display of fuel quantity function sequence
^ Display of travel distance function sequence
^ Gear indicator function sequence
^ Engine oil level indicator function sequence

Additional function requirements for vehicle speed display
^ Circuit 15 On

Speed display function sequence
The wheel speeds determined via the left front rpm sensor (L6/1), right front rpm sensor (L6/2), left rear rpm sensor (L6/3) and right rear rpm sensor (L6/4) are read in by the SBC hydraulic unit (A7/3) and transmitted to the ESP, SPS [PML] and BAS control unit (N47-5). From here the signal is passed on to the instrument cluster via the engine compartment CAN. The instrument cluster calculates the current speed from the values received. This is adjusted with a stored speedometer characteristic and displayed via a stepper motor in the electronic speedometer (A1p8).

The instrument cluster makes the recorded speed value available via interior CAN and engine compartment CAN.

Comparison with the speedometer characteristic is performed to compensate for mechanical inaccuracies and meet the legal requirements with respect to display tolerances.

Additional function requirements for display of engine speed
^ Circuit 61 ON

Display of engine speed function sequence
The crankshaft speed recorded by the crankshaft Hall sensor (B70) is read in by the ME-SFI [ME] control unit (N3/10) and placed on the engine compartment CAN.
The instrument cluster receives this data and actuates the tachometer accordingly via a stepper motor (A1p5).

Additional function requirements for coolant temperature display
^ Circuit 15 On

Display of coolant temperature function sequence
The coolant temperature recorded by the coolant temperature sensor (B11/4) is read in by the ME-SFI [ME] control unit and forwarded via engine compartment CAN.
The instrument cluster receives the signal and actuates the stepper motor of the coolant temperature display (A1p1) accordingly.
If the signal is faulty or missing, the pointer of the temperature display is moved back to the start of the scale (40 °C) and a fault is stored in the fault memory of the instrument cluster.

- T = 0 to 96 °C:
The temperature displayed increases as the coolant temperature increases. However, display first takes place as of T = 40 °C.
- T = 96 to 116 °C:
The display remains in the temperature range of T = 96 °C.
- T = 116 to 120 °C:
The temperature displayed increases as the coolant temperature increases.
- T = 120 °C to 130 °C (start of red warning range):
The actual 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 left multifunction display (A1p13).

If the engine and air conditioning electric suction fan with integrated control (M4/7) is recognized to be defective, the actual values are displayed.

Additional function requirements for fuel quantity display
^ Circuit 15 On

Display of fuel quantity function sequence
The display of the fuel quantity consists of the following subfunctions:
^ Display of fuel quantity function sequence
^ Refueling detection function sequence with circuit 15 ON

Display of fuel quantity function sequence
The fill level measured via the fuel level indicator sensor (B4) is read in by the rear SAM control unit (N10/8) and transmitted to the instrument cluster via the interior CAN. The received values are evaluated with the aid of a tank characteristic and displayed in the fuel level and reserve indicator (A1p2) via a stepper motor.

If the reserve range has been reached (approx. 12.5 % of the maximum tank contents), the fuel reserve warning lamp (A1e4) comes on. When 50 % of the reserve value is reached, the distance to empty display also switches to the gasoline pump symbol in the left multifunction display.

Display behavior:
- Display with engine OFF: After circuit 15 ON, the current fill level is displayed. In the process the pointer runs up in a damped manner.
- Display with circuit 15 OFF: After circuit 15 OFF, the pointer gradually returns to zero.

Refueling detection function sequence with circuit 15 ON
"Refueling" is detected by comparing the current display value with the measured tank content.

When the difference between the two values is greater than the defined value (3 liters with circuit 15 OFF, 7 liters with circuit 15 ON), then "refueling" is detected. When the ignition is switched off, the fuel content is measured again and stored. When circuit 15 is switched back on, the display is updated and the pointer moves up accordingly.

Additional function requirements for travel distance display
^ Circuit 15 On

Display of travel distance function sequence
The function of the display of travel distance is comprised of several 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 wheel speeds determined by the rpm sensors are read in by the SBC hydraulic unit and forwarded to the ESP, SPS [PML] and BAS control unit. From here, the information reaches the instrument cluster via engine compartment CAN. The instrument cluster calculates the distance covered from the values received in combination with the tire size.
Tire size is coded using STAR DIAGNOSIS.

Display of main odometer reading function sequence
The display appears in the left multifunction display. The maximum displayed counter reading of the main odometer reading is 999.999. The display then resets to 000,000. However, the actual kilometer reading continues to be stored internally in the instrument cluster.

Display of trip distance function sequence
The display takes place in the right multifunction display (A1p15). The maximum displayed counter reading of the trip distance is 9999.9. If this value is achieved, the figure returns to zero. In contrast to the main odometer reading, the trip odometer is hidden if another vehicle function is active.

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 voltage supply is decoupled. The current reading of the trip odometer is likewise stored in the nonvolatile memory of the instrument cluster.
However the current counter reading is first transferred from the volatile memory to the nonvolatile memory after a circuit change from circuit 15 ON to circuit 15 OFF.

Additional function requirements for gear indicator
^ Circuit 15 On

Function sequence for gear indicator
The current gear is displayed to the left of the trip distance in the right multifunction display and the current transmission mode is displayed to the right.
The required data are transmitted by the full integrated transmission control unit (VGS) (Y3/8n4) via engine compartment CAN.

Additional function requirements for engine oil level indicator
^ Circuit 15 On

Engine oil level indicator function sequence
The engine oil level is monitored via the oil level check switch (S43). It is read in by the ME-SFI [ME] control unit. Where necessary, the ME-SFI [ME] control unit transmits a message to the instrument cluster via engine compartment CAN.

The instrument cluster then displays the following messages in the left multifunction display and right multifunction display:
- "Engine oil level"
"Stop; Engine off."
- "At refueling stop" "Check oil level"