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

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

General function requirements
^ Circuit 15 On

Terminal status c. 15 is provided by the EIS control unit (N73) to the interior CAN.

Display operating conditions, general
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:
^ Function sequence for vehicle speed display
^ Display of engine speed function sequence
^ Display of coolant temperature function sequence
^ Display of fuel quantity function sequence
^ Function sequence of display of travel distance
^ Function sequence, gear display and transmission mode display
^ Function sequence for transfer case control messages (with model 164 with code (430) Off-road package)

Function sequence for vehicle speed display
The signals from 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), which define the wheel speeds for all four wheels, are read- in by the ESP control unit (N47-5) and sent over the engine compartment CAN to the instrument cluster (A1). The instrument cluster uses the received signals to calculate the current vehicle speed signals and actuates the electronic speedometer (A1p8) through a stepper motor.

The instrument cluster sends the calculated vehicle speed to other control units over both the interior CAN and the engine compartment CAN

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

Function sequence of display of motor speed
The engine speed is recorded by the camshaft Hall sensor (B70). The signals of the camshaft Hall sensor are read in by the CDI control unit (N3/9) (with diesel engine) or by the ME-SFI [ME] control unit (N3/10) (with gasoline engine) and sent over the engine compartment CAN to the instrument cluster.
The instrument cluster actuates the tachometer (A1p5) accordingly through a stepper motor.

Function sequence of display of coolant temperature
Coolant temperatures are monitored by the coolant temperature sensor (B11/4). The signal of the coolant temperature sensor is read-in by the CDI control unit or by the ME-SFI [ME] control unit and sent over the engine compartment-CAN to the instrument cluster.
The coolant temperature is shown in the upper area of the multifunction display (A1p13).
The coolant temperature display is actuated by a characteristic curve. This correction characteristic defines four temperature ranges in which the coolant temperature is displayed as follows:
- T = 0 to 95 °C
The actual temperature is shown.
However, display first takes place as of T = 40 °C.
- T = 95 to 115 °C
A constant value of T = 95 °C is shown.
- T = 115 to 120 °C
The gap in the displayed temperature to the actual coolant temperature is closed.
- T = 120 °C to 130 °C (start of red warning range)
The actual temperature is displayed.

At coolant temperatures of T > 130 °C a warning message is output in the instrument cluster. If the engine and air conditioning electric suction fan with integrated control (M4/7) is recognized to be defective, the actual values are displayed. In parallel with this a warning is output in the multifunction display. If the instrument cluster does not receive a coolant temperature or receives a faulty value, then the minimum value of T = 40 °C is shown in the coolant temperature display.

Function sequence for fuel quantity display
The fill level as measured by the left tank half fuel level indicator sensor (B4/1) and right tank half fuel level indicator sensor (B4/2) is read-in by the rear SAM control unit (N10/8).

The rear SAM control unit sends this over the interior CAN to the instrument cluster. The instrument cluster evaluates the received data with the aid of a tank characteristic and then actuates the fuel level and reserve indicator (A1p2) through 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).
If the tank reserve drops to approx. 50 %, then a fuel station symbol in the form of a gasoline pump is shown in the multifunction display.

Display characteristics of fuel level indicator:
- 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 after engine start
The display value is updated every t = 0.8 s for t = 4 s, to obtain a value under full on-board voltage. After this time, or as soon as the vehicle starts off, the display is updated with a delay.
- Display with circuit 15 OFF
After circuit 15 OFF, the pointer of the fuel level indicator gradually returns to zero.

Function sequence of display of travel distance
The travel distance display function is made up of the following subfunctions:
^ Function sequence, determination of travel distance
^ Function sequence, display of main odometer reading
^ Function sequence, display of trip distance
^ Function sequence, security of counter readings

Determination of travel distance function sequence
The signals of the rpm sensor are read in by the ESP control unit and sent over the engine compartment CAN to the instrument cluster. The instrument cluster calculates the travel distance from the received signals.

Function sequence, display of main odometer reading
The main odometer reading display is shown in the multifunction display. The maximum displayed counter reading of the main odometer (in km) is 999,999.
No overflow to zero occurs once the maximum counter reading is reached. An internal counter continues operating up to a maximum value of 1.677.721 km. The internal processing generally takes place in km, a conversion taking place for a display in miles.

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 km or miles. If this value is reached, an overflow to zero occurs. The counter reading of the (A1s3) trip distance can be reset manually to zero by pressing the trip odometer reset button for t > 2 s..

Function sequence, storing of counter readings
When the battery is disconnected the main odometer reading remains stored G1) for at least five years. The trip distance is likewise protected against data loss when the battery is disconnected.

Function sequence, gear display and transmission mode display
The current gear and the current transmission mode are shown in the multifunction display.
The required data are sent by the fully integrated transmission control unit (VGS) (Y3/8n4) and the intelligent servo module for DIRECT SELECT (A80) over the engine compartment CAN to the instrument cluster.

Function sequence for transfer case control messages
For vehicles with code (430) Off-road package a permanent all-wheel drive with two lockable differentials (transfer case and rear axle) is used. The two differentials are actuated by the transfer case control unit (N15/7) and the rear axle differential lock control unit (N15/9). The driver can use the Low Range switch (N72s31) to switch between the "High" on-road ratio and the "Low" low- range gearbox.
The differential lock selector wheel (N72s34) can be used to operate or adjust the differential locks in the transfer case and the rear axle. The downhill speed regulation can be switched on and off using the Downhill Speed Regulation switch (N72s30 ). The corresponding control switches are installed in the lower control panel control unit (N72). The corresponding request is read-in by the upper control panel control unit (N72/1) over the instrument panel LIN and sent to the interior CAN.
The actual adjustment of the differential locks is shown in the multifunction display.