GF54.30-P-3041LE Display Operating Conditions, Function
GF54.30-P-3041LE Display Operating Conditions, Function
General function requirements
^ Circuit 15 On
The EIS [EZS] control unit provides the circuit status of circuit 15N73 on the chassis CAN. The central gateway control unit (N93) passes this on via the central CAN to the instrument cluster (A1).
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, display of vehicle speed
^ Display of engine speed function sequence
^ Display of coolant temperature function sequence
^ Display of fuel quantity function sequence
^ function sequence - display of travel distance
^ Function sequence, gear display and transmission mode display
Additional function requirements - display of vehicle speed
^ Vehicle speed v > 0 km/h
Function sequence, display of vehicle speed
The ESP control unit (N47-5) reads in the signals from the left front rpm sensor (L6/1), right front rpm sensor (L6/2), left rear rpm sensor (L6/3) and the right rear rpm sensor (L6/4) directly and transmits these on the chassis CAN.
The central gateway control unit passes these signals on to the instrument cluster via the central CAN. The instrument cluster receives the signals from the rpm sensor, calculates the current vehicle speed and actuates the electronic speedometer (A1p8) via a stepper motor.
In addition a digital speedometer can be displayed in the "Trip" menu. On vehicles with code (833) Great Britain version the vehicle speed is displayed digitally and permanently in the multifunction display (A1p13).
Additional function requirements - function sequence - display of engine speed
^ Circuit 61 ON
Function sequence - display of motor speed
The engine speed is recorded by the crankshaft Hall sensor (B70) (on engine 156, 272, 273, 629 and 642) or by the crankshaft position sensor (L5) (on engine 275). The CDI control unit (N3/9) (on diesel engine) or motor electronics control unit (N3/10) (on gasoline engine) reads in the signals from the crankshaft Hall sensor or from the crankshaft position sensor, calculates the engine speed from this and transmits a corresponding value on the chassis CAN. The central gateway control unit passes this on via the central CAN to the instrument cluster. The instrument cluster receives the value for the engine speed and actuates the tachometer (A1p5) accordingly via a stepper motor.
Function sequence - display of coolant temperature
Coolant temperatures are monitored by the coolant temperature sensor (B11/4). The CDI control unit or the motor electronics control unit reads in the signal from the coolant temperature sensor, calculates the coolant temperature from this and transmits a corresponding value on the chassis CAN. The central gateway control unit passes this on via the central CAN to the instrument cluster. The instrument cluster receives the value for coolant temperature and actuates the coolant temperature display (A1p1) accordingly.
Function sequence - fuel quantity display
The fuel level indicator sensor, left tank half (B4/1) and fuel level indicator sensor, right tank half (B4/2) record the fill level of the fuel tank. The rear SAM control unit with fuse and relay module (N10/2) reads in the signals from the fuel level indicator sensor and transmits these on the interior CAN. The central gateway control unit passes these signals on to the instrument cluster via the central CAN.
The instrument cluster receives these signals, evaluates them and actuates the fuel level and reserve indicator (A1p2) accordingly via a stepper motor.
When the reserve range is reached, the instrument cluster actuates the fuel reserve warning lamp (A1e4). The reserve range is defined by a comparison of the measured fill level with a stored tank characteristic.
If the reserve range has fallen to approx. 50 %, a gas station symbol in the form of a gasoline pump is represented in the range menu in place of the mileage detail.
Display characteristics of fuel level indicator:
- The current fill level is displayed after circuit 15 is switched on. In the process, the pointer runs up without being buffered.
- While the vehicle is driving, the display is updated via a buffering system.
- After switching off circuit 15 the needle of the fuel level and reserve indicator is moved back to zero.
Sticking of the fuel level indicator sensor is detected by the comparison of the change in fill level of the fuel tank with the calculated average fuel consumption. If over a certain stretch of road the fill level decreases to a greater extent than is technically possible through the average fuel consumption, a defective fuel level indicator sensor is detected and a corresponding message is output in the multifunction display.
Function sequence - display of travel distance
The travel distance display function is made up of the following partial functions:
^ 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 instrument cluster calculates the travel distance covered from the signals received from the rpm sensors taking into account the tire circumference.
Tire size is coded using STAR DIAGNOSIS.
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 reading is 999,999. An overflow to zero takes place afterwards. However, the actual kilometer reading continues to be stored internally in the instrument cluster.
Display of trip distance function sequence
The trip distance display is shown in the multifunction display. The maximum displayed counter reading of the trip distance is 9999,9. If this value is achieved, the figure returns to zero.
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 also guarantees the retention of the counter reading for at least five years when the battery (G1) is disconnected. The current reading of the trip odometer is likewise stored in the nonvolatile memory of the instrument cluster.
Function sequence, gear display and transmission mode display
The data required for the gear indicator are transmitted by the ETC [EGS] control unit (N15/3) (on transmission 722.6) or the fully integrated transmission control unit (VGS) (Y3/8n4) (on transmission 722.9) on the drive train CAN.
The intelligent servo module for DIRECT SELECT (A80) likewise makes available the information for the transmission mode on the drive train CAN. The CDI control unit or the motor electronics control unit relay the information to the central gateway control unit via the chassis CAN. The central gateway control unit passes the information on to the instrument cluster via the central CAN. The current gear and the current transmission mode are shown via the gear indicator (A1p12) in the multifunction display.
