Display operating conditions, function - GF54.30-P-3041CE

MODEL 204.0/2 as of model year 2009 

/YoM 08 

MODEL 204.3 

MODEL 204.9 

Function requirements, general 

• Circuit 15R ON

The circuit 15 status is sent by the electronic ignition lock control unit (N73) over the chassis CAN (CAN E) and interior CAN (CAN B).

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 comprises the following subfunctions:

• Function sequence for vehicle speed display 
• 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 and transmission mode display function sequence (with transmission 722) 
• Function sequence for "ECO" display 

  (with model 204.0/2 as of 1.6.10 with code (B03) ECO start/stop function, with model 204.9 as of 1.12.10 with code (B03) ECO start/stop function) 

• Function sequence for offroad displays (on model 204.9 with code (430) Offroad package) 

Additional function requirements for vehicle speed display 

• Vehicle speed v > 0 km/h

Function sequence for vehicle speed display 

The Electronic Stability Program control unit (N30/4) reads in the signals of the left front axle RPM sensor (L6/1), right front axle RPM sensor (L6/2), left rear axle RPM sensor (L6/3) and the right rear axle RPM sensor (L6/4) directly and sends them over the chassis CAN to the instrument cluster (A1). The instrument cluster receives the signals for the RPM sensors, calculates the current vehicle speed and then actuates the speedometer (A1p8) to match by means of a stepper motor.

Additional function requirements for display of engine speed 

• Circuit 61 ON or "PT_Rdy" (drivetrain ready) signal set (sent by CDI control unit (N3/9) (with diesel engine) or by ME-SFI [ME] control unit (N3/10) (with gasoline engine) over chassis CAN)

Display of engine speed function sequence 

The engine RPM is recorded by the crankshaft position sensor (L5) (on engine 271, 646, 651) or by the crankshaft Hall sensor (B70) (on engine 156, 272, 642). The CDI control unit or the ME-SFI [ME] control unit reads in the signals for the crankshaft position sensor or the crankshaft Hall sensor, uses them to calculate the engine speed and then sends a corresponding value over the engine compartment 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 T40 ≥°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.

At coolant temperatures of T > 130°C the coolant temperature warning lamp (A1e54) is also actuated and a warning message issued via the travel distance display (A1p7) (model 204.0/2/3/9 (except 204.077/277/375) without code (442) Comfort multifunction steering wheel) or the multifunction display (A1p13) (for code (442) Comfort multifunction steering wheel, model 204.077/277/375)

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 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 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 also shown on the travel distance display or 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 over a specific distance drops faster that is technically feasible with the composite mileage, the fuel level indicator sensor is deemed to be faulty and a corresponding message issued on the travel distance display or the multifunction display.

Display of travel distance function sequence 

The travel distance display function is made up of 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.

Display of main odometer reading function sequence 

The total distance is shown on the travel distance display or the multifunction display. The maximum displayed counter reading of the main odometer reading is 999, 999 km or miles. This is followed by an overflow to 0. The actual kilometer reading however continues to be counted internally in the instrument cluster.

Display of trip distance function sequence 

The trip distance is shown on the travel distance display or the multifunction display.

The maximum displayed counter reading for the trip distance is 9999, 9 km or miles.

The display then overflows to 0.

Pressing the OK (S110s6) button in the left multi function steering wheel button group (S110) enables the counter reading for the trip distance to be reset to 0.

If the unit for the trip distance is changed at a value that lies between 6213.7 and 9999.9 (e.g. from km to miles), the trip odometer is automatically reset to 0. This reset cannot be revoked when the unit is changed again.

Function sequence, storing of counter readings 

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.

Gear and transmission mode display function sequence (with transmission 722) 

The data required for gear indicator is sent by the electronic selector lever module control unit(N15/5) over the drive train CAN (CAN C). The CDI control unit or ME-SFI [ME] control unit forward the data to the instrument cluster over the chassis CAN. The instrument cluster receives all the relevant information and displays this on the gear indicator (A1p12) (model 204.0/2/3/9 (except 204.077/277/375) without code (442) Comfort multifunction steering wheel) or the multifunction display (with code (442) Comfort multifunction steering wheel, model 204.077/277/375).

Function sequence for "ECO" display 

(with model 204.0/2 as of 1.6.10 with code (B03) ECO start/stop function, with model 204.9 as of 1.12.10 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 ECO start/stop function button is read-in by the UCP control unit, and forwarded over the instrument panel LIN (LIN 1) to the front SAM control unit.

The front SAM control unit sends the status over the chassis CAN to the ME-SFI [ME] control unit. When the function requirements are met the readiness for operation of the engine start/stop-automatic is shown to the driver by the "ECO" symbol in the travel distance display or in the multifunction display of the instrument cluster.

The request for this is sent by the ME-SFI [ME] control unit over the chassis CAN to the instrument cluster.

If while driving the ME-SFI control unit determines by means of the currently prevailing parameters, that it is possible for the engine is possible automatically, but no neutral has been engaged, the gearshift recommendation "→ N" is output in the travel distance display or in the multifunction display.

Function sequence for offroad displays (on model 204.9 with code (430) Offroad package) 

Pressing the offroad program button (N72/1s25) or the Downhill Speed Regulation button (N72/1s24) enables various offroad functions to be switched on and off. The current status for these functions is shown in the travel distance display or in the multifunction display.

The information required for this is sent by the front SAM control unit with fuse and relay module (N10/1) over the interior CAN. The corresponding status of the offroad program button or the Downhill Speed Regulation button is read in by the front SAM control unit over the instrument panel LIN.

	Electrical function schematic of instrument cluster, operating condition display		PE54.30-P-2055-97FAB
	Overview of system components, instrument cluster (IC) component description		GF54.30-P-9996CE