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

MODEL 166 up to model year 2016 

Function requirements, general 

• Terminal 15 ON

The electronic ignition lock control unit (N73) sends the status of circuit 15 over chassis CAN 2 (CAN E2) 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 comprises 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 
• Function sequence for gear display and transmission mode display 
• Function sequence for "ECO" display (with CODE B03 (ECO start/stop function)) 
• Function sequence for displaying transport mode (as of 01.07.2012) 

Display of speed function sequence 

The vehicle speed is calculated on the basis of the wheel speeds.

The Electronic Stability Program control unit (N30/4) transmits information about the wheel speeds via chassis CAN 1 (CAN E1), electronic ignition lock control unit and chassis CAN 2 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.

Display of engine speed function sequence 

The CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) sends information about engine rpm over the chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster. The instrument cluster receives this information and actuates the tachometer (A1p5) accordingly through a stepper motor.

Display of coolant temperature function sequence 

The CDI control unit or the ME-SFI control unit transmits information about coolant temperature via chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 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 = 40 up to 80 °C: The coolant temperature gauge displays the actual coolant temperature.
• T = 80 to 115 °C: The coolant temperature gauge constantly shows a value of T = 90 °C.
• T = 115 to 120 °C: The coolant temperature gauge constantly shows a value of T = 95 °C.
• T = 120 to 130 °C (start of red warning range): The coolant temperature gauge shows the actual coolant temperature.

At coolant temperatures of T > 130 °C the instrument cluster actuates the coolant temperature warning lamp (A1e54). A corresponding message is shown in the instrument cluster's multifunction display (A1p13). 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.

If a fan motor (M4/7) is detected to be faulty, the actual coolant temperature is displayed. The coolant temperature warning lamp is also actuated.

Display of travel distance function sequence 

The instrument cluster calculates the traveled distance from the wheel speeds, taking the tire circumference into consideration.

The Electronic Stability Program control unit sends information on the wheel speeds over the chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster.

The tire size is coded via the diagnostics tester.

The total distance is shown on the instrument cluster's multifunction display. The maximum displayed counter reading of the main odometer reading is 9.999.999. The display then overflows to 0. However, the actual kilometer reading continues to be stored internally in the instrument cluster.

The trip distance is shown on the instrument cluster's multifunction display. The maximum displayed counter reading of the trip distance is 9999.9. If this value is reached, the figure returns to 0.

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 distance 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 tank fill level indicator sensor (B4/1) and the right fuel tank fill level indicator sensor (B4/2). The SAM control unit (N10) reads in the signals of the fuel display for the fuel level sensors and sends them over the interior CAN (CAN B) to the instrument cluster. The instrument cluster receives the signals for the fuel tank fill level sensors, evaluates 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 in the instrument cluster's 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 gradually moves back.

By comparing the change in the fill level of the fuel tank against the calculated composite mileage, it is possible to determine when the fuel level indicator fill level sensors have jammed. If the fill level over a certain distance drops more quickly than technically feasible based on composite mileage, the fill level sensor is recognized as being jammed, and the corresponding message is shown in the instrument cluster's multifunction display.

Function sequence for gear display and transmission mode display 

Information on the engaged gear is shown on the gear indicator (A1p12).

Transmission mode information is shown in the transmission mode display (A1p16).

Gear indicator:

The fully integrated transmission control unit (Y3/8n4) sends information on the engaged gear range over the drive train CAN (CAN C), CDI control unit or the ME-SFI [ME] control unit, chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster. The instrument cluster receives this and actuates the gear indicator accordingly.

Transmission mode display:

The fully integrated transmission control unit sends information on the selected transmission mode over the drive train CAN, CDI control unit or the ME-SFI [ME] control unit, chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster. The instrument cluster receives this and actuates the transmission mode display accordingly.

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 upper control panel control unit reads in the status of the ECO start/stop function button directly and sends this over the battery sensor LIN (LIN B15), SAM control unit, interior CAN, electronic ignition lock control unit and chassis CAN 1 to the CDI control unit or the ME-SFI [ME] control unit. The CDI control unit or the ME-SFI [ME] control unit checks all the function requirements and sends the status of the automatic engine start/stop over chassis CAN 1, electronic ignition lock control unit and chassis CAN 2 to the instrument cluster. The readiness of the automatic start/stop engine function is displayed for the driver on the instrument cluster's multifunction display with the symbol "ECO".

If, when in driving mode, the CDI control unit or the ME-SFI [ME] control unit determines on account of the currently applied parameters, that it is possible to automatically stop the engine, although a neutral gear has not been engaged, the gearshift recommendation "→ N" is shown on the instrument cluster's multifunction display.

Function sequence for transport mode (as of 01.07.2012) 

Transport mode is activated at the factory at the end of the product process and sets the entire vehicle to a defined special state (e.g. limited vehicle speed or restricted outside lamp 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 transport mode is active, the message "Transport mode" and the charge level of the on-board electrical system battery are shown in the multifunction display of the instrument cluster in the form of a bar graph with 40 segments.

Detailed information on the operating state of the transport mode is given in the separate function description "Energy management function".

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