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

Model 217, 222 

Function requirements in general 

• Tml. 15 ON:

  The electronic ignition lock control unit (N73) sends the status of circuit 15 via user interface CAN (CAN HMI) 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 operating conditions function includes 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 
• Function sequence for display of fuel quantity/charge level (model 222.004/057/104/157/163/173) 
• Function sequence for gear display and transmission mode display 
• Function sequence for "ECO" display 
• Function sequence for displaying transport mode 

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 the information about the wheel speed over the suspension FlexRay (Flex E), the electronic ignition lock control unit and the user interface CAN to the instrument cluster. The instrument cluster calculates the current vehicle speed and displays it.

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) transmits information about engine speed via the engine CAN (CAN C), the drivetrain control unit (N127), the suspension FlexRay, the electronic ignition lock control unit and the user interface CAN to the instrument cluster. The instrument cluster receives the engine rpm value and then displays it.

The engine speed is not displayed permanently.

Display of coolant temperature function sequence 

The CDI control unit or ME-SFI control unit sends information on the coolant temperature to the instrument cluster via engine CAN, drivetrain control unit, suspension FlexRay, electronic ignition lock control unit and user interface CAN. The instrument cluster receives the value for the coolant temperature and then displays it.

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 displayed. The display is not shown until T ≥ 40°C.

T = 80 to 115°C:

The coolant temperature display is consistently actuated at a value of T = 90°C.

T = 115 to 120°C:

The coolant temperature display is consistently actuated at a value of T = 95°C.

T = 120 to 130°C (start of red warning area):

The actual coolant temperature is displayed.

At coolant temperatures of T > 130°C, the coolant temperature warning display is also shown and a warning message is issued via the instrument cluster. If the instrument cluster does not receive any value for the coolant temperature, it actuates the coolant temperature warning indicator. The coolant temperature display is not actuated.

Display of travel distance function sequence 

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

The Electronic Stability Program control unit sends the wheel speeds via the suspension FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster.

The travel distance can be set in the "Instrument cluster" submenu in the "Settings" menu to be permanently displayed.

The tire size is coded via the diagnostics tester.

The total distance indication is shown on the instrument cluster. The maximum displayed counter reading for the total distance is 1, 609344 for a kilometer reading (1, 000000 for a mileage reading), after this the display stops moving.

The trip distance is shown on the instrument cluster. 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.

Function sequence for display of fuel quantity/charge level (model 222.004/057/104/157/163/173) 

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 fuel system control unit (N118) reads in the signals of the fuel tank fuel level indicator fill level sensors and sends them over the drive train CAN (CAN C1), powertrain control unit, suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the instrument cluster. The instrument cluster receives the signals from the fuel tank fill level sensor fuel level indicator, evaluates them and displays the tank capacity as a percentage. If the reserve range has been reached (approx. 12.5 % of maximum tank capacity), the fuel reserve warning lamp lights up and the instrument cluster issues an additional message.

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.

When half the fuel reserve has been reached, the percentage is no longer displayed and a only a filling station symbol is shown in the form of a gasoline pump in the center. When the fuel reserve is reached the filling station symbol is shown in the form of a gasoline pump (yellow) and a warning message is issued.

Display characteristics of fuel level indicator:

• After switching on circuit 15, the current fill level is displayed. The fuel level indicator's pointer runs up in a buffered manner here.
• 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.

Possible jamming of the fuel tank's fill level sensor for the fuel level indicator is detected by comparing the change in fill level of the fuel tank with the calculated composite mileage. If the fill level drops faster over a specific distance than is technically feasible based on the composite mileage, the fuel tank's fill level sensor for the fuel level indicator is deemed to be defective and a corresponding message issued on the instrument cluster.

Charge level (model 222.004/057/104/157/163/173) 

Information on the charge level of the high-voltage battery (A100g1) is sent by the battery management system control unit (N82/2) via the hybrid CAN (CAN L), powertrain control unit, suspension FlexRay, electronic ignition lock control unit and user interface CAN to the instrument cluster. The instrument cluster receives these messages, evaluates them and displays the charge level accordingly.

Function sequence for gear display and transmission mode display 

The gear indicator and transmission mode display are shown on the instrument cluster. Information on the gear indicator and transmission mode display is sent by the fully integrated transmission control unit (Y3/8n4) over the drive train CAN, powertrain control unit, suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the instrument cluster.

Function sequence for "ECO" display 

Automatic engine start/stop is activated automatically after each ignition change and can be deactivated or reactivated using the touchpad (A105) (as of 01.06.2017 (model 222) or 01.12.2017 (model 217) with code 446 (Touchpad only) or code 448 (Touchpad)) or using the Audio/COMAND control panel (A40/9) (up to 31.05.2017 (model 222) or 30.11.2017 (model 217) and as of 01.06.2017 (model 222) or 01.12.2017 (model 217) with code 448 (Touchpad)).

The status of the ECO start/stop function is transmitted by the touchpad (as of 01.06.2017 (model 222) or 01.12.2017 (model 217) with code 446 (Touchpad only) or code 448 (Touchpad)) or by the Audio/COMAND control panel (up to 31.05.2017 (model 222) or 30.11.2017 (model 217) and as of 01.06.2017 (model 222) or 01.12.2017 (model 217) with code 448 (Touchpad)) to the CDI control unit or ME-SFI control unit via the telematics CAN (CAN A), head unit (A26/17) (as of 01.06.2017 (model 222) or 01.12.2017 (model 217)) or COMAND controller unit (A40/3) (up to 31.05.2017 (model 222) or 30.11.2017 (model 217)), user interface CAN, electronic ignition lock control unit, suspension FlexRay, powertrain control unit and engine CAN.

If the function requirements are fulfilled, the driver is notified of the automatic engine start/stop readiness by the "ECO" symbol in the instrument cluster. The request for this is sent by the CDI control unit or the ME-SFI [ME] control unit over the engine CAN, powertrain control unit, suspension FlexRay, electronic ignition lock control unit and the user interface CAN to the instrument cluster.

Function sequence for displaying transport mode 

The transport mode brings the vehicle into a precisely defined condition. This allows only for restricted use of the vehicle during transport (e.g. limited vehicle speed and limited exterior light functions) and serves to protect the on-board electrical system battery. The transport mode is activated at the factory before loading of the vehicle, remains active during delivery and is deactivated again by the dealer before handover to the end customer. In active transport mode, the message "Transport mode" and the charge condition of the on-board electrical system battery are shown in the instrument cluster in the form of a bar graph with 40 stages.

Detailed information on transport mode is available in a separate document.

	Electrical function schematic of instrument cluster, operating condition display		PE54.30-P-2055-97SEA
	Overview of system components, instrument cluster (IC) component description	Model 217, 222 up to model year 2018	GF54.30-P-9996LF
		Model 217, 222 as of model year 2018	GF54.30-P-9996LFM