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

MODEL 218 

Function requirements, general 

• Terminal 15 ON

The electronic ignition lock control unit (N73) sends the circuit status of circuit 15 over the interior CAN (CAN B) 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" indicator (with code (B03) ECO start/stop function) (except with engine 157) 
• Function sequence for transport mode indicator (model 218.3 as of 01.06.2012, model 218.9) 

Display of speed function sequence 

The vehicle speed is calculated from the wheel speed.

The Electronic Stability Program control unit (N30/4) (without code (233) DISTRONIC PLUS, or without engine 157) or the Premium Electronic Stability Program control unit (N30/7) (with code (233) DISTRONIC PLUS or with engine 157) sends information on the wheel speed to the instrument cluster via chassis CAN (CAN E) up to 28.02.2013, or to the instrument cluster via chassis CAN 1 (CAN E1), the front SAM control unit with fuse and relay module (N10/1) and chassis CAN 2 (CAN E2) as of 01.03.2013.

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 control unit (N3/10) (with gasoline engine) sends information about engine rpm to the instrument cluster over the chassis CAN up to 28.02.2013, or over chassis CAN 1, front SAM control unit and chassis CAN 2 as of 01.03.2013.

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 CDI control unit or the ME-SFI control unit sends information on coolant temperature up to 28.02.2013 via the chassis CAN to the instrument cluster or as of 01.03.2013 via chassis CAN 1, the front SAM 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 to 80 °C: The coolant temperature gauge shows 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 also displays the coolant temperature warning lamp (A1e54). A corresponding warning is shown in the multifunction display (A1p13) of the instrument cluster. 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.

When a faulty combustion engine and air conditioning fan motor with integrated control (M4/7) is detected, the actual coolant temperature is displayed in the coolant temperature gauge. The coolant temperature warning lamp is also 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 information on wheel speed up to 28.02.2013 via the chassis CAN to the instrument cluster or as of 01.03.2013 to the instrument cluster via chassis CAN 1, the front SAM control unit and chassis CAN 2.

The tire size is coded via the diagnostics tester.

The total distance is displayed in the multifunction display of the instrument cluster. The maximum displayed total distance counter reading is 1, 000, 000 miles or 1, 609, 300 km.

It does not overrun to "0" and it does not continue to count internally.

The trip distance is displayed in the multifunction display of 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.

Display of fuel quantity function sequence 

The left fuel level indicator fuel tank fill level sensor (B4/1) and right fuel level indicator fuel tank fill level sensor (B4/2) detect 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 tank fill level sensors directly and sends them via the interior CAN 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 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.

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 tank 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 

The information on the engaged gear and on the selected transmission mode are displayed in the multifunction display of the instrument cluster.

Gear indicator (except with engine 157):

The intelligent servo module for DIRECT SELECT (A80) sends information on the engaged gear range via drive train CAN (CAN C), CDI control unit or ME-SFI control unit and up to 28.02.2013 to the instrument cluster via chassis CAN or up to 01.03.2013 to the instrument cluster via chassis CAN 1, front SAM control unit and chassis CAN 2.

Transmission mode display (except with engine 157):

The fully integrated transmission control unit (Y3/8n4) sends information on the engaged transmission mode via drive train CAN, CDI control unit or ME-SFI control unit and up to 28.02.2013 to the instrument cluster via chassis CAN or as of 01.03.2013 to the instrument cluster via chassis CAN 1, front SAM control unit and chassis CAN 2.

On vehicles with engine 157, the transmission mode control unit (N145) sends the information to the instrument cluster via the chassis CAN (up to 28.02.2013) or via chassis CAN 2 as of 01.03.2013.

Function sequence for "ECO" indicator (with code (B03) ECO start/stop function) (except with engine 157) 

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 directly reads in the status of the ECO start/stop function button and sends it via instrument panel LIN (LIN 1), front SAM control unit and up to 28.02.2013 via chassis CAN or as of 01.03.2013 via chassis CAN 1 to the CDI control unit or ME-SFI control unit. The CDI control unit or the ME-SFI control unit checks all the function requirements and sends the status of the automatic engine start/stop up to 28.02.2013 via chassis CAN to the instrument cluster or as of 01.03.2013 via chassis CAN 1, the front SAM control unit and chassis CAN 2 to the instrument cluster. The operational readiness of the automatic engine start/stop is displayed for the driver on the multifunction display of the instrument cluster with the symbol "ECO".

If the CDI control unit or ME-SFI control unit establishes in driving mode by means of the currently applied parameters that it is possible for the engine to stop automatically but neutral was not engaged, the gearshift recommendation "→ N" is output in the multifunction display.

Function sequence for transport mode indicator (model 218.3 as of 01.06.2012, model 218.9) 

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.

In active transport mode, the message "Transport mode" and the charge condition of the on-board electrical system battery are shown in the multifunction display in the form of a bar graph with 40 stages.

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	MODEL 218 up to model year 2014	PE54.30-P-2055-97XAA
	MODEL 218 as of model year 2014	PE54.30-P-2055-97XAB
Overview of system components, instrument cluster (IC) component description		GF54.30-P-9996FQ