GF54.30-P-3020GZ Display Coolant Temperature, Function

GF54.30-P-3020GZ Display Coolant Temperature, Function

Component Identification:

The coolant temperature sensor is an NTC resistor, this changes its resistance value depending on coolant temperature. The resistance value reduces as the temperature increases.
The coolant temperature sensor is read in by the ME-SFI [ME] control unit or by the CDI control unit and transmitted to the instrument cluster via the CAN C.
The instrument cluster receives these signals and actuates the coolant temperature display in the multifunction display.

The display takes place in the form of a bar graph display digitally in the upper display of the multifunction display.
The coolant temperature display is actuated via a so-called plateau characteristic, in other words the temperature display in the instrument cluster remains at 95 degrees Celsius, when the real temperature remains within a range of 95 and 115 degrees Celsius.

This characteristic was introduced in order to compensate the permanently changing coolant temperatures, so that driver is not disturbed by a fluctuating temperature display. All the real temperatures are displayed again above 120 degrees Celsius.

Problems
If the signal of a defective engine fan is placed on CAN C by the ME-SFI [ME] control unit or the CDI control unit, then the instrument cluster actuates the coolant temperature display without the plateau characteristic. The real temperatures are then displayed in this case.
If the instrument cluster receives an implausible or even no coolant temperature from the ME-SFI [ME] control unit or CDI control unit, then the smallest display value is actuated.

Warnings
The red warning range encompasses all temperature as of 120 degrees Celsius. As of this temperature value the bar graph display is represented filled out to the full extent.

As of coolant temperatures of 130 degrees Celsius and higher, in addition the red stored warning note "Coolant, stop, engine Off" is displayed in the multifunction display.