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Coolant temperature

Coolant temperature

The coolant temperature gauge gives the driver information regarding the engine coolant temperature.

The main instrument unit receives information from the temperature sensor located in the left-hand end of the cylinder head, in contact with engine coolant. The sensor is of the NTC type. The MIU measures the coolant temperature by supplying 5 V to an integral 680 Ohm resistor from pin 15 (K22). The sensor is grounded via pin 7 (K22) of the MIU. The voltage across the resistor in the MIU is proportional to the temperature of the coolant. The MIU sends out the current coolant temperature over the bus, thereby making it available to the DICE.

DICE uses the coolant temperature to control operation of the radiator fan.

The coolant temperature gauge scale is divided into 5 fixed points. The main instrument unit is programmed to guide the gauge needle to the fixed points at the specified temperatures in order to give stable indication at normal coolant temperatures.

The following fixed points are programmed in the main instrument unit (factory setting):



Gauge needle:

Coolant temperature

- in the "blue" range

30°C (fixed value)

- out of "blue" range

50°C

- in "horizontal" position

80°C

- out of "horizontal" position

115°C

- in "red" range

129°C

- out of "red" range

133°C (fixed value)



Diagnosis

For diagnosis see group 3, “Main instrument unit MIU“.