Coolant Temperature

The engine coolant temperature sensor is connected to the control module. The coolant temperature sensor consists of an NTC resistor which is mounted in the cylinder block (4 cylinder) or in the coolant bridge (6 cylinder).

The control module is connected to the coolant temperature sensor with two leads. 1 V is fed from control module pin 34 and grounded on control module pin 27. The control module calculates engine temperature using the resistance in the resistor.

The control module uses this information to control the radiator fan (both steps 1 and 2 depending on the variant), disconnect the A/C compressor at high engine temperatures and control the coolant temperature sensor.

Control of the temperature display is in the control module, that is to say the break points in temperature display are programmed into the control module which feeds out a voltage on pin 30 in the range 1 - 9 V depending on the temperature display. The function of the temperature display is the same as the fuel level gauge display.

If the resistance in the resistor is under 66 Ohms or over 100 kOhms, a diagnostic trouble code is generated in the control module and the control module starts the radiator fan until the fault is remedied.