Coolant Temperature Sensor/Switch (For Computer): Description and Operation

GF07.04-P-6040MAR Coolant Temperature Sensor, Component Description
- refinement package
- as of model year 09

Component Identification:

Location
The temperature sensor is located at the front of the RH cylinder head.

Task
The temperature sensor detects the coolant temperature and transmits a corresponding voltage signal to the ME-SFI [ME] control unit (N3/10).

Design
The temperature sensor consists of a very rapidly responding NTC resistor and a 2-pin plug connection. The bottom part of the housing which is plugged in the cylinder head consists of metal.

NTC
NTC means " Negative Temperature Coefficient", which means: the electrical resistance reduces for an increasing temperature (NTC thermistor).

Function
The NTC resistor integrated in the temperature sensor alters its electrical resistance in line with the coolant temperature. The ME-SFI [ME] control unit applies a sensor voltage of 5 V and evaluates the signal voltage in accordance with the coolant temperature.

Example:
Coolant temperature Resistance value Signal voltage
20 °C 3123 ohms 0.312 V
60 °C 632 ohms 0.063 V
120 °C 101 ohms 0.010 V