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

GF07.04-P-6040MLK 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 cylinder crankcase, under the electric air pump (M33).

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 housing lower section is made of metal and is plugged into the cylinder crankcase.

Function

Component Identification:

The NTC resistor integrated in the coolant 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 Resistor
20 °C 3090 ohms ±5%
80 °C 320 ohms ±5%

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