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Component description for the coolant temperature sensor - GF07.04-P-6043CY

WARNING: This page is about a different car, the 2011 Mercedes-Benz C300, 2010 Mercedes-Benz C300, 2009 Mercedes-Benz C300, and 2008 Mercedes-Benz C300. However, it is still accessible from the selected car via links, so may be relevant.

ENGINE 272.911 in MODEL 204.0 up to Model Year 2008 

ENGINE 272.921 in MODEL 204.0/2 up to Model Year 2008 

ENGINE 272.947 in MODEL 204.0/2 up to Model Year 2008 

ENGINE 272.948 in MODEL 204.0 up to Model Year 2008 

ENGINE 272.961 in MODEL 204.0/2 up to Model Year 2008 

ENGINE 272.971 in MODEL 204.0 up to Model Year 2008 

Location 

Fig 1: Locating Coolant Temperature Sensor
G07068107Courtesy of MERCEDES-BENZ USA

The temperature sensor is located at the rear on the left 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 connector. The housing bottom section which is inserted in the cylinder head is made out of metal.

IMPORTANT The connection assignment (polarity) of pin 1 and 2 is arbitrary.

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.

The signal voltage is plausible between 0.1 V to 4.93 V, otherwise a fault is identified and a substitute value taken by the ME-SFI [ME] control unit from a stored temperature model.

NTC means " egative emperature oefficient", which means: the electrical resistance reduces for an increasing temperature (NTC thermistor).

Example: 

Coolant temperature

20°C

80°C

Resistor

3090 Ω ± 5%

320 Ω ± 5%

IMPORTANT The NTC resistor is supplied with a 5 V voltage by the ME-SFI [ME] control unit via a series resistor with 14701%. Following a short-circuit to battery voltage or sensor voltage without series resistor, the temperature sensor is defective.