SLK 230 (170.449) L4-2.3L SC (111.983) (2001)
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Air Flow Meter/Sensor: Description and Operation
GF07.07-P-4118-02GS Hot Film Mass Air Flow Sensor, Function
GF07.07-P-4118-02GS Hot Film Mass Air Flow Sensor, Function
The electronics in the hot film mass air flow sensor control the temperature of the heating resistor (RH) by means of a variable voltage so that its
temperature is 160 degrees C above the intake air temperature detected by the temperature resistor (RL).
The temperature of the thermistor is measured over the sensor resistance (RS).
Temperature changes which take place as a result of an increased or decreased flow of air regulate the electronics according to the voltage of the
thermistor until the temperature difference of 160 degrees C is again reached. This control voltage is used by the engine control unit as a measure for the
metered air mass.
The intake air temperature is measured by a further NTC resistance in the hot film mass air flow sensor.