E 320 BLUETEC (211.022) V6-3.0L DSL Turbo (642.920) (2007)
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Air Flow Meter/Sensor: Description and Operation
GF07.07-P-6000P Component Description For The Hot Film Mass Air Flow Sensor
Location
The left and right hot film MAF sensors are located on the intake pipe behind the respective air filter.
Task
The hot film MAF sensor detects the sucked in air mass and the integrated intake air temperature sensor (B2/6b1) and intake air temperature sensor
(B2/7b1) detect the intake air temperature.
Function
The electronics in the hot film MAF sensors regulate the constant specified temperature (approx. 160 °C) of the respective heating resistor via a variable
voltage. The temperature of the heating resistor is detected via a sensor resistor.
If a temperature change occurs as a result of increased or reduced air flow, the integrated electronics corrects voltage at the heating resistor until the
specified temperature is achieved again. This control current is converted by the hot film MAF sensors into a sensor voltage. The sensor voltage is used
by the CDI control unit (N3/9) as a measurement for the sucked in air mass.
The intake air temperature is detected via the integrated measuring resistor with negative temperature coefficients (NTC) and transmitted to the CDI
control unit as a voltage signal.
