Air Flow Meter/Sensor: Description and Operation

GF07.07-P-6000P Component Description For the Hot Film Mass Air Flow Sensor
ENGINE 642 in MODEL 164.1 /8, 203.0 /2, 221.0 /1, 251.0 /1 up to Model Year 2008
ENGINE 642 in MODEL 209.3 /4, 211.0 /2 /6, 219.3
ENGINE 642 in MODEL 463 up to 31.5.12





Shown except code (494) USA version

B2/6 Left hot film MAF sensor
B2/7 Right hot film MAF 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. The left and right hot film MAF sensors are located on the intake 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.