Avalon V6-3.0L (1MZ-FE) (1996)
Air Flow Meter/Sensor: Description and Operation
PURPOSE / 0PERATION
The hot wire air flow meter consists of a platinum hot wire, thermistor and a control circuit installed in a plastic housing. The hot wire airflow
meter works on the principle that the hot wire and thermistor located in the intake air bypass of the housing detect any changes in the intake air
temperature.
The hot wire is maintained at the set temperature by controlling the current flow through the hot wire. This current flow is then measured as the
output voltage of the airflow meter.
Mass Air Flow Meter Internal Circuit
The circuit is constructed so that the platinum hot wire and thermistor provide a bridge circuit, with the power transistor controlled so that the
potential of A and B remains equal to maintain the set temperature.