Air Flow Meter/Sensor: Testing and Inspection
MASS AIR FLOW (MAP) SENSOR AND INTAKE AIR TEMPERATURE (IAT) SENSORThis hot film type air flow sensor is composed of a hot film sensor, housing, metering duct (hybrid, sensor element). Mass air flow rate is measured by detection of heat transfer from a hot film probe because the change of the mass air flow rate causes change in the amount of heat being transferred from the hot film probe surface to the air flow. The air flow sensor generates a pulse so it repeatedly opens and closes between the 5 V voltage supplied from the engine control module. This results in the change of the temperature of the hat film probe and in the change of resistance.
Circuit Diagram:
