Air Flow Meter/Sensor: Description and Operation

DESCRIPTION
The Mass Air Flow (MAF) sensor measures the amount of air which passes through it in a given amount of time. The Engine Control Module (ECM) uses this information to determine the operating condition of the engine, to control fuel delivery. A large quantity of air movement indicates acceleration, while a small quantity indicates deceleration or idle.

CONSTRUCTION
The MAF sensor consists of a heat resistor, metering duct, straightening net, body and control circuit. This MAF sensor is of the thermal control type.

OPERATION
The heat resistor is cooled off by the air entering the MAF sensor. The control circuit controls the heat resistors temperature within a predetermined range of the ambient temperature. As the amount of air entering the sensor increases, then so does the sensors signal current to the ECM. As air flow decreases, then so does the signal current to the ECM. The MAF sensor is located in the air intake tube between the throttle body and the Air Cleaner (ACL).