Air Flow Meter/Sensor: Description and Operation

Mass Air Flow (MAF) Sensor Circuit Schematic:

Purpose:
The Mass Air Flow (MAF) sensor measures the flow of air which passes through it in a given time. The PCM uses this information to monitor the operating condition of the engine for fuel delivery calculations. A large quantity of air movement indicates acceleration, while a small quantity indicates deceleration or idle.

Operation:
The Mass Air Flow (MAF) sensor measures the flow of air which passes through it by measuring the electrical power required to maintain the sensing element at a specific number of degrees Celsius above the incoming air temperature. As the air enters the sample tube it passes over and cools the sensing element, which then requires additional current to maintain the prescribed uniform temperature. The PCM uses this information to monitor the operating condition of the engine for fuel delivery calculations.

Location:
The MAF sensor is mounted to the side of the throttle body.