Seville STS V8-4.6L VIN 9 (1998)
Mass Air Flow (MAF) Sensor: Description and Operation
Mass Air Flow (MAF) Sensor
MAF Sensor Assembly
The Mass Air Flow (MAF) sensor is located in between the air snorkel and the throttle body. It senses the amount of air entering the intake manifold.
This information is required by the PCM to control fuel and emissions.
The MAF sensor used on this vehicle is a hot wire type and is used to measure air flow rate (mass/unit time). The MAF sensor output is a variable
frequency square wave based on air mass traveling through the sensor. A low frequency output signal from the MAF sensor indicates low air flow and
high frequency indicates high air flow. The MAF sensor has two wires crossing the air stream through it. One senses ambient temperature and the other,
the hot wire, is kept at a fixed temperature above the ambient temperature. The MAF sensor senses air flow by measuring the power necessary to keep
the hot wire hot, which is proportional to air flow, and converts it to a frequency modulate output signal.
A high flow signal will be close to 9000 Hertz and a low flow signal will be close to 2000 Hertz.
