Air Flow Meter/Sensor: Description and Operation

MASS AIR FLOW (MAF) SENSOR

Mass Air Flow (MAF) Sensor:

The mass air flow (MAF) sensor (1) measures the changes in the intake air volume that result from the changes in throttle opening and the air density. The airflow measurements are used by the PCM in order to determine the engine fueling requirements.

The MAF sensor is a hot-wire design. A platinum hot-wire (2) and a thermistor (3) are located in the intake air bypass passage of the MAF sensor housing. The temperature of the platinum hot-wire is affected by exposure to air flow and by exposure to air temperature. The platinum hot-wire is maintained at a set temperature by controlling the current flow through the wire. The MAF sensor converts the changes in current flow to a voltage signal. The voltage signal from the MAF sensor enables the PCM to detect changes in the air density and changes in air volume.

The MAF sensor also contains the IAT sensor. The IAT sensor cannot be serviced separately from the MAF sensor.