Air Flow Meter/Sensor: Description and Operation

The Mass Air Flow (MAF) sensor measures the amount of air which passes through it. The PCM uses this information to determine the operating condition of the engine, to control fuel delivery. A large quantity of air indicates acceleration. A small quantity of air indicates deceleration or idle.

The scan toot reads the MAF value and displays it in grams per second (g/s). At idle, it should read between 6 g/s - 9 g/s on a fully warmed up engine. Values should change rather quickly on acceleration, but values should remain fairly stable at any given RPM. When the PCM detects a malfunction in the MAF sensor circuit, one or more of the following DTCs will set:
^ DTC P0101 MAF System Performance
^ DTC P0102 MAF Low Frequency
^ DTC P0103 MAF High Frequency