Circuit Description

This test determines if MAF sensor circuit failed, by monitoring the MAF signal. MAF sensor is a high-frequency device that measures the rate of airflow through the throttle body. MAF sensor outputs a series of pulses that varies in frequency with airflow. PCM uses this signal for fuel control.

MAF sensor readings during acceleration will be much higher than those during deceleration or idle. PCM reads the MAF sensor input each 4X ignition reference pulse. If MAF sensor output drops to less than 1135 Hz, DTC will set.