Circuit Description

The Mass Airflow (MAF) sensor measures changes in intake air volume that result from changes in throttle opening and air density. Airflow measurements are used by PCM in order to determine engine fueling requirements. MAF sensor is a hot wire design. A platinum hot wire and a thermistor are located in intake air by-pass passage of MAF sensor housing. Temperature of the platinum hot wire is affected by exposure to airflow and by exposure to air temperature. The platinum hot wire is maintained at a set temperature by controlling the current flow through the wire. MAF sensor converts changes in current flow to a voltage signal. Voltage signal from MAF sensor enables PCM to detect changes in air density and changes in air volume.

DTC will set when ignition is on or engine is running and an open or a short is detected in MAF sensor signal circuit when engine speed is less than 3000 RPM for at least 3 seconds or an open or a short is detected in MAF sensor signal circuit when engine speed is at least 3000 RPM for at least 3 seconds. DTC will set when any of this condition is present on 2 consecutive ignition cycles.