Note. For circuit reference, see WIRING DIAGRAMS - 4.3L article.
Circuit Description
Mass Airflow (MAF) sensor measures amount of air entering engine during a given time. VCM uses MAF sensor information for fuel delivery calculations. MAF sensor readings during acceleration are much higher than those during deceleration or idle.
VCM calculates what MAF sensor reading should be received from sensor under certain conditions using engine speed (RPM), throttle position, and altitude parameters. When these test conditions are met, VCM will compare its calculated MAF value to actual value received from sensor.
Conditions for setting DTC
- Engine running.
- Engine run time at least .4 second.
- System voltage at least 8 volts.
- MAF sensor is at least 10400 Hz.
- Conditions present for a period greater than zero seconds.