Note. For circuit reference, see WIRING DIAGRAMS article.
Circuit Description
Mass Airflow (MAF) sensor measures amount of air entering engine during a given time. PCM uses MAF sensor information for fuel delivery calculations. MAF sensor readings during acceleration are much higher than those during deceleration or idle.
PCM calculates what MAF sensor reading should be when received from sensor under certain conditions using engine speed (RPM), throttle position, and barometric pressure parameters. When certain test conditions are met, PCM will compare its calculated MAF value to actual value received from sensor. DTC will set if signal from MAF sensor is less than a predetermined value.
For duplication of DTC, ensure
- Engine is running.
- System voltage is greater than 8 volts.
- Throttle angle is less than 75 percent.
- MAF signal frequency is less than 1200 Hertz (Hz).
These conditions must be present for a predetermined amount of time.