Circuit Description

Mass Airflow (MAF) sensor measures amount of air entering engine during a given time. Vehicle Control Module (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 MAF sensor reading 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 met for greater than 2 seconds required to set DTC:

• Engine is running.
• No MAP or TP sensor DTCs are set.
• No EVAP system DTCs are set.
• EGR DTC P0401 not set.
• MAF sensor DTC P0102 or P0103 not set.
• System voltage is 11-16 volts.
• Canister purge duty cycle is 99.6 percent or less.
• Change in throttle position is 3.9 percent or less.
• EGR duty cycle is 89.8 percent or less.
• EGR pintle position is 89.8 percent or less.
• Throttle position is 89.8 percent or less.
• Engine vacuum is 75 kPa or less.