Circuit Description

Mass Air Flow (MAF) sensor measure amount of air entering engine at a given time to determine fuel delivery. MAF sensor produces a frequency signal of about 2000 Hz at idle to 8000 Hz at maximum engine load. DTC will set if MAP signal does not match expected value based on barometric pressure, throttle position and engine speed parameters.

DTC will set when the following conditions are present:

• Engine is running.
• No TP sensor DTCs are set.
• No MAP sensor DTCs are set.
• No EVAP DTCs are set.
• EGR DTC P0401 is not set.
• MAF DTCs P0102 or P0103 is not set.
• System voltage is greater than 11 volts but less than 16 volts.
• Canister purge duty cycle is less than 99.6 percent.
• Change in throttle position is less than 3.9 percent.
• EGR duty cycle is less than 89.9 percent.
• EGR pintle position is less than 89.9 percent.
• Engine vacuum is less than 90 kPa.
• Throttle position is less than 89.8 percent.
• Listed conditions are met for greater than 2 seconds.
• Change in MAF sensor is greater than a calculated value.