DTC P0101: Mass Air Flow Circuit Range/Performance: DTC Detecting Condition

The ECM compares the actual measured Mass Air Flow signal to the modeled Mass Air Flow value and sets the DTC P0101 when the difference between these two value is too high or too low with lambda deviation in opposite direction. The ECM illuminates the MIL on the second consecutive driving cycle that the diagnostic runs and fails. The modeled Mass Air Flow value is determined by engine speed, throttle angle and ISCA duty.