Some information below from the Holden Service CD - however, no quantitative info on readings.
"The signal that is sent from the mass air flow sensor is sent in the form of a frequency output. A large quantity of air passing through the sensor (such as when accelerating) will be indicated as a high frequency output. A small quantity of air passing through the sensor will be indicated as a low frequency output (such as when decelerating or at idle). The Tech 1 scan tool displays MAF sensor information in frequency, and in grams per second and calculated in mg per cylinder. At idle the readings should be low and increase with engine RPM. As the PCM receives this frequency signal from the mass air flow sensor, it searches its pre-programmed tables of information to determine the pulse width of the fuel injectors required to match the mass air flow signal. If a problem occurs in the mass air flow sensor circuit, after a period of time, the PCM will store a DTC in its memory. The PCM will turn "ON" the "Check Powertrain" lamp, indicating there is a problem. If this occurs, the PCM will calculate a "substitute" mass air flow signal based on engine speed and throttle position sensor signal. No field service adjustment is necessary or possible with this mass air flow sensor. A failure in the mass air flow sensor circuit should set a DTC 32. Remember, this code indicates a failure in the circuit, so proper use of the diagnostic chart will lead to either repairing a wiring problem or replacing the MAF Sensor, to properly repair a problem."
