Key on engine not running,top of sensor plate even with lower edge of cylindrical part of air funnel,plug installed but pulled back enough to measure voltage. Pins 1 and 3 should read about half a volt, at pins 1 and 2 read .2 to .5 volts.
Slowly push sensor plate all the way down and you should see the voltage rise continuosly to 5 volts at full travel.
Mike