You should be able to back probe that pin with your multimeter, ground the other probe, set to ac volts, and have a friend lightly tap with a metal object in the vicinity of the sensor, or anywhere on the block really. You should see it generate a voltage, I don't have a spec for you, However it will have to be over a certain threshold for the PCM to "hear" it.
I would say if it's under a volt replace it.