alesv

I have a problem turning the vent valve off with my solus scantool. This should be a basic chevy evap system where the driver grounds the control wire to close vent valve. In my test I do have 12 volts to power and control wire vent open. However when trying to close vent using the test light method (one lead on pos bat then touching control wire) using scan tool to operate solinoid should turn light on and off. this doent happen. I dont want to assume its the driver in the computer is there any more to test i can do???
thank in advance