2006 silverado 1500 crew 4x4

so i got a service 4wd and my 4wd drive isn't working. no lights on the indicator at all. it has been intermittent in the past few months and finally quit for good. i got code CO327 encoder circuit malfunction.

i have done some research and it could be the encoder sensor. it could also be the shift control module. i have a flow chart from alldata to help narrow it down but here lies my problem.

my obd2 program won't show the voltages i need. i know that i need a "tech2" tool but that is just way out of my budget. is there software that i can buy cheap (or aquire!) from the internet that will provide me with more than just basic obd2 software?

Thanks for the help guys!

btw: the ground on the left frame rail looks good.

 

Look for Bluetooth obd2 in google I seen for 20$ they hook to android and have slot.of info