Picked up a 2000 Jimmy SLT, Will not shift in auto, No speedo, P0502, had an Evap code Small leak. Manual shifting works, Third feels a little funny but no plates on it so testing in the driveway in 4 low and 2 Hi. Swapped a VSS with my 99 Blazer. Ran continuity test on VSS circuit, OK. Did a Voltage test on vss at pins 29 & 30, jacked up both wheels spinning tire...no voltage. Suggestions?

 

You are on the right track. As soon as you get the speed signal into the PCM taken care of you should see shifting return.