Transmission Shift pattern -slips going into third gear, but first to second ok.

What is your question?

Shifting appears normal for first and second gear, except it occurs somewhat faster than desired. But in going into third gear, engine revs up and transmission slips before engaging the gear. Third to fourth shift appears normal. Error Code P1700 is shown on diag read-out. What is our best solution to eliminate this ? The only way to avoid this when driving is to release the throttle pressure when second gear has shifted to allow third to "drop into place".