What car is this code from? I have no info from it and the GM service page says it doesnt exist on a GP from 99-04 range. If it really is for the trans range switch then it IS external on 99-03 grand prixs as Toasty said above. There is also a pressure switch manifold inside the trans bolted to the valve body which has hydraulic switches to tell the pcm when each gear position is hydraulically applied. As long as your trans works fine and your gear indicator lights on the dash work properly for each position you should be fine and I would really be curious if that code popped up again as its not making a lot of sense right now.
