01 accent codes

I pulled codes on a 01 accent that my buddy has last night we had four of them P0133, P1529, P0734, P0717 The transmission was not shifting to overdrive. He stoped on his way home from work and shut it off and re started it and it was fine again he drove another 30 miles and no problems. It did this about 2 months ago and never did it till yesterday again. I am thinking it is a sensor being it does not do it all the time like a burnt trans any help would be great.