Slow1 trans am

thanks for taking a look! ok heres my issue have a 2002 camaro auto that had a tranny issue after it warmed up would not shift past second gear the codes then where p1810 trans fluid pressure position circuit. i change the pressure position swith and tested the shift solenoids. they ohmed out good.
after that all was good.

last weeked my wife was driving up the I5 grapevine ( a long pull up a moutan) my wife called and said the car as she described it was at 4k on the tach and going 55-60 acting funny.

long story short i got the car drove it home and the car would some times not shift to 4th (D). threw my scanner on it and got 3 codes

P1637 generator L trminal circuit (dont think thats related to my trans issue chargingat 13v)

P1810 trans fluid pressure position circuit (wtf again!)

C0240 traction control not allowed

thanks in advance! trans looked good when i had the pan off the 1st time shift nice no shake nothing leading me to belive mechanical failure. leaning to what i like to call magic (electrical)

What do you guys think it is? Or what can I test to rule out