I have a 1993 Honda Accord Station Wagon. Tnis car is in exceptional condition with one current problem which my repair shop seems unable to remedy. Frequently, it will stop shifting properly. The first indication is on the display data on the dash. When starting the car the “D” box will light up and remain lit when shifting to park, reverse, third, etc. The gear being shifted to also displays. At such times I am usually able to manually shift up from 2nd to 3rd. Fourth gear will not kick in during these episodes. The next time I use the car it operates normally. I have had the transmission checked and am told there is nothing wrong with it! As a clue, I have had a battery problem recently and it was replaced by warranty. Right after the new battery was put in the tranny worked flawlessly for a while and then went back to intermittent problem shifting.
Presumably your repair shop is a general repair shop rather than one that specializes in transmissions. You need one that specializes in transmissions. Do not go to any kind of corporate chain-type of shop (such as AAMCO or Cottman). Ask around for a local and independent shop. Someone who knows transmissions should be able to figure this out.
(I am out on a limb here as I don’t know this car and am not a transmission specialist myself, but I’d guess that you have a sensor that tells the car’s computer which gear you have selected with the shifter. It sounds to me like there is a good chance that the problem lies there. If so, it shouldn’t be any big problem to straighten it out).