I’m not with “coding”. It’s like a backronym, the characters are written, the actor and director interpret them, we see them and apply our own interpretation. Our interpretation tries to reverse engineer all of that and then put the character into a known box. Helluva game of telephone.

A character written to be autistic (or have gay affections, or whatever else) is not “coded”, they’re written to be gay or autistic.

Now, that’s not to say that writers, directors, and actors don’t all have biases and may have chosen certain traits knowingly or unconsciously and applied them to a character. There are definitely characters that do appear to have non-normative traits like BBT’s Sheldon, but the show left his character hanging. I can imagine why. If they said he was ASD the ASD community would vilify the show with “That’s not who we are!!!” and “Don’t mock people with ASD!” Justifiably.

But the wiki on the show says this:

Co-creator Bill Prady has stated that Sheldon's character was neither conceived nor developed with regard to Asperger's, although Parsons has said that in his opinion, Sheldon "couldn't display more traits" of Asperger's syndrome.