Hi new here
I have a 1994 Grand Prix SE 3.1 does not go into 1 st gear starts out in 2 nd is there a sensor for the second gear start and if so where is it?
have the codes pulled, sounds like you have a bad shift solenoid that's not shifting down into first gear. Try some seafoam or Trans-X and see if it frees it up. Also try manually shifting it down into first to see if it goes.
The shift solenoids are in the valve body, and require the pan to be removed to service them. I would advise against attempting it yourself, unless you know what you are doing and have a clean place to work on it. Try the seafoam/Trans-x trick to see if it frees up.