98 Bonneville Overdrive solenoid stuck

If anyone could tell me how to access the overdrive solenoid, if possible, I would prefer a diagram. I just bought the vehicle today and it threw a code, all the signs were there that the solenoid was bad, I confirmed at Advanced Auto. Thanks guys.

It is a 4t60e

Side cover must come off the trans, careful here, some codes can falsely point to the tcc sol. when it is another problem, what was the code.