Code=B Solenoid stuck in off position.No 3or4th gear.Can Solenoid be reengaged?

What is your question?

Trans fluid ran beyond low. Began slipping at shifts.Added fluid.Did smell burnt. It continued to only respond to 1st and 2nd gear.Code shows B solenoid stuck in off position. (Inducing limp mode) I am becoming a DIY'er tomorrow via YouTube and Google.Can it be 'reset' to ON position? Would fluid-filter change possibly be the issue? Am I doomed? Thanks so much!