Transmission not shifting, in limp mode, designation: low voltage to Transmission Control Module

I have a problem with code P0882.

My Avenger starts good wen it starts but wen it sits without me driving it for bout 4 days battery goes dead n have to jump it. So it started a few days sgo, i was warming it up, idling in driveway, g… 

Battery light is still on after testing the battery and changing the alternator

El rayo encendido, dejo de acelerar o cuando llega a una temperatura se acelera y desacelera, ya se le cambio el pedal , se le reviso sensores y cableado , se le hizo limpieza de catalizador y sigue i…