I came to care for this 2007 Nissan Altima that would go into limp mode with transmission codes.
A 6T40 in a 2011 Chevy Malibu comes in to R.C. Trans and Repair in failsafe with a hard code P0601: Transmission Control Module (TCM) Read Only Memory (ROM). This code is straightforward. Verifying power and grounds to the TECHM are the initial checks to make. Once verified, replacing the computer would be a safe repair. Such was the case with R.C. Trans and Repair.
I happened to be looking through some newly received factory bulletins from GM and came across an interesting one concerning the Saturn Vue and Ion. These models that are equipped with the AF33/23-5 five speed automatic have been around since 2002.