Diagnostic Aids
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
When attempting to set TCM internal DTCs let the engine run for at least 1 minute and then shut the engine off for at least 30 seconds. Following this procedure will allow a complete TCM shutdown. Reprogram the TCM and retest the DTC to see if the DTC resets.