Needs to be done with a subscription to AC Delco TIS website and a j 2534 passthru device. Pretty simple .Make sure The TCM Is the correct Part # Just had one in yesterday Had the wrong TCM And would not program.Causes a Bad day

 So after you got the correct TCM #, were you then able to reflash it successfully from the AC Delco TIS website with a Maxi Flash Pro, or use another pass through device to achieve the reflash?

  Witsend. Love the name. Lol. No I have a tech 2 also a cardaq M I used the cardaq to program This unit. I do not have the maxi flash pro just the maxisys.