Maxisys Pro can't support to program GM, but only Benz and BMW. If you want to program GM, you need to purchase the OEM software from this site:
http://www.gmtechinfo.com/

" wow that makes it worth all the extra money" you should be embarrased to call it a pro tool it is a scanner with a couple of extras with a value of $300 not $3000 why dont you just tell them to but OEM tools and be done with it.......................

 did you think ,you must do everything that oem can do only with 3000$?!!

Buy another scantool and you won't get as much as autel gives you and you'll pay
more. Autel is a great tool. If you know of a perfect tool for this amount let me know
'cause I'll buy it. Autel all the way

 you guys just dont get it or have not had you tools very long maxisys USED to be a fantastic tool until they were caught out staling all the OEM coding and software NOW it only does half of what it did(because the thad to do some work instead of stealing it ) and now costs a lot more money and the updates you pay big bucks for are worh jack shit becuas you might gain one function but lose 2 more dont take my word for it look up ede65,s posts he also tells it how it is..