A few days ago my Maxisys 906 BT started having issues on some GM vehicles.  So far it has happened on 3 different models ranging from 2005 to 2012.  Here are the examples:

2005 Saturn Ion -- could not control the vent solenoid in Active Tests -- I had communication until I attempted to run the test then the scan tool screen gave the standard "lost communication" message. 

2006 Chevrolet Cobalt -- could not reset transmission adaptives in Special Functions -- again, I had communication until I attempted to reset adaptives, then the scan tool screen gave the "lost communication" message.

2012 GM Yukon -- Intermittently I could not view live data in the ABS menu without losing communication

I tried to perform these tasks several times and it never worked. Battery level was absolutely not an issue on any of the vehicles.  I ended up using my Tech 2 in each case with NO issues at all.

It's important to note that I DID have communication with the modules listed above.  It was not until I attempted to perform the tests that it would lose communication.  I am also able to communicate with all of the modules on each vehicle, and I can view and erase codes. 

I tried my personal 2005 Silverado which is not a CAN vehicle, and it didn't have any communication issues.

Am I the only person having this issue?  My subscription is current and the GM software is current as well.  I even deleted the GM app, and reloaded it in the scan tool.  It is still not working.  I tried other makes with no issues noted at this time.  I cannot operate like this much longer. 

Please help.

I just checked, and the VCI is updated.  Thanks for your help.