Seems now that i have the tuner in when i got my monthly onstar email it couldnt get diagnostics due to the tuner. If i turn off the tuner or unplug it will the data get sent? Or is this to block data so GM doesn't learn about the tune i'm using? The email stated : We were unable to successfully complete a diagnostic test. This issue may be caused by an aftermarket device plugged into your vehicle's diagnostic port.
• If an indicator light is lit on your dashboard, push your blue OnStar button

You probably need to unplug or turn off the power on the device connected to the OBD. There is a message populated on the CAN when a device is plugged into OBD.

had the same problem. just unplug the obd plug when not driving. onstar usually looks for an update in the early morning hours or overnight when less activity on vehicle.