When you use the GM MDI, But it can not connect your laptop, just as the follw pciture, we will help you how to deal with it
Technician from obd2eshop.com provide Solutions as follow:
1.The main unit no connect with power and USB.
2.Press the blank key on the main unit, and then connect with USB.
3.Please let go the blank key when the five light lit on.
4.And then mian unit connect USB and laptop,