No or Poor Cellular Reception - OnStar

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

TEST DESCRIPTION
The following numbers refer to the steps in the table.
2. This step inspects that the phone is presently capable of placing a call.
3. This step inspects that the phone is presently capable of placing a call.
5. The vehicle needs to be in a area capable of transmitting and receiving cellular communications.
6. This step inspects the antenna for proper installation and condition.