Operator Unable to Hear Caller - OnStar

Diagnostic Chart:

TEST DESCRIPTION
The following numbers refer to the steps in the table.
2. This step that the OnStar (R) call will go through. It is possible that the call may take up to 3 minutes to complete.
3. This checks the operation of the microphone. The operator may say that this call is a "Voice call with no data". This does not mean that the microphone is operating properly.
4. This step inspects that the microphone circuit from the Microphone to the VIU.
5. This step inspects Microphone circuit between the VIU and the VCU.