Circuit/System Verification

NOTE: It is necessary to have the vehicle in a quiet, open outside area where a cellular call can be successfully placed and GPS data can be received from satellites.

Ignition ON/vehicle in Service Mode.
Verify that DTC B2455 is not set.
- If DTC B2455 is set
  Refer to DTC B2455 .
- If DTC B2455 is not set
Verify that your voice is heard clearly by the OnStar Call Center after completing a blue button press.
- If your voice can not be heard clearly
  Refer to Circuit/System Testing - Microphone Malfunction.
- If your voice can be heard clearly
Verify that a successful OnStar voice command when completing a blue button press.
- If your voice can not be heard clearly
  Refer to Circuit/System Testing - Cellular Telephone Voice Malfunction.
- If your voice can be heard clearly
All OK.