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Symptoms - Cellular Communication: Notes

NOTE:

The following steps must be completed before using the symptom table.

Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:
- There are no DTCs set.
- The control modules can communicate via the serial data link.
Review the system operation in order to familiarize yourself with the system functions. Refer to OnStar Description and Operation .