Diagnostic System Check - Cellular Communication

DIAGNOSTIC SYSTEM CHECK - CELLULAR COMMUNICATION

TEST DESCRIPTION

Steps 1-3:

Steps 4-8:

The numbers below refer to the step numbers on the diagnostic table.
2. Lack of communication may be due to a partial malfunction or a total malfunction of the class 2 serial data circuit. The specified procedure will determine the condition.
4. This step will determine which version of OnStar(R) is installed on the vehicle and which set of diagnostic procedures should be used.
5. The presence of DTCs which begin with "U" indicate some other system control module is not communicating.