Global Positioning System: Testing and Inspection

OnStar(R) System Check:

TEST DESCRIPTION
The number(s) below refer to the step number(s) 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. The presence of DTC's which begin with "U" indicate some other system control module is not communicating.