Diagnostic Starting Point - Data Communications

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Begin the system diagnosis with Diagnostic System Check - Vehicle (without HP2) or Diagnostic System Check - Vehicle (with HP2) . The Diagnostic System Check - Vehicle will provide the following information:

The identification of the control modules which are not communicating
The identification of any stored diagnostic trouble codes (DTCs) and their status

The use of the Diagnostic System Check - Vehicle will identify the correct procedures to begin vehicle diagnosis. These must be performed before system DTC or symptom diagnosis.