LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 2012 >> Escalade EXT >> Repair and Diagnosis (Single Page) >> External Pages >> Different car >> Section 1549 (Cellular Systems, Entertainment Systems & Navigation Systems) >> Diagnostic Information and Procedures >> Unable to Contact OnStar Call Center >> Circuit/System Verification
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit/System Verification

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify that the cellular antenna and cellular antenna coupling assembly are not damaged.
    • If damage is found, repair or replace as necessary.
  2. Ignition ON, press the OnStar® Call Center button. Verify the system activates and the message Connecting to OnStar® is heard.
  3. If the system activates but does not connect with the OnStar® call center, refer to Circuit/System testing.