Unable to Connect to OnStar Message
If there is limited cellular coverage or the cellular network has reached maximum capacity, this message may come on. Push 
to try the call again or try again after driving a few miles into another cellular area.
See also:
How the System Works
The LDW camera sensor is on the windshield ahead of the rearview mirror.
To turn LDW on and off, press the LANE DEPART control on the steering wheel.
The control indicator will light when LDW is ...
If the Off Indicator Is Lit for an Adult-Size Occupant
If a person of adult-size is sitting in the front outboard passenger seat, but the off indicator is lit, it could be because that person is not sitting properly in the seat. Use the following steps ...
Service Publications Ordering Information
Service Manuals
Service Manuals have the diagnosis and repair information on the engines, transmission, axle, suspension, brakes, electrical, steering, body, etc.
Service Bulletins
Service Bulletin ...