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:
Underbody Maintenance
Use plain water to flush dirt and
debris from the vehicle's underbody.
Your dealer or an underbody car
washing system can do this. If not
removed, rust and corrosion can
develop. ...
Maintenance When Trailer Towing
Your vehicle will need service more often when
you’re pulling a trailer. See the Maintenance
Schedule for more on this. Things that are
especially important in trailer operation are
automatic tr ...
Base Headlamp Assembly
The base model vehicle has a
halogen high-beam headlamp, a
low-beam/Daytime Running Lamp
(DRL) headlamp, and a turn signal/parking lamp on the headlamp
assembly.
For replacement of the turn s ...