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:
Anti-theft Alarm System Messages
THEFT ATTEMPTED
This message displays if the vehicle detects a tamper condition. ...
Active Fuel Management™
Your vehicle’s V8 engine may have Active Fuel
Management™. This system allows the engine to
operate on either all or half of its cylinders,
depending on your driving conditions.
When less po ...
Setting the 12/24 Hour Format
1. Press the CONFIG button and
select Time and Date Settings,
or press .
2. Highlight Set Time Format.
3. Press SELECT to select the
12 hour or 24 hour display
format. ...