Diagnostics
OnStar Vehicle Diagnostics will perform a vehicle check every month. It will check the engine, transmission, antilock brakes, and major vehicle systems.
It also checks the tire pressures, if the vehicle is equipped with the Tire Pressure Monitoring System.
If a diagnostics check is needed between e-mails, push 
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Advisor can run a check.
See also:
Skip Shift (CTS–V)
Under light acceleration, the
transmission will only allow you to
shift from 1 (First) to 4 (Fourth).
Shifts from 1 (First) to 2 (Second) or
3 (Third) are not allowed. This helps
improve fuel ...
Front Fog Lamp Light
The fog lamp light comes on when
the fog lamps are in use.
The light goes out when the fog
lamps are turned off. See Fog
Lamps. ...
Checking Coolant
The vehicle must be on a level
surface when checking the coolant
level.
The engine coolant reservoir is
located in the engine compartment
on the driver side of the vehicle.
See Engine Compar ...