Windows

WARNING!
Leaving children, helpless adults, or pets in a vehicle with the windows closed is dangerous.
They can be overcome by the extreme heat and suffer permanent injuries or even death from heat stroke. Never leave a child, a helpless adult, or a pet alone in a vehicle, especially with the windows closed in warm or hot weather.

The vehicle aerodynamics are

The vehicle aerodynamics are designed to improve fuel economy performance. This may result in a pulsing sound when a window is partially open. To reduce the sound, open another window or the sunroof (if equipped).

See also:

Interior Quality & Comfort
The CTS' cabin quality has held up well since this generation first hit the road as a 2008 model, and it's still competitive against newer entrants like the 535i and M37. Among the highlights are ...

Driving in Mud, Sand, Snow, or Ice
Use a low gear when driving in mud – the deeper the mud, the lower the gear. Keep the vehicle moving to avoid getting stuck. Traction changes when driving on sand. On loose sand, such as on beaches ...

Key and Lock Messages
REPLACE BATTERY IN REMOTE KEY This message displays if a Remote Keyless Entry (RKE) transmitter battery is low. The battery needs to be replaced in the transmitter. See “Battery Replacement” unde ...