Cadillac 2011 DTS Owner's Manual page 176

The alert symbol flashes and a warning beep sounds
when driver action may be required. If ACC is engaged,
the alert symbol will flash when:
ACC cannot apply sufficient braking because you
are approaching a vehicle too rapidly.
The vehicle speed drops below about 32 km/h
(20 mph).
A temporary condition prohibits ACC from
operating. See DIC Warnings and Messages on
page 4 62 for more information.
A malfunction is detected in the system. See DIC
Warnings and Messages on page 4 62 for more
information.
See Defensive Driving on page 5 2.
4-18
The ACC alert symbol is
located on the display at
the top of the instrument
panel to the right of the
driver.
Adaptive Cruise Control has only limited braking
ability to slow your vehicle. In some cases,
Adaptive Cruise Control may not have time to
slow your vehicle enough to avoid a collision. Be
ready to take action and apply the brakes
yourself. See Defensive Driving on page 5 2.
The vehicle ahead symbol only appears when a vehicle
is detected in your path.
If this symbol does not appear, or disappears briefly,
ACC will not respond to vehicles you may see ahead.
The vehicle ahead symbol
is located on the top of
the instrument panel to
the right of the driver.