GMC 2003 Yukon Owner's Manual page 258

RDS Messages
ALERT!: Alert warns of local or national emergencies.
When an alert announcement comes on the current
radio station, ALERT! will appear on the display. You will
hear the announcement, even if the volume is muted
or a compact disc is playing. If the compact disc player
is playing, play will stop during the announcement.
You will not be able to turn off alert announcements.
ALERT! will not be affected by tests of the emergency
broadcast system. This feature is not supported by
all RDS stations.
INFO (Information): If the current station has a
message, INFO will appear on the display. Press this
button to see the message. The message may display
the artist and song title, call in phone numbers, etc.
If the whole message is not displayed, parts of it
will appear every three seconds. To scroll through the
message at your own speed, press the INFO button
repeatedly. A new group of words will appear on
the display with each press. Once the complete
message has been displayed, INFO will disappear from
the display until another new message is received.
The old message can be displayed by pressing
the INFO button until a new message is received or a
different station is tuned to.
3-104
TRAF (Traffic): If TRAF appears on the display, the
tuned station broadcasts traffic announcements.
To receive the traffic announcement from the tuned
station, press this button. Brackets will be displayed
around TRAF and when a traffic announcement comes
on the tuned radio station you will hear it.
If the current tuned station does not broadcast traffic
announcements, press this button and the radio
will seek to a station that does. When the radio finds a
station that broadcasts traffic announcements, it will
stop and brackets will be displayed around TRAF. When
a traffic announcement comes on the tuned radio
station you will hear it. If no station is found, NO
TRAFFIC will appear on the display.
If the brackets are on the display and TRAF is not, you
can then press the TRAF button to remove the
brackets or use the TUNE knob or the SEEK arrows to
go to a station that supports traffic announcements.
If no station is found, NO TRAFFIC will appear on the
display.
Your radio will play the traffic announcement even if the
volume is muted or interrupt the play of a CD if the
last tuned station broadcasts traffic announcements.
This function does not apply to XM™ Satellite Radio
Service.