Pontiac Aztek 2003 Owner's Manual page 203

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 announcements even if the
volume is muted or interrupt the play of a cassette tape or
CD if the last tuned station broadcasts traffic
announcements.
This function does not apply to XM™ Satellite Radio
Service.
Radio Messages
CALIBRATE: Your audio system has been calibrated
for your vehicle from the factory. If CALIBRATE appears
on the display, it means that your radio has not been
configured properly for your vehicle and must be
returned to the dealership for service.
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