GMC 2006 Sierra - Manual (Page 268)

SCAN: Scan the stations within a PTY by performing
the following:
1. Press the TYPE button to activate program type
select mode. TYPE and the last selected PTY will
appear on the display.
2. Turn the TYPE knob or press and release the
TYPE button to select a PTY.
3. Once the desired PTY is displayed, press and
hold either the TYPE or the SCAN arrows for
two seconds, and the radio will begin scanning
the stations in the PTY.
4. Press either the TYPE or the SCAN arrows to stop
at a station.
BAND (Alternate Frequency): Alternate frequency
allows the radio to switch to a stronger station with the
same program type. To turn alternate frequency on, press
and hold BAND for two seconds. AF ON will appear on
the display. The radio may switch to stations with a
stronger frequency.
To turn alternate frequency off, press and hold BAND
again for two seconds. AF OFF will appear on the
display. The radio will not switch to other stations.
This function does not apply for XM™ Satellite Radio
Service.
Setting Preset PTYs (RDS Only)
These buttons have factory PTY presets. Up to 12 PTYs
(six FM1 and six FM2), can be programmed on the
six numbered pushbuttons, by performing the following
steps:
1. Press BAND to select FM1 or FM2.
2. Press the TYPE button to activate program type
select mode. TYPE and the last selected PTY will
appear on the display.
3. Turn the TYPE knob or press and release the
TYPE button to select a PTY.
4. Press and hold one of the six numbered pushbuttons
until you hear a beep. Whenever that numbered
pushbutton is pressed, while in PTY select mode,
the PTY that was set will return.
5. Repeat the steps for each pushbutton.
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