GMC 2009 Sierra - Manual (Page 120)

How the System Works
URPA comes on automatically when the shift lever is
moved into REVERSE (R). The rear display will
then briefly illuminate to let you know the system is
working.
URPA operates only at speeds less than 5 mph
(8 km/h). If you are above this speed, the red light on
the rear display will flash.
To be detected, objects must be at least 10 inches
(25.4 cm) off the ground and below tailgate level.
Objects must also be within 8 feet (2.5 m) from your
rear bumper. This distance may be less during warmer
or humid weather.
A single beep will sound the first time an object is
detected between 20 inches (0.5 m) and 8 feet (2.5 m)
away. Beeping will occur for three seconds when
you are closer than 1 foot (0.3 m) from the object.
The following describes what will occur with the URPA
display as you get closer to a detected object:
Description English Metric
amber light 8 ft 2.5 m
amber/amber lights 40 in 1.0 m
amber/amber/red lights 23 in 0.6 m
amber/amber/red lights
flashing and beep for
three seconds
1 ft 0.3 m
The system can be
disabled by pressing the
rear park aid disable button
located next to the radio.
The indicator light will
come on to indicate that
URPA is off.
Notice: If you use URPA while the tailgate is
lowered, it may not detect an object behind your
vehicle, and you might back into the object and
damage your vehicle. Always verify the tailgate is
closed when using URPA or turn off URPA when
driving with the tailgate lowered.
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