Buick 2001 Park Avenue - Manual (Page 168)

2-100
A chime will sound the first time an object is
detected, if the object is between 20 inches (0.5 m) and
5 feet (1.5 m) away.
URPA can detect objects 3 inches (7.6 cm) and wider,
and at least 10 inches (2.5 cm) tall, but cannot detect
objects that are above trunk level. In order for the rear
sensors to recognize an object, it must be within
operating range.
If the URPA system is not functioning properly, the
display will flash red, indicating that there is a problem.
The light will also flash red when you are driving if a
trailer is attached to your vehicle, or if you have a
bicycle or an object hanging out of your trunk. The light
will continue to flash until the trailer or the object is
removed and your vehicle is driven forward at least
15 mph (25 km/h).
It may also flash red if the ultrasonic sensors are not
kept clean. So be sure to keep your rear bumper free of
mud, dirt, snow, ice and slush or the system may not
work properly. If after cleaning the rear bumper and
then driving at least 15 mph (25 km/h), the display
continues to flash red, see your dealer. It may also flash
red if your vehicle is moving in REVERSE (R) at a
speed greater than 3 mph (5 km/h). Other conditions that
may affect system performance include things like, the
vibrations from a jackhammer or the compression of
airbrakes on a very large truck.
As always, drivers should use care when backing up a
vehicle. Always look behind you, being sure to check for
other vehicles, obstructions and blind spots. For cleaning
instructions, see “Cleaning Your Vehicle” in the Index.