Cadillac 2008 XLR Owner's Manual page 100

To be detected, objects must be at least 10 inches
(25.4 cm) off the ground and below trunk level.
Objects must also be within 5 feet (1.5 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 5 feet (1.5 m)
away. Repeated beeping will occur when you are
closer than 20 inches (0.5 m) from the object.
The following describes what will occur with the URPA
display as you get closer to a detected object:
Description
amber light
amber/amber lights
amber/amber/red
lights/continuous beep
amber/amber/red
lights flashing and
continuous beep
2-40
English Metric
5 ft 1.5 m
40 in 1.0 m
20 in 0.5 m
1 ft 0.3 m
When the System Does Not Seem to
Work Properly
•
The ultrasonic sensors are not clean, a red URPA
display light may illuminate when the vehicle is in
REVERSE (R). Keep your rear bumper free of mud,
dirt, snow, ice and slush. For cleaning instructions,
see Washing Your Vehicle on page 6-83.
•
A trailer was attached to your vehicle, or a bicycle
or an object was hanging out of your trunk during
your last drive cycle, the red light may illuminate.
Once the attached object is removed, URPA
will return to normal operation.
•
The vehicle's bumper is damaged. Take the vehicle
to your dealer/retailer to repair the system.
•
Other conditions may affect system performance,
such as vibrations from a jackhammer or the
compression of air brakes on a very large truck.
If the system is still disabled, after driving forward at
least 15 mph (25 km/h), take your vehicle to your
dealer/retailer.