Jeep 2007 Grand Cherokee Series Owner's Manual page 143

WARNING!
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Drivers must be careful when backing up even when
using the Rear Park Assist System. Always check
carefully behind your vehicle, look behind you, and
be sure to check for pedestrians, animals, other
vehicles, obstructions, and blind spots before back-
ing up. You are responsible for safety and must
continue to pay attention to your surroundings. Fail-
ure to do so can result in serious injury or death.
•
Before using the Rear Park Assist System, it is
strongly recommended that the ball mount and hitch
ball assembly is disconnected from the vehicle when
the vehicle is not used for towing. Failure to do so
can result in injury or damage to vehicles or ob-
stacles because the hitch ball will be much closer to
the obstacle than the rear fascia when the warning
display turns the red LEDs ON. Also, the sensors
could detect the ball mount and hitch ball assembly,
depending on its size and shape, giving a false
indication that an obstacle is behind the vehicle.
UNDERSTANDING THE FEATURES OF YOUR VEHICLE 143
NOTE: Clean all four Rear Park Assist Sensors regularly,
taking care not to scratch or damage them. The sensors
must not be covered with ice, snow, slush, mud, dirt or
debris. Failure to do so can result in the system not
working properly. The system might not detect an ob-
stacle behind the fascia or it could provide a false
indication that an obstacle is behind the fascia.
Assure objects are not within 11.8 inches (30 cm) from the
rear fascia while driving the vehicle. Failure to do so can
result in the system misinterpreting a close object as a
sensor problem, causing the SERVICE PARK ASSIST
SYSTEM message to be displayed in the instrument
cluster.
Ultrasonic noise from airbrakes of nearby trucks, air
powered jackhammers and air powered shop tools, to
name a few, will cause the Rear Park Assist System to be
disabled until the ultrasonic noise is no longer present.
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