Mazda CX-9 2016 Owner's Manual page 313

The system may not operate normally under the following conditions:
Mud, ice, or snow is adhering to the sensor area (Returns to normal operation when
removed).
The sensor area is frozen (Returns to normal operation when the ice is thawed).
The sensor is covered by a hand.
The sensor is excessively shocked.
The vehicle is excessively tilted.
Under extremely hot or cold weather conditions.
The vehicle is driven on bumps, inclines, gravel, or grass covered roads.
Anything which generates ultrasound is near the vehicle, such as another vehicle's
horn, the engine sound of a motorcycle, the air brake sound of a large-sized vehicle, or
another vehicle's sensors.
The vehicle is driven in heavy rain or in road conditions causing water-splash.
A commercially-available fender pole or an antenna for a radio transmitter is installed
to the vehicle.
The vehicle is moving towards a tall or square curbstone.
An obstruction is too close to the sensor.
Obstructions under the bumper may not be detected. Obstructions that are lower than the
bumper or thin which may have been initially detected but are no longer detected as the
vehicle approaches more closely.
The following types of obstructions may not be detected:
Thin objects such as wire or rope
Things which absorb sonic waves easily such as cotton or snow
Angular shaped objects
Very tall objects, and those which are wide at the top
Small, short objects
Always have the system inspected at an Authorized Mazda Dealer if any shock is applied
to the bumpers, even in a minor accident. If the sensors are deviated, they cannot detect
obstructions.
The system may have a malfunction if the beep does not operate or the indicator
light does not illuminate when the park assist sensors switch is turned on. Consult an
Authorized Mazda Dealer.
The system may have a malfunction if the beep sound which indicates a system
malfunction is heard and the indicator light ashes. Consult an Authorized Mazda Dealer.
The beeper which indicates a system malfunction may not be heard if the ambient
temperature is extremely cold, or mud, ice, or snow adheres to the sensor area. Remove
any foreign material from the sensor area.
When installing a trailer hitch, consult an Authorized Mazda Dealer.
Parking Sensor System
When Driving
4–165