Mazda CX-5 2018 Owner's Manual page 352

Reverse
Do not rely completely on the SCBS R system:
The SCBS R system is only designed to reduce damage in the event of a collision. Over
reliance on the system leading to the accelerator pedal or brake pedal being mistakenly
operated could result in an accident.
To assure the correct operation of the SCBS R, heed the following cautions.
Do not apply a sticker to an ultrasonic sensor (rear) (including transparent stickers).
Otherwise, the ultrasonic sensor (rear) may not be able to detect vehicles or obstructions
which could result in an accident.
Do not disassemble an ultrasonic sensor (rear).
If cracks or damage caused by flying gravel or debris is visible around an ultrasonic
sensor (rear), stop using the SCBS R system immediately and have your vehicle inspected
by an expert repairer, we recommend an Authorised Mazda Repairer. If the vehicle
continues to be driven with cracks or scratch marks left around an ultrasonic sensor, the
system may operate unnecessarily and cause an unexpected accident.
Refer to Stopping the Smart City Brake Support [Reverse] (SCBS R) System Operation on
page 4-201.
Consult an expert repairer, we recommend an Authorised Mazda Repairer for rear
bumper replacement.
Do not modify the suspension:
If the vehicle height or inclination is changed, the SCBS R system may not operate correctly
because it cannot detect obstructions correctly.
Ultrasonic sensor (rear)