2021 MAZDA MODEL 3 HATCHBACK brake sensor

Changing the Set Vehicle Speed
(To accelerate/decelerate using the
RES switch)
When the RES switch is pressed up
(SET+), the vehicle accelerates and
when the RES switch is pressed down
(SET-), it decelerates.
Press and release immediately: 1
km/h (1 mph)
Press and hold: 10 km/h (5 mph)
(To increase speed using accelerator
pedal)
Depress the accelerator pedal and
press the RES switch up (SET+) or
down (SET -) at the desired speed. If
the switch is not operated, the system
returns to the set speed after you
release your foot from the accelerator
pedal.
NOTE
The warnings and brake control do
not operate while the accelerator
pedal is depressed.
The setting speed can be changed by
operating the RES switch up (SET+)
or down (SET -) during stop hold
control.
Canceling the system
When the following operations are
performed, the MRCC with Stop & Go
function system is canceled, and the
MRCC with Stop & Go function set
indication (green) switches to the
MRCC with Stop & Go function
standby indication (white) at the same
time.
The CANCEL switch is pressed.The brake pedal is depressed.The selector lever is in the P (Park), N
(Neutral), or R (Reverse) position.

Under the following conditions, the
MRCC with Stop & Go function cancel
indication is displayed in the
multi-information display and a single
beep sound is heard.
The DSC has operated.The Smart Brake Support (SBS) has
operated.
When traveling on a downslope for a
long period of time.
There is a problem with the system.The parking brake is automatically
applied during stop hold control.
The front radar sensor cannot detect
target objects (during rain, fog , snow
or other inclement weather
conditions, or when the radiator
grille is dirty).
The parking brake is applied.Any of the doors is opened.The driver's seat belt is unfastened.The operation frequency of the
braking by the MRCC with Stop &
Go function control is high.
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In the following cases, the TJA cancel indication is displayed and a sound is activated
one time.
The DSC has operated.The Smart Brake Support (SBS) has operated.The vehicle is driven on a downslope for a long time.There is a problem with the system.The front radar sensor cannot detect target objects (during rain, fog , snow or other
inclement weather conditions, or when the radiator grille is dirty).
The parking brake is applied.Any of the doors is opened.The driver's seat belt is unfastened.The operation frequency of the braking by the TJA control is high.(Automatic transmission vehicle)
The parking brake is automatically applied during stop hold control.
(Manual transmission vehicle)
The vehicle speed decreases below 25 km/h (15 mph).The shift lever is in the neutral posi tion for a certain period of time.The clutch pedal is depressed for a certain period of time.The engine has stalled.

Steering assist function
If any of the following conditions occurs, the steering assist function is temporarily
canceled.
The headway control function is canceled.White (yellow) lane lines cannot be detected or a vehicle ahead cannot be
recognized.
Your vehicle speed is more than about 64 km/h (40 mph).The accelerator pedal is operated.The turn signal lever is operated.The vehicle is being driven on a sharp curve.The width of a lane is excessively narrow or wide.The vehicle crosses a lane line.The driver takes his/her hands o ff the steering wheel.The steering wheel is operated abruptly.There is a problem with the system.The temperature in the Forward Sensing Camera (FSC) is too high or too low.The windshield around the Forward Sensing Camera (FSC) is foggy.The windshield around the Forward Sensing Camera (FSC) is blocked by an
obstruction, causing poor forward visibility.

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Smart Brake Support(SBS)
*
▼Smart Brake Support (SBS)
The SBS alerts the driver of a possible
collision using the warning indications
in the display and a warning sound if
the front radar sensor and Forward
Sensing Camera (FSC) determine that
there is the possibility of a collision
with a vehicle ahead, pedestrian, or a
bicycle. Furthermore, if a collision is
unavoidable, the automatic brake
control is performed to reduce damage
in the event of a collision. In addition,
when the driver depresses the brake
pedal, the brakes are applied
firmly
and quickly to assist.
(Vehicles with Driver Monitoring
(DM))
When the SBS determines that the
driver is not paying attention to the
road using the driver monitoring
camera and it determines that there is
the possibility of a collision with an
obstruction, the SBS activates the
collision warning earlier than normal.
WARNING
Do not rely completely on the SBS:
The SBS is only designed to reduce
damage in the event of a collision.
The ability to detect obstructions is
limited depending on the obstructions,
weather conditions, or traffic
conditions. Over reliance on the
system leading to the accelerator pedal
or brake pedal being mistakenly
operated could result in an accident.
CAUTION
In the following cases, turn the system
o ff to prevent an unexpected
operation.
 The vehicle is being towed or when
towing another vehicle.
 The vehicle is on a chassis roller.
 When driving on rough roads such as
in areas of dense grass or o ff-road.
See the next page on how to turn off
the system.
Refer to Stopping the Smart Brake
Support (SBS) System Operation on
page 4-160.
Operation conditions
The SBS operates when all of the
following conditions are met.
The ignition is switched ON.The SBS is on.The i-ACTIVSENSE warning
indication/warning light is not
turned on.
(Object is vehicle ahead)
The vehicle speed is about 4 km/h
(2 mph) or higher.
(Object is a pedestrian or bicycle)
The vehicle speed is between about
10 to 80 km/h (6.2 to 50 mph).
The DSC does not operate.
NOTE
Under the following conditions, the
SBS may not operate.
If there is the possibility of hitting
only a part of a vehicle or
obstruction ahead.
You are driving your vehicle at the
same speed as the vehicle ahead.
When the driver deliberately
performs driving operations
(accelerator operation, steering
wheel operation).
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The accelerator pedal is depressed
abruptly.
The brake pedal is being
depressed.
The steering wheel is being
operated.
The selector lever is being shifted.The turn signal lever is being
operated.
When warnings and messages,
such as a dirty windshield, related
to the Forward Sensing Camera
(FSC) or front radar sensor are
being displayed on the
multi-information display.
The SBS may operate under the
following conditions.
There is an object in the road at
the entrance to a curve (including
guardrails and snow banks).
Passing an approaching vehicle
while rounding a curve.
When crossing a narrow bridge,
and passing through low gates,
narrow gates, car washing
machines, or tunnels.
When passing through a toll gate.When entering an underground
parking area.
There is a metal object, bump, or a
protruding object on the road.
If you suddenly come close to a
vehicle ahead.
There is an animal, wall, or tree.Notifies the driver with a warning
indication on the multi-information
display and the active driving display
(vehicles with active driving display)
while the system is operating.
If a malfunction is detected or the
system temporarily stops the
function due to dirty sensors (such as
radar sensor or Forward Sensing
Camera (FSC)), the i-ACTIVSENSE
warning indication/warning light
turns on and a message is displayed
on the multi-information display.
On a manual transmission vehicle,
the engine stops if the clutch pedal is
not depressed when the vehicle is
stopped by the SBS brake operation.
If the vehicle is stopped by the SBS
brake operation and the brake pedal
is not depressed, the SBS brake is
automatically released after about 2
seconds.
▼ Collision Warning
When there is a possibility of a
collision with a vehicle ahead, the
collision warning sound is activated
continuously and a warning is
displayed on the multi-information
display and the active driving display.
Multi-information display
1. “BRAKE!” message is displayed

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Active driving display
1. “BRAKE!” message is displayed
NOTE
The collision warning sound is
activated intermittently while the SBS
brake or brake assist (SBS brake
assist) is operating.
The operation distance and volume
of the collision warning can be
changed.
Refer to the Settings section in the
Mazda Connect Owner's Manual.
▼Stopping the Smart Brake Support
(SBS) System Operation
The SBS can be changed to inoperable.
Refer to the Settings section in the
Mazda Connect Owner's Manual.
When the SBS is canceled, the SBS OFF
indicator light turns on.
NOTE
When the ignition is switched OFF
while the SBS is canceled, the SBS is
automatically enabled the next time
the ignition is switched ON.
Smart Brake Support
[Rear] (SBS -R)
*
▼ Smart Brake Support [Rear]
(SBS
-R)
The SBS -R is a system which is
designed to reduce damage in the
event of a collision by operating the
brake control (SBS brake) when the
system’s sensors detect an obstruction
at the rear of the vehicle while driving
at a speed of about 2 to 8 km/h (2 to
4 mph) and the system determines that
a collision is unavoidable.
WARNING
Do not rely completely on the SBS -R
system:
 The
SBS-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 SBS -R, heed the following
cautions.
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Do not apply a sticker to a rear
ultrasonic sensor and rear camera.
Otherwise, the rear ultrasonic
sensor and rear camera may not be
able to detect vehicles or
obstructions which could result in
an accident.
 Do not disassemble a rear
ultrasonic sensor and rear camera.
 If cracks or damage caused by
flying gravel or debris is visible
around a rear ultrasonic sensor and
rear camera, stop using the SBS -R
system immediately and have your
vehicle inspected by an Authorized
Mazda Dealer. 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 Brake
Support [Rear] (SBS -R) System
Operation on page 4-163.
 Consult an Authorized Mazda
Dealer for rear bumper removal.
Do not modify the suspension:
If the vehicle height or inclination is
changed, the SBS -R system may not
operate correctly because it cannot
detect obstructions correctly.Do not apply a strong force to a rear
ultrasonic sensor and rear camera:
When washing the vehicle, do not
spray highly pressurized water against a
rear ultrasonic sensor and rear camera,
or rub it strongly. In addition, do not
hit the rear bumper forcefully when
loading and unloading cargo.
Otherwise, the sensors may not detect
obstructions correctly which could
cause the SBS -R system to not operate
normally, or it could operate
unnecessarily.
CAUTION
 When driving o ff-road in areas where
there is grass or foliage, it is
recommended that the SBS-R system
be turned o ff.
 Always use tires of the speci fied size
and the same manufacturer, brand,
and tread pattern on all 4 wheels. In
addition, do not use tires with signi ficantly di fferent wear patterns
on the same vehicle. Otherwise, the SBS -R system may not operate
normally.
 If ice or snow is stuck on the rear
ultrasonic sensor and rear camera
they may not be able to detect
obstructions correctly depending on
the conditions. In such cases, the
system may not be able to perform
controls correctly. Always drive
carefully and pay attention to the
rear of the vehicle.
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NOTE
The vehicle posture changes
depending on the accelerator pedal,
brake pedal and steering wheel
operations, which could make itdi fficult for the system to recognize
an obstruction, or it could facilitate
unnecessary detection. In such cases,
the SBS -R may or may not operate.
The SBS -R system will operate under
the following conditions.
The engine is running for 3 seconds
or more.
The shift lever (manual
transmission ve hicle) or the
selector lever (automatic
transmission vehicle) is in the R
(reverse) position.
i-ACTIVSENSE warning indication/
warning light is not displayed in the
multi-information display.
The vehicle speed is between
about 2 to 8 km/h (2 to 4 mph).
The SBS -R is not turned o ff.The DSC is not malfunctioning.In the following cases, the rear
ultrasonic sensor and rear camera
cannot detect obstructions and the
SBS -R may not operate.
The height of the obstruction is
low such as low walls or trucks
with low loading platforms.
The height of the obstruction is
high such as trucks with high
loading platforms.
The obstruction is small.The obstruction is thin such as a
signpost.
The surface of the obstruction is
not pointed vertically relative to
the vehicle.
The obstruction is soft such as a
hanging curtain or snow stuck to a
vehicle.
The obstruction is shaped
irregularly.
The obstruction is extremely close.In the following cases, the rear
ultrasonic sensor and rear camera
cannot detect obstructions correctly
and the SBS
-R may not operate.
Something is stuck on the bumper
near a rear ultrasonic sensor.
The brake or accelerator pedal is
operated.
There is another obstruction near
one obstruction.
During inclement weather such as
rain, fog and snow.
High or low humidity.High or low temperaturesStrong winds.The path of travel is not flat.Heavy luggage is loaded in the
luggage compartment or on the
rear seat.
Objects such as a wireless antenna,
fog light, or illuminated license
plate is installed near a rear
ultrasonic sensor.
The orientation of a rear ultrasonic
sensor has deviated for reasons
such as a collision.
The vehicle is
aff ected by other
sound waves such as the horn,
engine noise, ultrasonic sensor of
another vehicle.
In the following cases, a rear
ultrasonic sensor and rear camera
may detect something as a target
obstruction which could cause the SBS -R system to operate.
There is a steep slope or bump.There are wheel blocks or a
curbstone.
There are hanging curtains, gate
poles such as at toll gates and
railroad crossing.
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When traveling near objects such
as foliage, barriers, vehicles, walls,
and fences along a road.
When driving off-road in areas
where there is grass and forage.
When passing through low gates,
narrow gates, car washing
machines, and tunnels.
A trailer is connected.An exterior accessory such as a
bicycle carrier is installed around a
rear ultrasonic sensor.
(Manual transmission)
If the vehicle is stopped by the SBS -R
operation and the clutch pedal is not
depressed, the engine stops.
When the system operates, the user
is noti fied by the multi-information
display.
The collision warning beep sounds
intermittently while the SBS -R brake
is operating.
If the vehicle is stopped by the SBS -R
operation and the brake pedal is not
depressed, displaying in meter
“Emergency Braking Activated.
Depress Brake Pedal to Hold Stop”,
after about 2 seconds and the SBS -R
brake is automatically released.
Tu r n o ff the SBS-R system while
pulling a trailer or while an accessory
such as a bicycle carrier is installed to
the rear of the vehicle.
▼ Collision Warning
If there is a possibility of a collision, the
collision warning sound is activated
continuously and a warning is
displayed on the active driving display
and the multi-information display.
Multi-information display
1. “BRAKE!” message is displayed

Active driving display
1. “BRAKE!” message is displayed
▼Stopping the Smart Brake Support
[Rear] (SBS
-R) System Operation
The SBS -R can be changed to
inoperable.
Refer to the Settings section in the
Mazda Connect Owner's Manual.
When the SBS -R is canceled, the SBS
OFF indicator light turns on.
NOTE
When the SBS -R is canceled, the Smart
Brake Support [Rear Crossing]
(SBS -RC) is also canceled.
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