2021 MAZDA MODEL 3 HATCHBACK sensor

▼Side Air Bags
The side air bags are mounted in the
outboard sides of the front seatbacks.
When the air bag crash sensors detect
a side impact of greater than moderate
force, the system in
flates the side air
bag only on the side in which the
vehicle was hit. The side air bag in flates
quickly to reduce injury to the driver or
front passenger's chest caused by
directly hitting interior parts such as a
door or window.
For more details about air bag
deployment, refer to "SRS Air Bag
Deployment Criteria" (page 2-67).
(With Front Passenger Occupant
Classi fication System)
In addition, the front passenger side air
bag is designed to only deploy in
accordance with the total seated
weight on the front passenger seat. For
details, refer to the front passenger
occupant classi fication system (page
2-70).

▼ Curtain Air Bags
The curtain air bags are mounted in the
front and rear window pillars, and the
roof edge along both sides.
When the air bag crash sensors detect
a side impact of greater than moderate
force, the curtain air bag in
flates
quickly and helps to reduce injury
mainly to the driver and front and rear
outboard passengers' heads caused by
directly hitting interior parts such as a
door or window.
For more details about air bag
deployment, refer to "SRS Air Bag
Deployment Criteria" (page 2-67).
In a side impact:
Greater than moderate impact to one
side of the vehicle will cause the
curtain air bag on that side only to
in flate.

Only one side curtain air bag will
deploy on the side of the vehicle that
receives the force of an impact.
Essential Safety Equipment
SRS Air Bags
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Limitations to roll-over detection
(With Front Passenger Occupant
Classification System):
The following illustration is an example
of an accident that may not be
detected as a roll-over accident.
Therefore, the front seat belt
pretensioners and curtain air bags may
not deploy.

Pitch end over end
Driver and Front
Pa s s e n g e r O cc u p a n t
Classi fication System
*
▼ Driver and Front Passenger
Occupant Classi
fication System
First, please read "Supplemental
Restraint System (SRS) Precautions"
(page 2-55) carefully.
▼ Driver Seat Slide Position Sensor
Your vehicle is equipped with a driver
seat slide position sensor as a part of
the supplemental restraint system. The
sensor is located under the driver seat.
The sensor determines whether the
driver seat is fore or aft of a reference
position and sends the seat position to
the diagnostic module (SAS unit).
The SAS unit is designed to control the
deployment of the driver air bag
depending on how close the driver
seat is to the steering wheel.
The air bag/front seat belt
pretensioner system warning light
fl
ashes if the sensor has a possible
malfunction (page 2-66).
Essential Safety Equipment
SRS Air Bags
2-70*Some models.
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▼Front Passenger Seat Weight
Sensors
Your vehicle is equipped with a front
passenger seat weight sensors as a part
of the supplemental restraint system.
These sensors are located under both
of the front passenger seat rails. These
sensors determine the total seated
weight on the front passenger seat and
monitor the seat belt buckle for the
front passenger seat. The SAS unit is
designed to prevent the front
passenger front and side air bags and
knee air bags, and seat belt
pretensioner system from deploying if
the front passenger air bag
deactivation indicator light illuminates.
To reduce the chance of injuries
caused by deployment of the front
passenger air bag, the system
deactivates the front passenger front
and side air bags and knee air bags,
and also the seat belt pretensioner
system when the front passenger air
bag deactivation indicator light
illuminates. Refer to the following
table for the front passenger air bag
deactivation indicator light
illumination conditions.

This system shuts o
ff the front
passenger front and side air bags and
knee air bags, and seat belt
pretensioner system, so make sure the
front passenger air bag deactivation
indicator light illuminates according to
the following table.

The air bag/front seat belt
pretensioner system warning light
fl ashes and the front passenger air bag
deactivation indicator light illuminates
if the sensors have a possible
malfunction. If this happens, the front
passenger front and side air bags and
knee air bags, and seat belt
pretensioner system will not deploy.
Front passenger air bag deactivation
indicator light
This indicator light illuminates to
remind you that the front passenger
front and side air bags and knee air
bags, and seat belt pretensioners will
not deploy during a collision.
Essential Safety Equipment
SRS Air Bags
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If the front passenger weight sensors
are normal, the indicator light
illuminates when the ignition is
switched ON. The light turns off after a
few seconds. Then, the indicator light
illuminates or is o ff under the following
conditions:
Front passenger air bag deactivation
indicator light on/off condition chart
Condition
detected by the
front pas-
senger oc- cupant
classifi ca-
tion sys- tem Front pas-
senger air
bag deacti-
vation indi- cator light Front pas-
senger
front and side andknee air
bags Front
passen-
ger seat
belt pre-
tensioner
system
Empty
(Not occu-
pied) On
Deactivat-
ed Deacti-
vated
Child or
child-re-
straint sys-
tem
*1
On Deactivat-
ed Deacti-
vated
Adult
*2Off Ready Ready
*1 If a larger child sits on the front passenger
seat, the sensors might detect the child as
being an adult depending on the child's
physique.
*2 If a smaller adult sits on the front passengerseat, the sensors might detect the person as
being a child depending on the person's
physique.
The curtain air bag is ready for in flating
regardless of what the front passenger air bag
deactivation indicator light on/o ff condition
chart indicates.

If the front passenger air bag
deactivation indicator light does not
illuminate when the ignition is
switched ON and does not illuminate
as indicated in the front passenger air
bag deactivation indicator light on/o ff
condition chart, do not allow a child to
sit in the front passenger seat and
consult an Authorized Mazda Dealer
as soon as possible. The system may
not work properly in an accident.
WARNING
Do not decrease the total seated
weight on the front passenger seat:
When an adult or large child sits on the
front passenger seat, decreasing the
total seated weight on the front
passenger seat required for air bag
deployment is dangerous. The front
passenger seat weight sensors will
detect the reduced total seated weight
condition and the front passenger front
and side air bags and knee air bags,
and the seat belt pretensioner system
will not deploy during an accident. The
front passenger will not have the
supplementary protection of the air
bag, which could result in serious
injury. Decreasing the total seated
weight on the front passenger seat
could result in an air bag not deploying
under the following conditions, for
example:
Essential Safety Equipment
SRS Air Bags
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A front passenger is seated as shown
in the following figure:
A rear passenger pushes up on the
front passenger seat with their feet.
Luggage or other items placed under
the front passenger seat or between
the front passenger seat and driver
seat that push up the front passenger
seat bottom.
 Any accessories which might
decrease the total seated weight on
the front passenger seat are attached
to the front passenger seat.
The front passenger front and side air
bags and knee air bags, and the seat
belt pretensioner system will
deactivate if the front passenger air
bag deactivation indicator light
illuminates.

Do not increase the total seated
weight on the front passenger seat:
When an infant or small child sits on
the front passenger seat, increasing the
total seated weight on the front
passenger seat is dangerous. The front
passenger seat we ight sensors will
detect the increased total seated
weight, which could result in the
unexpected deployment of the front
passenger front and side air bags and
knee air bags, and seat belt
pretensioner system in an accident and
may cause serious injury. Increasing the
total seated weight on the front
passenger seat could result in the front
passenger front and side air bags and
knee air bags, and seat belt
pretensioner system deployment in an
accident under the following
conditions, for example:
 Luggage or other items are placed on
the seat with the child in the
child-restraint system.
 A rear passenger or luggage push or
pull down on the front passenger
seatback.
Essential Safety Equipment
SRS Air Bags
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A rear passenger steps on the front
passenger seat rails with their feet.
 Luggage or other items are placed on
the seatback or hung on the head
restraint.
 Heavy items are placed in the
seatback map pocket.
 The seat is washed.
 Liquids are spilled on the seat.
 The front passenger seat is moved
backward, pushing into luggage or
other items placed behind it.
 The front passenger seatback
contacts the rear seat.
 Luggage or other items are placed
between the front passenger seat
and driver seat.
 Any accessories which might increase
the total seated weight on the front
passenger seat are attached to the
front passenger seat.
CAUTION
To assure proper deployment of the
front air bag and to prevent damage
to the sensors in the front seat
bottoms:
 Do not place sharp objects on the
front seat bottoms or leave heavy
luggage on them.
 Do not spill any liquids on the
front seats or under the front seats.
 To allow the sensors to function
properly, always perform the
following:
 Adjust the front seats as far back as
possible and always sit upright
against the seatbacks with seat
belts worn properly.
If you place your child on the front
passenger seat, secure the
child-restraint system properly and
slide the front passenger seat as far
back as possible (page 2-47).
NOTE
The system requires about 10
seconds to alternate between turning
the front passenger front and side air
bags and knee air bags, and seat belt
pretensioner system on or o ff.
The front passenger air bag
deactivation indicator light may
illuminate repeatedly if luggage or
other items are put on the front
passenger seat, or if the temperature
of the vehicle's interior changes
suddenly.
The front passenger air bag
deactivation indicator light may
illuminate for 10 seconds if the total
seated weight on the front passenger
seat changes.
The air bag/front seat belt
pretensioner system warning light
might illuminate if the front
passenger seat receives a severe
impact.
If the front passenger air bag
deactivation indicator light does not
illuminate after installing a
child-restraint system on the front
passenger seat,
first, re-install your
child-restraint system according to
the procedure in this owner's
manual. Then, if the front passenger
air bag deactivation indicator light
still does not illuminate, install the
child-restraint system on the rear seat
and consult an Authorized Mazda
Dealer as soon as possible.
Essential Safety Equipment
SRS Air Bags
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If the front passenger air bag
deactivation indicator light
illuminates when an adult is seated
in the front passenger seat, have the
passenger re-adjust their posture by
sitting with their feet on the floor,
and then re-fastening the seat belt. If
the front passenger air bag
deactivation indicator light still
illuminates, move the passenger to
the rear seat. If sitting in the rear seat
is not possible, slide the front
passenger seat as far back as
possible. Consult an Authorized
Mazda Dealer as soon as possible.
▼ Driver and Front Passenger Buckle
Switches
The buckle switches on the front seat
belts detect whether or not the front
seat belts are securely fastened and
further control the deployment of the
air bags.
Constant Monitoring
▼Constant Monitoring
The following components of the air
bag systems are monitored by a
diagnostic system:

Front air bag sensorsCrash sensors, and diagnostic
module (SAS unit)
Side crash sensorsAir bag modulesFront seat belt pretensionersAir bag/Front seat belt pretensioner
system warning light
Related wiring
(With Driver and Front Passenger
Occupant Classification System)
Driver seat slide position sensorFront passenger occupant
classi fication sensor
Front passenger occupant
classi fication module
Front passenger air bag deactivation
indicator light
Front passenger seat belt buckle
switch

The diagnostic module continuously
monitors the system's readiness. This
begins when the ignition is switched
ON and continues while the vehicle is
being driven.
Essential Safety Equipment
SRS Air Bags
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Advanced Keyless EntrySystem
*
▼Advanced Keyless Entry System
WARNING
Radio waves from the key may a
ffect
medical devices such as pacemakers:
Before using the key near people who
use medical devices, ask the medical
device manufacturer or your physician
if radio waves from the key will aff ect
the device.
The advanced keyless function allows
you to lock/unlock the door, liftgate,
and fuel- filler lid, or open the liftgate/
trunk lid while carrying the key.

System malfunctions or warnings are
indicated by the following warning
beeps.
Touch Sensor Inoperable Warning
Beep
Refer to Touch Sensor Inoperable
Warning Beep (With the advanced
keyless function) on page 7-44.
Liftgate Door-lock Switch Inoperable
Warning Beep
Refer to Liftgate Door-lock Switch
Inoperable Warning Beep (With the
advanced keyless function) on page
7-44.
Key Left-in-luggage Compartment/
Trunk Warning Beep
Refer to Key Left-in-luggage
Compartment/Trunk Warning Beep
(With the advanced keyless function)
on page 7-44.
Key Left-in-vehicle Warning Beep
Refer to Key Left-in-vehicle Warning
Beep (With the advanced keyless
function) on page 7-44.
NOTE
The advanced keyless entry system
functions can be deactivated to
prevent any possible adverse eff ect on
a user wearing a pacemaker or other
medical device. If the system is
deactivated, you will be unable to start
the engine by carrying the key. Consult
an Authorized Mazda Dealer for
details. If the advanced keyless entry
system has been deactivated, you can
start the engine by following the
procedure indicated when the key
battery goes dead.
Refer to Engine Start Function When
Key Battery is Dead on page 4-8.
Before Driving
Advanced Keyless Entry System
*Some models.3-9
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