2021 MAZDA MODEL 3 HATCHBACK ECU

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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3Before Driving
Use of various features, including keys, doors, mirrors and
windows.
Keys........................................ 3-2 Keys...................................... 3-2
Keyless Entry System...............3-4
Advanced Keyless Entry
System.....................................3-9 Advanced Keyless Entry
System
*................................. 3-9
Operational Range...............3-10
Doors and Locks..................... 3-11 Door Locks.......................... 3-11
Liftgate/Trunk Lid.................3-19
Inside Trunk Release Lever (4-
door)
*................................. 3-24
Fuel and Emission................... 3-25 Fuel and Engine Exhaust
Precautions......................... 3-25
Fuel-Filler Lid and Cap..........3-27
Mirrors.................................. 3-30 Mirrors................................3-30
Windows............................... 3-34 Power Windows...................3-34
Moonroof*.......................... 3-37
Security System.......................3-40 Modi fication and Add-
On Equipment..................... 3-40
Immobilizer System..............3-40
Theft-Deterrent System
*........3-42
Driving Tips............................ 3-44 Break-In Period.................... 3-44
Saving Fuel and Protection of the
Environment........................ 3-44
Hazardous Driving............... 3-45
Floor Mat............................ 3-46
Rocking the Vehicle..............3-46
Winter Driving..................... 3-47
Driving In Flooded Area........3-49
Overloading........................ 3-49
Driving on Uneven Road.......3-50
Turbocharger Information
(SKYACTIV -G 2.5T).............. 3-50
Towing.................................. 3-51 Trailer Towing...................... 3-51
Recreational Towing............. 3-51
*Some models.3-1
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Door Locks
▼Door Locks
WARNING
Always take all children and pets with
you or leave a responsible person
with them:
Leaving a child or a pet unattended in
a parked vehicle is dangerous. In hot
weather, temperatures inside a vehicle
can become high enough to cause
brain damage or even death.
Do not leave the key in your vehicle
with children and keep them in a
place where your children will not
fi
nd or play with them:
Leaving children in a vehicle with the
key is dangerous. This could result in
someone being badly injured or even
killed.
Keep all doors locked when driving:
Unlocked doors in a moving vehicle
are dangerous. Passengers can fall out
if a door is accidentally opened and
can more easily be thrown out in an
accident.
Always close all the windows and
moonroof, lock the doors, fuel-filler
lid, and liftgate and take the key with
you when leaving your vehicle
unattended:
Leaving your vehicle unlocked is
dangerous as children could lock
themselves in a hot vehicle, which
could result in death. Also, a vehicle
left unlocked becomes an easy target
for thieves and intruders.
After closing the doors and the
liftgate/trunk lid, always verify that
they are securely closed:
Doors and the liftgate/trunk lid not
securely closed are dangerous, if the
vehicle is driven with a door and the
liftgate/trunk lid not securely closed,
the door and the liftgate/trunk lid
could open unexpectedly resulting in
an accident.
Always con firm the safety around the
vehicle before opening a door and the
liftgate/trunk lid:
Suddenly opening a door and the
liftgate/trunk lid is dangerous. A
passing vehicle or a pedestrian could
be hit and cause an accident.
CAUTION
 Always
confirm the conditions
around the vehicle before opening/
closing the doors and the liftgate/
trunk lid and use caution during
strong winds or when parked on an
incline. Not being aware of the
conditions around the vehicle is
dangerous because fingers could get
caught in the door and the liftgate/
trunk lid or a passing pedestrian
could be hit, resulting in an
unexpected accident or injury.
Before Driving
Doors and Locks
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▼Unlocking with Auxiliary Key
Only the driver's door can be unlocked
using the auxiliary key.
Refer to Keys on page 3-2.
Insert the auxiliary key while the
driver's door handle is pulled and turn
the key to the unlock side. Turn the
auxiliary key back to its original
position before removing it.
NOTE
If you attempt to open the driver’s
door using an unauthorized auxiliary
key, the key cylinder will spin around
but the door will not unlock.
▼Locking , Unlocking with Touch
Sensor, Door Handle (With the
advanced keyless function)
By touching the sensing area of the
touch sensor, various locking/
unlocking operations can be done
without taking the key out of a bag or
pocket.
There are two types of touch sensors
used for locking and unlocking, and
each sensor is built into the outer door
handle on the driver and front
passenger's doors.
1. Sensing area of door lock touch
sensor (Depression on outer side of
door handle)
2. Sensing area of door release touch
sensor (Inner side of door handle)
NOTE
When locking/unlocking with the
transmitter carried, securely touch
the sensing area of the touch sensor
as follows.
Locking
Unlocking
The system may not operate normally
under the following conditions.
You touch the sensing area of the
door lock touch sensor and the
sensing area of the door release
touch sensor at the same time.
You touch the sensing area of the
touch sensor whil e wearing gloves.
Foreign matter such as snow or dirt
is stuck on the sensing area of the
touch sensor.
Before Driving
Doors and Locks
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You pull the door handle just after
touching the sensing area of the
touch sensor.
The system may operate if the outer
side door handle of a front door is
splashed with water by a car wash or
rain while the transmitter is in the
operation range.
If the system does not operate even
though you touch the sensing area of
the touch sensor correctly, release
the touch sensor once, and then
touch the sensing area of the touch
sensor again after waiting about 3
seconds.
Locking
When locking, touch the sensing area
of the door lock touch sensor with all
of the following conditions met.
The ignition is switched OFF.All the doors are closed.You are carrying the transmitter.
The following locations are locked by
touching the sensing area of the door
lock touch sensor.
All doorsFuel- filler lidLiftgate
When locking, the hazard warning
lights and sound operate one time.
Unlocking
When unlocking, touch the sensing
area of the door release touch sensor
with all of the following conditions
met.
The ignition is switched OFF.The driver’s door is locked.Three seconds or longer have passed
since the doors were locked.
You are carrying the transmitter.
(Unlocking from the driver's door)
The following locations are unlocked
by touching the sensing area of the
door release touch sensor of the
driver's door.
Driver’s doorFuel- filler lid
NOTE
The location to be unlocked can be
changed.
Refer to the Settings section in the
Mazda Connect Owner's Manual.
When unlocking , the hazard warning
lights and sound operate two times.

(Unlocking from the front passenger’s
door)
The following locations are unlocked
by touching the sensing area of the
door release touch sensor of the front
passenger's door.
All doorsFuel- filler lidLiftgate
When unlocking , the hazard warning
lights and sound operate two times.
NOTE
Con firm that all the doors and
liftgate/trunk lid are securely locked.
For the liftgate/trunk lid, move it
without pressing the electric liftgate/
trunk lid opener to verify that the
liftgate/trunk lid has not been left
ajar.
Before Driving
Doors and Locks
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▼Rear Door Child Safety Locks
Rear doors that have been locked
using the child safety lock switched to
the lock side cannot be opened from
inside the vehicle.
For child safety, switch the child safety
lock on both rear doors to the lock
side.
When opening a rear door with the
child safety lock switched to the lock
side, pull the outer door handle with
the lock knob inside the vehicle
switched to the unlock side.
1. Auxiliary key (page 3-2)
2. Lock
3. Unlock
Liftgate/Trunk Lid
▼Liftgate/Trunk Lid
WARNING
Never allow a person to ride in the
luggage compartment/trunk:
Allowing a person to ride in the
luggage compartment/trunk is
dangerous. The person in the luggage
compartment/trunk could be seriously
injured or killed during sudden braking
or a collision.
Do not drive with the liftgate/trunk
lid open:
Exhaust gas in the cabin of a vehicle is
dangerous. An open liftgate/trunk lid
in a moving vehicle will cause exhaust
gas to be drawn into the cabin. This
gas contains CO (carbon monoxide),
which is colorless, odorless, and highly
poisonous, and it can cause loss of
consciousness and death. Moreover,
an open liftgate/trunk lid could cause
occupants to fall out in an accident.
Do not stack or leave loaded luggage
unsecured in the luggage
compartment:
Otherwise, the luggage may move or
collapse, resulting in injury or an
accident. In addition, do not load
luggage higher than the seatbacks. It
may a
ffect the side or rear field of view.
Additionally, if the air bags deploy, the
cargo may scatter which could result in
serious injury or death.
Before Driving
Doors and Locks
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The trunk lid can be closed when the
doors are locked with the key left in
the vehicle. However, to prevent
locking the key in the vehicle, the
trunk lid can be opened by pressing
the electric trunk lid opener. If the
trunk lid cannot be opened despite
doing this procedure, press the
electric trunk lid opener to fully open
the trunk lid after pushing the trunk
lid completely closed.
If the vehicle battery is dead or there
is a malfunction in the electrical
system and the trunk lid cannot be
unlocked, the trunk lid can be
opened by performing the
emergency procedure.
Refer to When Liftgate/Trunk Lid
Cannot be Opened on page 7-48.
Closing the liftgate/trunk lid
Lower the liftgate/trunk lid slowly
using the liftgate/trunk lid grip recess,
then push the liftgate/trunk lid closed
using both hands.
Do not slam it. Pull up on the liftgate/
trunk lid to make sure it is secure.
(5–door)
(4–door)
WARNING
Do not drive the vehicle with the
liftgate-ajar warning indication
displayed :
Otherwise, the liftgate/trunk lid may
open unexpectedly and result in an
accident.
NOTE
Con firm that the liftgate/trunk lid is
securely closed.
Move the liftgate/trunk lid without
pressing the electric liftgate/trunk lid
opener to verify that the liftgate/trunk
lid has not been left ajar.
▼ Luggage Compartment
Luggage compartment cover (5-door)
WARNING
Do not place anything on top of the
cover:
Placing luggage or other cargo on top
of the luggage compartment cover is
dangerous. During sudden braking or a
collision, the cargo could become a
projectile that could hit and injure
someone.
Before Driving
Doors and Locks
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Make sure luggage and cargo are
secured before driving:
Not securing cargo while driving is
dangerous as it could move or be
crushed during sudden braking or a
collision and cause injury.
CAUTION
Make sure the luggage compartment
cover is firmly secured. If it is not
firmly secured, it could unexpectedly
disengage resulting in injury.
The luggage compartment can be
accessed by opening the liftgate when
the straps are attached to the sides of
the liftgate.

Removing the luggage compartment
cover
This cover can be removed for more
room.
1. Remove the straps from the hooks.
2. Press the luggage compartment cover upward from near the pins
and remove the luggage
compartment cover from the pins.
1. Pin

3. Lift the front end of the luggage compartment cover and remove it.
Before Driving
Doors and Locks
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