2021 MAZDA MODEL 3 HATCHBACK ECU

Keep all flames and sparks
away from open battery cells because
hydrogen gas is produced from open
battery cells while charging the
battery or adding battery fluid:
Flames and sparks near open battery
cells are dangerou s. Hydrogen gas,
produced during normal battery
operation, could ignite and cause the
battery to explode. An exploding
battery can cause serious burns and
injuries. Keep all flames including
cigarettes and sparks away from open
battery cells.
NOTE
Before performing battery
maintenance, remove the battery
cover.

▼ Battery Maintenance
To get the best service from a battery:
Keep it securely mounted.Keep the top clean and dry.Keep terminals and connections
clean, tight, and coated with
petroleum jelly or terminal grease.
Rinse o
ff spilled electrolyte
immediately with a solution of water
and baking soda.
If the vehicle will not be used for an
extended time, disconnect the
battery cables and charge the battery
every 6 weeks.
▼ Battery Replacement
Contact an Authorized Mazda Dealer
for battery replacement.
Maintenance and Care
Owner Maintenance
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3. Pull the fuse straight out with thefuse puller provided on the fuse
block located in the engine
compartment.
4. Inspect the fuse and replace it if it is
blown.
1. Normal
2. Blown

5. Insert a new fuse of the same
amperage rating , and make sure it
fits tightly. If it does not
fit tightly,
have an expert install it. Consult an
Authorized Mazda Dealer.
If you have no spare fuses, borrow
one of the same rating from a
circuit not essential to vehicle
operation, such as the audio or
accessory socket circuit.
CAUTION
Always replace a fuse with a
genuine Mazda fuse or equivalent
of the same rating. Otherwise, you
may damage the electric system.
6. Reinstall the cover and make sure that it is securely installed.
Replacing the fuses under the hood
If the headlights or other electrical
components do not work and the fuses
in the cabin are normal, inspect the
fuse block under the hood.
If a fuse is blown, it must be replaced.
Follow these steps:

1. Make sure the ignition is switched
off, and other switches are
off.
2. Remove the fuse block cover.
3. If any fuse but the MAIN fuse is blown, replace it with a new one of
the same amperage rating .
1. Normal
2. Blown

Maintenance and Care
Owner Maintenance
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WARNING
Do not replace the main fuse by
yourself. Have an Authorized
Mazda Dealer perform the
replacement:
Replacing the fuse by yourself is
dangerous because the MAIN fuse
is a high current fuse. Incorrect
replacement could cause an
electrical shock or a short circuit
resulting in a fire.
4. Reinstall the cover and make sure that it is securely installed.
Maintenance and Care
Owner Maintenance
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▼Active Driving Display
Maintenance*
The dust-proof sheet has a coating.
When cleaning , do
not use a hard or
rough-surface cloth, or cleaning
detergent. In addition, if a chemical
solvent gets on the active driving
display, wipe it o ff immediately. The
dust-proof sheet could be damaged
and the surface coating could be
scratched. Use a fine, soft cloth such as
those used for cleaning eyeglasses.
NOTE
Use of compressed air when cleaning
the dust-proof sheet is recommended.
▼ Panel Maintenance
If a panel becomes soiled, wipe it o
ff
with a soft cloth soaked in clean water
and thoroughly wrung out.
If some areas require further cleaning ,
use the following procedure:
1. Wipe the soiled area with a soft cloth soaked in a mild detergent
(approx. 5 %) diluted with water.
2. Wipe o ff the remaining detergent
using a cloth soaked in clean water
and wrung out well.
NOTE
Be particularly careful when cleaning
shiny surface panels and metallic parts
such as plating as they can be
scratched easily.
▼ Cleaning the Window Interiors
If the windows become covered with
an oily, greasy, or waxy
film, clean
them with glass cleaner. Follow the
directions on the container.
CAUTION
 Do not scrape or scratch the inside
of the window glass. It could
damage the thermal filaments and
the antenna lines.
 When washing the inside of the
window glass, use a soft cloth
dampened in lukewarm water, gently
wiping the thermal filaments and the
antenna lines.
Use of glass cleaning products could
damage the thermal filaments and
the antenna lines.
▼ Cleaning the Floor Mats
Rubber
floor mats should be cleaned
with mild soap and water only.
WARNING
Do not use rubber cleaners, such as
tire cleaner or tire shine, when
cleaning rubber floor mats:
Cleaning the rubber floor mats with
rubber cleaning products makes the
fl oor mats slippery.
This may cause an accident when
depressing the accelerator, brake, or
clutch (Manual transmission) pedal or
when getting in or out of the vehicle.
After removing the floor mats for
cleaning, always reinstall them securely
(page 3-46).
Maintenance and Care
Appearance Care
6-56*Some models.
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2. Remove the cover.
3. Turn the wing bolt and jack screwcounterclockwise.

1. Wing bolt
2. jack screw

5–Door
1. Remove the luggage mat.
2. Remove the jack.

To s e c u r e t h e j a c k
4–Door
1. Insert the wing bolt into the jackwith the jack screw pointing to the
front and turn the wing bolt
clockwise to temporarily tighten it.
2. Turn the jack screw clockwise.
1. Wing bolt
2. jack screw

3. Turn the wing bolt completely to secure the jack.
NOTE
If the jack is not completely secured, it
could rattle while driving. Make sure
the jack screw is su fficiently tightened.
If Trouble Arises
Flat Tire
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(Vehicles without sub-woofer)
Turn the spare tire hold-down bolt
counterclockwise and remove the
spare tire.

1. Spare tire hold-down bolt
NOTE
If the spare tire hold-down bolt
cannot be loosened, hold the edge
of the tire and turn it
counterclockwise until the spare
tire hold-down bolt rotates.
To secure the spare tire
Store the spare tire in the reverse order
of removal. After storing , verify that the
spare tire is stored securely.
Changing a Flat Tire
▼ Changing a Flat Tire
NOTE
If the following occurs while driving , it
could indicate a fl
at tire.
Steering becomes
difficult.The vehicle begins to vibrate
excessively.
The vehicle pulls in one direction.
If you have a flat tire, drive slowly to a
level spot that is well o ff the road and
out of the way of tra ffic to change the
tire.
Stopping in tra ffic or on the shoulder
of a busy road is dangerous.
WARNING
Be sure to follow the directions for
changing a tire:
Changing a tire is dangerous if not
done properly. The vehicle can slip o ff
the jack and seriously injure someone.
No person should place any portion of
their body under a vehicle that is
supported by a jack.
Never allow anyone inside a vehicle
supported by a jack:
Allowing someone to remain in a
vehicle supported by a jack is
dangerous. The occupant could cause
the vehicle to fall resulting in serious
injury.
NOTE
Make sure the jack is well lubricated
before using it.
If Trouble Arises
Flat Tire
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WARNING
Do not apply oil or grease to lug
nuts and bolts and do not tighten
the lug nuts beyond the
recommended tightening torque:
Applying oil or grease to lug nuts
and bolts is dangerous. The lug nuts
could loosen while driving and
cause the tire to come off, resulting
in an accident. In addition, lug nuts
and bolts could be damaged if
tightened more than necessary.
4. Turn the jack handle
counterclockwise using the lug
wrench and lower the vehicle.
5. Use the lug wrench to tighten the
nuts in the order shown.

If you are unsure of how tight the
nuts should be, have them
inspected at an Authorized Mazda
Dealer.
Nut tightening torque
N·m (kgf·m, ft·lbf) 108―
147 (12 ―14,
80― 108)
WARNING
Always securely and correctly
tighten the lug nuts:
Improperly or loosely tightened lug
nuts are dangerous. The wheel
could wobble or come
off. This
could result in loss of vehicle
control and cause a serious
accident.
Be sure to reinstall the same nuts
you removed or replace them with
metric nuts of the same
con figuration:
Because the wheel studs and lug
nuts on your Mazda have metric
threads, using a non-metric nut is
dangerous. On a metric stud, it
would not secure the wheel and
would damage the stud, which
could cause the wheel to slip o ff
and cause an accident.
6. (Aluminum wheel equipped
vehicle)
Remove the center cap by tapping
it from the backside of the wheel
using the lug wrench.
7. Store the damaged tire in the trunk (4-door) or luggage compartment
(5-door).

8. Secure the damaged tire to thevehicle using the following method.
If Trouble Arises
Flat Tire
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(Vehicles with flat tire hold-down
bolt (excluding vehicles with
sub-woofer for 5-door))
1. Spread apart the tabs on the spare tire hold-down bolt that
was removed when removing
the spare tire and remove the
bolt for securing the spare tire.
1. Tabs
2. Bolt for securing spare tire
3. Spare tire hold-down bolt

2. Remove the bolt for securing the
flat tire from its stored position
and install it in place of the
removed spare tire hold-down
bolt.
1. Bolt for securing the flat tire
2. Spare tire hold-down bolt

NOTE
The longer bolt is used as the
bolt for securing the flat tire,
and the shorter one is used as
the bolt for securing the spare
tire. When installing a bolt,
check the bolt's length.
3. Secure the damaged tire to the vehicle using the flat tire
hold-down bolt.
(Vehicles with flat tire hold-down
bolt and with sub-woofer for
5-door))
1. Remove the bolt for securing the
flat tire from its stored position.
2. Secure the damaged tire to the vehicle using the flat tire
hold-down bolt.
1. Flat tire hold-down bolt
2. Sub-woofer

If Trouble Arises
Flat Tire
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