2023 TOYOTA BZ4X battery

4597-2. Maintenance
Owners Manual_USA_M42C01_en
7
Maintenance and care
The OBD system determines
that a problem exists some-
where in the emission control
system. Your vehicle may not
pass the I/M test and may need
to be repaired. Contact your
Toyota dealer to service the
vehicle.
When the 12-volt battery is dis-
connected or discharged
Readiness codes that are set
during ordinary driving are
erased.
Also, depending on your driving
habits, the readiness codes may
not be completely set. The error code in the OBD sys-
tem will not be cleared unless
the vehicle is driven 40 or more
times.
Contact your Toyota dealer to
prepare the vehicle for re-test-
ing.
Emission inspection
and mainte
nance (I/M)
programs
Some states have vehicle
emission inspection pro-
grams which include OBD
(On Board Diagnostics)
checks. The OBD system
monitors the operation of
the emission control sys-
tem.
If the malfunc tion indica-
tor lamp comes on
Your vehicle may not pass
the I/M test in the follow-
ing situations:
When the malfunction
indicator lamp still
remains on after several
driving trips
If your vehicle does not
pass the I/M test

4607-3. Do-it-yourself maintenance
Owners Manual_USA_M42C01_en
7-3.Do-it-yourself maintenance
Do-it-yourself ser vice
precautions
If you perform maintenance
by yourself, be sure to fol-
low the correct procedure
as given in these sections.
Maintenance
ItemsParts and tools
12-volt bat-
tery condi-
tion (P.468)
•Warm water
• Baking soda
•Grease
• Conventional
wrench (for termi-
nal clamp bolts)
Brake fluid
level
( P.468)
• FMVSS No.116
DOT 3 or SAE
J1703 brake fluid
FMVSS No.116
DOT 4 or SAE
J1704 brake fluid
• Rag or paper towel
• Funnel (used only for adding brake
fluid)
Power control
unit coolant
level
( P.467)
• In order to ensure
maximum perfor-
mance of the trac-
tion battery
cooling system
and limit risks of
battery short-cir-
cuit and other
damage to your
vehicle, Toyota
recommends
using “Toyota
Genuine Traction
Battery Coolant”
or similar high-
quality ethylene
glycol-based, low
electric conductiv-
ity coolant, non-
amine and non-
borate coolant
with azole addi-
tives.
• Funnel (used only for adding coolant)
ItemsParts and tools

4617-3. Do-it-yourself maintenance
Owners Manual_USA_M42C01_en
7
Maintenance and care
Heater cool-
ant level
(  P.465)
• “Toyota Super
Long Life Cool-
ant” or a similar
high quality eth-
ylene glycol-based
non-silicate, non-
amine, non-nitrite
and non-borate
coolant with long-
life hybrid organic
acid technology
“Toyota Super
Long Life Cool-
ant” is pre-mixed
with 50% coolant
and 50% deion-
ized water.
• Funnel (used only for adding coolant)
Fuses
( P.499)• Fuse with same
amperage rating
as original
Headlight aim
( P.501)Phillips-head
screwdriver
Radiator and
condenser
( P.466)

Tire inflation
pressure
( P.491)• Tire pressure
gauge
• Compressed air source
Washer fluid
( P.471)
• Water or washer
fluid containing
antifreeze (for win-
ter use)
• Funnel (used only for adding water or
washer fluid)
ItemsParts and toolsWARNING
The motor compartment contains
many mechanisms and fluids that
may move suddenly, become hot,
or become electrically energized.
To avoid death or serious injury,
observe the following precautions.
■When working on the motor
compartment
●Make sure that “POWER ON”
on the multi-information display
and the “READY” indicator are
both off.
●Keep hands, clothing and tools
away from the moving fan.
●Be careful not to touch the
motor, power control unit, radia-
tor, etc., right after driving as
they may be hot. Coolant and
other fluids may also be hot.
●Do not leave anything that may
burn easily, such as paper and
rags, in the motor compartment.
●Do not smoke, cause sparks or
expose an open flame to the 12-
volt battery. 12-volt battery
fumes are flammable.
●Be extremely cautious when
working on the 12-volt battery. It
contains poisonous and corro-
sive sulfuric acid.
●Never touch, disassemble,
remove or replace the high volt-
age parts, cables and their con-
nectors. It can cause severe
burns or electric shock that may
result in death or serious injury.

4657-3. Do-it-yourself maintenance
Owners Manual_USA_M42C01_en
7
Maintenance and care
Heater coolant reservoir ( P.465)
Washer fluid tank ( P.471)
Power control unit coolant reservoir ( P.467)
12-volt battery ( P.468)
Brake fluid reservoir ( P.468)
Fuse box ( P.499)
Radiator ( P.466)
Condenser ( P.466)
Electric cooling fan
The coolant level is satisfactory
if it is between the “MAX” and “MIN” lines on the reservoir
when the EV system is cold.
Motor compar tment
Components
Checking the heater cool-
ant

4677-3. Do-it-yourself maintenance
Owners Manual_USA_M42C01_en
7
Maintenance and care
The coolant level is satisfactory
if it is between the “MAX” and
“MIN” lines on the reservoir
when the EV system is cold. Reservoir cap
“MAX” line
“MIN” line
If the level is on or below the “MIN”
line, add coolant up to the “MAX”
line.
■Coolant selection
In order to ensure maximum perfor-
mance of the traction battery cooling
system and limit risks of battery
short-circuit and other damage to your vehicle, Toyota recommends
using “Toyota Genuine Traction Bat-
tery Coolant” or similar high-quality
ethylene glycol-based, low electric
conductivity coolant, non-amine and
non-borate coolant with azole addi-
tives.
Toyota cannot guarantee that the
use of a product o
ther than “Toyota
Genuine Traction Battery Coolant”
will prevent risks of battery short-cir-
cuit or other damage.
Never use water as it will cause
damage.
Do not reuse cool ant that has been
removed from the radiator.
For more details about coolant, con-
tact your Toyota dealer.
■If the coolant level drops within
a short time of replenishing
Visually check the hoses, heater
coolant reservoir caps, drain cock
and water pump.
If you cannot find a leak, have your
Toyota dealer, t est the cap and
check for leaks in the cooling sys-
tem.
WARNING
■When the electric cooling fan
are operating
Do not touch the motor compart-
ment.
With the power switch in ON, the
electric cooling fan may automati-
cally start to run if the air condi-
tioning is on and/or the coolant
temperature is high. Be sure the
power switch is OFF when work-
ing near the electric cooling fan or
radiator grille.
Checking the power con-
trol unit coolant
WARNING
■When the EV system is hot
Do not remove the power control
unit coolant reservoir caps.
The cooling system may be under
pressure and may spray hot cool-
ant if the cap is removed, causing
serious injuries, such as burns.

4687-3. Do-it-yourself maintenance
Owners Manual_USA_M42C01_en
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN”
lines on the tank.
Reservoir cap
“MAX” line
“MIN” line
■Adding fluid
Make sure to check the fluid
type and prepare the necessary
item.
 Fluid type
FMVSS No.116 DOT 3 or SAE J1703 brake fluid
FMVSS No.116 DOT 4 or SAE
J1704 brake fluid

Item
Clean funnel
■Brake fluid can absorb moisture
from the air
Excess moisture in the brake fluid
can cause a dangerous loss of brak-
ing efficiency. Use only newly
opened brake fluid.
Check the 12-volt battery as fol-
lows.
■12-volt battery exterior
Make sure that the 12-volt bat-
tery terminals are not corroded
NOTICE
■When adding coolant
Coolant is neither plain water nor
straight antifreeze. The correct
mixture of water and antifreeze
must be used to provide proper
lubrication, corrosion protection
and cooling. Be sure to read the
antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to
prevent it from d amaging parts or
paint.
Checking and adding the
brake fluidWARNING
■When filling the reservoir
Take care as brake fluid can harm
your hands and eyes and damage
painted surfaces.
If fluid gets on your hands or in
your eyes, flush the affected area
with clean water immediately. If
you still experience discomfort,
see a doctor.
NOTICE
■If the fluid level is low or high
It is normal for the brake fluid level
to go down slight ly as the brake
pads wear out or when the fluid
level in the accumulator is high.
If the reservoir needs frequent
refilling, there m ay be a serious
problem.
Checking the 12-volt bat-
tery

4697-3. Do-it-yourself maintenance
Owners Manual_USA_M42C01_en
7
Maintenance and care
and that there are no loose con-
nections, cracks, or loose
clamps. Terminals
Hold-down clamp
■Checking 12-volt battery
fluid
Check that the level is between
the “UPPER LEVEL” and
“LOWER LEVEL” lines.
“UPPER LEVEL” line
“LOWER LEVEL” line
If the fluid level is at or below the
“LOWER LEVEL” line, add distilled
water.
■Adding distilled water
1 Remove the vent plug.
2 Add distilled water.
If the “UPPER LEVEL” cannot be
seen, check the fluid level by look- ing directly at the cell.
3
Put the vent plug back on
and close it securely.
■Before recharging
When recharging, the 12-volt bat-
tery produces hydrogen gas which
is flammable and explosive. There-
fore, observe the following precau-
tions before recharging:
●If recharging with the 12-volt bat-
tery installed on the vehicle, be
sure to disconnect the ground
cable.
●Make sure the power switch on
the charger is off when connecting
and disconnecting the charger
cables to the 12-volt battery.
■After recharging/reconnecting
the 12-volt battery
●The EV system may not start. Fol-
low the procedure below to initial-
ize the system.
1 Shift the shift position to P.
2 Open and close any of the doors.
3 Restart the EV system.
●Unlocking the doors using the
Smart key system may not be
possible immediately after recon-
necting the 12-volt battery. If this
happens, use the wireless remote
control or the mechanical key to
lock/unlock the doors.
●Start the EV system with the
power switch in ACC. The EV sys-
tem may not start with the power
switch turned off. However, the EV
system will operate normally from

4707-3. Do-it-yourself maintenance
Owners Manual_USA_M42C01_enthe second attempt.
●The power switch mode is
recorded by the vehicle. If the 12-
volt battery is
disconnected and
reconnected, the vehicle will
return the power switch mode to
the status it was in before the 12-
volt battery was disconnected.
Make sure to turn off the power
switch before disconnecting the
12-volt battery. Take extra care
when connecting the 12-volt bat-
tery if the power switch mode prior
to the 12-volt battery being dis-
connected is unknown.
If the EV system will not start even
after multiple att empts at all the
methods above, contact your Toyota
dealer.
WARNING
■Chemicals in the 12-volt bat-
tery
Batteries contai n poisonous and
corrosive sulfuric acid and may
produce hydrogen gas which is
flammable and explosive. To
reduce the risk of death or serious
injury, take the following precau-
tions while working on or near the
12-volt battery:
●Do not cause sparks by touch-
ing the 12-volt battery terminals
with tools.
●Do not smoke or light a match
near the 12-volt battery.
●Avoid contact with eyes, skin
and clothes.
●Never inhale or swallow electro-
lyte.
●Wear protective safety glasses
when working near the 12-volt
battery.
●Keep children away from the
12-volt battery.
■Where to safely charge the
12-volt battery
Always charge the 12-volt battery
in an open area. Do not charge
the 12-volt battery in a garage or
closed room where there is insuf-
ficient ventilation.
■Emergency measures regard-
ing electrolyte
●If electrolyte gets in your eyes
Flush your eyes with clean
water for at least 15 minutes
and get immediate medical
attention. If possible, continue
to apply water with a sponge or
cloth while traveling to the near-
est medical facility.
●If electrolyte gets on your skin
Wash the affected area thor-
oughly. If you feel pain or burn-
ing, get medical attention
immediately.
●If electrolyte gets on your
clothes
It can soak through clothing on
to your skin. Imm ediately take
off the clothing and follow the
procedure above if necessary.
●If you accidentally swallow elec-
trolyte
Drink a large quantity of water
or milk. Get emergency medical
attention immediately.
■When there is insufficient 12-
volt battery fluid
Do not use if there is insufficient
fluid in the 12-volt battery. There
is a possible danger that the 12-
volt battery may explode.