Get Maintenance and care -> Motor compartment Guide for Toyota bZ4X SUV Second Generation (2025-2026)

465

7-3. Do-it-yourself maintenance

Motor compartment

Components

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)

7

Radiator (P.466)

Condenser (P.466)

Electric cooling fan

“MIN” lines on the reservoir

when the EV system is cold.

Checking the heater cool-

ant

The coolant level is satisfactory

if it is between the “MAX” and

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466

7-3. Do-it-yourself maintenance

WARNING

■When the heater system is

hot

Do not remove the heater coolant

reservoir caps.

The heater system may be under

pressure and may spray hot cool-

ant if the cap is removed, causing

serious injuries, such as burns.

Reservoir cap

NOTICE

“MAX” line

“MIN” line

■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 the level is on or below the “MIN”

line, add coolant up to the “MAX”

line. (P.545)

■Coolant selection

■If you spill coolant

Only use “Toyota Super Long Life

Coolant” or a similar high quality

ethylene glycol based non-silicate,

non-amine, non-nitrite, and nonbo-

rate coolant with long-life hybrid

organic acid technology.

Be sure to wash it off with water to

prevent it from damaging parts or

paint.

Checking the radiator and

condenser

“Toyota Super Long Life Coolant” is

a mixture of 50% coolant and 50%

deionized water. (Minimum tem-

perature: -31°F [-35°C])

Check the radiator and con-

denser and clear away any for-

eign objects.

For more details about coolant, con-

tact your Toyota dealer.

■If the coolant level drops within

a short time of replenishing

If either of the above parts is

extremely dirty or you are not

sure of their condition, have

your vehicle inspected Toyota

dealer.

Visually check the radiator, hoses,

power control unit coolant reservoir

caps, drain cock and water pump.

If you cannot find a leak, have your

Toyota dealer, test the cap and

check for leaks in the cooling sys-

tem.

WARNING

■When the EV system is hot

Do not touch the radiator or con-

denser as they may be hot and

cause serious injuries, such as

burns.

Owners Manual_USA_M42C01_en

467

7-3. Do-it-yourself maintenance

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.

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.

Toyota cannot guarantee that the

use of a product other 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 coolant that has been

removed from the radiator.

Checking the power con-

trol unit coolant

For more details about coolant, con-

tact your Toyota dealer.

■If the coolant level drops within

The coolant level is satisfactory

if it is between the “MAX” and

“MIN” lines on the reservoir

when the EV system is cold.

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, test the cap and

check for leaks in the cooling sys-

tem.

WARNING

7

■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.

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

Owners Manual_USA_M42C01_en

468

7-3. Do-it-yourself maintenance

J1703 brake fluid

NOTICE

FMVSS No.116 DOT 4 or SAE

J1704 brake fluid

■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.

 Item

Clean funnel

■Brake fluid can absorb moisture

from the air

■If you spill coolant

Excess moisture in the brake fluid

can cause a dangerous loss of brak-

ing efficiency. Use only newly

opened brake fluid.

Be sure to wash it off with water to

prevent it from damaging parts or

paint.

WARNING

Checking and adding the

brake fluid

■When filling the reservoir

Take care as brake fluid can harm

your hands and eyes and damage

painted surfaces.

■ Checking fluid level

The brake fluid level should be

between the “MAX” and “MIN”

lines on the tank.

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 slightly as the brake

pads wear out or when the fluid

level in the accumulator is high.

If the reservoir needs frequent

refilling, there may be a serious

problem.

Reservoir cap

“MAX” line

Checking the 12-volt bat-

tery

“MIN” line

■ Adding fluid

Check the 12-volt battery as fol-

lows.

Make sure to check the fluid

type and prepare the necessary

item.

■ 12-volt battery exterior

 Fluid type

Make sure that the 12-volt bat-

tery terminals are not corroded

FMVSS No.116 DOT 3 or SAE

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469

7-3. Do-it-yourself maintenance

ing directly at the cell.

and that there are no loose con-

nections, cracks, or loose

clamps.

3 Put the vent plug back on

and close it securely.

Terminals

■Before recharging

Hold-down clamp

When recharging, the 12-volt bat-

tery produces hydrogen gas which

is flammable and explosive. There-

fore, observe the following precau-

tions before recharging:

■ Checking 12-volt battery

fluid

Check that the level is between

the “UPPER LEVEL” and

“LOWER LEVEL” lines.

●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.

7

■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.

“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-

●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

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470

7-3. Do-it-yourself maintenance

the second attempt.

■Where to safely charge the

●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.

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 the EV system will not start even

after multiple attempts at all the

methods above, contact your Toyota

dealer.

●If electrolyte gets on your skin

Wash the affected area thor-

oughly. If you feel pain or burn-

ing, get medical attention

immediately.

WARNING

■Chemicals in the 12-volt bat-

tery

●If electrolyte gets on your

clothes

It can soak through clothing on

to your skin. Immediately take

off the clothing and follow the

procedure above if necessary.

Batteries contain 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:

●If you accidentally swallow elec-

trolyte

Drink a large quantity of water

or milk. Get emergency medical

attention immediately.

●Do not cause sparks by touch-

ing the 12-volt battery terminals

with tools.

■When there is insufficient 12-

volt battery fluid

●Do not smoke or light a match

near the 12-volt battery.

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.

●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.

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471

7-3. Do-it-yourself maintenance

NOTICE

■When recharging the 12-volt

battery

■Do not use any fluid other

than washer fluid

Never recharge the 12-volt bat-

tery while the EV system is oper-

ating. Also, be sure all

Do not use soapy water or anti-

freeze instead of washer fluid.

Doing so may cause streaking on

the vehicle’s painted surfaces, as

well as damaging the pump lead-

ing to problems of the washer

fluid not spraying.

accessories are turned off.

■When adding distilled water

Avoid overfilling. Water spilled

during 12-volt battery recharging

may cause corrosion.

■Diluting washer fluid

Dilute washer fluid with water as

necessary.

Refer to the freezing tempera-

tures listed on the label of the

washer fluid bottle.

Adding the washer fluid

If the warning message appears

on the multi-information display,

the washer tank may be empty.

Add washer fluid.

7

WARNING

■When adding washer fluid

Do not add washer fluid when the

EV system is hot or operating as

washer fluid contains alcohol and

may catch fire if spilled on the

motor, etc.

Owners Manual_USA_M42C01_en

Maintenance and care -> Motor compartment for Your Toyota bZ4X SUV Second Generation (2025-2026)

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