2019 LEXUS UX250H cooling

3376-3. Do-it-yourself maintenance
6
Maintenance and care
Fuse boxes (P.370)
Engine coolant reservoir ( P.339)
Engine oil filler cap ( P.338)
Power control unit coolant reservoir ( P.340)
Brake fluid reservoir ( P.341)
Radiator ( P.340)
Condenser ( P.340)
Electric cooling fans
Engine oil level dipstick ( P.337)
Washer fluid tank ( P.341)
■12-volt battery
 P.342
With the engine at operating tempera-
ture and turned off, check the oil level
Engine compartment
Components
A
B
C
D
E
F
G
H
I
J
Checking and adding the engine
oil

3406-3. Do-it-yourself maintenance
■Power control unit coolant reser-
voirReservoir cap
“F” line
“L” line
If the level is on or below the “L” line, add
coolant up to the “F” line.
■Coolant selection
Only use “Toyota Super Long Life Coolant”
or a similar high quality ethylene glycol
based non-silicate, non-amine, non-nitrite,
and non-borate coolant with long-life
hybrid organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is a mix-
ture of 50% coolant and 50% deionized
water.
(Minimum temperature: -31°F [-35°C])
Canada:
“Toyota Super Long Life Coolant” is a mix-
ture of 55% coolant and 45% deionized
water.
(Minimum temperature: -44°F [-42°C])
For more details about coolant, contact
your Lexus dealer.
■If the coolant level drops within a short
time of replenishing
Visually check the radiator, hoses,
engine/power control unit coolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have your Lexus
dealer test the cap and check for leaks in
the cooling system.
Check the radiator and condenser and
clear away any foreign objects.
If either of the above parts is extremely
dirty or you are not sure of their condi-
tion, have your vehicle inspected by
your Lexus dealer.
A
B
C
WARNING
■When the hybrid system is hot
Do not remove the en gine/power control
unit coolant reservoir caps.
The cooling system may be under pres-
sure and may spray hot coolant if the cap
is removed, causing serious injuries, such
as burns.
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 pre-
vent it from damaging parts or paint.
Checking the radiator and con-
denser
WARNING
■When the hybrid system is hot
Do not touch the radiator or condenser
as they may be hot and cause serious
injuries, such as burns.

3416-3. Do-it-yourself maintenance
6
Maintenance and care
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN” lines
on the tank.
■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
Items
Clean funnel
■Brake fluid can absorb moisture from
the air
Excess moisture in the brake fluid can cause
a dangerous loss of braking efficiency. Use
only newly opened brake fluid.
If none of the washer do not work or
the “Windshield Washer Fluid Low”
appears on the multi-information dis-
play, the washer tank may be empty.
Add washer fluid.
WARNING
■When the electric cooling fans are
operating
Do not touch the engine compartment.
With the power switch in ON, the elec-
tric cooling fans may automatically start
to run if the air conditioning is on and/or
the coolant temperature is high. Be sure
the power switch is OFF when working
near the electric cooling fans or radiator
grille.
Checking and adding the brake
fluid
WARNING
■When filling the reservoir
Take care as brake fluid can harm your
hands and eyes and damage painted sur-
faces.
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 leve l in the accumulator
is high.
If the reservoir need s frequent refilling,
there may be a serious problem.
Adding the washer fluid

3656-3. Do-it-yourself maintenance
6
Maintenance and care
filter.
Remove the dust from the air intake
vent with a vacuum cleaner etc.
Make sure to only use a vacuum to suck
out dust and clogs. Attempting to blow out
dust and clogs using an airgun etc. may
push it into the air intake vent.
If dust and clogs cannot be completely
removed with the air intake vent cover
installed, remove the cover and clean
NOTICE
■When using the air conditioning sys-
tem
Make sure that a filter is always installed.
Using the air conditioning system without
a filter may cause damage to the system.
■To prevent damage to the filter cover
When moving the filter cover in the
direction of arrow to release the fitting,
pay attention not to apply excessive force
to the claws. Otherwise, the claws may
be damaged.
Cleaning the hybrid battery
(
traction battery) air intake
v
ent and filter
To prevent the fuel economy from
being affected, visually inspect the
hybrid battery (traction battery) air
intake vent periodically for dust and
clogs. If it is dusty or clogged or if
“Maintenance required for Traction
battery cooling parts See owner’s
manual” is shown on the multi-infor-
mation display, clean the air intake
vent using the following proce-
dures:
Cleaning the air intake vent
If dust and clogs cannot be com-
pletely removed

3676-3. Do-it-yourself maintenance
6
Maintenance and care
7Install the air intake vent cover.
1
Insert the tab of the cover as shown
in the illustration.
2
Push the cover to engage the 5
claws.
8
Using a Phillips screwdriver, install
the clip.
■Scheduled maintenance of the air
intake vent is necessary when
In some situations such as when the vehicle
is used frequently or in heavy traffic or dusty
areas, the air intake vent may need to be
cleaned more regularly. For details, refer to
the “Warranty and Service Guide”,
“Owner’s Manual Supplement” or “Sched-
uled Maintenance”.
■Cleaning the air intake vent
●Dust in the air intake vent may interfere
with the cooling of the hybrid battery
(traction battery). If charging/discharging
of the hybrid battery (traction battery)
becomes limited, the distance that the
vehicle can be driven using the electric
motor (traction motor) may be reduced
and the fuel economy may be reduced. Inspect and clean the air intake vent peri-
odically.
●Improper handling of the air intake vent
cover and filter may result in damage to
them. If you have any concerns about
cleaning the filter, contact your Lexus
dealer.
■If “Maintenance required for Traction
battery cooling parts See owner’s man-
ual” is shown on the multi-information
display
●If this warning message is shown on the
multi-information display, remove the air
intake vent cover and clean the filter.
(
 P.365)
●After cleaning the air intake vent, start
the hybrid system and check that the
warning message is no longer shown. It
may take approximately 20 minutes after
the hybrid system is started until the
warning message disappears. If the warn-
ing message does not disappear, have the
vehicle inspected by your Lexus dealer.
WARNING
■When cleaning the air intake vent
●Do not use water or other liquids to
clean the air intake vent. If water is
applied to the hybrid battery (traction
battery) or other components, a mal-
function or fire may occur.
●Before cleaning the air intake vent,
make sure to turn the power switch off
to stop the hybrid system.
■When removing the air intake vent
cover
Do not touch the service plug located
near the air intake vent. ( P.66)

3686-3. Do-it-yourself maintenance
■If the electronic key battery is depleted
The following symptoms may occur:
●The smart access system with push-but-
ton start and wireless remote control will
not function properly.
●The operational range will be reduced.
■When the card key battery needs to be
replaced (if equipped)
The battery for the card key is available only
at Lexus dealers. Your Lexus dealer can
replace the battery for you.
Prepare the following before replacing
the battery:
 Flathead screwdriver
 Small flathead screwdriver
 Lithium battery CR2032
■Use a CR2032 lithium battery
●Batteries can be purchased at your Lexus
dealer, local electrical appliance shops or
camera stores.
●Replace only with the same or equivalent
type recommended by the manufacturer.
●Dispose of used batteries according to
the local laws.
NOTICE
■When cleaning the air intake vent
When cleaning the air intake vent, make
sure to only use a vacuum to suck out
dust and clogs. If a compressed air blow
gun, etc. is used to blow out dust and
clogs, the dust or clogs may be pushed
into the air intake ve nt, which may affect
the performance of the hybrid battery
(traction battery) and cause a malfunc-
tion.
■To prevent damage to the vehicle
●Do not allow water or foreign matter to
enter the air intake vent when the
cover is removed.
●Carefully handle the removed filter so
that it will not be damaged. If the filter
is damaged, have it replaced with a
new filter by your Lexus dealer.
●Make sure to reinstall the filter and
cover to their original positions after
cleaning.
●Do not install anything to the air intake
vent other than the exclusive filter for
this vehicle or use the vehicle without
the filter installed.
■If “Maintenance required for Traction
battery cooling parts See owner’s
manual” is shown on the multi-infor-
mation display
If the vehicle is continuously driven with
the warning message (indicating that
charging/discharging of the hybrid bat-
tery [traction battery] may become lim-
ited) displayed, the hybrid battery
(traction battery) may malfunction. If the
warning message is shown, clean the air
intake vent immediately.
Electronic key battery
Replace the battery with a new one
if it is depleted.
Items to prepare

3987-2. Steps to take in an emergency
reset. If necessary, perform maintenance.
Please reset the message after the mainte-
nance is performed. (P.328)
*: Refer to the separa te “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the maintenance interval
applicable to your vehicle.
■If “Maintenance Required Visit Your
Dealer” is displayed
Indicates that all maintenance is required to
correspond to the driven distance on the
maintenance schedule
*.
Comes on approximately 5000 miles
(8000 km) after the message has been
reset. (The indicator will not work properly
unless the message ha s been reset.) Per-
form the necessary maintenance. Please
reset the message after the maintenance is
performed. ( P.328)
*: Refer to the separa te “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the maintenance interval
applicable to your vehicle.
■If “Oil Maintenance Required Soon” is
displayed
Indicates that the engine oil should be
scheduled to be changed.
Check the engine oil and change it if neces-
sary. After changing the engine oil, make
sure to reset the message. ( P.339)
■If “Oil Maintenance Required” is dis-
played
Indicates that the engine oil should be
changed.
Check and change the en gine oil, and oil fil-
ter by your Lexus deal er. After changing the
engine oil, make sure to reset the message.
(  P.339)
■If a message that in dicates the need for
visiting your Lexus dealer is displayed
The system or part shown on the multi-
information display is malfunctioning. Have
the vehicle inspected by your Lexus dealer
immediately.
■If a message that indicates the need for
referring to Owner’ s Manual is dis-
played
●If any of the following messages are
shown on the multi-information display,
follow the instructions.
• “Engine Coolant Temp High” ( P.410)
• “Front Camera Unavailable” ( P.196)
• “Radar Cruise Control Unavailable” ( P.196)
●If any of the following messages are
shown on the multi-info rmation display, it
may indicate a malf unction. Have the
vehicle inspected by your Lexus dealer
immediately.
• “Access System with Elec. Key Malfunc-
tion”
• “Hybrid system malfunction”
•“Check Engine”
• “Hybrid battery system malfunction”
• “Accelerator system malfunction”
●If any of the following messages are
shown on the multi-info rmation display, it
may indicate a malfun ction. Immediately
stop the vehicle and contact your Lexus
dealer.
• “Braking Power Low”
• “Charging System Malfunction”
• “Oil Pressure Low”
●If “Low Auxiliary Battery See Owner’s
Manual” is shown
• When the display goes off after several
seconds
*:
Maintain the hybrid system operation for
more than 15 minutes and charge the 12-
volt battery.
• When the display does not go off:
Start up the hybrid system using the proce-
dures for “If the 12-volt battery is dis-
charged” ( P.405)
*: Displays for about 6 seconds
●If “Maintenance required for Traction bat-
tery cooling parts See owner’s manual” is
shown, the filter may be clogged, the air
intake vent may be blocked, or there may
be a gap in the duct. Therefore, perform
the following correction procedure.
• If the air intake vent and filter of the hybrid battery (traction battery) are dirty, per-

4107-2. Steps to take in an emergency
If the engine coolant temperature
gauge enters the red zone or
“Engine Coolant Temp High Stop in
a Safe Place See Owner’s Manual”
is shown on the multi-information
display
1
Stop the vehicle in a safe place and
turn off the air conditioning system,
and then stop the hybrid system.
2
If you see steam:
Carefully lift the hood after the
steam subsides.
If you do not see steam:
Carefully lift the hood.
3
After the hybrid system has cooled
down sufficiently, inspect the hoses
WARNING
■When replacing the 12-volt battery
●When the vent plug is close to the hold
down clamp, the battery fluid (acid)
may leak.
●For information regarding battery
replacement, contact your Lexus
dealer.
●After exchanging, securely attach the
elbow connected to the exhaust hose,
and exhaust hole plug to the exhaust
hole of the exchanged 12-volt battery.
If not properly installed, gases (hydro-
gen) may leak into the vehicle interior,
and there is the possible danger of the
gas igniting and exploding.
NOTICE
■When handling jumper cables
When connecting the jumper cables,
ensure that they do not become entan-
gled in the cooling fans or belt.
■To prevent damaging the vehicle
The exclusive jump starting terminal is to
be used when charging the 12-volt bat-
tery from another vehicle in an emer-
gency. It cannot be used to jump start
another vehicle.
If your vehicle overheats
The following may indicate that
your vehicle is overheating.
 The engine coolant temperature
gauge ( P.78, 82) enters the
red zone, or a loss of hybrid sys-
tem power is experienced. (For
example, the vehicle speed does
not increase.)
 “Engine Coolant Temp High Stop
in a Safe Place See Owner’s
Manual” or “Hybrid system over-
heated Output power reduced” is
shown on the multi-information
display.
 Steam comes out from under the
hood.
Correction procedures