2021 TOYOTA SIENNA HYBRID cooling

4466-3. Do-it-yourself maintenance
NOTICE
■When cleaning the air intake
vents
When cleaning the air intake
vents, 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
vents, which may affect the per-
formance of the hybrid battery
(traction battery) and cause a
malfunction.
■To prevent damage to the
vehicle
●Do not allow water or foreign
matter to enter t he air intake
vents when the covers are
removed.
●Carefully handle the removed
filter so that it will not be dam-
aged. If the filter is damaged,
have it replaced with a new filter
by your Toyota dealer.
●Make sure to reinstall the filters
and covers to their original posi-
tions after cleaning.
●Do not install anything to the air
intake vents other than the
exclusive filters for this vehicle
or use the vehicle without the fil-
ters installed.
■If “Maintenance Required for
Traction Battery Cooling
Parts See Owner’s Manual” is
shown on the multi-informa-
tion display
If the vehicle is continuously
driven with the warning message
(indicating that charging/discharg-
ing of the hybrid battery [traction
battery] may become limited) dis-
played, the hybrid battery (traction
battery) may malfunction. If the
warning message is displayed,
clean the air intake vents immedi-
ately.

4797-2. Steps to take in an emergency
7
When trouble arises
tion display, it may indicate a mal-
function. Immediately stop the
vehicle and contact your Toyota
dealer.
•“Braking Power Low”
• “12-Volt Battery Charging System
Malfunction”
• “Oil Pressure Low”
●If any of the following messages
are shown on the multi-informa-
tion display, the vehicle may have
run out of fuel. Stop the vehicle in
a safe place and, if the fuel level is
low, refuel the vehicle.
• “Hybrid System Stopped”
• “Engine Stopped”
●If “Low Auxiliary Battery See
Owner’s Manual” is shown
• When the display goes off after
several seconds
*:
Maintain the hybri d system opera-
tion 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
procedures for “If the 12-volt battery
is discharged” ( P.506)
*: Displays for about 6 seconds
●If “Maintenance Required for Trac-
tion Battery Cooling Parts See
Owner’s Manual” is shown, the fil-
ter 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 or filter of the hybrid battery (traction battery)
are dirty, perform the procedures
on P.443to clean them.
• If the warning message is shown when the air intake vent and filter
of the hybrid battery (traction bat-
tery) are not dirty, have the vehicle
inspected at your Toyota dealer.
■If “Engine Oil Level Low Add or
Replace” is displayed
The engine oil level may be low.
Check the level of the engine oil, and add engine oil if necessary.
This message may be displayed if
the vehicle is stopped on a slope.
Move the vehicle to a level surface
and check if the message disap-
pears.
■If “Hybrid System Stopped
Steering Power Low” is dis-
played
This message is displayed if the
hybrid system is stopped while driv-
ing.
When steering wheel operations are
heavier than usual, grip the steering
wheel firmly and operate it using
more force than usual.
■If “Hybrid System Overheated
Output Power Reduced” is
shown
The message may be shown when
driving under severe operating con-
ditions. (For example, when driving
up a long steep hill or driving up a
steep hill in reverse.)
Coping method: P.514
■If “Traction Battery Needs to be
Protected Refrain from the Use
of N Position” is shown
This message may be displayed
when the shift lever is in N.
As the hybrid battery (traction bat-
tery) can not be charged when the
shift lever is in N, shift the shift lever
to P when the vehicle is stopped.
■If “Traction Battery Needs to be
Protected Shift into P to
Restart” is shown
This message is displayed when the
hybrid battery (traction battery)
charge has becom e extremely low
because the shift lever has been left
in N for a certain amount of time.
When operating the vehicle, shift to
P and restart the hybrid system.
■If “Shift to P Before Exiting
Vehicle” is shown
Message is displayed when the
driver’s door is opened without turn-

5107-2. Steps to take in an emergency
WARNING
●Always wash your hands after
handling the 12-volt battery sup-
port, terminals, and other bat-
tery-related parts.
●Do not allow children near the
12-volt battery.
■After recharging the 12-volt
battery
Have the 12-volt battery
inspected at your Toyota dealer
as soon as possible.
If the 12-volt battery is deteriorat-
ing, continued use may cause the
12-volt battery to emit a malodor-
ous gas, which may be detrimen-
tal to the health of passengers.
■When replacing the 12-volt
battery
●For information regarding 12-
volt battery replacement, con-
tact your To yota dealer.
●After exchanging, securely
attach the exhaust hose and
exhaust hole plug to the
exhaust hole of the exchanged
12-volt battery. If not properly
installed, gases (hydrogen) 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 entangled in the cooling
fan, etc.
■To prevent damaging the
vehicle
The exclusive jump starting termi-
nal is to be used when charging
the 12-volt battery from another
vehicle in an emergency. It cannot
be used to jump start another
vehicle.

5117-2. Steps to take in an emergency
7
When trouble arises
■If the engine coolant tem-
perature gauge enters the
red zone or “Engine Cool-
ant 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 con-
ditioning 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 and radia-
tor core (radiator) for any
leaks.
Radiator
Cooling fan
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
4The coolant level is satisfac-
tory if it is between the
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL” line
If your vehicle over-
heats
The following may indicate
that your vehicle is over-
heating.
The needle of the engine
coolant temperature gauge
( P.97, 101) enters the red
zone, or a loss of hybrid
system power is experi-
enced. (For example, the
vehicle speed does not
increase.)
 “Engine Coolant Temp High
Stop in a Safe Place See
Owner’s Manual” or “Hybrid
System Overheated Output
Power Reduced” is shown
on the multi-information dis-
play.
 Steam comes out from
under the hood.
Correction procedures
A
B
A
B

5127-2. Steps to take in an emergency
“LOW” line
5 Add coolant if necessary.
Water can be us ed in an emer-
gency if engine coolant is unavail-
able.
6 Start the hybrid system and
turn the air conditioning sys-
tem on to check that the radi-
ator cooling fan operates and
to check for coolant leaks
from the radiator or hoses.
The fan operates when the air con-
ditioning system is turned on imme-
diately after a cold start. Confirm
that the fan is op erating by check-
ing the fan sound and air flow. If it is
difficult to check th ese, turn the air
conditioning system on and off
repeatedly. (The f an may not oper-
ate in freezing temperatures.)
7 If the fan is not operating:
Stop the hybrid system
immediately and contact your
Toyota dealer.
If the fan is operating:
Have the vehicle inspected at
the nearest Toyota dealer.
8 Check if “Engine Coolant
Temp High Stop in a Safe
Place See Owner’s Manual”
is shown on the multi-infor-
mation display.
If the message does not disappear:
Stop the hybrid system and contact
your Toyota dealer.
If the message is not displayed:
Have the vehicle inspected at the
nearest Toyota dealer.
■If “Hybrid System Over-
heated Output Power
Reduced” is shown on the
multi-information display
1 Stop the vehicle in a safe
place.
2 Stop the hybrid system and
carefully lift the hood.
3 After the hybrid system has
cooled down, inspect the
hoses and radiator core (radi-
ator) for any leaks.
Radiator
Cooling fan
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
4The coolant level is satisfac-
tory if it is between the
C
A
B

5147-2. Steps to take in an emergency
1Stop the hybrid system. Set
the parking brake and shift
the shift lever to P.
2 Remove the mud, snow or
sand from around the stuck
tire.
3 Place wood, stones or some
other material to help provide
traction under the tires.
4 Restart the hybrid system
5 Shift the shift lever to D or R
and release the parking
brake. Then, while exercising
caution, depress the acceler-
ator pedal.
■When it is difficult to free the
vehicle
Press to turn off TRAC.
(  P.336)
NOTICE
■To prevent damage to the
cooling system
Observe the following precau-
tions:
●Avoid contaminating the coolant
with foreign matter (such as
sand or dust, etc.).
●Do not use any coolant additive.
If the vehicle becomes
stuck
Carry out the following pro-
cedures if the tires spin or
the vehicle becomes stuck
in mud, dirt or snow:
Recovering procedure

5228-1. Specifications
Outside temperature
Oil viscosity (0W-16 is explained
here as an example):
• The 0W in 0W-16 indicates the characteristic of the oil
which allows cold startability.
Oils with a lower value before
the W allow for easier starting
of the engine in cold weather.
• The 16 in 0W-16 indicates the viscosity characteristic of the
oil when the oil is at high tem-
perature. An oil with a higher
viscosity (one with a higher
value) may be better suited if the vehicle is operated at high
speeds, or under extreme
load conditions.
How to read oil container label:
API registered mark is added to
some oil containers to help you
select the oil you should use.
*: The coolant capacity is the quantity of reference.
If replacement is ne cessary, contact your Toyota dealer.
A
Cooling system
Capacity*Gasoline engine11.4 qt. (10.8 L, 9.5 Imp. qt.)
Power control unit2.0 qt. (1.9 L, 1.7 Imp. qt.)
Coolant type
Use either of the following:
“Toyota Super Long Life Coolant”
 Similar high-quality ethylene gly-
colbased non-silic ate, non-amine,
non-nitrite, and non-borate cool-
ant with long-life hybrid organic
acid technology
Do not use plain water alone.
Ignition system (spark plug)
MakeDENSO FC16HR-Q8
Gap0.031 in. (0.8 mm)

Alphabetical Index573
Coat hooks .............................. 388
Condenser .............................. 420
Console box ............................ 367
Consumption screen.............. 122
Conversation mirror ............... 370
CoolantChecking .............................. 419
Preparing and c hecking before
winter.................................. 343
Warning light ........................ 467
Cooling system ...................... 419 Hybrid system overheating... 511
Cruise control Dynamic radar cruise control with full-speed range .......... 288
Cup holders ............................ 368
Current fuel consumption ..... 125
Current fuel economy ............ 106
Curtain shield airbags ............. 41
Customizable features ........... 540
D
Daytime running light system248 Replacing light bulbs ............ 451
Defogger Outside rear view mirrors ..... 350
Rear window ........................ 350
Windshield............................ 349
Digital Rear-view Mirror ......... 188 Adjustment ........................... 190
Cleaning ............................... 193
Dinghy towing ........................ 230
Display BSM (Blind Spot Monitor)..... 300
Consumption screen ............ 122
Drive information .................. 111
Driving information ............... 106
Dynamic radar cruise control with full-speed range .......... 288
Energy monitor ..................... 122
Head-up display ................... 118
Intuitive parking assist .......... 308 LTA (Lane Traci
ng Assist) ....281
Multi-information display.......104
RCD (Rear Camera Detection) ...........................................315
RCTA ....................................300
Warning messages ...............477
Do-it-yourself maintenance..................407, 411
Door lock Back door .............................150
Front doors ...........................132
Sliding doors.........................137
Smart key system .................164
Wireless remote control........130
Doors Automatic door locking and unlocking system ................136
Back door .............................150
Door glasses ........................201
Door lock ..............................132
Front doors ...........................132
Open door warning buzzer ...136
Outside rear view mirrors .....198
Sliding door child-protectors .142
Sliding doors.........................137
Drive information ....................111
Driver’s seat belt reminder light ...............................................473
Drive-start control ..................209
Driving Break-in tips .........................209
Correct posture .......................33
Driving mode select switch ...333
Hybrid vehicle dri ving tips .....341
Procedures ...........................208
Winter drive tips....................343
Driving informatio n display ...106
Driving mode select switch ...333
Driving position memory .......178 Memory recall function .........180
Power easy access system ..178
Driving support system informa-