2021 TOYOTA SIENNA HYBRID overheating

992-1. Instrument cluster
2
Vehicle status information and indicators
eration” refers to the conversion of
energy created by the movement
of the vehicle into electrical
energy.
In the following situ ation, the Hybrid
System Indicator does not operate.
●“READY” indicator is not illumi-
nated.
●The shift lever is in a range other
than D or S.
■Outside temperature display
●In the following si tuations, the cor-
rect outside tempe rature may not
be displayed, or the display may
take longer than normal to
change.
• When stopped, or driving at low speeds (less than 12 mph [20
km/h])
• When the outside temperature has changed suddenly (at the
entrance/exit of a garage, tunnel,
etc.)
●When “--” or “E” is displayed, the
system may be malfunctioning.
Take your vehicle to your Toyota
dealer.
●Displays the outside temperature
within the range of -40°F (-40°C)
to 122°F (50°C).
●When the outside temperature is
approximately 37°F (3°C) or
lower, the low outside temperature
indicator will flash for approxi-
mately 10 seconds , then stay on.
■Liquid crystal display
 P.105Switches the items of the odom-
eter, trip meter A, trip meter B
and oil maintenance by pressing
the “ODO TRIP” switch.
When the trip meter is dis-
played, pressing and holding the
switch will reset the trip meter.
WARNING
■The information display at
low temperatures
Allow the interior of the vehicle to
warm up before using the liquid
crystal information display. At
extremely low temperatures, the
display monitor may respond
slowly, and display changes may
be delayed.
For example, there is a lag
between the driver’s shifting and
the new shift range appearing on
the display. This lag could cause
the driver to downshift again,
causing rapid and excessive
engine braking and possibly an
accident resulting in death or
injury.
NOTICE
■To prevent damage to the
engine and its components
The engine may be overheating if
the engine coolant temperature
gauge is in the red zone (“H”). In
this case, immediately stop the
vehicle in a safe place, and check
the engine after it has cooled
completely. ( P.511)
Changing the trip meter
display

1032-1. Instrument cluster
2
Vehicle status information and indicators
energy.
In the following situ ation, the Hybrid
System Indicator does not operate.
●“READY” indicator is not illumi-
nated.
●The shift lever is in a range other
than D or S.
■Outside temperature display
●In the following si tuations, the cor-
rect outside tempe rature may not
be displayed, or the display may
take longer than normal to
change.
• When stopped, or driving at low speeds (less than 12 mph [20
km/h])
• When the outside temperature has changed suddenly (at the
entrance/exit of a garage, tunnel,
etc.)
●When “--” or “E” is displayed, the
system may be malfunctioning.
Take your vehicle to your Toyota
dealer.
●Displays the outside temperature
within the range of -40°F (-40°C)
to 122°F (50°C).
●When the outside temperature is
approximately 37°F (3°C) or
lower, the low outside temperature
indicator will flash for approxi-
mately 10 seconds , then stay on.
■Liquid crystal display
 P.105
■Customization
Settings (e. g. meter display) can be
changed on the screen of the
multi-informat ion display. (P.541)Switches the items of the odom-
eter, trip meter A, trip meter B
and oil maintenance by pressing
the “ODO TRIP” switch.
When the trip meter is dis-
played, pressing and holding the
switch will reset the trip meter.
WARNING
■The information display at
low temperatures
Allow the interior of the vehicle to
warm up before using the liquid
crystal information display. At
extremely low temperatures, the
display monitor may respond
slowly, and display changes may
be delayed.
For example, there is a lag
between the driver’s shifting and
the new shift range appearing on
the display. This lag could cause
the driver to downshift again,
causing rapid and excessive
engine braking and possibly an
accident resulting in death or
injury.
NOTICE
■To prevent damage to the
engine and its components
The engine may be overheating if
the engine coolant temperature
gauge is in the red zone (“H”). In
this case, immediately stop the
vehicle in a safe place, and check
the engine after it has cooled
completely. ( P.511)
Changing the trip meter
display

2134-1. Before driving
4
Driving
WARNING
●Do not leave a door or window
open if the curved glass is
coated with a metallized film
such as a silver-colored one.
Reflected sunlight may cause
the glass to act as a lens, caus-
ing a fire.
●Always apply the parking brake,
shift the shift lever to P, stop the
hybrid system and lock the vehi-
cle.
Do not leave the vehicle unat-
tended while the “READY” indi-
cator is illuminated.
If the vehicle is parked with the
shift lever in P but the parking
brake is not set, the vehicle may
start to move, possibly leading
to an accident.
●Do not touch the exhaust pipes
while the “READY” indicator is
illuminated or immediately after
turning the hybrid system off.
Doing so may cause burns.
■When taking a nap in the
vehicle
Always turn the hybrid system off.
Otherwise, if you accidentally
move the shift lever or depress
the accelerator pedal, this could
cause an accident or fire due to
hybrid system overheating. Addi-
tionally, if the vehicle is parked in
a poorly ventilated area, exhaust
gases may collect and enter the
vehicle, leading to death or a seri-
ous health hazard.
■When braking
●When the brakes a re wet, drive
more cautiously.
Braking distance increases
when the brakes are wet, and
this may cause one side of the
vehicle to brake differently than
the other side. Also, the parking
brake may not securely hold the
vehicle.
●If the electronically controlled
brake system does not operate,
do not follow other vehicles
closely and avoid hills or sharp
turns that require braking.
In this case, braking is still pos-
sible, but the brake pedal
should be depressed more
firmly than usual. Also, the brak-
ing distance will increase. Have
your brakes fixed immediately.
●The brake system consists of 2
or more individual hydraulic sys-
tems; if one of the systems fails,
the other will still operate. In this
case, the brake pedal should be
depressed more firmly than
usual and the braking distance
will increase. Have your brakes
fixed immediately.
■If the vehicle becomes stuck
(AWD models)
Do not spin the wheels exces-
sively when any of the tires is up
in the air, or the vehicle is stuck in
sand, mud, etc. This may damage
the driveline components or pro-
pel the vehicle forward or back-
ward, causing an accident.
NOTICE
■When driving the vehicle
●Do not depress the accelerator
and brake pedals at the same
time during driving, as this may
restrain the hybrid system out-
put.
●Do not use the accelerator
pedal or depress the accelera-
tor and brake pedals at the
same time to hold the vehicle on
a hill.

2284-1. Before driving
Avoid jerky starts or sudden
acceleration.
 Avoid jerky steering and
sharp turns, and slow down
before making turn.
 Note that when making a turn,
the trailer wheels will be
closer than the vehicle wheels
to the inside of the turn. Com-
pensate by making a wider
than normal turning radius.
 Slow down before making a
turn, in cross winds, on wet or
slippery surfaces, etc.
Increasing vehicle speed can
destabilize the trailer.
Take care when passing other
vehicles. Passing requires
considerable distance. After
passing a vehicle, do not for-
get the length of your trailer,
and be sure you have plenty
of room before changing
lanes.
 To maintain engine braking
efficiency and charging sys-
tem performance, when using
engine braking, do not use
the transmission in D.
 Instability happens more fre-
quently when descending
steep or long downhill grades.
Before descending, slow
down and downshift. Do not
make sudden downshifts
while descending steep or
long downhill grades.
 Avoid holding the brake pedal down too long or applying the
brakes too frequently. This
could cause the brakes to
overheat and result in
reduced braking efficiency.
 Due to the added load of the
trailer, your vehicle’s hybrid
system may overheat on hot
days (at temperatures over
85°F [30°C]) when driving up
a long or steep grade. If the
engine coolant temperature
gauge indicates overheating,
immediately turn off the air
conditioning (if in use), pull
your vehicle off the road and
stop in a safe spot. ( P.511)
 Always place wheel blocks
under both the vehicle’s and
the trailer’s wheels when
parking. Apply the parking
brake firmly, and put the
transmission in P. Avoid park-
ing on a slope, but if unavoid-
able, do so only after
performing the following:
1 Apply the brakes and keep
them applied.
2 Have someone place wheel
blocks under both the vehi-
cle’s and trailer’s wheels.
3 When the wheel blocks are in
place, release the brakes
slowly until the blocks absorb
the load.
4 Apply the parking brake
firmly.

2324-2. Driving procedures
■When the ambient temperature
is low, such as during winter
driving conditions
When starting the hybrid system,
the flashing time of the “READY”
indicator may be long. Leave the
vehicle as it is u ntil the “READY”
indicator is steady on, as steady
means the vehicle is able to move.
■Sounds and vibrations specific
to a hybrid vehicle
 P.81
■If the 12-volt battery is dis-
charged
The hybrid system cannot be
started using the smart key system.
Refer to P.506to re start the hybrid
system.
■Electronic key battery depletion
 P.128
■Conditions affecting operation
 P.166
■Note for the entry function
 P.166
■Steering lock function
●After turning the power switch to
OFF and opening and closing the
doors, the steer ing wheel will be
locked due to the steering lock
function. Operating the power
switch again automatically can-
cels the steering lock.
●When the steering lock cannot be
released, “Push Power Switch
while Turning the Steering Wheel
in Either Direction” will be dis-
played on the multi-information
display.
Check that the shift lever is set in
P. Press the power switch shortly
and firmly while turning the steer-
ing wheel left and right.
●To prevent the steering lock motor
from overheating , the motor may
be suspended if the hybrid system
is turned on and off repeatedly in
a short period of ti me. In this case,
refrain from operating the power
switch. After about 10 seconds,
the steering lo ck motor will
resume functioning.
■If there is a malfunction in the
smart key system
If “Smart Key System Malfunction
See Owner’s Manual” is displayed
on the multi-information display, the
system may be malfunctioning.
Have the vehicle inspected by your
Toyota dealer immediately.
■If the “READY” indicator does
not come on
In the event that the “READY” indi-
cator does not come on even after
performing the proper procedures
for starting the vehicle, contact your
Toyota dealer immediately.
■When “Check Fuel Cap” is dis-
played on the multi-information
display
 P.261
■If the hybrid sys tem is malfunc-
tioning
 P.86
■Electronic key battery
 P.447
■Operation of the power switch
●If the switch is not pressed shortly
and firmly, the power switch mode
may not change o r the hybrid sys-
tem may not start.
●If attempting to res tart the hybrid

2454-2. Driving procedures
4
Driving
■If “Parking Brake Unavailable”
is displayed on the multi-infor-
mation display
Operate the parking brake switch. If
the message does not disappear
after operating the switch several
times, the system may be malfunc-
tioning. Have the vehicle inspected
by your Toyota dealer.
■Parking brake operation sound
When the parking brake operates, a
motor sound (whirring sound) may
be heard. This does not indicate a
malfunction.
■Parking brake indicator light
●Depending on the power switch
mode, the parking brake indicator
light will turn on and stay on as
described below:
ON: Comes on until the parking
brake is released.
Not in ON: Stays on for approxi-
mately 15 seconds.
●When the power switch is turned
off with the parking brake set, the
parking brake indicator light will
stay on for about 15 seconds. This
does not indicate a malfunction.
■When the parking brake switch
malfunctions
Automatic mode (automatic brake
setting and releas ing) will be turned
on automatically.
■Parking the vehicle
 P.208
■Parking brake engaged warning
buzzer
A buzzer will sound if the vehicle is
driven with the parking brake
engaged. “Parking Brake ON” is dis-
played on the multi-information dis-
play (with the vehicle reaching a
speed of 3 mph [5 km/h]).
■If the brake system warning
light comes on
 P.466
■Usage in winter time
 P.344
WARNING
■When parking the vehicle
Do not leave a child in the vehicle
alone. The parking brake may be
released unintentionally by a child
and there is the danger of the
vehicle moving that may lead to
an accident resulting in death or
serious injury.
■Parking brake switch
Do not set any objects near the
parking brake switch. Objects
may interfere with the switch and
may lead the parking brake to
unexpectedly operate.
NOTICE
■When parking the vehicle
Before you leave the vehicle, shift
the shift lever to P, set the parking
brake and make s ure that the
vehicle does not move.
■When the system malfunc-
tions
Stop the vehicle in a safe place
and check the warning messages.
■When the parking brake can-
not be released due to a mal-
function
Driving the vehicle with the park-
ing brake set will lead to brake
components overheating, which
may affect braking performance
and increase brake wear. Have
the vehicle inspected by your
Toyota dealer immediately if this
occurs.

3384-5. Using the driving support systems
●When the power switch is turned
off.
●If only the TRAC system is turned
off, the TRAC will turn on when
vehicle speed increases.
If both the TRAC and VSC sys-
tems are turned off, automatic re-
enabling will not occur when vehi-
cle speed increases.
■Operating conditions of Active
Cornering Assist
The system operates when the fol-
lowing occurs.
●TRAC/VSC can operate
●The driver is at tempting to accel-
erate while turning
●The system detects that the vehi-
cle is drifting to the outer side
●The brake pedal is released
■Reduced effectiveness of the
EPS system
The effectiveness of the EPS sys-
tem is reduced to prevent the sys-
tem from overheating when there is
frequent steering input over an
extended period of time. The steer-
ing wheel may feel heavy as a
result. Should this occur, refrain
from excessive steering input or
stop the vehicle and turn the hybrid
system off. The EPS system should
return to normal within 10 minutes.
■Secondary Collision Brake
operating conditions
The system operates when the SRS
airbag sensor de tects a collision
while the vehicle is in motion. How-
ever, the system does not operate in
any of the following situations.
●The vehicle speed is below 6 mph
(10 km/h)
●Components are damaged
■Secondary Collision Brake
automatic cancellation
The system is automatically can-
celed in any of th e following situa-
tions.
●The vehicle speed drops below
approximately 6 mph (10 km/h)
●A certain amount of time elapses
during operation
●The accelerator pedal is
depressed a large amount
■If a message about AWD is
shown on the multi-information
display (AWD models)
If one of the follo wing messages is
shown on the multi-information dis-
play, perform each action.
●“AWD System Overheated
Switching to 2WD Mode”
The AWD system is overheating.
Drive the vehicle at low speeds and
stop the vehicle in a safe place with
the hybrid system operating until the
message is cleared. If the message
disappears, it is possible to drive the
vehicle normally.
●“AWD System Overheated 2WD
Mode Engaged”
The AWD system has been can-
celed and switch ed to the front-
wheel drive due to overheating.
Drive the vehicle at low speeds and
stop the vehicle in a safe place with
the hybrid system operating until the
message is cleared. If the message
disappears, it is possible to drive the
vehicle normally.
●“AWD System Malfunction 2WD
Mode Engaged Visit Your Dealer”
The AWD system has been stopped
and switched to the front-wheel
drive due to a malfunction. Have
your vehicle inspected by your
Toyota dealer immediately.

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-