2021 TOYOTA SIENNA HYBRID warning

3304-5. Using the driving support systems
■The Parking Support Brake
function (rear-crossing vehi-
cles) will operate when
The function will operate when the
PKSB OFF indicator is not illumi-
nated ( P.93, 95) and all of the fol-
lowing conditions are met:
●Hybrid system output restriction
control
• The Parking Support Brake is enabled.
• The vehicle speed is approxi-
mately 9 mph (15 km/h) or less.
• Vehicles are approaching from the right or left at th e rear of the vehi-
cle at a traveling speed of more
than approximately 5 mph (8
km/h)
• The shift lever is in R.
• The Parking Support Brake deter- mines that a stronger than normal
brake operation is necessary to
avoid a collision with an approach-
ing vehicle.
●Brake control
• Hybrid system output restriction control is operating
• The Parking Support Brake deter- mines that an emergency brake
operation is necessary to avoid a
collision with an approaching vehi-
cle.
■The Parking Support Brake
function (rear-crossing vehi-
cles) will stop operating when
The function will stop operating if
any of the following conditions are
met:
●Hybrid system output restriction
control
• The Parking Support Brake is dis- abled.
• The collision becomes avoidable
with normal brake operation.
• A vehicle is no longer approaching from the right or left at the rear of
the vehicle.
●Brake control
• The Parking Support Brake is dis- abled.
• Approximately 2 seconds have
elapsed since the vehicle was
stopped by brake control.
• The brake pedal is depressed
after the vehicle is stopped by
brake control.
• A vehicle is no longer approaching
from the right or left at the rear of
the vehicle.
■Re-enabling the Parking Sup-
port Brake (rear-crossing vehi-
cles)
 P.322
■Detection area of the Parking
Support Brake function (rear-
crossing vehicles)
The detection area of the Parking
Support Brake function (rear-cross-
ing vehicles) differs from the detec-
tion area of the RCTA function
(  P.306). Therefore, even if the
RCTA function detects a vehicle
and provides an alert, the Parking
Support Brake function (rear-cross-
ing vehicles) may not start operat-
ing.
WARNING
●Do not modify, disassemble or
paint the sensors.
●Do not replace a rear radar sen-
sor with a part o ther than a gen-
uine part.
●Do not damage the rear radar
sensors, and always keep the
radar sensors and their sur-
rounding area on the bumper
clean.
●If the area around a rear radar
sensor is subjected to an
impact, the system may not
operate properly due to a sen-
sor malfunction. Have the vehi-
cle inspected by your Toyota
dealer.
●Observe the rear radar sensor
handling precautions. ( P.301)

3374-5. Using the driving support systems
4
Driving
*: PCS will also be disabled (only Pre-Collision warning is avail-
able). The PCS warning light will
come on and a message will be
displayed on the multi-information
display. ( P.274)
■When the message is dis-
played on the multi-information
display showing that TRAC has
been disabled even if has
not been pressed
TRAC is temporary deactivated. If
the information continues to show,
contact your Toyota dealer.
■Operating conditions of hill-
start assist control
When the following four conditions
are met, the hill-start assist control
will operate:
●The shift lever is in a position
other than P or N (when starting
off forward/backward on an
upward incline).
●The vehicle is stopped.
●The accelerator pedal is not
depressed.
●The parking brake is not engaged.
■Automatic system cancelation
of hill-start as sist control
The hill-start assis t control will turn
off in any of the following situations:
●The shift lever is shifted to P or N.
●The accelerator pedal is
depressed.
●The parking brake is engaged.
●2 seconds at maximum elapsed
after the brake pedal is released.
■Sounds and vibrations caused
by the ABS, brake assist, VSC,
Trailer Sway Control, TRAC and
hill-start assist control systems
●A sound may be heard from the
engine compartment when the
brake pedal is dep ressed repeat-
edly, when the hybrid system is started or just after the vehicle
begins to move. This sound does
not indicate that a malfunction has
occurred in any of these systems.
●Any of the following conditions
may occur when the above sys-
tems are operating. None of these
indicates that a malfunction has
occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard also after the vehicle comes to a stop.
■ECB operating sound
ECB operating sound may be heard
in the following cases, but it does
not indicate that a malfunction has
occurred.
●Operating sound heard from the
engine compartment when the
brake pedal is operated.
●Motor sound of the brake system
heard from the f ront part of the
vehicle when the driver’ door is
opened.
●Operating sound heard from the
engine compartment when one or
two minutes passed after the stop
of the hybrid system.
■Active Cornering Assist opera-
tion sounds and vibrations
When the Active Cornering Assist is
operated, operation sounds and
vibrations may be generated from
the brake system, but this is not a
malfunction.
■EPS operation sound
When the steering wheel is oper-
ated, a motor sound (whirring
sound) may be heard. This does not
indicate a malfunction.
■Automatic reactivation of
TRAC, Trailer Sway Control and
VSC systems
After turning the TRAC, Trailer
Sway Control and VSC systems off,
the systems will be a utomatically re-
enabled in the following situations:

3394-5. Using the driving support systems
4
Driving
WARNING
■The ABS does not operate
effectively when
●The limits of tire gripping perfor-
mance have been exceeded
(such as excessively worn tires
on a snow covered road).
●The vehicle hydroplanes while
driving at high speed on wet or
slick roads.
■Stopping distance when the
ABS is operating may exceed
that of normal conditions
The ABS is not designed to
shorten the vehicle’s stopping dis-
tance. Always maintain a safe dis-
tance from the vehicle in front of
you, especially in the following sit-
uations:
●When driving on d irt, gravel or
snow-covered roads
●When driving with tire chains
●When driving over bumps in the
road
●When driving over roads with
potholes or uneven surfaces
■TRAC/VSC may not operate
effectively when
Directional control and power may
not be achievable while driving on
slippery road surfaces, even if the
TRAC/VSC system is operating.
Drive the vehicle carefully in con-
ditions where stability and power
may be lost.
■Active Cornering Assist does
not operate effectively when
●Do not overly rely on Active
Cornering Assist. Active Corner-
ing Assist may not operate
effectively when accelerating
down slopes or driving on slip-
pery road surfaces.
●When Active Corn ering Assist
frequently operates, Active Cor-
nering Assist may temporarily
stop operating to ensure proper
operation of the brakes, TRAC
and VSC.
■Hill-start assist control does
not operate effectively when
●Do not overly rely on hill-start
assist control. Hill-start assist
control may not operate effec-
tively on steep inclines and
roads covered with ice.
●Unlike the parking brake, hill-
start assist control is not
intended to hold the vehicle sta-
tionary for an extended period
of time. Do not attempt to use
hill-start assist control to hold
the vehicle on an incline, as
doing so may lead to an acci-
dent.
■When the
TRAC/ABS/VSC/Trailer Sway
Control is activated
The slip indicator flashes. Always
drive carefully. Reckless driving
may cause an accident. Exercise
particular care when the indicator
light flashes.
■When the TRAC/VSC/Trailer
Sway Control systems are
turned off
Be especially careful and drive at
a speed appropriate to the road
conditions. As these are the sys-
tems to help ensure vehicle stabil-
ity and driving force, do not turn
the TRAC/VSC/Tra iler Sway Con-
trol systems off unless necessary.
Trailer Sway Control is part of the
VSC system and will not operate
if VSC is turned off or experiences
a malfunction.

3404-5. Using the driving support systems
WARNING
■Replacing tires
Make sure that all tires are of the
specified size, brand, tread pat-
tern and total load capacity. In
addition, make sure that the tires
are inflated to the recommended
tire inflation pressure level.
The ABS, TRAC, Trailer Sway
Control and VSC systems will not
function correctly if different tires
are installed on the vehicle.
Contact your Toyota dealer for
further information when replacing
tires or wheels.
■Handling of tires and the sus-
pension
Using tires with any kind of prob-
lem or modifying the suspension
will affect the driving assist sys-
tems, and may cause a system to
malfunction.
■Trailer Sway Control precau-
tion
The Trailer Sway Control system
is not able to reduce trailer sway
in all situations . Depending on
many factors such as the condi-
tions of the vehicle, trailer, road
surface and driving environment,
the Trailer Sway Control system
may not be effective. Refer to
your trailer owner’s manual for
information on how to tow your
trailer properly.
■If trailer sway occurs
Observe the following precau-
tions.
Failing to do so may cause death
or serious injury.
●Firmly grip the steering wheel.
Steer straight ahead. Do not try
to control trailer sway by turning
the steering wheel.
●Begin releasing the accelerator
pedal immediately but very
gradually to reduce speed.
Do not increase speed. Do not
apply vehicle brakes.
If you make no extreme correction
with the steering or brakes, your
vehicle and traile r should stabi-
lize. ( P.220)
■Secondary Collision Brake
Do not rely solely upon the Sec-
ondary Collision Brake. This sys-
tem is designed to help reduce
the possibility of further damage
due to a secondary collision, how-
ever, that effect changes accord-
ing to various conditions. Overly
relying on the system may result
in death or serious injury.

3434-6. Driving tips
4
Driving
Use fluids that are appropriate
to the prevailing outside tem-
peratures.
• Engine oil
• Engine coolant
• Power control unit coolant
• Washer fluid
Have a service technician
inspect the condition of the
12-volt battery.
 Have the vehicle fitted with
four snow tires or purchase a
set of tire chains for the front
tires.
*
Ensure that all tires are the same
size and brand, and that chains
match the size of the tires.
*: Tire chains cannot be mounted
on vehicles with 20-inch tires.
Winter driving tips
Carry out the necessary
preparations and inspec-
tions before driving the
vehicle in winter. Always
drive the vehicle in a man-
ner appropriate to the pre-
vailing weather conditions.
Pre-winter preparations
WARNING
■Driving with snow tires
Observe the following precautions
to reduce the risk of accidents.
Failure to do so may result in a
loss of vehicle control and cause
death or serious injury.
●Use tires of the specified size.
●Maintain the recommended
level of air pressure.
●Do not drive in excess of 75
mph (120 km/h), regardless of
the type of snow tires being
used.
●Use snow tires on all, not just
some wheels.
■Driving with tire chains (vehi-
cles with 17-inch or 18-inch
tires)
Observe the following precautions
to reduce the risk of accidents.
Failure to do so may result in the
vehicle being unable to be driven
safely, and may cause death or
serious injury.
●Do not drive in excess of the
speed limit specifi ed for the tire
chains being used, or 30 mph
(50 km/h), whichever is lower.
●Avoid driving on bumpy road
surfaces or over potholes.
●Avoid sudden acceleration,
abrupt steering, sudden brak-
ing and shifting operations that
cause sudden engine braking.
●Slow down sufficiently before
entering a curve to ensure that
vehicle control is maintained.
●Do not use LTA (Lane Tracing
Assist) system.

3444-6. Driving tips
Perform the following according
to the driving conditions:
Do not try to forcibly open a
window or move a wiper that
is frozen. Pour warm water
over the frozen area to melt
the ice. Wipe away the water
immediately to prevent it from
freezing.
 To ensure proper operation of
the climate control system
fan, remove any snow that
has accumulated on the air
inlet vents in front of the wind-
shield.
 Check for and remove any
excess ice or snow that may
have accumulated on the
exterior lights, vehicle’s roof,
chassis, around the tires or on
the brakes.
 Remove any snow or mud
from the bottom of your shoes
before getting in the vehicle. Accelerate the vehicle slowly,
keep a safe distance between
you and the vehicle ahead, and
drive at a reduced speed suit-
able to road conditions.

Park the vehicle and move
the shift lever to P without set-
ting the parking brake. The
parking brake may freeze up,
preventing it from being
released. If the vehicle is
parked without setting the
parking brake, make sure to
block the wheels.
Failure to do so may be dan-
gerous because it may cause
the vehicle to move unexpect-
edly, possibly leading to an
accident.
When the parking brake is in
automatic mode, release the
parking brake after shifting
the shift lever to P. ( P.243)
 If the vehicle is left parked
with the brakes damp in cold
temperatures, there is a pos-
sibility of the brakes freezing.
 If the vehicle is parked without
setting the parking brake,
confirm that the shift lever
cannot be moved out of P
*.
*: The shift lever will be locked if it is
attempted to be shifted from P to
any other position without
NOTICE
■Repairing or replacing snow
tires
Request repairs or replacement of
snow tires from your Toyota
dealer or legitimate tire retailers.
This is because the removal and
attachment of snow tires affects
the operation of the tire pressure
warning valves and transmitters.
Before driving the vehicle
When driving the vehicle
When parking the vehicle

3454-6. Driving tips
4
Driving
depressing the brake pedal. If the
shift lever can be shifted from P,
there may be a problem with the
shift lock system. Have the vehi-
cle inspected by your Toyota
dealer immediately.
Vehicles with 17-inch or 18-
inch tires
Use the tire chains of correct
size and type.
Use SAE Class “S” type radial
tire chains, with the exception of
radial cable chains or V-bar type
chains.
Vehicles with 20-inch tires
Tire chains cannot be mounted.
Snow tires should be used
instead.
Regulations regarding the use
of tire chains vary depending on
location and type of road.
Always check local regulations
before installing chains.
■Tire chain installation
Observe the followi ng precautions
when installing and removing
chains:
●Install and remove tire chains in a
safe location.
●Install tire chains on the front tires
only. Do not install tire chains on
the rear tires.
●Install tire chains on front tires as
tightly as possible. Retighten
chains after drivi ng 1/4 - 1/2 mile
(0.5 - 1.0 km).
●Install tire chains following the
instructions provided with the tire
chains.
WARNING
■When parking the vehicle
When parking the v ehicle without
applying the parking brake, make
sure to chock the wheels. If you
do not chock the wheels, the vehi-
cle may move unexpectedly, pos-
sibly resulting in an accident.
Selecting tire chains
Regulations on the use of
tire chains (vehicles with
17-inch or 18-inch tires)
NOTICE
■Fitting tire chains
The tire pressure warning valves
and transmitters may not function
correctly when tire chains are fit-
ted.

3525-1. Using the air conditioning system and defogger
(Customizable features: P.551)
■Main control screen
Adjust the left side seat tem-
perature setting
Adjust the fan speed setting
Select the air flow mode
: Air flows to the upper body
: Air flows to the upper body and
feet
: Air flows to the feet
: Air flows to the feet and the
windshield defogger operates
Adjust the right side seat
temperature setting
Display the option control
screen. ( P.353)
“AUTO” switch (automatic
mode)
Set automatic mode on/off
(  P.353)
“OFF” switch
Turn the fan off
Set cooling and dehumidifi-
cation function
If “A/C” switch is not pressed, the
WARNING
■To prevent the windshield
from fogging up
Do not use the windshield defog-
ger switch during cool air opera-
tion in extremely humid weather.
The difference between the tem-
perature of the outside air and
that of the windshield can cause
the outer surface of the wind-
shield to fog up, blocking your
vision.
■To prevent burns
●Vehicles with outside rear view
mirror defoggers: Do not touch
the outside rear view mirror sur-
faces, as they can become very
hot and burn you.
●Vehicles with windshield wiper
deicer: Do not touch the glass at
lower part of the windshield or
to the side of the front pillars
when the windshield wiper de-
icer is on.
NOTICE
■To prevent 12-volt battery dis-
charge
Do not leave the air conditioning
system on longer than necessary
when the hybrid system is off.
■When repairing/replacing
parts of the air conditioning
system
Have repair/replacement per-
formed by your Toyota dealer.
When a part of th e air condition-
ing system, such as the evapora-
tor, is to be replaced, it must be
replaced with a new one.
Front air conditioning
control screen
A
B
C
D
E
F
G
H