2021 TOYOTA SIENNA HYBRID ABS

3354-5. Using the driving support systems
4
Driving■ECB (Electronically Con-
trolled Brake System)
The electronically controlled
system generates braking force
corresponding to the brake
operation
■ABS (Anti-lock Brake Sys-
tem)
Helps to prevent wheel lock
when the brakes are applied
suddenly, or if the brakes are
applied while driving on a slip-
pery road surface
■Brake assist
Generates an increased level of
braking force after the brake
pedal is depressed when the
system detects a panic stop sit-
uation
■VSC (Vehicle Stability Con-
trol)
Helps the driver to control skid-
ding when swerving suddenly or
turning on slippery road sur-
faces.
■Enhanced VSC (Enhanced
Vehicle Stability Control)
Provides cooperative control of
the ABS, TRAC, VSC and EPS.
Helps to maintain directional
stability when swerving on slip-
pery road surfaces by con-
trolling steering performance.
■Trailer Sway Control
Helps the driver to control trailer
sway by selectively applying
brake pressure for individual
wheels and reducing driving
torque when trailer sway is
detected.
■TRAC (Traction Control)
Helps to maintain drive power
and prevent the drive wheels
from spinning when starting the
vehicle or accelerating on slip-
pery roads
■Active Cornering Assist
(ACA)
Helps to prevent the vehicle
from drifting to the outer side by
performing inner wheel brake
control when attempting to
accelerate while turning
■Hill-start assist control
Helps to reduce the backward
Driving assist systems
To keep driving safety and
performance, the following
systems operate automati-
cally in response to various
driving situations. Be
aware, however, that these
systems are supplementary
and should not be relied
upon too heavily when oper-
ating the vehicle.
Summary of the driving
assist systems

3364-5. Using the driving support systems
movement of the vehicle when
starting on an uphill
■EPS (Electric Power Steer-
ing)
Employs an electric motor to
reduce the amount of effort
needed to turn the steering
wheel
■E-Four (Electronic On-
Demand AWD system)
(AWD models)
Automatically switches from
front wheel drive to all-wheel
drive (AWD) according to the
driving conditions, helping to
ensure reliable handling and
stability. Examples of condi-
tions where the system will
switch to AWD are when corner-
ing, going uphill, starting off or
accelerating, and when the road
surface is slippery due to snow,
rain, etc.
■The Secondary Collision
Brake
When the airbag sensor detects
a collision, the brakes and brake
lights are automatically con-
trolled to reduce the vehicle
speed and that helps reduce the
possibility of further damage
due to a secondary collision
■When the
TRAC/VSC/ABS/Trailer Sway
Control systems are operating
The slip indicator will flash while the
TRAC/VSC/ABS/Trai ler Sway Con-
trol systems are operating.
■Disabling the TRAC system
If the vehicle gets stuck in mud, dirt
or snow, the TRAC system may
reduce power from the hybrid sys-
tem to the wheels.
Pressing to turn the system off
may make it easier for you to rock
the vehicle in order to free it.
To turn the TRAC system off,
quickly press and release .
“Traction Control Turned Off” will be
shown on the multi-information dis-
play.
Press again to turn the system
back on.
■Turning off the
TRAC/VSC/Trailer Sway Con-
trol systems
To turn the TRAC/VSC/Trailer Sway
Control systems of f, press and hold
for more than 3 seconds while
the vehicle is stopped.
The VSC OFF indicator light will
come on and the “Traction Control
Turned Off” will be shown on the
multi-informat ion display.
*
Press again to turn the systems
back on.

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.

4216-3. Do-it-yourself maintenance
6
Maintenance and care
J1703 brake fluid
FMVSS No.116 DOT 4 or SAE
J1704 brake fluid
Item
Clean funnel
■Brake fluid can absorb moisture
from the air
Excess moisture in the brake fluid
can cause a dangerous loss of brak-
ing efficiency. Use only newly
opened brake fluid.
If any washer does not work or
“Windshield Washer Fluid Low”
is shown on the multi-informa-
tion display, the washer tank
may be empty. Add washer
fluid.
WARNING
■When filling the reservoir
Take care as brake fluid can harm
your hands and eyes and damage
painted surfaces.
If fluid gets on your hands or in
your eyes, flush th e affected area
with clean water immediately.
If you still experien ce 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.
Adding the washer fluid
WARNING
■When adding washer fluid
Do not add washer fluid when the
hybrid system is hot or operating
as washer fluid contains alcohol
and may catch fire if spilled on the
hybrid system, etc.
NOTICE
■Do not use any fluid other
than washer fluid
Do not use soapy water or engine
antifreeze 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.
■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.

4687-2. Steps to take in an emergency
■SRS warning light
■ABS warning light
■Electric power steering system warning light (warning
buzzer)
Warning lightDetails/Actions
Indicates a malfunction in:
The SRS airbag system;
 The front passenger occupan t classification system;
or
 The seat belt pretensioner system
 Have the vehicle insp ected by your Toyota
dealer immediately.
Warning lightDetails/Actions
(U.S.A.)
(Canada)
Indicates a malfunction in:
 The ABS; or
 The brake assist system
 Have the vehicle insp ected by your Toyota
dealer immediately.
Warning lightDetails/Actions
(Red/yellow)
Indicates a malfun ction in the EPS (Electric Power
Steering) system
 Have the vehicle insp ected by your Toyota
dealer immediately.

4757-2. Steps to take in an emergency
7
When trouble arises
■Conditions that the tire pres-
sure warning system may not
function properly
 P.428
WARNING
■If both the ABS and the brake
system warning lights remain
on
Stop your vehicle in a safe place
immediately and contact your
Toyota dealer. The vehicle will
become extremely unstable
during braking, and the ABS sys-
tem may fail, which could cause
an accident resulting in death or
serious injury.
■When the electric power
steering system warning light
comes on
When the light comes on yellow,
the assist to the power steering is
restricted. When the light comes
on red, the assist to the power
steering is lost and handling oper-
ations of the steering wheel
become extremely heavy.
When steering wheel operations
are heavier than usual, grip the
steering wheel firmly and operate
it using more force than usual.
■If the tire pressure warning
light comes on
Be sure to observe the following
precautions. Failure to do so
could cause a loss of vehicle con-
trol and result in death or serious
injury.
●Stop your vehicle in a safe
place as soon as possible.
Adjust the tire inflation pressure
immediately.
●If the tire pressure warning light
comes on even after tire infla-
tion pressure adjustment, it is
probable that you have a flat
tire. Check the tires. If a tire is
flat, change it with the spare tire
and have the flat tire repaired by
the nearest Toyota dealer.
●Avoid abrupt maneuvering and
braking. If the vehicle tires dete-
riorate, you could lose control of
the steering wheel or the
brakes.
■If a blowout or sudden air
leakage should occur
The tire pressure warning system
may not activate immediately.
■Maintenance of the tires
Each tire, includi ng the spare (if
provided), should be checked
monthly when cold and inflated to
the inflation pressure recom-
mended by the vehicle manufac-
turer on the vehicle placard or tire
inflation pressure label (tire and
load information label). (If your
vehicle has tires of a different size
than the size indicated on the
vehicle placard or tire inflation
pressure label [tire and load infor-
mation label], you should deter-
mine the proper tire inflation
pressure for those tires.)