2023 TOYOTA SIENNA HYBRID ABS

3354-5. Using the driving support systems
4
Driving
■Canceling a driving mode
●Sport mode is automatically can-
celed and the driving mode
returns to normal mode when the
power switch is turned off.
●Normal mode and Eco drive mode
are not canceled until another
driving mode is sel ected. (Even if
the power switch is turned off, nor-
mal mode and Eco drive mode will
not be automatically canceled).
■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
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
■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 maintai n 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 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 controls the drive
system such as to front-wheel
drive or AWD (all wheel drive)
according to various running
conditions including normal driv-
ing, during cornering, on a
uphill, when starting off, during
acceleration, on a slippery roads
due to snow or rain, thus con-
tributing to stable operability and
driving stability.
■The Secondary Collision
Brake
When the SRS airbag sensor
detects a collision and the sys-
tem operates, the brakes and
brake lights are automatically
controlled to reduce the vehicle
speed and help reduce the pos-
sibility of further damage due to
a secondary collision.
■When the
TRAC/VSC/ABS/T railer Sway
Control systems are operating
The slip indicator light will flash
while the TRAC/VSC/ABS/Trailer
Sway Control systems are operat-
ing.

3384-5. Using the driving support systems
■Sounds and vibrations caused
by the ABS, brake assist, VSC,
TRAC, Trailer Sway Control 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 t he 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 front part of the
vehicle when the driver’s 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 b e generated from
the brake system, but this is not a
malfunction.
■EPS operation sound
When the steering wheel is oper-
ated, a motor sou nd (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:
●When the power switch is turned
off
●If only the TRAC sy stem is turned
off, the TRAC will turn on when
vehicle speed increases
If both the TRAC and VSC sys-
tems are turned of f, 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 attempting 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 effect iveness 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 a nd 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
when the components are dam-
aged.

3394-5. Using the driving support systems
4
Driving
■Secondary Collision Brake
automatic cancellation
The system is automatically can-
celed in any of th e following situa-
tions.
●The vehicle speed drops to
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)
Perform the following actions.
●“AWD System Overheated
Switching to 2WD Mode”
AWD system is overheated. Stop
the vehicle in a safe place with the
hybrid system operating.
*
If the message disappears after a
while, there is n o problem. If the
message remains, have the vehicle
inspected by your Toyota dealer
immediately.
●“AWD System Overheated 2WD
Mode Engaged”
AWD system has been temporarily
released and switched to front-
wheel drive due to overheating.
Stop the vehicle in a safe place with
the hybrid system operating.
*
If the message disappears after a
while, AWD system will automati-
cally recover. If the message
remains, have the vehicle inspected
by your Toyota dealer immediately.
●“AWD system Malfunction 2WD
Mode Engaged Visit Your Dealer”
A malfunction occurs in the AWD
system. Have the vehicle inspected
by your Toyota dealer immediately.
*: When stopping the vehicle, do not stop the hybrid system until the
display message has turned off.
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 veh icle in front of
you, especially in the following sit-
uations:
●When driving on dirt, 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.

3404-5. Using the driving support systems
WARNING
■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 Cornering 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 light 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.
■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 p ressure 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 red uce trailer sway
in all situations. Depending on
many factors such as the condi-
tions of the vehicle, trailer, road
surface and drivi ng 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.

4186-3. Do-it-yourself maintenance
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.

4416-3. Do-it-yourself maintenance
6
Maintenance and care
1Turn the power switch off.
2 Using a Phillips screwdriver,
remove the clip.
3 Remove the air intake vent
cover.
Pull the cover as shown in the illus-
tration to disengage the claws,
starting from the claw in the upper
right corner and pull the cover
toward the front of the vehicle to remove it.
4
Remove the filter from the air
intake vent cover.
Disengage the 3 center claws from
the filter.
If dust has accumula ted on the air
intake vent cover, remove the dust
with a vacuum cleaner, etc.
5 Remove the dust and sand
from the filter.
Using a vacuum cleaner, etc.,
absorb dust and sand from the filter
by profiling the nozzle lightly along
the fold.
NOTICE
■If “Maintenance Required for
Traction Battery Cooling
Parts See Owner’s Manual” is
displayed on the multi-infor-
mation display
Clean the air intake vents immedi-
ately.
If the vehicle is continuously
driven with the warning message
displayed, it may cause a mal-
function or output restriction of the
hybrid battery (tr action battery).
Cleaning procedure

4667-2. 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.