2021 TOYOTA SIENNA HYBRID power steering

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.

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.

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.

3615-1. Using the air conditioning system and defogger
5
Interior features
*: If equipped
Turns the heated steering wheel
on/off
The indicator light comes on when
the heated steering wheel is oper-
ating.
■Operation condition
The power switch is in ON.
Each time the switch is pressed,
the operation condition changes
as follows.
Hi (3 segments lit)  Mid (2
segments lit)  Lo (1 segment
Heated steering
wheel*/seat heat-
ers*/seat ventilators*
 Heated steering wheel
Warm up the grip of the steer-
ing wheel
 Seat heaters
Warm up the seat upholstery
 Seat ventilators
Maintain good ventilation by
sucking air through the seat
upholstery
WARNING
■To prevent minor burn inju-
ries
Care should be taken if anyone in
the following categories comes in
contact with the steering wheel or
seats when the heater is on:
●Babies, small children, the
elderly, the sick and the physi-
cally challenged
●Persons with sensitive skin
●Persons who are fatigued
●Persons who have taken alco-
hol or drugs that induce sleep
(sleeping drugs, cold remedies,
etc.)
NOTICE
■To prevent damage to the
seat heaters and seat ventila-
tors
Do not put heavy objects that
have an uneven surface on the
seat and do not stick sharp
objects (needles, nails, etc.) into
the seat.
■To prevent 12-volt battery dis-
charge
Do not use the functions when the
hybrid system is off.
Heated steering wheel
Operating the seat heat-
ers

4597-1. Essential information
7
When trouble arises
1Steadily step on the brake
pedal with both feet and
firmly depress it.
Do not pump the brake pedal
repeatedly as this will increase the
effort required to slow the vehicle.
2Shift the shift lever to N.
If the shift lever is shifted to N
3 After slowing down, stop the
vehicle in a safe place by the
road.
4 Stop the hybrid system.
If the shift lever cannot be
shifted to N
3 Keep depressing the brake
pedal with both feet to reduce
vehicle speed as much as
possible.
4 Press and hold the power
switch for 2 consecutive sec-
onds or more, or press it briefly 3 times or more in suc-
cession.
5 Stop the vehicle in a safe
place by the road.
If your vehicle has to
be stopped in an emer-
gency
Only in an emergency, such
as if it becomes impossible
to stop the vehicle in the
normal way, stop the vehi-
cle using the following pro-
cedure:
Stopping the vehicle
WARNING
■If the hybrid system has to be
turned off while driving
●Power assist for the steering
wheel will be lost, making the
steering wheel heavier to turn.
Decelerate as much as possible
before turning off the hybrid sys-
tem.

4637-2. Steps to take in an emergency
7
When trouble arises
The following may indicate a
problem with your transmission.
Contact your Toyota dealer or
commercial towing service
before towing. 
The hybrid system warning
message is shown on the
multi-information display and
the vehicle does not move.
 The vehicle makes an abnor-
mal sound.
From the front (2WD models)
Release the parking brake.
Turn automatic mode off.
( P.244)
From the front (AWD models)
Use a towing dolly under the
rear wheels.
NOTICE
■To prevent damage to the
vehicle when towing using a
wheel-lift type truck
●Do not tow the vehicle from the
rear when the power switch is
off. The steering lock mecha-
nism is not strong enough to
hold the front wheels straight.
●When raising the vehicle,
ensure adequate ground clear-
ance for towing at the opposite
end of the raised vehicle. With-
out adequate clearance, the
vehicle could be damaged while
being towed.
■To prevent damage to the
vehicle when towing with a
sling-type truck
Do not tow with a sling-type truck,
either from the front or rear.
■Recreational towing (behind
motor home, etc.)
Never dinghy tow your vehicle to
prevent causing serious damage
to the AWD system and transmis-
sion. ( P.230)
Situations when it is nec-
essary to contact dealers
before towing
Towing with a wheel-lift
type truck

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.