2021 TOYOTA SIENNA HYBRID brakes

2224-1. Before driving
■GCWR (Gross Combination
Weight Rating)
The maximum allowable gross
combination weight. The gross
combination weight is the sum
of the total vehicle weight
(including the occupants, cargo
and any optional equipment
installed on the vehicle) and the
weight of the trailer being towed
(including the cargo in the
trailer).
■GVWR (Gross Vehicle
Weight Rating)
The maximum allowable gross
vehicle weight. The gross vehi-
cle weight is the total weight of
the vehicle. When towing a
trailer, it is the sum of the vehi-
cle weight (including the occu-
pants, cargo and any optional
equipment installed on the vehi-
cle) and the tongue weight.
■GAWR (Gross Axle Weight
Rating)
The maximum allowable gross
axle weight. The gross axle
weight is the load placed on
each axle (front and rear).
Front GAWR
WARNING
●If the gross trailer weight
exceeds unbraked TWR, trailer
brakes are required. Toyota rec-
ommends trailers with brakes
that conform to all applicable
federal and state/provincial reg-
ulations.
●Never tap into y our vehicle’s
hydraulic system, as this will
lower the vehicle’s braking
effectiveness.
●Never tow a trailer without using
a safety chain securely attached
to both the traile r and the vehi-
cle. If damage occurs to the
coupling unit or hitch ball, there
is danger of the trailer wander-
ing into another lane.
Towing related terms
A

2234-1. Before driving
4
Driving
Rear GAWR
■TWR (Trailer Weight Rating)
The maximum allowable gross
trailer weight. The gross trailer
weight is the sum of the trailer
weight and the weight of the
cargo in the trailer.
TWR is calculated assuming
base vehicle with one driver,
one front passenger, hitch and
hitch systems (if required).
Additional optional equipment, pas-
sengers and cargo in the vehicle
will reduce the tra iler weight rating
so as not to exceed GCWR, GVWR
and GAWR.
If the gross traile r weight exceeds
3000 lb. (1360 kg), it is recom-
mended to use a trailer with 2 or
more axles.
(With brakes)
■Unbraked TWR (Unbraked
Trailer Weight Rating)
The trailer weight rating for tow-
ing a trailer without a trailer ser-
vice brake system. (Without brakes)
■Tongue Weight
The load placed on the trailer
hitch ball. ( P.224)
 The gross trailer weight must
never exceed 3500 lb. (1585
kg)
*.
*: The towing package is required.
Toyota does not recommend tow-
ing with this vehicle without the tow-
ing package.
 The gross combination weight
must never exceed the
GCWR described below:
2WD models
8818 lb. (4000 kg)
*

AWD models
8995 lb. (4080 kg)
*
B
A
Weight limits
A

2244-1. Before driving
*: The towing package is required.
Toyota does no t recommend tow-
ing with this vehicle without the tow-
ing package.
 The gross vehicle weight
must never exceed the
GVWR indicated on the Certi-
fication Label.
 The gross axle weight on
each axle must never exceed
the GAWR indicated on the
Certification Label.
 If the gross trailer weight is
over the unbraked TWR,
trailer service brakes are
required.
 If the gross trailer weight is
over 2000 lbs. (907 kg), a
sway control device with suffi-
cient capacity is required.
Confirm that the gross trailer
weight, gross combination
weight, gross vehicle weight,
gross axle weight and tongue
weight are all within the limits.
■GCWR*
2WD models
8818 lb. (4000 kg)
AWD models
8995 lb. (4080 kg)
*: This model meets the tow-vehicle trailering requirement of SAE
International per SAE J2807.
The towing package is required.
Toyota does not recommend tow-
ing with this vehicle without the tow-
ing package.
■TWR*
3500 lb. (1585 kg)
*: This model meets the tow-vehicle trailering requirement of SAE
International per SAE J2807.
The towing package is required.
Toyota does not recommend tow-
ing with this vehicle without the tow-
ing package.
■Unbraked TWR*
1000 lb. (450 kg)
*: This model meets the tow-vehicle trailering requirement of SAE
International per SAE J2807.
 A recommended tongue
weight varies in accordance
with the types of trailers or
towing as described below.
 To ensure the recommended
values shown below, the
trailer must be loaded by
referring to the following
GCWR, TWR and
Unbraked TWRTrailer Tongue Weight

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.

2294-1. Before driving
4
Driving
5Shift into P and turn off the
hybrid system.
 When restarting after parking
on a slope:
1 With the transmission in P,
start the hybrid system. Be
sure to keep the brake pedal
depressed.
2 Shift into a forward gear. If
reversing, shift into R.
3 If the parking brake is in man-
ual mode, release the park-
ing brake. ( P.243)
4 Release the brake pedal, and
slowly pull or back away from
the wheel blocks. Stop and
apply the brakes.
5 Have someone retrieve the
blocks.
■Break-in schedule
If your vehicle is new or equipped
with any new power train compo-
nents (such as an engine, transmis-
sion, differential or wheel bearing),
Toyota recommends that you do not
tow a trailer unt il the vehicle has
been driven for over 500 miles (800
km).
After the vehicle has been driven for
over 500 miles (800 km), you can
start towing. However, for the next
500 miles (800 km), drive the vehi-
cle at a speed of less than 45 mph
(72 km/h) when towing a trailer, and
avoid full throttle acceleration.
■Maintenance
●If you tow a traile r, your vehicle
will require more f requent mainte-
nance due to the additional load.
(See “Scheduled Maintenance
Guide” or “Owner’s Manual Sup-
plement”.)
●Retighten the fixing bolts of the
towing ball and bracket after
approximately 600 miles (1000
km) of tra iler towing.
■If trailer sway occurs
One or more factors (crosswinds,
passing vehicles, rough roads, etc.)
can adversely affect handling of
your vehicle and t railer, causing
instability.
●If trailer swaying occurs:
• Firmly grip the steering wheel. Steer straight ahead.
Do not try to contr ol trailer sway-
ing by turning the steering wheel.
• Begin releasing the accelerator pedal immediately but very gradu-
ally 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 trailer should stabilize (if
enabled, Trailer Sway Control can
also help to stabilize the vehicle and
trailer.).
●After the trailer swaying has
stopped:
• Stop in a safe place. Get all occu- pants out of the vehicle.
• Check the tires of the vehicle and the trailer.
• Check the load in the trailer.
Make sure the load has not
shifted.
Make sure the tongue weight is
appropriate, if possible.
• Check the load in the vehicle. Make sure the vehicle is not over-
loaded after occupants get in.
If you cannot find any problems, the
speed at which trailer swaying
occurred is beyond the limit of your
particular vehicle-trailer combina-
tion. Drive at a lower speed to pre-
vent instability. Remember that
swaying of the towing vehicle-trailer
increases as speed increases.

2464-2. Driving procedures
Press the brake hold switch to
turn the brake hold system on
The brake hold standby indicator
(green) comes on. While the
system is holding the brake, the
brake hold operated indicator (yel-
low) comes on.
■Brake hold system operating
conditions
The brake hold system cannot be
turned on in the following condi-
tions:
●The driver’s doo r is not closed.
●The driver is not wearing the seat
belt.
If any of the cond itions above are
detected when the brake hold sys-
tem is enabled, the system will turn
off and the brake hold standby indi-
cator light will go off. In addition, if
any of the conditions are detected
while the system is holding the
brake, a warning buzzer will sound
and a message will be shown on the
multi-information display. The park-
ing brake will then be set automati-
cally.
■Brake hold function
●If the brake pedal is left released
for a period of about 3 minutes
after the system has started hold-
ing the brake, the parking brake
will be set automatically. In this
case, a warning buzzer sounds
and a message is shown on the
multi-information display.
●To turn the syste m off while the
system is holding the brake, firmly
depress the brake pedal and
press the button again.
●The brake hold function may not
hold the vehicle when the vehicle
is on a steep incline. In this situa-
tion, it may be ne cessary for the
driver to apply the brakes. A warn-
ing buzzer will sound and the
multi-information display will
inform the driver of this situation. If
a warning message is shown on
the multi-information display, read
the message and follow the
instructions.
■When the parking brake is set
automatically while the system
is holding the brakes
Perform any of the following opera-
tions to release the parking brake:
●Depress the accelerator pedal.
(The parking brake will not be
released automatically if the seat
belt is not fastened.)
●Operate the parkin g brake switch
with the brake pedal depressed.
Brake Hold
The brake hold system
keeps the brake applied
when the shift lever is in D,
S or N with the system on
and the brake pedal has
been depressed to stop the
vehicle. The system
releases the brake when the
accelerator pedal is
depressed with the shift
lever in D or S to allow
smooth start off.
Enabling the system
A
B

2674-5. Using the driving support systems
4
Driving
The system can detect the fol-
lowing:
Vehicles
 Bicyclists
 Pedestrians
■Pre-collision warning
When the system determines
that the possibility of a frontal
collision is high, a buzzer will
sound and a warning message
will be displayed on the multi-
information display to urge the
driver to take evasive action.
■Pre-collision brake assist
When the system determines
that the possibility of a frontal
collision is high, the system
applies greater braking force in
relation to how strongly the
brake pedal is depressed.
■Pre-collision braking
If the system determines that
the possibility of a frontal colli-
sion is extremely high, the
brakes are automatically applied
to help avoid the collision or
reduce the impact of the colli-
sion.
PCS (Pre-Collision Sys-
tem)
The pre-collision system
uses a radar sensor and
front camera to detect
objects ( P.267) in front of
the vehicle. When the sys-
tem determines that the
possibility of a frontal colli-
sion with an object is high,
a warning operates to urge
the driver to take evasive
action and the potential
brake pressure is increased
to help the driver avoid the
collision. If the system
determines that the possi-
bility of a frontal collision
with an object is extremely
high, the brakes are auto-
matically applied to help
avoid the collision or help
reduce the impact of the
collision.
The pre-collision system can
be disabled/enabled and the
warning timing can be
changed. ( P.269)
Detectable objects
System functions

2744-5. Using the driving support systems
such as heavy rain, fog, snow or a
sandstorm
• When driving through steam or
smoke
• When the surrounding area is dim, such as at dawn or dusk, or while
at night or in a t unnel, making a
detectable object appear to be
nearly the same color as its sur-
roundings
• When driving in a place where the surrounding brightness changes
suddenly, such as at the entrance
or exit of a tunnel
• After the hybrid system has
started the vehicle has not been
driven for a certain amount of time
• While making a left/right turn and
for a few seconds after making a
left/right turn
• While driving on a curve and for a
few seconds after driving on a
curve
• If your vehicle is skidding
• If the front of the vehicle is raised
or lowered
• If the wheels are misaligned
• If a wiper blade is blocking the front camera
• The vehicle is being driven at extremely high speeds
• When driving on a hill
• If the radar sensor or front camera
is misaligned
●In some situations such as the fol-
lowing, sufficien t braking force
may not be obtained, preventing
the system from performing prop-
erly:
• If the braking functions cannot operate to their full extent, such as
when the brake parts are
extremely cold, extremely hot, or
wet • If the vehicle is not properly main-
tained (brakes or tires are exces-
sively worn, imprope r tire inflation
pressure, etc.)
• When the vehicle is being driven on a gravel road or other slippery
surface
■If VSC is disabled
●If VSC is disabled ( P.336), the
pre-collision brak e assist and pre-
collision braking functions are also
disabled.
●The PCS warning light will turn on
and “VSC Turned Off Pre-Colli-
sion Brake System Unavailable”
will be displayed on the multi-
information display.