2021 TOYOTA SIENNA HYBRID horn

1863-4. Adjusting the steering wheel and mirrors
To sound the horn, press on or
close to the mark.
*: If equipped
The height of the rear view mir-
ror can be adjusted to suit your
driving posture.
Adjust the height of the rear
view mirror by moving it up and
down.
WARNING
■Caution while driving
Do not adjust the steering wheel
while driving.
Doing so may cause the driver to
mishandle the vehicle and cause
an accident, resul ting in death or
serious injury.
■After adjusting the steering
wheel (manual type)
Make sure that the steering wheel
is securely locked.
Otherwise, the steering wheel
may move suddenly, possibly
causing an accident, and resulting
in death or serious injury. Also,
the horn may not sound if the
steering wheel is not securely
locked.
Sounding the horn
Inside rear view mir-
ror*
The rear view mirror’s posi-
tion can be adjusted to
enable sufficient confirma-
tion of the rear view.
Adjusting the height of
rear view mirror
WARNING
■Caution while driving
Do not adjust the position of the
mirror while driving.
Doing so may lead to mishandling
of the vehicle and cause an acci-
dent, resulting in death or serious
injury.

3124-5. Using the driving support systems
sensor.
• There will be a short delay
between static object detection
and display (warning buzzer
sounds). Even at low speeds,
there is a possibilit y that the object
will come within approximately
11.9 in. (30 cm) before the display
is shown and the warning buzzer
sounds.
• It might be difficult to hear the buzzer due to the volume of the
audio system or air flow noise of
the air conditioning system.
• It may be difficult to hear the
sound of this system due to the
buzzers of other systems.
■Conditions under which the
function may not function cor-
rectly
Certain vehicle conditions and the
surrounding environment may affect
the ability of a sensor to correctly
detect objects. Particular instances
where this may occur are listed
below.
●There is dirt, snow or ice on a sen-
sor. (Cleaning the sensors will
resolve this problem.)
●A sensor is frozen. (Thawing the
area will resolve this problem.)
In especially cold weather, if a
sensor is frozen the sensor dis-
play may be displayed abnor-
mally, or objects, such as a wall,
may not be detected.
●A sensor is covered in any way.
●When a sensor or the area around
a sensor is extremely hot or cold.
●On an extremely bumpy road, on
an incline, on gravel, or on grass.
●The vicinity of the vehicle is noisy
due to vehicle horns, motorcycle
engines, air brakes of large vehi-
cles, or other l oud noises produc-
ing ultrasonic waves.
●There is another vehicle equipped
with parking assist sensors in the
vicinity.
●A sensor is coated with a sheet of spray or heavy rain.
●If a sensor is hit by a large amount
of water, such as when driving on
a flooded road.
●If the vehicle is significantly tilted.
●The vehicle is approaching a tall
or curved curb.
●If objects draw too close to the
sensor.
■Objects which may not be prop-
erly detected
The shape of the object may pre-
vent the sensor from detecting it.
Pay particular atte ntion to the fol-
lowing objects:
●Wires, fences, ropes, etc.
●Cotton, snow and other materials
that absorb sound waves
●Sharply-angled objects
●Low objects
●Tall objects with upper sections
projecting outwards in the direc-
tion of your vehicle
People may not be detected if they
are wearing certain types of cloth-
ing.

3274-5. Using the driving support systems
4
Driving
tion of your vehicle
■Situations in which the Parking
Support Brake function (static
objects) may not operate
When the shift lever is in N
■Intuitive parking assist buzzer
Regardless of whether the intuitive
parking assist syste m is enabled or
not ( P.310), if the Parking Support
Brake function (static objects) is
enabled ( P.320), the front or rear
sensors detect an object and brake
control and hybrid system output
restriction control are performed, the
intuitive parking assist buzzer will
sound to notify the driver of the
approximate distanc e to the object.
■Situations in which the Parking
Support Brake function (static
objects) may operate even if
there is no possibility of a colli-
sion
In some situations, such as the fol-
lowing, the Parking Support Brake
function (static objects) may operate
even though there is no possibility of
a collision.
●Vehicle surroundings
• When driving on a narrow road
• When driving on a gravel road or in an area with tall grass
• When driving toward a banner, flag, low-hanging branch or boom
barrier (such as those used at rail-
road crossings, toll gates and
parking lots)
• When there is a structure on the roadside (such as when driving in
a narrow tunnel , on a narrow
bridge or on a narrow road)
• When parallel parking
• When there is a rut or hole in the
surface of the road
• When driving on a metal cover
(grating), such as those used for
drainage ditches
• When driving up or down a steep
slope
• If a sensor is hit by a large amount of water, such as when driving on
a flooded road
• When loaded on ships or trucks
• Moving type automatic car wash
• Lift type parking area or multi- story parking lot
• Underground parking area
• Structures on the ground (speed
bumps, cat’s eyes, etc.)
• Differences in height
• When moving straight ahead or
turning right
• Snow-melting pipes
• Devices for detecting vehicles,
such as traffic lig hts, devices for
detecting traffic congestion, or
devices for detecting empty
spaces in parking areas
• Railroad tracks
• H-shaped steel
• When there are vehicles on both sides, or there is a vehicle that
resembles this vehicle
●Weather
• If a sensor is covered with ice, snow, dirt, etc. (when cleared, the
system will return to normal)
• If heavy rain or water strikes a sensor
• When driving in inclement weather such as fog, snow or a sandstorm
• When strong winds are blowing
●Other sonic wave sources
• When vehicle horns, vehicle detectors, motorcycle engines, air
brakes of large vehicles, the clear-

3284-5. Using the driving support systems
ance sonar of other vehicles or
other devices which produce ultra-
sonic waves are near the vehicle
• If a sticker or an electronic compo- nent, such as a backlit license
plate (especially fluorescent type),
fog lights, fender pole or wireless
antenna is insta lled near a sensor
●Changes in the vehicle posture
• If the vehicle is significantly tilted
• If the front of the vehicle is raised or lowered due to the carried load
• If the orientation of a sensor has been changed due t o a collision or
other impact
■Situations in which the Parking
Support Brake function (static
objects) may not operate prop-
erly
In some situations, such as the fol-
lowing, this function may not oper-
ate properly.
●Weather
• When a sensor or the area around a sensor is extremely hot or cold
• When strong winds are blowing
• If a sensor is covered with ice, snow, dirt, etc. (when cleared, the
system will return to normal)
• If heavy rain or water strikes a
sensor
• When driving in inclement weather such as fog, snow or a sandstorm • A sensor is froz
en. (Thawing the
area will resolve this problem.)
●Vehicle surroundings
• When an object that cannot be detected is between the vehicle
and a detected object
• If an object such as a vehicle, motorcycle, bicycle or pedestrian
cuts in front of the vehicle or runs
out from the side of the vehicle
• The vehicle is approaching a tall
or curved curb.
• On an extremely bumpy road, on an incline, on gravel, or on grass.
• The objects draw too close to the sensor.
●Other ultrasonic waves sources
• When vehicle horns, vehicle detectors, motorcycle engines, air
brakes of large vehicles, the clear-
ance sonar of ot her vehicles or
other devices which produce ultra-
sonic waves are near the vehicle
• If a sticker or an electronic compo- nent, such as a backlit license
plate (especially fluorescent type),
fog lights, fender pole or wireless
antenna is installed near a sensor
●Changes in the v ehicle posture
• If the vehicle is significantly tilted
• If the front of the v ehicle is raised
or lowered due to the carried load
• If the orientation of a sensor has
been changed due to a collision or
other impact
• When equipment that may
obstruct a sensor is installed, such
as a bumper protector (an addi-
tional trim strip, etc.), hitch-
mounted bicycle carrier, or snow
plow
• If the suspension has been modi-
fied or tires of a size other than
specified are installed
• If paint or a stic ker is applied to
the sensor

5017-2. Steps to take in an emergency
7
When trouble arises
One of the following may be the
cause of the problem:
The electronic key may not be
functioning properly.
( P.504)
 There may not be sufficient
fuel in the vehicle’s tank.
Refuel the vehicle. ( P.259)
 There may be a malfunction
in the immobilizer system.
( P.88)
 There may be a malfunction
in the steering lock system.
 The hybrid system may be
malfunctioning due to an elec-
trical problem such as elec-
tronic key battery depletion or
a blown fuse. However,
depending on the type of mal-
function, an interim measure
is available to start the hybrid
system. ( P.501) One of the following may be the
cause of the problem:

The 12-volt battery may be
discharged. ( P.506)
 The 12-volt battery terminal
connections may be loose or
corroded. ( P.423)
One of the following may be the
cause of the problem:
 The 12-volt battery may be
discharged. ( P.506)
 One or both of the 12-volt bat-
tery terminals may be discon-
nected. ( P.423)
Contact your Toyota dealer if
the problem cannot be repaired,
or if repair procedures are
unknown.
When the hybrid system does
not start, the following steps can
be used as an interim measure
to start the hybrid system if the
power switch is functioning nor-
If the hybrid system
will not start
Reasons for the hybrid sys-
tem not starting vary
depending on the situation.
Check the following and
perform the appropriate
procedure:
The hybrid system will not
start even though the cor-
rect starting procedure is
being followed ( P.231)
The interior lights and
headlights are dim, or the
horn does not sound or
sounds at a low volume
The interior lights and
headlights do not turn on,
or the horn does not
sound
Starting the hybrid sys-
tem in an emergency

569What to do if... (Troubleshooting)
weak or depleted?
In this case, the hybrid sys-
tem can be started in a tem-
porary way. (P.505)
 Is the 12-volt battery dis-
charged? ( P.506)
 Is the power switch in ON?
If you cannot release the shift
lever by depressing the brake
pedal with the power switch in
ON ( P.240)
 It is locked automatically to
prevent theft of the vehicle.
( P.232)
 Is the window lock switch
pressed?
The power window except for
the one at the driver’s seat
cannot be operated if the win-
dow lock switch is pressed.
( P.203)
 The auto power off function
will be operated if the vehicle is left in ACC or ON (the
hybrid system is not operat-
ing) for a period of time.
(
P.235)
 The seat belt reminder light is
flashing
Are the driver and the passengers
wearing the seat belts? (
P.473)
The parking brake indicator is
on
Is the parking br ake released?
( 
P.243)
Depending on the situation,
other types of warning buzzer
may also sound. ( P.466, 477)
 Did anyone inside the vehicle
open a door during setting the
alarm?
The sensor detects it and the
alarm sounds. ( P.89)
To stop the alarm, turn the power
switch to ON or start the hybrid sys-
tem.
 Is the message displayed on
the multi-information display?
Check the message on the
The shift lever cannot be
shifted from P even if you
depress the brake pedal
The steering wheel can-
not be turned after the
hybrid system is stopped
The windows do not open
or close by operating the
power window switches
The power switch is
turned off automatically
A warning buzzer sounds
during driving
An alarm is activated and
the horn sounds (if
equipped)
A warning buzzer sounds
when leaving the vehicle

576Alphabetical Index
Heated steering wheel ........... 361
HeatersFront automatic air conditioning system ................................ 348
Heated steering wheel ......... 361
Outside rear view mirrors ..... 350
Rear automatic air conditioning system ................................ 358
Seat heaters ......................... 361
High mounted stoplight Replacing light bulbs ............ 451
Hill-start assist control .......... 335
Hood ........................................ 413
Hooks Cargo hooks ......................... 372
Coat hooks ........................... 388
Grocery bag hooks ............... 387
Retaining hooks (floor mat) .... 32
Horn ......................................... 186
Hybrid battery (tr action battery)
Location.................................. 83
Specification ......................... 521
Hybrid battery (traction battery) air intake vents ............... 85, 443
Hybrid battery (traction battery) air intake vents and filters ... 443
Hybrid battery air vent ............. 85
Hybrid system .......................... 79 ACC...................................... 234
Acoustic Vehicle Alerting System............................................. 81
Emergency shut off system .... 86
Energy monitor/consumption screen ................................ 122
EV drive mode...................... 236
High voltage components....... 83
How to start the hybrid system ........................................... 231
Hybrid battery (traction battery) air vents.............................. 443
Hybrid System In dicator . 97, 101
Hybrid system precautions ..... 83 Hybrid vehicle dri
ving tips .....341
If the hybrid sys tem will not start
...........................................501
If your vehicle has to be stopped in an emergency .................459
Ignition switch (power switch) ...........................................231
Overheating ..........................511
Power (ignition) switch .........231
Regenerative braking .............80
Starting the hybrid system ....231
Hybrid System Indicator ..................98, 102, 121
Hybrid transmissio n ...............238
S mode .................................241
I
I/M test .....................................410
Identification Engine ..................................520
Vehicle..................................519
Ignition switch (power switch) ...............................................231Auto power off fun ction.........235
Changing the power switch modes.................................234
If your vehicle has to be stopped in an emergency .................459
Starting the hybrid system ....231
Immobilizer system ..................88
Indicators ..................................95
Initialization Items to initialize ...................554
Oil maintenance ...................418
Tire pressure warning system...........................................430
Inside rear view m irror ...186, 188
Instrument panel light control .............................99, 103
Interior lights...........................363 Switch ...................................364
Wattage ................................526