2017 TOYOTA SIENNA brake sensor

SIENNA_OM_OM08007U_(U)
3034-5. Using the driving support systems
4
Driving
◆Pre-collision braking
When there is a high po ssibility of a frontal collision, the system
warns the driver using a warning light, warning display and buzzer.
If the system determines that a collision is unavoidable, the brakes
are automatically applied to redu ce the collision speed. Pre-colli-
sion braking can be disabled usin g the pre-collision braking off
switch.
Pre-collision braking disabled
Pre-collision braking enabled
The pre-collision system warning
light will turn on when pre-collision
braking is disabled.
The radar sensor detects vehi-
cles or other obstacles on or near
the road ahead and determines
whether a collision is imminent
based on the position, speed, and
heading of the obstacles.
Disabling pre-collision braking
1
2
Radar sensor

SIENNA_OM_OM08007U_(U)
3054-5. Using the driving support systems
4
Driving
■Conditions that may trigger the system even if there is no possibility of a
collision
In any of the following situations where the frontal area of the radar sensor is
interrupted, the radar sensor may detect possibility of a frontal collision and
the system may be activated.
●When passing by an oncoming vehicle in a curve or a turn to the right or the
left.
● When rapidly approaching an obstacle ahead (e.g. preceding vehicle, toll
gate barrier, etc.)
● When there is a structural object (billboard, low ceiling, fluorescent light,
etc.) above the uphill road ahead
● When driving on a narrow road or through under a low overhead structure
(bridge, tunnel, fly-under, etc.)
● When driving on an uneven road surface
● When there is a metal object, bump, or protrusion on the road surface
● When vehicle’s front part is raised or lowered depending on loading condi-
tions
● When the direction of radar sensor is misaligned by strong impact applied
on an area around the radar sensor, etc.
● When there is an obstacle (guard rail, etc.) by the roadside at the entrance
to a curve
● When the front of your vehicle is pointing upwards (caused by towing a
trailer, during emergency towing or putting a heavy load in the luggage com-
partment etc.)
When the system is activated in the situations described above, there is also
a possibility that the seat belts will retract quickly and the brakes may be
applied with a force greater than normal. When the seat belt is locked in the
retracted position, stop the vehicle in a safe place, release the seat belt and
refasten it.
■ Obstacles not detected
The sensor cannot detect plastic obstacles such as traffic cones. There may
also be occasions when the radar sens or cannot detect pedestrians, animals,
bicycles, motorcycles, trees, or snowdrifts.
■ Situations in which the pre-collis ion system does not function properly
The system may not function effectively in situations such as the following:
● On roads with sharp bends or uneven surfaces
● If a vehicle suddenly moves in front of your vehicle, such as at an intersec-
tion
● If a vehicle suddenly cuts in front of your vehicle, such as when overtaking
● In inclement weather such as heavy rain, fog, snow or sand storms
● When your vehicle is skidding with the VSC system off
● When the axis of the radar is out of adjustment
● When an extreme change in vehicle height occurs

308
SIENNA_OM_OM08007U_(U)
4-5. Using the driving support systems
WARNING
■When the sensor may not be correct ly detecting the vehicle ahead
Apply the brakes as necessary in any of the following situations.
● When water or snow thrown up by the surrounding vehicles hinders the
functioning of the sensor
● When your vehicle is pointing upwards (caused by a heavy load in the lug-
gage compartment etc.)
● Vehicles that cut in suddenly
● Vehicles with small rear ends (trailers with no load on board etc.)
● Motorcycles traveling in the same lane
■ Handling the radar sensor
Observe the following to ensure the pre-collision system can function effec-
tively:
●Keep the sensor and front grille clean at all times.
Clean the sensor and front grille with a soft cloth so you do not mark or
damage them.
● Do not subject the sensor or surrounding area to a strong impact.
If the sensor moves even slightly off position, the system may become
inaccurate or malfunction. If the sensor or surrounding area is subject to a
strong impact, always have the area inspected and adjusted by your Toy-
ota dealer.
● Do not disassemble the sensor.
● Do not attach accessories or stickers to the sensor, grille or surrounding
area.
● Do not modify or paint the sensor and grille cover.
● If the sensor needs to be replaced, contact your Toyota dealer.

653What to do if... (Troubleshooting)
SIENNA_OM_OM08007U_(U)
●The seat belt reminder light is flashing
Are the driver and the front passenger wearing the seat belts? (P. 547)
●The brake system warning light is on
Is the parking brake released? (P. 241)
Depending on the situation, other types of warning buzzer may also sound.
(  P. 545, 554)
●Did anyone inside the vehicle open a door during setting the alarm?
The sensor detects it and the alarm sounds. ( P. 77)
To stop the alarm, turn the engine switch to the “ON” position (vehicles with-
out a smart key system) or IGNITION ON mode (vehicles with a smart key
system) or start the engine.
●Is the message displayed on the multi-information display?
Check the message on the multi-information display. ( P. 554)
A warning buzzer sounds during driving
An alarm is activated and the horn sounds (if equipped)
A warning buzzer sounds when leaving the vehicle
(vehicles with a smart key system)

664Alphabetical index
SIENNA_OM_OM08007U_(U)
Parking assist sensors (intuitive parking assist) ....... 279
Parking brake ........................... 241 Operation .............................. 241
Parking brake engaged warning
buzzer/message ......... 545, 558
Parking lights
Light switch ........................... 242
Replacing light bulbs..... 525, 531
Wattage ................................ 608
PCS (Pre-Collision System) Function ................................ 302
Pre-collision braking off switch ................................. 303
Warning light ......................... 546
Warning message ............. 555, 560, 564
Personal lights Switch ................................... 428
Wattage ................................ 608
Power back door...................... 133
Power outlets ........................... 445
Power windows Jam protection function......... 185
Operation .............................. 184
Window lock switch............... 184
Pre-collision system (PCS) Function ................................ 302
Pre-collision braking off switch ................................. 303
Warning light ......................... 546
Warning message ............. 555, 560, 564 Quarter windows ..................... 187
Radar cruise control
(dynamic radar cruise
control)................................... 266
Radiator .................................... 491
Radio
*...................................... 340
Rear automatic air conditioning system ............. 421
Rear ceiling light ..................... 429
Rear seat
Adjustment............................ 152
Folding third seats ........ 159, 160
Installing second seats ......... 158
Removing second seats ....... 156
Stowing third seats ....... 161, 163
Rear seat entertainment system
*
Rear turn signal lights Replacing light bulbs ............ 528
Turn signal lever ................... 240
Wattage ................................ 608
Rear view mirror Compass .............................. 457
Inside rear view mirror .......... 179
Outside rear view mirrors ..... 181
Rear view monitor system ...... 287
Rear window defogger ............ 416
Rear window wiper .................. 257
Replacing Electronic key battery ........... 511
Fuses .................................... 514
Light bulbs ............................ 517
Rear seat entertainment system control battery
*
Tires...................................... 572
Wireless remote control battery ................................ 511
PQ
R