brake TOYOTA 4RUNNER 2023 Service Manual

2394-5. Using the driving support systems
4
Driving
4RUNNER (U)
◆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 colli-
sion is high, the system applies greater braking force in relat ion to
how strongly the brake pedal is depressed.
◆Pre-collision braking
When the system determines that the possibility of a frontal colli-
sion is high, the system warns the driver. If the system determ ines
that the possibility of a frontal collision is extremely high, the brakes
are automatically applied to hel p avoid the collision or reduce the
collision speed.
PCS (Pre-Collision System)
The pre-collision system uses a radar sensor and front camera
to detect vehicles and pedestrians in front of your vehicle. Wh en
the system determines that the possibility of a frontal collisi on
with a vehicle or pedestrian i s high, a warning operates to urg e
the driver to take evasive action and the potential brake pres-
sure is increased to help the driver avoid the collision. If the sys-
tem determines that the possibi lity of a frontal collision with a
vehicle or pedestrian is extremely high, the brakes are automat i-
cally applied to hel p avoid the collision or help reduce the
impact of the collision.
The pre-collision system can b e disabled/enabled and the warnin g
timing can be changed. ( P. 2 4 2 )

2404-5. Using the driving support systems
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WARNING
■Limitations of the pre-collision system
● The driver is solely responsible for safe driving. Always drive safely, taking
care to observe your surroundings.
Do not use the pre-collision system instead of normal braking o perations
under any circumstances. This system will not prevent collision s or lessen
collision damage or injury in every situation. Do not overly re ly on this sys-
tem. Failure to do so may lead to an accident, resulting in dea th or serious
injury.
● Although this system is designed to help avoid a collision or h elp reduce
the impact of the collision, its effectiveness may change according to vari-
ous conditions, therefore the system may not always be able to achieve
the same level of performance.
Read the following conditions carefully. Do not overly rely on this system
and always drive carefully.
• Conditions under which the system may operate even if there is no pos- sibility of a collision: P. 244
• Conditions under which the system may not operate properly: P. 246
● Do not attempt to test the operation of the pre-collision syste m yourself.
Depending on the objects used for testing (dummies, cardboard o bjects
imitating detectable objects, etc.), the system may not operate properly,
possibly leading to an accident.
■ Pre-collision braking
● When the pre-collision braking function is operating, a large a mount of
braking force will be applied.
● If the vehicle is stopped by the operation of the pre-collision braking func-
tion, the pre-collision braking function operation will be canceled after
approximately 2 seconds. Depress the brake pedal as necessary.
● The pre-collision braking function may not operate if certain operations are
performed by the driver. If the accelerator pedal is being depressed
strongly or the steering wheel is being turned, the system may determine
that the driver is taking evasive action and possibly prevent the pre-colli-
sion braking function from operating.
● In some situations, while the pre-collision braking function is operating,
operation of the function may be canceled if the accelerator pedal is
depressed strongly or the steering wheel is turned and the syst em deter-
mines that the driver is taking evasive action.
● If the brake pedal is being depressed, the system may determine that the
driver is taking evasive action and possibly delay the operation timing of
the pre-collision braking function.

2434-5. Using the driving support systems
4
Driving
4RUNNER (U)
■Operational conditions
The pre-collision system is enabled and the system determines that the pos-
sibility of a frontal collision with a vehicle or pedestrian is high.
Each function is operational at the following speeds:
● Pre-collision warning:
• Vehicle speed is between approximately 7 and 110 mph (10 and 1 80
km/h). (For detecting a pedestrian, vehicle speed is between ap proxi-
mately 7 and 50 mph [10 and 80 km/h].)
• The relative speed between your vehicle and the vehicle or ped estrian
ahead is approximately 7 mph (10 km/h) or more.
● Pre-collision brake assist:
• Vehicle speed is between approximately 20 and 110 mph (30 and 180
km/h). (For detecting a pedestrian, vehicle speed is between ap proxi-
mately 20 and 50 mph [30 and 80 km/h].)
• The relative speed between your vehicle and the vehicle or ped estrian
ahead is approximately 20 mph (30 km/h) or more.
● Pre-collision braking:
• Vehicle speed is between approximately 7 and 110 mph (10 and 1 80
km/h). (For detecting a pedestrian, vehicle speed is between ap proxi-
mately 7 and 50 mph [10 and 80 km/h].)
• The relative speed between your vehicle and the vehicle or ped estrian
ahead is approximately 7 mph (10 km/h) or more.
The system may not operate in the following situations:
● If a battery terminal has been disconnected and reconnected and then the
vehicle has not been driven for a certain amount of time
● If the shift lever is in R
● If VSC is disabled (only the pre-collision warning function wil l be opera-
tional)
● If the low speed four-wheel drive indicator is illuminated (onl y the pre-colli-
sion warning function will be operational)
■ Pedestrian detection function
The pre-collision system detects pedestri-
ans based on the size, profile, and motion
of a detected object. However, a pedes-
trian may not be detected depending on
the surrounding brightness and the
motion, posture, and angle of the
detected object, preventing the system
from operating properly. (P. 248)

2484-5. Using the driving support systems
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In some situations such as the following, sufficient braking fo rce may not be
obtained, preventing the system from performing properly:
• 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 maintained (brakes or tires are excessively
worn, improper tire inflation pressure, etc.)
• When the vehicle is being driven on a gravel road or other sli ppery sur-
face
● Some pedestrians such as the following may not be detected by t he radar
sensor and front camera, preventing the system from operating p roperly:
• Pedestrians shorter than approximately 3.2 ft. (1 m) or taller than approx-
imately 6.5 ft. (2 m)
• Pedestrians wearing oversized clothing (a rain coat, long skir t, etc.), mak-
ing their silhouette obscure
• Pedestrians who are carrying large baggage, holding an umbrella, etc., hiding part of their body
• Pedestrians who are bending forward or squatting
• Pedestrians who are pushing a stroller, wheelchair, bicycle or other vehi-
cle
• Groups of pedestrians which are close together
• Pedestrians who are wearing white and look extremely bright
• Pedestrians in the dark, such as at night or while in a tunnel
• Pedestrians whose clothing appears to be nearly the same color or
brightness as their surroundings
• Pedestrians near walls, fences, guardrails, or large objects
• Pedestrians who are on a metal object (manhole cover, steel plate, etc.)
on the road
• Pedestrians who are walking fast
• Pedestrians who are changing speed abruptly
• Pedestrians running out from behind a vehicle or a large objec t
• Pedestrians who are extremely close to the side of the vehicle (outside
rear view mirror, etc.)
■ If VSC is disabled
●If VSC is disabled ( P. 324, 325), the pre-collision brake assist and pre-col-
lision braking functions are also disabled.
● The PCS warning light will turn on and “VSC Turned Off Pre-Coll ision Brake
System Unavailable” will be displayed on the multi-information display.

2614-5. Using the driving support systems
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Driving
4RUNNER (U)
This mode employs a radar sensor to detect the presence of vehicles
up to approximately 320 ft. (100 m) ahead, determines the curre nt
vehicle-to-vehicle following distance, and operates to maintain a suit-
able following distance from the vehicle ahead.
Note that vehicle-to-vehicle distance will close in when traveling on long
downhill slopes.
Example of constant speed cruising
When there are no vehicles ahead
The vehicle travels at the speed set by the driver. The desired vehicle-to-
vehicle distance can also be set by operating the vehicle-to-ve hicle dis-
tance switch.
Example of deceleration crui sing and follow-up cruising
When a preceding vehicle driving slower than the set speed
appears
When a vehicle is detected running ahead of you, the system automatically
decelerates your vehicle. When a greater reduction in vehicle s peed is
necessary, the system applies the brakes (the stop lights will come on at
this time). The system will respond to changes in the speed of the vehicle
ahead in order to maintain the vehicle-to-vehicle distance set by the driver.
Approach warning warns you when the system cannot decelerate su ffi-
ciently to prevent your vehicle fr om closing in on the vehicle ahead.
Example of acceleration
When there are no longer any preceding vehicles driving slower
than the set speed
The system accelerates until the set speed is reached. The syst em then
returns to constant speed cruising.
Driving in vehicle-to-vehi cle distance control mode
1
2
3

2654-5. Using the driving support systems
4
Driving
4RUNNER (U)
Pulling the lever toward you
cancels the speed control.
The speed setting is also canceled
when the brake pedal is
depressed.
Pushing the lever up resumes
the cruise control and returns
vehicle speed to the set speed.
However, cruise control does not resume when the vehicle speed is
approximately 25 mph (40 km/h) or less.
When your vehicle is too close to
a vehicle ahead, and sufficient
automatic deceleration via the
cruise control is not possible, the
display will flash and the buzzer
will sound to alert the driver. An
example of this would be if
another driver cuts in front of you
while you are following a vehicle.
Depress the brake pedal to
ensure an appropriate vehicle-to-
vehicle distance.
■Warnings may not occur when
In the following instances, war nings may not occur even when th e
vehicle-to-vehicle distance is small.
● When the speed of the preceding vehicle matches or exceeds
your vehicle speed
● When the preceding vehicle is traveling at an extremely slow
speed
● Immediately after the cruise control speed was set
● When depressing the accelerator pedal
Canceling and resuming the speed control
1
2
Approach warning (vehicle-to-v ehicle distance control mode)

2684-5. Using the driving support systems
4RUNNER (U)■
Automatic cancelation of c onstant speed control mode
Constant speed control mode is automatically canceled in the following situa-
tions:
● Actual vehicle speed is more than approximately 10 mph (16 km/h ) below
the set vehicle speed.
● Actual vehicle speed falls below approximately 25 mph (40 km/h) .
● VSC is activated.
● TRAC is activated for a period of time.
● When the VSC or TRAC system is turned off.
● Pre-collision braking is activated.
If constant speed control mode is automatically canceled for an y other rea-
son, there may be a malfunction in the system. Contact your Toyota dealer.
■ Brake system operation sound
If the brakes are applied automatically while the vehicle is in vehicle-to-vehi-
cle distance control mode, a brake system operation sound may b e heard.
This does not indicate a malfunction.
■ Warning messages and buzzers for d ynamic radar cruise control
Warning messages and buzzers are used to indicate a system malfunction or
to inform the driver of the need for caution while driving. If a warning message
is shown on the multi-information display, read the message and follow the
instructions.
■ When the sensor may not be correctly detect ing the vehicle ahead
In the case of the following and depending on the conditions, o perate the
brake pedal when deceleration of the system is insufficient or operate the
accelerator pedal when acceleration is required.
As the sensor may not be able to correctly detect these types o f vehicles, the
approach warning ( P. 265) may not be activated.
● Vehicles that cut in suddenly
● Vehicles traveling at low speeds
● Vehicles that are not moving in the same lane
● Vehicles with small rear ends (trailers with no load on board, etc.)
● Motorcycles traveling in the same lane

2694-5. Using the driving support systems
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Driving
4RUNNER (U)●
When water or snow thrown up by the surrounding vehicles hinders the
detecting of the sensor
■ Conditions under which the vehic le-to-vehicle distance control mode
may not function correctly
In the case of the following conditions, operate the brake peda l (or accelera-
tor pedal, depending on the situation) as necessary.
As the sensor may not be able to correctly detect vehicles ahead, the system
may not operate properly.
● When the vehicle ahead of you decelerates suddenly
● When driving on a road surrounded by a structure, such as in a tunnel or on
a bridge
● While the vehicle speed is decreasing to the set speed after th e vehicle
accelerates by depressing the accelerator pedal
●
When your vehicle is pointing upwards
(caused by a heavy load in the luggage
compartment, etc.)
● Preceding vehicle has an extremely
high ground clearance
●When the road curves or when the
lanes are narrow
● When steering wheel operation or your
position in the lane is unstable

2824-5. Using the driving support systems
4RUNNER (U)■
Situations in which the syst em may not operate properly
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, water drops or ice on a sensor. (Cleaning the sensors
will resolve this problem.)
● A sensor is frozen. (Thawing t he area will resolve this problem .)
In especially cold weather, if a sensor is frozen the sensor di splay may be
displayed abnormally, or objects, such as a wall, may not be detected.
● On an extremely bumpy road, on an incline, on gravel, or on grass.
● When vehicle horns, vehicle detectors, motorcycle engines, air brakes of
large vehicles, the clearance sonar of other vehicles or other devices which
produce ultrasonic waves are near the vehicle
● A sensor is coated with a sheet of spray or heavy rain.
● If objects draw too close to the sensor.
● When a pedestrian is wearing clothing that does not reflect ult rasonic waves
(ex. skirts with gathers or frills).
● When objects that are not perpendicular to the ground, not perpendicular to
the vehicle traveling direction, uneven, or waving are in the d etection range.
● Strong wind is blowing
● When driving in inclement weather such as fog, snow or a sandst orm
● When an object that cannot be detected is between the vehicle a nd 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
● If the orientation of a sensor has been changed due to a collis ion or other
impact
● When equipment that may obstruct a sensor is installed, such as a towing
eyelet, bumper protector (an additional trim strip, etc.), bicy cle carrier, or
snow plow
● If the front of the vehicle is raised or lowered due to the car ried load
● If the vehicle cannot be driven in a stable manner, such as whe n the vehicle
has been in an accident or is malfunctioning
● When a tire chains, compact spare tire or an emergency tire pun cture repair
kit is used
●
When a sensor or the area around a
sensor is extremely hot or cold.

2834-5. Using the driving support systems
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Driving
4RUNNER (U)■
Situations in which the system may operate even if there is no possibil-
ity of a collision
In some situations, such as the following, the system may opera te even
though there is no possibility of a collision.
● When driving toward a banner, flag, low-hanging branch or boom barrier
(such as those used at railroad crossings, toll gates and parking lots)
● 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 dri ving on a
flooded road
● There is dirt, snow, water drops or ice on a sensor. (Cleaning the sensors
will resolve this problem.)
● A sensor is coated with a sheet of spray or heavy rain
● When driving in inclement weather such as fog, snow or a sandst orm
● When vehicle horns, vehicle detectors, motorcycle engines, air brakes of
large vehicles, the clearance sonar of other vehicles or other devices which
produce ultrasonic waves are near the vehicle
● If the front of the vehicle is raised or lowered due to the car ried load
● If the orientation of a sensor has been changed due to a collis ion or other
impact
● The vehicle is approaching a tall or curved curb
● Driving close to columns (H-shaped steel beams, etc.) in multi- story parking
garages, construction sites, etc.
● If the vehicle cannot be driven in a stable manner, such as whe n the vehicle
has been in an accident or is malfunctioning
●
When driving on a narrow road
● When strong winds are blowing