2014 Lexus GX460 brake

340
GX460_OM_OM60K80U_(U)4-5. Using the driving support systems
■Operating tips
The system will operate when the shift lever is
in a position other than P, however to make
effective use of the system it is recommended that the shift lever be shifted to 2 or 1 range
of S mode.
■If the four-wheel drive control switch is in H4
The system does not operate.
■When the downhill assist control system is operated continuously
This may cause the brake actuator to overheat. In this case, the downhill assist control
system will stop operating, a buzzer will sound and the downhill assist control system
indicator will start flashing, and the “TRAC O FF” will be shown on the multi-information
display. Refrain from using the system until the downhill assist control system indicator
stays on and the message goes off. (The vehicl e can be driven normally during this time.)
■Sounds and vibrations caused by the downhill assist control system
●A sound may be heard from the engine compartment when the engine is started or just
after the vehicle begins to move. This sound does not indicate that a malfunction has
occurred in downhill assist control system.
●Either of the following conditions may occur when the downhill assist control system is
operating. None of these are indicators that a malfunction has occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard after the vehicle comes to a stop.
■System malfunction
●The downhill assist control system indicator does not come on when the engine switch
is turned to IGNITION ON mode.
●The downhill assist control system indicato r does not come on when the “DAC” switch
is pressed.
●The slip indicator comes on.
In the above cases, have your vehicle checked by your Lexus dealer.
CAUTION
■When using downhill assist control system
Do not rely overmuch on the downhill assist control system. This function does not
extend the vehicle’s performance limitations. Always thoroughly check the road condi-
tions, and drive safely.
■The system may not operate on the following surfaces, which may lead to an accident
causing death or serious injury
●Slippery surfaces such as wet or muddy roads
●Icy surface
●Unpaved roads

341
GX460_OM_OM60K80U_(U)4-5. Using the driving support systems
4
Driving
Driving assist systems
◆ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied suddenly, or if the brakes are
applied while driving on a slippery road surface
◆Multi Terrain ABS (Anti-lock Brake System) (vehicles with a Multi-terrain
Select system)
Helps to prevent wheel lock when the brakes are applied suddenly, or if the brakes are
applied while driving on a slippery road su
rface, or in off-road conditions (such as
rough roads, sand and mud)
The Multi Terrain ABS operates in synchr onization with the Multi-terrain Select
◆Brake assist
Generates an increased level of braking force after the brake pedal is depressed
when the system detects a panic stop situation
◆VSC (Vehicle Stability Control)
Helps the driver to control skidding when swerving suddenly or turning on slippery
road surfaces
◆TRAC (Traction Control) for H4 position
Helps to maintain drive power and prevent the drive wheels from spinning when start-
ing the vehicle or accelerating on slippery roads
To help enhance driving safety and performance, the following systems oper-
ate automatically in response to various driving situations. Be aware, however,
that these systems are supplementary and should not be relied upon too
heavily when operating the vehicle.

342
GX460_OM_OM60K80U_(U)4-5. Using the driving support systems
◆Active TRAC (Traction Control) for L4 position*
Helps to maintain drive power and prevent
the 4 wheels from spinning when starting
the vehicle or accelerating on slippery roads, or in off-road conditions
◆Hill-start assist control (if equipped)
Helps to prevent the vehicle from rolling backward when starting on an incline or slip-
pery slope
◆KDSS (Kinetic Dynamic Suspension System)
KDSS helps to enhance ride comfort and handling response by using a hydraulic con-
trol system to control the suspension stabiliz er bars in response to road surface and
driving conditions during cornering or off-road driving
◆PCS (Pre-Collision system) (if equipped)
 P. 3 5 7
◆Trailer Sway Control
Helps the driver to control trailer sway by selectively applying brake pressure for indi-
vidual wheels and reducing engine to rque when trailer sway is detected.
Trailer Sway Control is part of the VSC system and will not operate if VSC turned off
or experiences a malfunction.
*: The function only works in vehicles with Multi-terrain Select when Multi-terrain
Select is switched on
If the vehicle is in danger of slipping or
rolling backward when starting on an
incline, or if any of the drive wheels
spins, the slip indicator light flashes to
indicate that the TRAC or Active
TRAC/VSC/Trailer Sway Control/hill-
start assist control systems are operat-
ing.
A buzzer (intermittent) sounds to indicate that VSC is operating.
The stop lights and high mounted stoplight tu rn on when the hill-start assist control
system is operating.
When the TRAC or Active TRAC/VSC /Trailer Sway Control/hill-start
assist control systems are operating

GX460_OM_OM60K80U_(U)
3434-5. Using the driving support systems
4
Driving
If the vehicle gets stuck in fresh snow or mud, the TRAC or Active TRAC/VSC/
Trailer Sway Control systems may reduce power from the engine to the wheels.
You may need to turn the system off to enable you to rock the vehicle in order to
free it.
■Turning off TRAC or Active TRAC system only
To turn the TRAC or Active TRAC
system off, quickly press and release
the switch.
The “TRAC OFF” will be shown on
the multi-information display.
Press the switch again to turn the sys-
tem back on.
■Turning off both TRAC or Active TRAC and VSC/Trailer Sway Control sys-
tems
To turn the TRAC or Active TRAC
and VSC/Trailer Sway Control sys-
tems off, press and hold the switch
for 3 seconds and more while the
vehicle is stopped.
The VSC OFF indicator light will
come on and the “TRAC OFF” will
be shown on the multi- information
display.
Press the switch again to turn the sys-
tem back on.
■When the “TRAC OFF” is displayed on the multi-information display even if the VSC
OFF switch has not been pressed
TRAC/Active TRAC, hill-start assist control, downhill assist control and Crawl Control
cannot be operated. Contact your Lexus dealer.
■Hill-start assist control operation conditions
●The shift lever is in D or S.
●The brake pedal is not depressed.
Disabling the TRAC or Active TRAC/VSC/Trailer Sway Control sys-
tems

344
GX460_OM_OM60K80U_(U)4-5. Using the driving support systems
■Sounds and vibrations caused by the ABS/Multi Terrain ABS, brake assist, TRAC/
Active TRAC, VSC/Trailer Sway Control
and hill-start assist control systems
●A sound may be heard from the engine compartment when the engine is started or just
after the vehicle begins to move. This sound does not indicate that a malfunction has
occurred in any of these systems.
●Any of the following conditions may occur when the above systems are operating.
None of these indicates that a malfunction has occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard after the vehicle comes to a stop.
• The brake pedal may pulsate slightly afte r the ABS/Multi Terrain ABS is activated.
• The brake pedal may move down slightly after the ABS/Multi Terrain ABS is acti- vated.
■Reactivation of the TRAC or Active TRAC/VSC/Trailer Sway Control systems after
turning off the engine
Turning off the engine after turning off the TRAC or Active TRAC/VSC/Trailer Sway
Control systems will automatically re-enabled them.
■Reactivation of the TRAC or Active TRAC system linked to vehicle speed
When only the TRAC or Active TRAC system is turned off, the TRAC or Active TRAC
system will turn on when vehicle speed increases. However, when both TRAC or Active
TRAC and VSC/Trailer Sway Control systems are turned off, the systems will not turn on
even when vehicle speed increases.
■When the brake system operates continuously
The brake actuator may overheat. In this case, the TRAC or Active TRAC and hill-start
assist control systems will stop operating, a buzzer will sound and the “TRAC OFF” will
be shown on the multi-information display. Refrain from using the system until the mes-
sage goes off. (There is no proble m with continuing normal driving.)
■If the slip indicator comes on...
It may indicate a malfunction in the TRAC /Active TRAC, VSC/Trailer Sway Control or
hill-start assist control system. Consult your Lexus dealer.

346
GX460_OM_OM60K80U_(U)4-5. Using the driving support systems
CAUTION
■Trailer Sway Control precaution
The Trailer Sway Control system is not able to reduce trailer sway in all situations.
Depending on many factors such as the condit
ions of the vehicle, trailer, road surface,
and driving environment, the Trailer Sway Co ntrol system may not be effective. Refer to
your trailer owner’s manual for information on how to tow your trailer properly.
■If trailer sway occurs
Observe the following precautions.
Failing to do so may caus e death or serious injury.
●Firmly grip the steering wh eel. Steer straight ahead.
Do not try to control trailer swaying by turning the steering wheel.
●Begin releasing the accelera tor pedal immediately but very gradually 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. ( P. 1 76 )

357
GX460_OM_OM60K80U_(U)4-5. Using the driving support systems
4
Driving
PCS (Pre-Collision system)
◆Pre-collision seat belts (front seat belts only)
If the system detects that a collision is
unavoidable, the system will retract the
seat belt before the collision occurs.
The same will happen if the driver makes an emergency braking or loses con-
trol of the vehicle. ( P. 2 9 )
However, when the VSC system is disabled, the system will not operate in the
event of skidding.
◆Pre-collision brake assist
When there is a high possibility of a frontal collision, the system applies
greater braking force in relation to ho w strongly the brake pedal is depressed.
◆Pre-collision braking
When there is a high possibility of a frontal collision, the system warns the
driver using a warning light, warning di splay and buzzer. If the system deter-
mines that a collision is unavoidable, the brakes are automatically applied to
reduce the collision speed. Pre-collisio n braking can be disabled using the
pre-collision braking off switch.
◆AVS (Adaptive Variable Suspension System) control (if equipped)
When the system determines that there is a high possibility of a frontal colli-
sion, the AVS optimizes the damping effect ( P. 3 3 1 )
: If equipped
When the radar sensor detects possibility of a frontal collision, the pre-colli-
sion system such as the brakes and seat belts are automatically engaged to
lessen impact as well as vehicle damage.

360
GX460_OM_OM60K80U_(U)4-5. Using the driving support systems
■The pre-collision system is operational when
●Pre-collision seat belts (situation 1):
• Vehicle speed is greater
than about 4 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running ahead of you is greater than about 19 mph (30 km/h).
• The front occupants are wearing a seat belt.
●Pre-collision seat belts (situation 2):
• Vehicle speed is greater than about 19 mph (30 km/h).
• The system detects sudden braking or skidding.
• The front occupants are wearing a seat belt.
●Pre-collision brake assist:
• Vehicle speed is greater than about 19 mph (30 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running ahead of you is greater than about 19 mph (30 km/h).
• The brake pedal is depressed.
●Pre-collision braking:
• The pre-collision braking off switch is not pressed.
• Vehicle speed is greater th an about 10 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running
ahead of you is greater than about 10 mph (15 km/h).
●AVS (Adaptive Variable Suspension System) control (if equipped):
• Vehicle speed is greater than about 4 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running ahead of you is greater than about 19 mph (30 km/h).
●Pre-collision alert braking (vehicles with driver monitor system):
• The system determines that th e driver is not facing forward.
• The speed at which your vehicle is approaching the vehicle running ahead of you is greater than about 25 mph (40 km/h).
• Vehicle speed is greater than about 25 mph (40 km/h).
• The pre-collision braking off switch is not pressed.
• The steering is not being turned.
■Situations in which the pre-collision 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 intersection
●If a vehicle suddenly cuts in front of your vehicle, such as when overtaking
●In inclement weather such as heav y rain, fog, snow or sand storms
●When your vehicle is skidding with the VSC system off
●When an extreme change in vehicle height occurs
●When the axis of the radar is out of adjustment