2015 LEXUS RX450h Owners Manual

2732-4. Using other driving systems
2
When driving ■ Turning off both TRAC and VSC systems
To turn the TRAC and VSC sys-
tems off, press and hold the switch
for 3 seconds or more while the
vehicle is stopped. A message will be shown on the
multi-information display and VSC
off indicator light will come on.
Press the switch again to turn the
systems back on.■
When the message is displayed on the multi-information display showing that
TRAC has been disabled even if the VSC off switch has not been pressed
TRAC and hill-start assist control cannot be operated. Contact your Lexus dealer.■
Sounds and vibrations caused by th e ABS, VSC, TRAC and brake assist ●
A sound may be heard from the engine compartment when the hybrid system 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 operat-
ing. 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 after the ABS is activated.
• The brake pedal may move down s lightly after the ABS is activated.■
EPS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may be
heard. This does not indicate a malfunction.
■
Reactivation of the TRAC /VSC systems
Turning off the hybrid system after turning off the TRAC/VSC systems will automat-
ically reactivate them.

2742-4. Using other driving systems
■
Reactivation of the TRAC sy stem linked to vehicle speed
When only the TRAC system is turned off, the TRAC system will turn on when vehi-
cle speed increases. However, when both TRAC and VSC systems are turned off,
the systems will not turn on even when vehicle speed increases.■
Reduced effectiveness of the EPS system
The effectiveness of the EPS system is reduced to prevent the system from over-
heating when there is frequent steering in put over an extended period of time. The
steering wheel may feel heavy as a result. Should this occur, refrain from excessive
steering input or stop the vehicle and turn the hybrid system off. The EPS system
should return to normal within 10 minutes.
CAUTION■
The ABS does not operate effectively when ●
The limits of tire gripping performance have been exceeded (such as excessively
worn tires on a snow covered road).●
The vehicle hydroplanes while driving at high speed on a wet or slick road.■
Stopping distance when the ABS is operating may exceed that of normal condi-
tions
The ABS is not designed to shorten the vehicle’s stopping dist ance. Always main-
tain a safe distance from the vehicle in fron t of you, especially in the following situa-
tions: ●
When driving on dirt, gravel or snow-covered roads●
When driving with tire chains●
When driving over bumps in the road●
When driving over roads with potholes or roads with uneven surfaces■
TRAC may not operate effectively when
Directional control and power may not be ac hievable while driving on slippery road
surfaces, even if the TRAC system is operating.
Drive the vehicle carefully in conditions where stability and power may be lost.

2752-4. Using other driving systems
2
When driving CAUTION■
When the VSC is activated
The slip indicator light flashes. Always drive carefully. Reckless driving may cause
an accident, resulting in death or serious injury. Exercise particular care when the
indicator light flashes.■
When the TRAC/VSC systems are turned off
Be especially careful and drive at a speed appropriate to the road conditions. As
these are the systems to help ensure vehicle stability and driving force, do not turn
the TRAC/VSC systems off unless necessary.■
Replacing tires
Make sure that all tires are of the same size, brand, tread pattern and total load
capacity. In addition, make sure that the tires are inflated to the recommended tire
inflation pressure level.
The ABS and VSC systems will not function correctly if different tires are installed
on the vehicle.
Contact your Lexus dealer for further info rmation when replacing tires or wheels.■
Handling of tires and suspension
Using tires with any kind of problem or modifying the suspension will affect the driv-
ing assist systems, and may cause a system malfunction.

2762-4. Using other driving systems
Hill-start assist control
■
Hill-start assist control can be operated when ●
The shift lever is in a position other than P.●
The parking brake is not applied.●
The accelerator peda l is not depressed.■
Hill-start assist control ●
While hill-start assist control is operating, the brakes remain automatically
applied after the driver releases the br ake pedal. The stop lights and the high
mounted stoplight turn on.●
Hill-start assist control operates for about 2 seconds after the brake pedal is
released.●
If the slip indicator does not flash and the buzzer does not sound when the brake
pedal is further depressed, slightly redu ce the pressure on the brake pedal (do
not allow the vehicle to roll backward) and then firmly depress it again. If the sys-
tem still does not operate, check if th e operating conditions explained above
have been met.Hill-start assist control helps to prevent the vehicle from rolling backwards
when starting on an incline or slippery slope.
To engage hill-start assist con-
trol, further depress the brake
pedal when the vehicle is
stopped completely. A buzzer will sound once to
indicate the system is activated.
The slip indicator will also start
flashing.

2772-4. Using other driving systems
2
When driving ■
Hill-start assist control buzzer ●
When hill-start assist control is act ivated, the buzzer will sound once.●
In the following situations, hill-start assist control will be canceled and the
buzzer will sound twice.
• No attempt is made to drive the vehi cle within approximately 2 seconds of
releasing the brake pedal.
• The shift lever is moved to P.
• The parking brake is applied.
• The brake pedal is depressed again.
• The brake pedal has been depressed for more than approximately 3 minutes.●
If a buzzer other than the hill-start assist control buzzer is sounding, the hill-start
assist control buzzer may not sound when the system is activated or canceled.■
If the slip indicator comes on
It may indicate a malfunction in th e system. Contact your Lexus dealer.
CAUTION■
Hill-start assist control ●
Do not overly rely on hill-start assist cont rol. Hill-start assist control may not oper-
ate effectively on extremely steep inclines or roads covered in ice.●
Unlike the parking brake, hill-start assist control is not intended to hold the vehi-
cle stationary for an extended period of time. Do not attempt to use hill-start
assist control to hold the vehicle on an incline for an extended period of time, as
doing so may lead to an accident.

2782-4. Using other driving systems
Pre-Collision System When the radar sensor detects the possib ility of a frontal collision, the pre-
collision system such as the brakes and seat belts are automatically
engaged to lessen impact as well as vehicle damage.
■ Pre-collision seat belts (front seat belts only) If the pre-collision sensor detects that a collision is unavoidable, the pre-
collision system will retract the seat belt before the collision occurs.
The same will happen if the driver makes an emergency braking or loses
control of the vehicle. (  P. 1 0 0 )
However, the system will not operate in the event of skidding when the
VSC system is disabled.
■ Pre-collision brake assist When there is a high possibility of a frontal collision, the system applies
greater braking force in relation to how strongly the brake pedal is
depressed. The system may not warn the driver using a warning light,
warning display and buzzer when the system detects and judges braking
operations.
■ Pre-collision braking When there is a high possibility of a frontal collision, the system warns the
driver using a warning light, warnin g display and buzzer. If the system
determines that a collision is unavoidable, the brakes are automatically
applied to reduce the collision speed. Pre-collision braking can be dis-
abled using the pre-collision braking off switch.
 : If equipped

2792-4. Using other driving systems
2
When driving Disabling pre-collision braking
Pre-collision braking disabled
Pre-collision braking enabled The pre-collision system warning
light turn on when pre-collision
braking is disabled.
Radar sensor
The radar sensor detects vehicles
or other obstacles on or near the
road ahead and determines
whether a collision is imminent
based on the posit ion, speed, and
heading of the obstacles.

2802-4. Using other driving systems
■
The pre-collision system is operational when ●
Pre-collision seat belts (type A):
• 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 (type B):
• Vehicle speed is greater than about 19 mph (30 km/h).
• The system detects sudd en 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 than 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).