2010 Lexus HS250h warning

218
2-4. Using other driving systems
■Turning the LKA system on
The lane departure warning function and lane keeping assist func-
tion will be activated depending on the recognit ion condition of lane
markers, vehicle speed and the setting of radar cruise control (vehi-
cle-to-vehicle dist ance control mode).
Press the “LKA” switch to acti-
vate the system.
“LKA” indicator will come on.
Press the switch again to turn
the LKA system off.

219
2-4. Using other driving systems
2
When driving
■Operating conditions for each function
*1: Vehicle speed is between about 30 and 125 mph (48 and 200 km/h)
*2: Vehicle speed is between about 45 and 112 mph (72 and 180 km/h).
“LKA”
switchCruise control
(vehicle-to-vehicle
distance control mode)Lane departure warning
function
*1
Lane keeping
assist function*2
On
OffAv a i l a b l eNot available
On
(While cruising in vehi- cle-to-vehicle distance
control mode with the set vehicle speed
approx. 44 mph [approx. 71 km/h] or less)
Av a i l a b l eNot available
On
(While cruising in vehi- cle-to-vehicle distance
control mode with the set vehicle speed
approx. 45 mph [approx.
72 km/h] or more)
Av a i l a b l eAvailable

220
2-4. Using other driving systems
Indication on the multi-information display
While the LKA system is on, the lane line display and steering wheel dis-
play (in case of lane k eeping as
sist function) are shown on the multi-infor -
mation display to inform that the LKA system is on.
Steering wheel display
The lane keeping assist function is
active.
Dynamic radar cruise control
display
Lane line display
When thin lines are shown:
A lane marker is not recognized by
the s
ystem, or the LKA system
functions are temporarily can -
celed. (When the lane keeping
as
sist function is canceled, buzzer
will beep twice.)
When solid lane lines are shown: 
The lane departure warning func -
tion is active.
■Temporary cancellation of the LKA system functions
If any of the following occurs, the LKA sy stem
functions will be temporarily can-
celed. The functions will resume after the necessary operating conditions have
re
turned.
●The turn signal le ver is operated.
●The steering wheel is turned as far as necessary to cause the vehicle to change
lanes.
●The brake pedal is depressed. 
However, the lane keeping assist function will not resume even after the brake
pe
dal is released because depressing the brake pedal also cancels the dynamic
radar cruise control. (only lane departure warning function will resume)

221
2-4. Using other driving systems
2
When driving
●The vehicle speed deviates from the operating range of the LKA system func-
tions.
●When the lane lines cannot be recognized while driving.
●Low speed or high speed wiper operation states. 
The buzzer may not beep when the LKA system functions are canceled
because the notification of dynamic radar cruise control cancellation takes pri-
ority over the LKA system and cancels the function.
●The no-handed driving warning activates while the lane keeping assist function
is active. (The buzzer will beep twice.)
■No-handed driving warning
If the steering wheel is not operated for about 15 seconds on a straight road or
about 5 seconds on a curve, the buzzer will beep twice, indicators on the multi-
information display will flash, and the lane keeping assist function will be temporarily
canceled. If you drive the vehicle with your hands lightly touching the steering
wheel, this may also be detected as no-handed driving.
■When the vehicle has been parked in the sun
The LKA system functions may not be available for a while after driving has started.
In such cases, turn the LKA system off and turn it on again after normal temperature
returns. When the temperature in the cab in decreases and the temperature around
the camera sensor becomes suitable for it s operation, the functions will begin to
operate.
■Warning lights and messages for LKA
Warning lights and messages ar e used to indicate a system malfunction or to inform
the driver of the need for caution while driving. ( P. 493, 505)

228
2-4. Using other driving systems
■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 input 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
●Tires with inadequate gripping ability are used (such as excessively worn tires on
a snow covered road).
●The vehicle hydroplanes while driving at high speed on wet or slick road.
■Stopping distance when the ABS is operating will 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 front of you in the following situations:
●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. 
Do not drive the vehicle in conditions where stability and power may be lost.
■When the VSC is activated
The slip indicator light flashes and a warning buzzer sounds. Always drive carefully.
Reckless driving may cause an accident. Exercise particular care when the indica-
tor light flashes and a buzzer sounds.
■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 ensure vehicle stability and driving force, do not turn the
TRAC/VSC systems off unless necessary.

232
2-4. Using other driving systems
Pre-Collision System
: If equipped
When the radar sensor detects an unavoidable frontal collision, safety sys-
tems such as the brakes and seat belts are automatically engaged to lessen
impact and injuries to

occupants 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 roll up the seat belt before the collision occurs. 
The same will happen if the driver makes an emergency braking or loses
contr
ol of the vehicle. ( P. 74 )
However, when the TRAC/VSC systems are disabled, the system will not
oper
ate 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 how 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 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 button.
■ Driver monitor system (if equipped)
When the system determines that ther e is a possibility of a collision, and
the driver is not facing forward, PC S warnings are given in advance to
warn the driver. If the driver contin ues to be not facing forward, and a
probable collision is detected, PCS in forms the driver of danger by per-
forming slight braking to provide a physically warning (pre-collision alert
br
aking). ( P. 2 3 5)

233
2-4. Using other driving systems
2
When driving
Disabling pre-collision braking
Pre-collision braking disabled
Pre-collision braking enabled
The “PCS” warning light will
come on when pr
e-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.
For vehicles equipped with the lane
keeping assist, in addition to the
radar sensor, the vehicle uses a
lane recognition camera in order
to determine whether or not a colli -
sion is likely to occur. ( P. 225)

234
2-4. Using other driving systems
Driver monitor sensor (if equipped)
The driver monitor sensor detects
the direction the driver is facing.
The system determines whether
the driver is facing forward.
■The pre-collision system is operational when
●Pre-collision warning
• Vehicle speed is greater than about 9 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or oncoming v
ehicle is greater than about 9 mph (15 km/h).
●Pre-collision seat belts (linked to brake operation)
• Vehicle speed is greater than about 18 mph (30 km/h).
• The system detects sudd en
braking or skidding.
• The front occupants are wearing a seat belt.
●Pre-collision seat belts (linked to the radar sensor)
• Vehicle speed is greater than about 3 mph (5 km/h).
• The speed at which your vehicle is approaching the obstacle or oncoming v
ehicle is greater than about 18 mph (30 km/h).
• The front occupants are wearing a seat belt.
●Pre-collision brake assist:
• Vehicle speed is greater than about 18 mph (30 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running
ahead of you is greate r than about 18 mph (30 km/h).
• The brake pedal is depressed.