2010 Lexus HS250h brake

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.

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2-4. Using other driving systems
2
When driving
●Pre-collision braking:
• The pre-collision braking off button is not pressed.
• Vehicle speed is greater than about 9 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 9 mph (15 km/h).
●Pre-collision alert braking (vehicle with driver monitor system):
• The pre-collision braking off button is not pressed.
• The system determines that the driver is not facing forward.
• Vehicle speed is greater than about 9 mph (15 km/h).
• The speed at which your vehicle is approaching the obstacle or the vehicle running ahead of you is greate r than about 24 mph (40 km/h).
■Conditions that may trigger the system even if there is no danger of a collision
●When there is an object by the roadside at the entrance to a curve
●When passing an oncoming vehicle on a curve
●When driving over a narrow iron bridge
●When there is a metal object on the road surface
●When driving on an uneven road surface
●When passing an oncoming vehicle on a left-turn
●When your vehicle rapidly closes on the vehicle in front
When the system is activated in the situations described above, there is also a possi-
bility that the seat belts will roll up quickly and the brakes will 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 sensor cannot detect pedestrians, animals, bicycles, motorcy-
cles, trees, or snowdrifts.
■When there is a malfunction in the system
Warning lights and/or warning messages will turn on or flash. ( P. 493, 502, 505)

237
2-4. Using other driving systems
2
When driving
CAUTION
■Limitations of the pre-collision system
Do not overly rely on the pre-collision system. Always drive safely, taking care to
observe your surroundings and checking for any obstacles or other road hazards.
■When the sensor may not be correctly 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 function-
ing of the sensor
●When your vehicle is pointing upwards (caused by a heavy load in the luggage
compartment etc.)
●Vehicles that cut in suddenly
●Vehicles with small rear ends (tra ilers 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 effectively:
●Keep the sensor and front grille cover clean at all times. 
Clean the sensor and front grille cover 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 malfunction. If the
sensor or surrounding area is subject to a strong impact, always have the area
inspected and adjusted by your Lexus dealer.
●Do not disassemble the sensor.
●Do not attach accessories or stickers to the sensor, grille cover or surrounding
area.
●Do not modify or paint the sensor and grille cover.

242
2-5. Driving information
CAUTION
■Things that must not be carried in the trunk
The following things may cause a fire if loaded in the trunk:
●Receptacles containing gasoline
●Aerosol cans
■Storage precautions
Observe the following precautions.
Failing to do so may result in death or serious injury.
●Stow cargo and luggage in th e trunk whenever possible.
●Do not place cargo or luggage in or on the following locations as the item may
get under the brake or accelerator pedal and prevent the pedals from being
depressed properly, block the driver’s vision, or hit the driver or passengers,
causing an accident:
• At the feet of the driver
• On the front passenger or rear seats (when stacking items)
• On the package tray
• On the instrument panel
•On the dashboard
●Secure all items in the occupant compartment, as they may shift and injure some-
one during sudden braking, sudd en swerving or an accident.
■Capacity and distribution
●Do not exceed the maximum axle weight ra ting or the total vehicle weight rating.
●Even if the total load of occupant’s weight and the cargo load is less than the total
load capacity, do not apply the load unevenly. Improper loading may cause dete-
rioration of steering or braking control which may cause death or serious injury.

244
2-5. Driving information
Winter driving tips
Carry out the necessary preparations and inspections before driving the
vehicle in winter. Always drive the vehicle in a manner appropriate to the
prevailing weather conditions.
■ Pre-winter preparations
●Use fluids that ar
e appropriate to the prevailing outside tempera -
tures.
• Engine oil
• Engine/power control unit coolant
• Washer fluid
● Ha
ve the vehicle fitted with four snow tires or purchase a set of
tire chains for the front tires.
Ensure that all tires are the same si ze and brand, and that chains match
the size of the tires.
■ Before driving the vehicle
Perform the following accord ing to the driving conditions:
● D
o not try to forcibly open a w indow or move a wiper that is fro-
zen. Pour warm water over the frozen ar
ea to melt the ice. Wipe
away the water immediately to prevent it from freezing.
● T
o ensure proper operation of the climate control system fan,
remove any snow that has accumulated on the air inlet vents in
front of the windshield.
● R
emove any ice that has accumul ated on the vehicle chassis.
● P
eriodically check for and remove any excess ice or snow that
may have accumulated in the wheel well or on the brakes.
■ When driving the v
ehicle
Accelerate the vehicle slowly and drive at a reduced speed suitable to the
road conditions.

245
2-5. Driving information
2
When driving
Selecting tire chains
Use the correct tire chain size when mounting the tire chains. Chain size
is regulated for each tire size.
Side chain:0.12 in. (3 mm) in diameter
Cross chain:
0.16 in. (4 mm) in diameter
Regulations on the use of tire chains
Regulations regarding the use of tire chains vary depending on location
and type of road. Always check local regulations before installing chains.
■When parking the vehicle
Park the vehicle and push the P position switch and block the wheel
under the vehicle without setting the parking brake. The parking
brake may freeze up, preventing it from being released.
■Tire chain installation
Observe the following precautions when installing and removing chains:
●Install and remove tire chains in a safe location.
●Install tire chains on the front tires only. Do not install tire chains on the rear tires.
●Install tire chains on front tires as tightly as possible. Retighten chains after driv -
ing 1 /4 
1/2 mile (0.5  1.0 km).
●Install tire chains following the instru ctions provided with the tire chains.

411
4-2. Maintenance
4
Maintenance and care
General maintenance
Engine compartment
Tr u n k
ItemsCheck points
Brake fluidIs the brake fluid at the correct level?
( P. 4 3 1 )
CoolantIs the engine coolant at the correct
level? ( P. 4 2 8 )
Engine oilIs the engine oil at the correct level? 
( P. 4 2 4 )
Exhaust systemThere should not be any fumes or
strange sounds.
Radiator/condenser
The radiator and condenser should
be free from foreign objects. 
( P. 4 3 0 )
Wa s h e r f l u i dIs there sufficient washer fluid? 
( P. 4 3 2 )
ItemsCheck points
12-volt batteryCheck the connections. ( P. 4 3 3 )
Listed below are the general maintenance items that should be performed
at the intervals specified in the “Warranty and Service Guide” or “Owner’s
Manual Supplement”. It is recommend ed that any problem you notice
should be brought to the attention of your Lexus dealer or qualified service
shop for advice.

412
4-2. Maintenance
Vehicle interior
ItemsCheck points
Accelerator pedal
• The accelerator pedal should move smoothly (without uneven pedal
effort or catching).
Brake pedal
• Does the brake pedal move
smoothly?
• Does the brake pedal have appro- priate clearance from the floor?
( P. 5 5 4 )
• Does the brake pedal have the cor- rect amount of free play? 
(  P. 5 5 4 )
Brakes
• The vehicle should not pull to one
side when the brakes are applied.
• The brakes should work effectively.
• The brake pedal should not feel
spongy.
• The brake pedal should not get too close to the floor when the brakes
are applied.
Head restraints• Do the head restraints move
smoothly and lock securely?
Hybrid transmission “Park” mecha-
nism• Can the vehicle be held securely on an incline with the shift position
in P?
Indicators/buzzers• Do the indicators and buzzers function properly?
Lights
• Do all the lights come on?
• Are the headlights aimed cor-rectly? ( P. 4 6 7 )