wheel Lexus IS250C 2014 Service Manual

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2-4. Using other driving systems
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When driving
IS250C/350C_U
CAUTION
■Conditions under which the vehicle-to-vehicle distance control may not function
correctly
Apply the brakes as necessary in the following conditions as the radar sensor may
not be able to correctly detect vehicles ahead, and a fatal or serious accident may
result.
●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 trunk etc.)
●When the road curves or when the lanes are narrow
●When steering wheel operation or your position in the lane is unstable
●When the vehicle ahead of you decelerates suddenly
■Handling the radar sensor
Observe the following to ensure the cruise control system can function effectively.
Otherwise, the system may not function correctly and could result in an accident.
●Keep the sensor and grille cover clean at all times.
Clean the sensor and 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 a 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.
●Do not replace them with non-genuine parts.

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2-4. Using other driving systems
IS250C/350C_U
Driving assist systems
To help enhance driving safety and performance, the following systems
operate 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.
■ 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.
■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)
Maintains drive power and prevents the rear wheels from spinning when
starting the vehicle or accelerating on slippery roads.
■Hill-start assist control
→ P. 220
■EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel.

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2-4. Using other driving systems
IS250C/350C_U
To disable TRAC/VSCIf the vehicle gets stuck in fresh snow or mud, TRAC and VSC 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
Quickly push and release the
switch to turn off TRAC.
A message will be shown on the
multi-information display.
Push the switch again to turn the
system back on.
■Turning off TRAC and VSC
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.
Push the switch again to turn the
system back on.

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2-4. Using other driving systems
IS250C/350C_U
■EPS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may be
heard. This does not indicate a malfunction.
■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 engine off. The EPS system should
return to normal within 10 minutes.
■If the slip indicator comes on
It may indicate a malfunction in the VSC or TRAC function.
Contact your Lexus dealer.
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 the 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 distance. Always main-
tain a safe distance from the vehicle in front 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 roads

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2-4. Using other driving systems
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When driving
IS250C/350C_U
CAUTION
■TRAC may not operate effectively when
Directional control and power may not be achievable 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. Always drive carefully. Reckless driving may cause
an accident, resulting in death or serious injury. Exercise particular care when the
indicator light flashes.
■When TRAC and VSC are off
Be especially careful and drive at a speed appropriate to the road conditions. As
these are systems to help enhance vehicle stability and driving force, do not turn off
TRAC and VSC unless necessary.
■Replacing tires
Make sure that all tires are of the specified size, brand, tread pattern and total load
capacity. In addition, make sure that the tires are inflated to the recommended tire
pressure level.
The ABS, VSC and TRAC systems will not function correctly if different tires are fit-
ted on the vehicle.
Contact your Lexus dealer for further information 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 the system to malfunction.

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2-5. Driving information
2
When driving
IS250C/350C_U
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 are appropriate to the prevailing outside tempera-
tures.
• Engine oil
• Engine coolant
• Washer fluid
● Have a service technician inspect the level and specific gravity of
battery electrolyte.
● Have the vehicle fitted with four snow tires or purchase a set of
tire chains for the rear tires.
Ensure that all tires are the specified size and the same brand, and that
chains match the size of the tires.
■ Before driving the vehicle
Perform the following according to the driving conditions.
●Do not try to forcibly open a window or move a wiper that is fro-
zen. Pour warm water over the frozen area to melt the ice. Wipe
away the water immediately to prevent it from freezing.
● To 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.
● Remove any ice that has accumulated on the vehicle chassis.
● Periodically check for and remove any excess ice or snow that
may have accumulated in the wheel well or on the brakes.

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2-5. Driving information
IS250C/350C_U
Selecting tire chainsThey cannot be mounted on 18-inch tires. Use the correct tire chain size
when mounting the tire chains. Chain size is regulated for each tire sizes. 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 according to location
and type of road. Always check local regulations before installing
chains.
● Install the chains on the rear tires.
● Retighten the chains after driving 1 /4  1 /2 mile (0.5  1.0 km).
■When driving the vehicle
Accelerate the vehicle slowly and drive at a reduced speed suitable
to road conditions.
■ When parking the vehicle (in the wi nter time or in the cold lati-
tudes)
Park the vehicle and move the shift lever to P and block the wheel
under the vehicle without setting the parking brake. The parking
brake may freeze up, preventing it from being released. If necessary,
block the wheels to prevent inadvertent sliding or creeping.

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2-5. Driving information
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When driving
IS250C/350C_U
■Tire chain installation (17-inch tires only)
Observe the following precautions when installing and removing chains.
●Install and remove tire chains in a safe location.
●Install tire chains on the rear tires only. Do not install tire chains on front tires.
●Install the tire chains on rear tires as tightly as possible. Retighten chains after
driving 1 /4
 1 /2 mile (0.5  1.0 km).
●Install tire chains following the instructions provided in the accompanying
instructions.
CAUTION
■Driving with snow tires
Observe the following precautions to reduce the risk of accidents.
Failing to do so may result in a loss of vehicle control and cause death or serious
injury.
●Use tires of the size specified for your vehicle.
●Maintain the recommended level of air pressure.
●Do not drive in excess of 75 mph (120 km/h), regardless of the type of snow tires
being used.
●Use snow tires on all, not just some wheels.
■Driving with tire chains (17-inch tires only)
Observe the following precautions to reduce the risk of accidents.
Failing to do so may result in the vehicle being unable to be driven safely, and may
cause death or serious injury.
●Do not drive in excess of the speed limit specified for the tire chains being used,
or 30 mph (50 km/h), whichever is lower.
●Avoid driving on bumpy road surfaces or over potholes.
●Avoid sudden turns and braking, as use of chains may adversely affect vehicle
handling.
●Slow down sufficiently before entering a curve to ensure that vehicle control is
maintained.

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2-5. Driving information
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When driving
IS250C/350C_U
Trailer towing
Lexus does not recommend towing a trailer with your vehicle. Lexus also
does not recommend the installation of a tow hitch or the use of a tow hitch
carrier for a wheelchair, scooter, bicycle, etc. Your Lexus is not designed
for trailer towing or for the use of tow hitch mounted carriers.

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2-5. Driving information
IS250C/350C_U
Dinghy towing
NOTICE
■To avoid serious damage to your vehicle
Do not tow your vehicle with four wheels on the ground.
Your vehicle is not designed to be dinghy towed (with 4 wheels on the
ground) behind a motor home.