wheel LEXUS RX400H 2008 Service Manual

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2-4. Using other driving systems
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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.
■Traction Control
Maintains drive power and prevents the front wheels (2WD models) or all
wheels (AWD models) from spinning wh en starting the vehicle or acceler-
ating on slippery roads.
■ EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel.
■VDIM (Vehicle Dynamics Integrated Management)
Provides integrated control of the ABS, brake assist, VSC, traction control
and EPS systems.
Maintains vehicle stability when swerving on slippery road surfaces by
controlling the brakes, engine output, and the movement of the front
wheels.

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When the VSC/traction control are operatingIf the vehicle is in danger of slip-
ping, or if the front wheels (2WD
models) or all wheels (AWD mod-
els) spin, the slip indicator light
flashes to indicate that the VSC/
traction control have been
engaged.
A buzzer (intermittent) sounds to
indicate that VSC is operating.
■Sounds and vibrations caused by the ABS, brake assist, VSC and traction control
●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 slightly after the ABS is activated.
■Reduced effectiveness of EPS
The effectiveness of EPS is reduced to prevent the system from overheating 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 system should return to nor-
mal within 10 minutes.

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CAUTION
■When the slip indicator flashes and a warning buzzer sounds
This situation occurs immediately while VSC is activated. Always drive carefully.
Reckless driving may cause an accident. Exercise particular care when the indica-
tor light flashes and a buzzer sounds.
■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
pressure level.
The ABS and VSC systems will not function correctly if different tires are fitted 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
VDIM, and may cause the system to malfunction.

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2-5. Driving information
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CAUTION
■Off-road driving precautions
Always observe the following precautions to minimize the risk of serious personal
injury or damage to your vehicle:
●Drive carefully when off the road. Do not take unnecessary risks by driving in
dangerous places.
●Do not grip the steering wheel spokes when driving off-road. A bad bump could
jerk the wheel and injure your hands. Keep both hands and especially your
thumbs on the outside of the rim.
●Always check your brakes for effectiveness immediately after driving in sand,
mud, water or snow.
●After driving through tall grass, mud, rock, sand, rivers, etc., check that there is no
grass, bush, paper, rags, stone, sand, etc. adhering or trapped on the underbody.
Clear off any such matter from the underbody. If the vehicle is used with these
materials trapped or adhering to the underbody, a breakdown or fire could occur.
●When driving off-road or in rugged terrain, do not drive at excessive speeds,
jump, make sharp turns, strike objects, etc. This may cause loss of control or vehi-
cle rollover causing death or serious injury. You are also risking expensive dam-
age to your vehicle’s suspension and chassis.
NOTICE
■To prevent the water damage
Take all necessary safety measures to ensure that water damage to the hybrid bat-
tery, hybrid system or other components does not occur.
●Water entering the engine compartment may cause severe damage to the hybrid
system. Water entering the interior may cause the hybrid battery stowed under
the rear seats to short circuit.
●Water entering the hybrid transaxle will cause deterioration in transmission qual-
ity. The malfunction indicator may come on, and the vehicle may not be drivable.
●Water can wash the grease from wheel bearings, causing rusting and premature
failure, and may also enter the transaxle case, reducing the gear oil’s lubricating
qualities.

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■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.
■ When driving the vehicle
Accelerate the vehicle slowly and drive at a reduced speed suitable
to road conditions.
■ When parking the vehicle
Park the vehicle and move the shift lever to P without setting the
parking brake. The parking brake may freeze up, preventing it from
being released.

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2-5. Driving information
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When driving
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■Snow 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 rear tires.
●Install tire chains following the instructions provided in the accompanying instruc-
tions.
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 snow chains
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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When driving
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■Break-in schedule
Lexus recommends that you do not use a new vehicle or a vehicle with any new
power train components (engine, transmission, differential, wheel bearings, etc.) to
tow a trailer for the first 500 miles (800 km) of driving.
■Maintenance
●If you tow a trailer, your vehicle will require more frequent maintenance due to
the additional load. (See “Warranty and Services Guide/ Owner's Manual Sup-
plement/ Scheduled Maintenance”.)
●Retighten the fixing bolts of the towing ball and bracket after approximately 600
miles (1000 km) of trailer towing.
CAUTION
■To avoid accident or injury
●The total trailer weight (trailer weight plus the weight of cargo) must not exceed
the following.
Without towing package: 2000 lb. (907 kg)
With towing package: 3500 lb. (1588 kg)
●If a trailer and cargo weigh over 2000 lb. (907 kg), use a sway control device
with sufficient capacity.
●The gross combined weight (sum of your vehicle weight plus its load and the total
trailer weight) must not exceed the following.
Without towing package: 7265 lb. (3295 kg)
With towing package: 8765 lb. (3976 kg)
●Do not exceed the trailer hitch assembly weight, gross vehicle weight, gross axle
weight and trailer tongue load capacities.
●Never load more weight in the back than in the front of the trailer. About 60% of
the load should be in the front half of the trailer, and the remaining 40% in the
rear.
●The tow hitch receiver installed on your vehicle must never be used on another
vehicle.

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CAUTION
■Hitches
●If you wish to install a trailer hitch, contact your Lexus dealer.
●Use only a hitch that conforms to the total trailer weight requirement.
●Follow the directions supplied by the hitch manufacturer.
●Lubricate the hitch ball with a light coat of grease.
●Remove the trailer hitch whenever you are not towing a trailer. After removing
the hitch, seal any mounting hole in the vehicle body to prevent entry of any sub-
stances into the vehicle.
■When towing a trailer
●If the total trailer weight exceeds 1000 lb. (450 kg), trailer brakes are required.
●Never tap into your vehicle's hydraulic system, as this will lower the vehicle's
braking effectiveness.
●Never tow a trailer without using a safety chain securely attached to both the
trailer and the vehicle. If damage occurs to the coupling unit or hitch ball, there is
danger of the trailer wandering into another lane.
NOTICE
■When installing a trailer hitch
●Use only the position recommended by your Lexus dealer. Do not install the
trailer hitch on the bumper; this may cause body damage.
●Do not use axle-mounted hitches, as they can cause damage to the axle housing,
wheel bearings, wheels or tires.
■Brakes
Lexus recommends trailers with brakes that conform to all applicable federal and
state/provincial regulations.

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Trailer towing tipsYour vehicle will handle differently when towing a trailer. The 3 main
causes of vehicle-trailer accidents are driver error, excessive speed and
improper trailer loading. Keep the following in mind when towing.
● Before starting out, check the trailer lights and the vehicle-trailer con-
nections. Recheck after driving a short distance.
● Practice turning, stopping and rever sing with the trailer attached in an
area away from traffic until you become accustomed to the feel of the
vehicle.
● Reversing with a trailer attached is difficult and requires practice. Grip
the bottom of the steering wheel and move your hand to the left to
move the trailer to the left. Move your hand to the right to move the
trailer to right. (This is generally opposite to reversing without a trailer
attached.) Avoid sharp or prolon ged turning. Have someone guide
you when reversing to reduce the risk of an accident.
● As stopping distance is increased when towing a trailer, vehicle-to-
vehicle distance should be increased. For each 10 mph (16 km/h) of
speed, allow at least one vehicle and trailer length.
NOTICE
■Safety chain
A safety chain must always be used between the towing vehicle and the trailer.
Leave sufficient slack in the chain for turns. The chain should cross under the trailer
tongue to prevent the tongue from dropping to the ground in the case that it
becomes damaged or separated. For the correct safety chain installation proce-
dure, ask your Lexus dealer.
■Do not directly splice trailer lights
Directly splicing trailer lights may damage your vehicle's electrical system and
cause a malfunction.

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2-5. Driving information
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Avoid sudden braking as you may sk id, resulting in jackknifing and loss
of control. This is especially true on wet or slippery surfaces.
● Avoid jerky starts or sudden acceleration.
● Avoid jerky steering and sharp turns, and slow down before making
turns.
● Note that when making a turn, the trailer wheels will be closer than the
vehicle wheels to the inside of the turn. Compensate by making a
larger than normal turning radius.
● Crosswinds and rough roads will adversely affect handling of your
vehicle and trailer, causing sway. Periodically check the rear to prepare
for being passed by large trucks or buses, which may cause your vehi-
cle and trailer to sway. If swaying occurs, firmly grip the steering wheel,
reduce speed immediately but gradually, and steer straight ahead.
Never increase speed. If you make no extreme correction with the
steering or brakes, your vehicle and trailer will stabilize.
● Take care when passing other vehicles. Passing requires considerable
distance. After passing a vehicle, do not forget the length of your
trailer, and be sure you have plenty of room before changing lanes.
● Due to the added load of the trailer, your vehicle's hybrid system may
overheat on hot days (at temperatures over 85°F [30°C]) when driv-
ing up a long or steep grade. If the coolant temperature gauge indi-
cates overheating, immediately turn off the air conditioning (if in use),
pull your vehicle off the road and stop in a safe spot. ( →P. 4 2 4 )