2008 LEXUS RX400H overheating

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1-1. Hybrid system
1
Before driving
RX400h_U
NOTICE
■Hybrid battery air vent
●Do not put foreign objects over the air vent. The hybrid battery (traction battery)
may overheat and be damaged.
●Clean the air vent regularly to prevent the hybrid battery (traction battery) from
overheating.
●Do not wet the air vent. It may cause a short circuit and damage the hybrid bat-
tery (traction battery).
●Do not load a large amount of water such as an aquarium into the vehicle. If water
spills over the hybrid battery (traction battery), the battery may be damaged.

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2-1. Driving procedures
RX400h_U
CAUTION
■Exhaust gases
Exhaust gases include harmful carbon monoxide (CO) that is colorless and odor-
less. Inhaling exhaust gases may lead to death or a serious health hazard.
●If the vehicle is in a poorly ventilated area, stop the hybrid system. In a closed
area, such as a garage, exhaust gases may collect and enter the vehicle. This may
lead to death or a serious health hazard.
●The exhaust should be checked occasionally. If there is a hole or crack caused by
corrosion, damage to a joint or abnormal exhaust noise, be sure to have the vehi-
cle inspected and repaired by your Lexus dealer. Failure to do so may allow
exhaust gases to enter the vehicle, resulting in death or a serious health hazard.
■When taking a nap in the vehicle
Always turn the hybrid system off. Otherwise, you may accidentally move the shift
lever or depress the accelerator pedal, which could cause an accident or fire due to
hybrid system overheating. Additionally, if the vehicle is parked in a poorly venti-
lated area, exhaust gases may collect and enter the vehicle, leading to death or a
serious health hazard.
■When braking the vehicle
●When the brakes are wet, drive more cautiously.
Braking distance increases when the brakes are wet, and may cause one side of
the vehicle to brake differently than the other side. Also the parking brake may
not securely hold the vehicle.
●If the power brake assist function does not operate, do not follow other vehicles
closely and avoid downhills or sharp turns that require braking.
In this case, braking is still possible, but it will require more force on the pedal than
usual. Braking distance may also increase.
●The brake system consists of 3 individual hydraulic systems: if one of the systems
fails, the other will still operate. In this case, the brake pedal should be depressed
more firmly than usual and braking distance becomes longer.
Do not drive your vehicle with only a single brake system. Have your brakes fixed
immediately.
■If the vehicle becomes stuck or bogged (AWD models)
Do not spin the wheels recklessly when any of the tires is up in the air, or stuck in
sand or mud, etc. This may damage the drive system components or propel the
vehicle forward (or in another direction) and cause an accident.

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2-2. Instrument cluster
2
When driving
RX400h_U
Instrument panel light controlThe brightness of the instrument panel lights can be adjusted. Darker
Brighter
NOTICE
■To prevent damage to the engine and its components
The engine may be overheating if the engine coolant temperature gauge is in the
red zone (H). In this case, immediately stop the vehicle in a safe place, and check
the engine after it has cooled completely. ( →P. 4 2 4 )

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2-4. Using other driving systems
RX400h_U
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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2-5. Driving information
RX400h_U●
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 )

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3-6. Other interior features
RX400h_U
Seat heaters (if equipped)
■The seat heaters can be used when
The engine switch is in the ON position.
■When not in use
Turn the knob counterclockwise. The indicator light turns off.
Press the knob into the recessed position.
CAUTION
■Burns
●Use caution when seating the following persons in a seat with the seat heater on
to avoid the possibility of burns:
• Babies, small children, the elderly, the sick and the disabled
• Persons with sensitive skin
• Persons who are fatigued
• Persons who have taken alcohol or drugs that induce sleep (sleeping drugs,cold remedies, etc.)
●Do not cover the seat with anything when using the seat heater.
Using the seat heater with a blanket or cushion increases the temperature of the
seat and may lead to overheating.
Pops the switch out
ON
The indicator light comes on.
Adjusts the seat temperature
The further you turn the knob
clockwise, the warmer the seat
becomes.
Driver’s
seat Front
passenger’s
seat

5
When trouble arises
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5-2. Steps to take in an emergency
RX400h_U
■Overheating
If you observe the following, your vehicle may be overheating.
●The message WATER TEMP is displayed on the multi-information display.
●The engine coolant temperature gauge enters the red zone or a loss of power is
experienced.
●Steam is coming from under the hood.
CAUTION
■To prevent an accident or injury when inspecting under the hood of your vehicle
●If steam is seen coming from under the hood, do not open the hood until the
steam has subsided. The engine compartment may be very hot, causing serious
injury such as burns.
●Keep hands and clothing away from the fan and other belts while the hybrid sys-
tem is running.
●Do not loosen the radiator cap while the hybrid system and radiator are hot.
Serious injury, such as burns, may result from hot coolant and steam released
under pressure.
Add engine coolant if required.
Water can be used in an emer-
gency measure if engine coolant
is unavailable. (→P. 4 3 5 )
Have the vehicle checked at your nearest Lexus dealer as soon as pos-
sible.
STEP5

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Alphabetical index
RX400h_U
CareExterior ................................................... 298
Interior.......................................................301
Seat belts ............................................... 302
Cargo capacity ....................................... 178
Cargo hooks .......................................... 284
CD changer CD .............................................................. 214
MP3 disc ............................................... 220
WMA disc ............................................ 220
CD player.................................................. 214
Chains......................................................... 184
Child restraint system Booster seats, definition.................. 108
Booster seats, installation ..................113
Convertible seats, definition ......... 108
Convertible seats, installation .........113
Front passenger occupant
classification system .......................103
Infant seats, definition ....................... 108
Infant seats, installation........................113
Installing CRS with lower
anchorages ...........................................116
Installing CRS with seat belts ..........113
Installing CRS with top straps ........ 118
Child safety
Air bag precautions ............................ 98
Battery precautions.............. 328, 423
Child restraint system ...................... 108
Child-protectors................................... 40
How your child should wear the seat belt ...........................................62
Installing child restraints ..................... 112
Moon roof precautions ...................... 77
Power window lock switch .............. 72
Power window precautions............. 74 Removed rear seat entertainment
system controller battery............. 351
Removed wireless remote control battery precautions .......................349
Seat belt comfort guide .....................59
Seat belt extender precautions...... 64
Seat belt precautions .......................... 62
Seat heater precautions................. 280
Child-protectors ...................................... 40
Cleaning Exterior................................................... 298
Interior ...................................................... 301
Seat belts ................................................302
Clock ......................................................... 274
Coin holder .............................................268
Compass .................................................. 292
Condenser .............................................. 325
Console box ........................................... 266
Cooling system Engine overheating........................... 424
Cruise control Cruise control........................................157
Dynamic laser cruise control ........ 160
Cup holder .............................................. 269
Curtain shield airbags............................. 91
Customizable features .......................458
Daytime running light system ........... 149
Defogger Rear window ........................................204
Side mirror.............................................204
Dimension................................................430
Dinghy towing ......................................... 196
Display
Dynamic laser cruise control ........ 160
Trip information ................................... 146C
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