engine overheat LEXUS RX450H 2016 Owners Manual

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6-1. Maintenance and care Cleaning and protecting the vehicle exterior ................ 458
Cleaning and protecting the vehicle interior.................. 462
6-2. Maintenance Maintenance requirements ............................ 465
General mainte nance.............. 467
Emission inspection and maintenance (I/M)
programs.................................... 470
6-3. Do-it-yourself maintenance
Do-it-yourself service precautions.................................. 471
Hood ............................................... 473
Positioning a floor jack ............ 474
Engine compartment ............... 475
12-volt battery ............................. 483
Tires ................................................. 487
Tire inflation pressure .............. 496
Wheels ........................................... 499
Air conditioning filter ................ 501
Windshield wiper inserts ........ 504
Electronic key battery.............. 506
Checking and replacing fuses..............................................508
Headlight aim ................................. 511
Light bulbs ..................................... 513 7-1. Essential information
Emergency flashers .................. 528
If your vehicle has to be stopped in an
emergency ................................ 529
7-2. Steps to take in an emergency
If your vehicle needs to be towed ........................................... 530
If you think something is wrong........................................... 535
If a warning light turns on or a warning buzzer
sounds ......................................... 536
If a warning message is displayed .................................... 543
If you have a flat tire .................. 549
If the hybrid system will not start .................................................561
If the shift lever cannot be shifted from P ........................... 563
If the electronic key does not operate properly ............. 564
If the 12-volt battery is discharged................................. 568
If your vehicle overheats......... 574
If the vehicle becomes stuck ............................................. 578
6Maintenance and care7When trouble arises

17Pictorial index
RX450h_U_OM0E013U
Windshield wipers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 260
Precautions against winter season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 390
To prevent freezing (windshield wiper de-icer)
*. . . . . . . . . . . . . . . . . . . . . . . P. 409
Precautions against car wash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 460
Fuel filler door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 267
Refueling method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 269
Fuel type/fuel tank capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 584
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 487
Tire size/inflation pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 589
Winter tires/tire chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 39 0
Checking/rotation/tire pressure warning system . . . . . . . . . . . . . . . . . . . . . . P. 487
Coping with flat tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 549
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 473
Opening. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 473
Engine oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 585
Coping with overheat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 574
Headlights/parking lights/daytime running lights. . . . . . . . . . . . . . . . . . P. 251
Turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 2 44
Fog lights. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 259
Cornering lights
*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 252
Stop/tail lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 251
License plate lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 251
Back-up lights
Shifting the shift lever to R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 239
Side marker lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 251
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Light bulbs of the exte rior lights for driving
(Replacing method: P. 513, Watts: P. 590)
*: If equipped
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1012. Instrument cluster
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Instrument cluster
RX450h_U_OM0E013U
■Tachometer
Hybrid System Indicator switches to the tachometer when driving mode is in sport mode.
The settings of the tachometer display can be changed on of the multi-information
display. ( P. 109)
■Engine speed
On hybrid vehicles, engine speed is precisel y controlled in order to help improve fuel
efficiency and reduce exhaust emissions etc.
There are times when the engine speed that is displayed may differ even when vehicle
operation and driving conditions are the same.
■Brightness of the meters (d ay mode and night mode)
The brightness of the meters is changed between day mode and night mode.
●Day mode: When the tail lights are off or when the tail lights are on but the surrounding
area is bright
●Night mode: When the tail lights are on and the surrounding area is dark
■Outside temperature display
●In the following situations, the correct outside temperature may not be displayed, or the
display may take longer than normal to change.
• When stopped, or driving at low speeds (less than 12 mph [20 km/h])
• When the outside temperature has changed suddenly (at the entrance/exit of a garage, tunnel, etc.)
●When “ ” or “E” is displayed, the sy stem may be malfunctioning.
Take your vehicle to your Lexus dealer.
■Clock settings screen
If the clock adjustment screen is displayed continuously when attempting to change the
clock settings, the system may be malfunctioning.
Have the vehicle inspected by your Lexus dealer.
■Customization
Some functions can be customized. ( P. 109)
NOTICE
■To prevent damage to the engine and its components
●Do not let the indicator needle of the tachometer enter the red zone, which indicates
the maximum engine speed.
●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. 574)

2074-1. Before driving
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Driving
RX450h_U_OM0E013U
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■When driving the vehicle
●During normal driving, do not turn off the hybrid system. Turning the hybrid system off
while driving will not cause loss of steering or braking control, however, power assist
to the steering will be lost. This will make it more difficult to steer smoothly, so you
should pull over and stop the vehicle as soon as it is safe to do so.
In the event of an emergency, such as if it becomes impossible to stop the vehicle in
the normal way:  P. 529
●Use engine braking (downshift) to maintain a safe speed when driving down a steep
hill.
Using the brakes continuously may cause th e brakes to overheat and lose effective-
ness. ( P. 239)
●Do not adjust the positions of the steering wheel, the seat, or the inside or outside rear
view mirrors while driving.
Doing so may result in a loss of vehicle control.
●Always check that all passengers’ arms, he ads or other parts of their body are not
outside the vehicle.
●AWD models: Do not drive the vehicle off-road.
This is not an AWD vehicle designed for of f-road driving. Proceed with all due cau-
tion if it becomes unavoidable to drive off-road.
●Do not drive across a river or through other bodies of water.
This may cause electric/electronic componen ts to short circuit, damage the hybrid
system or cause other serious damage to the vehicle.
●Do not drive in excess of the speed limit. Even if the legal speed limit permits it, do not
drive over 85 mph (140 km/h) unless your vehicle has high-speed capability tires.
Driving over 85 mph (140 km/h ) may result in tire failure, loss of control and possible
injury. Be sure to consult a tire dealer to determine whether the tires on your vehicle
are high-speed capability tires or no t before driving at such speeds.

2094-1. Before driving
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Driving
RX450h_U_OM0E013U
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■If you hear a squealing or scraping noise (brake pad wear limit indicators)
Have the brake pads checked and replaced by your Lexus dealer as soon as possible.
Rotor damage may result if the pads are not replaced when needed.
It is dangerous to drive the vehicle when the wear limits of the brake pads and/or those
of the brake discs are exceeded.
■When the vehicle is stopped
●Do not depress the accelerator pedal unnecessarily.
If the shift lever is in any position other than P or N, the vehicle may accelerate sud-
denly and unexpectedly, causing an accident.
●In order to prevent accidents due to the ve hicle rolling away, always keep depressing
the brake pedal while stopped with the “REA DY” indicator is illuminated, and apply
the parking brake as necessary.
●If the vehicle is stopped on an incline, in order to prevent accidents caused by the
vehicle rolling forward or backward, alwa ys depress the brake pedal and securely
apply the parking brake as needed.
●Avoid revving or racing the engine.
Running the engine at high speed while the vehicle is stopped may cause the exhaust
system to overheat, which could result in a fire if combustible material is nearby.
■When the vehicle is parked
●Do not leave glasses, cigarette lighters, sp ray cans, or soft drink cans in the vehicle
when it is in the sun.
Doing so may result in the following:
• Gas may leak from a cigarette lighter or spray can, and may lead to a fire.
• The temperature inside the vehicle may cau se the plastic lenses and plastic mate-
rial of glasses to deform or crack.
• Soft drink cans may fracture, causing the contents to spray over the interior of the vehicle, and may also cause a short circui t in the vehicle’s electrical components.
●Do not leave cigarette lighters in the vehicle. If a cigarette lighter is in a place such as
the glove box or on the floor, it may be lit accidentally when luggage is loaded or the
seat is adjusted, causing a fire.
●Do not attach adhesive discs to the windsh ield or windows. Do not place containers
such as air fresheners on th e instrument panel or dashboard. Adhesive discs or con-
tainers may act as lenses, ca using a fire in the vehicle.
●Do not leave a door or window open if the curved glass is coated with a metallized
film such as a silver-colored one. Reflecte d sunlight may cause the glass to act as a
lens, causing a fire.
●Always shift the shift lever to P, apply the parking brake, stop th e hybrid system and
lock the vehicle.
Do not leave the vehicle unattended whil e the “READY” indicator is illuminated.
●Do not touch the exhaust pipes while the “R EADY” indicator is illuminated or imme-
diately after turning the hybrid system off.
Doing so may cause burns.

2254-1. Before driving
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Driving
RX450h_U_OM0E013U
●To maintain engine braking efficiency and charging system performance
when using engine braking, do no t put the transmission in D. (P. 239)
●Instability happens more fr equently when descending steep or long downhill
grades. Before descending, slow down and downshift. Do not make sudden
downshifts while descending st eep or long downhill grades.
●Avoid holding the brake pedal down too long or applying the brakes too fre-
quently. This could cause the brakes to overheat and result in reduced braking
efficiency.
●Due to the added load of the trailer, yo ur vehicle’s engine may overheat on hot
days (at temperatures over 85 F [30 C]) when driving up a long or steep
grade. If the engine coolant temperat ure gauge indicates overheating, imme-
diately turn off the air conditioning (if in use), pull your vehicle off the road and
stop in a safe spot. ( P. 574)
●Always place wheel blocks under both the vehicle’s and the trailer’s wheels
when parking. Put the transmission in P and apply the parking brake. Avoid
parking on a slope, but if unavoidable, do so only after performing the follow-
ing:
Apply the brakes and keep them applied.
Have someone place wheel blocks under both the vehicle’s and trailer’s
wheels.
When the wheel blocks are in place, release the brakes slowly until the
blocks absorb the load.
Shift into P and apply the parking brake.
Turn off the hybrid system.
●When restarting afte r parking on a slope:
With the transmission in P, start the hybrid system. Be sure to keep the
brake pedal depressed.
Shift into a forward gear. If reversing, shift into R.
If the parking brake is in manual mode, release the parking brake.
( P. 246)
Release the brake pedal, and slowly pull or back away from the wheel
blocks. Stop and apply the brakes.
Have someone retrieve the blocks.
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5467-2. Steps to take in an emergency
RX450h_U_OM0E013U
■If “Shift Is in N Release Accelerator Before Shifting” is shown
Message is displayed when the accelerator pedal has been depressed and
the shift lever is in N. Release the accelerator pedal and shift the shift lever to
D or R.
■If “Depress Brake when Vehicle Is Stopped Hybrid System May Overheat”
is shown
Message is displayed when the accelerato r pedal is depressed to maintain the
vehicle position when stopped on a upward slope, etc.
If this continues, the hybrid system may overheat.
Release the accelerator pedal and depress the brake pedal.
■If “Power Turned Off to Save Battery” is displayed
This message is displayed when the power was cut off due to the automatic
power off function.
The next time the hybrid system is star ted, increase the engine speed slightly
and maintain it at that speed for approximately 5 minutes to recharge the 12-
volt battery.
■If “A New Key has been Registered Contact Your Dealer for Details” is dis-
played
This message will be displayed each time the driver's door is opened when the
doors are unlocked from the outside fo r approximately one week after a new
electronic key has been registered.
If this message is displayed but you ha ve not had a new electronic key regis-
tered, ask your Lexus dealer to check if an unknown electronic key (other than
those in your possession) has been registered.
■When “Headlight System Malfunction Visit Your Dealer” is displayed
The following systems may be malfunct ioning. Have the vehicle inspected by
your Lexus dealer immediately.
●The LED headlight system
●The automatic headlight leveling system
●Automatic High Beam (if equipped)
●AFS (Adaptive Front-lighting System) (if equipped)

5747-2. Steps to take in an emergency
RX450h_U_OM0E013U
■“Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” is
shown on the multi-information displayStop the vehicle in a safe place and turn off the air conditioning system, and
then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the hybrid system has
cooled down sufficiently, inspect
the hoses and radiator core (radi-
ator) for any leaks.Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact your Lexus
dealer.
The coolant level is satisfactory if
it is between the “FULL” and
“LOW” lines on the reservoir.Reservoir
“FULL” line
“LOW” line
Radiator cap
If your vehicle overheats
The following may indicate that your vehicle is overheating.
●The needle of the engine coolant temperature gauge ( P. 97) enters the
red zone, or a loss of hybrid system power is experienced. (For example, the
vehicle speed does not increase.)
●“Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” or
“Hybrid System Overheated Reduced Output Power” is shown on the
multi-information display.
●Steam comes out from under the hood.
Correction procedures
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5777-2. Steps to take in an emergency
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When trouble arises
RX450h_U_OM0E013U
Start the hybrid system and check if “Hybrid System Overheated Reduced
Output Power” is shown on the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer.
WARNING
■To prevent an accident or injury when inspecting under the hood of your vehicle
Observe the following precautions.
Failure to do so may result in serious injury such as burns.
●If steam is seen coming from under the h ood, do not open the hood until the steam
has subsided. The engine compartment may be very hot.
●After the hybrid system has been turned off, check that the “READY” indicator is off.
When the hybrid system is operating, the gasoline engine may automatically start, or
the cooling fans may suddenly operate even if the gasoline engine stops. Do not
touch or approach rotating parts such as th e fans, which may lead to fingers or cloth-
ing (especially a tie, a scarf or a muffler) getting caught, resulting in serious injury.
●Do not loosen the radiator cap and the coolant reservoir caps wh ile the hybrid system
and radiator are hot.
High temperature steam or coolant could spray out.
NOTICE
■When adding engine/power control unit coolant
Add coolant slowly after the hybrid system has cooled down sufficiently. Adding cool
coolant to a hot hybrid system too quickly can cause damage to the hybrid system.
■To prevent damage to the cooling system
Observe the following precautions:
●Avoid contaminating the coolant with foreig n matter (such as sand or dust etc.).
●Do not use any coolant additive.
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645Alphabetical index
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EngineACCESSORY mode...................... 233
Compartment......................................475
Engine switch ....................................... 232
Hood ........................................................ 473
How to start the hybrid system .................................................. 232
Identification number ...................... 583
If your vehicle has to be stopped in an emergency ..........529
Ignition switch (power switch) .... 232
Overheating .........................................574
Power switch........................................ 232
Engine coolant Capacity ................................................ 587
Checking................................................ 479
Preparing and checking before winter ................................... 390
Engine coolant temperature gauge .........................................................97
Engine oil Capacity ................................................ 585
Checking................................................ 476
Preparing and checking before winter ................................... 390
Engine oil maintenance data ........... 478
Engine switch ......................................... 232
Enhanced VSC ...................................... 381
EPS (Electronic Power Steering) ......... 381 Warning light .......................................537
EV drive mode....................................... 237
EV indicator ............................................... 78
Event data recorder (EDR) .................... 11 Flat tire ...................................................... 549
Floor mats................................................... 28
Fluid
Brake....................................................... 588
Transmission ....................................... 588
Washer ................................................... 482
Fog lights Replacing light bulbs .........................513
Switch ...................................................... 259
Front passenger footwell hooks.......................................................442
Front passenger occupant classification system ............................. 51
Front passenger’s seat belt reminder light ..................................... 538
Front seat heaters .................................. 415
Front seats ................................................. 164 Adjustment..............................................164
Cleaning................................................. 462
Correct driving posture .................... 30
Driving position memory................. 174
Head restraints ..................................... 179
Power easy access system ............. 174
Seat heaters ............................................415
Seat position memory ....................... 174
Front side marker lights Light switch............................................. 251
Replacing light bulbs .........................513
Wattage ................................................ 590F