2018 Lexus GS450h engine overheat

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GS450h_OM_OM30G62U_(U)
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6-3. Do-it-yourself maintenanceDo-it-yourself service precautions................................ 349
Hood ................................................ 351
Positioning a floor jack ............ 352
Engine compartment ............... 353
12-volt battery ............................. 362
Tires ................................................. 365
Tire inflation pressure .............. 375
Wheels ........................................... 378
Air conditioning filter ...............380
Electronic key battery.............. 382
Checking and replacing fuses.............................................. 384
Headlight aim (vehicles with single-beam head lights) ...... 389
Light bulbs ......................................391
7-1. Essential information Emergency flashers .................. 396
If your vehicle has to be stopped in an emergency.... 397 7-2. Steps to take in an emergency
If your vehicle needs to be towed ............................... 398
If you think something is wrong................ 403
If a warning light turns on or a warning buzzer sounds .... 404
If a warning message is displayed ................................. 410
If you have a flat tire ....................441
If the hybrid system will not start ............................... 450
If the parking brake cannot be released................................ 452
If the electronic key does not operate properly..................... 454
If the 12-volt battery is discharged............................. 457
If your vehicle overheats...........461
If the vehicle becomes stuck ............................................. 466
7When trouble arises

15Pictorial index
GS450h_OM_OM30G62U_(U)
Windshield wipers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 207
Precautions against winter season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 276
To prevent freezing (windshield wiper de-icer)
*. . . . . . . . . . . . . . . . . . . . . . . P. 293
Precautions against car wash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 338
Fuel filler door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 213
Refueling method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 213
Fuel type/fuel tank capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 472
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 365
Tire size/inflation pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 477
Winter tires/tire chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 27 6
Checking/rotation/tire pressure warning system . . . . . . . . . . . . . . . . . . . . . . P. 365
Coping with flat tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P . 441
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 351
Opening. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 351
Engine compartment cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 354
Engine oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 473
Coping with overheat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 46 1
Warning messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 4 12
Headlights/front side marker lights. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 200
Front turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 195
Parking lights/daytime running lights. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 200
Side turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 195
Tail lights/rear side marker lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 200
Rear turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 195
Stop lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 168
Back-up light
Shifting the shift lever to R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 189
License plate lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 200
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Light bulbs of the exte rior lights for driving
(Replacing method: P. 391, Watts: P. 480)
*: If equipped
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GS450h_OM_OM30G62U_(U)
2. Instrument cluster
WARNING
■The information display at low temperatures
Allow the interior of the vehicle to warm up before using the liquid crystal information
display. At extremely low temperatures, th e information display monitor may respond
slowly, and display changes may be delayed.
For example, there is a lag between the dr iver’s shifting and the new gear number
appearing on the display. This lag could ca use the driver to downshift again, causing
rapid and excessive engine braking and possibly an accident resulting in death or
injury.
NOTICE
■To prevent damage to the hybr id system and its components
●While the tachometer is displayed, 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. 461)

GS450h_OM_OM30G62U_(U)
1714-1. Before driving
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Driving
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■When starting the vehicle
Always keep your foot on the brake pedal while stopped with the “READY” indicator is
illuminated. This prevents the vehicle from creeping.
■When driving the vehicle
●Do not drive if you are unfamiliar with the location of the brake and accelerator ped-
als to avoid depressing the wrong pedal.
• Accidentally depressing the accelerator pedal instead of the brake pedal will
result in sudden acceleration that may lead to an accident.
• When backing up, you may twist your body around, leading to a difficulty in oper-
ating the pedals. Make sure to operate the pedals properly.
• Make sure to keep a correct driving po sture even when moving the vehicle only
slightly. This allows you to depress th e brake and accelerator pedals properly.
• Depress the brake pedal using your right foot. Depressing the brake pedal using your left foot may delay re sponse in an emergency, resulting in an accident.
●The driver should pay extra attention to pedestrians when the vehicle is powered only
by the electric motor (traction motor). As there is no engine noise, the pedestrians
may misjudge the vehicle’s movement. Even though the vehicle is equipped with the
vehicle proximity notification system, drive wi th care as pedestrians in the vicinity may
still not notice the vehicle if the surrounding area is noisy.
●Do not drive the vehicle over or stop the vehicle near flammable materials.
The exhaust system and exhaust gases can be extremely hot. These hot parts may
cause a fire if there is any flammable material nearby.
●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. 397
●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. 189)
●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, heads or other parts of their body are not
outside 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.

GS450h_OM_OM30G62U_(U)
1734-1. Before driving
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Driving
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury.
■When the vehicle is stopped
●Do not depress the accelerator pedal unnecessarily.
If the shift lever is any position other than P or N, the vehicle may accelerate suddenly
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 th e 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 apply the parking brake, shift the shif t lever to P, stop the hybrid system and
lock the vehicle.
Do not leave the vehicle unattended whil e the “READY” indicator is illuminated.
If the vehicle is parked with the shift leve r in P but the parking brake is not set, the
vehicle may start to move, possibly leading to an accident.
●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.

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4-5. Using the driving support systems
■ECB operation sound
ECB operating sound may be heard in the following cases, but it does not indicate that a
malfunction has occurred.
●Operating sound heard from the engine compartment when the brake pedal is oper-
ated.
●Motor sounds of the brake system heard from the front part of the vehicle when the
driver’s door is opened.
●Operating sound heard from the engine compartment when one or two minutes
passed after the stop of the hybrid system.
■EPS, VGRS and DRS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may be heard.
This does not indicate a malfunction.
■Automatic reactivation of TRAC and VSC systems
After turning the TRAC and VSC systems off, the systems will be automatically re-
enabled in the following situations:
●When the power switch is turned off
●If only the TRAC system is turned off, the TRAC will turn on when vehicle speed
increases
If both TRAC and VSC systems are turned off, automatic re-enabling will not occur
when vehicle speed increases.
■Reduced effectiveness of the EPS system
The effectiveness of the EPS system 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 EPS system should return to nor-
mal within 10 minutes.
■Operating conditions of hill-start assist control
When the following four conditions are met, the hill-start assist control will operate;
●The shift lever is in a position other than N or P (when starting off forward/backward on
an upward incline).
●The vehicle is stopped.
●The accelerator pedal is not depressed.
●The parking brake is not engaged.
■Automatic system cancelation of hill-start assist control
The hill-start assist control will be cancel ed in any of the following situations;
●The shift lever is shifted to N or P.
●The accelerator pedal is depressed.
●The parking brake is engaged.
●Approximately 2 seconds elapse after the brake pedal is released.

4187-2. Steps to take in an emergency
GS450h_OM_OM30G62U_(U)
Indicates that the parking brake system is overheatingA buzzer also sounds.
→ Do not use the parking brake until the message dis-
appears.
Indicates an engine malfunction
A buzzer also sounds.
→ Have the vehicle inspected by your Lexus dealer.
Indicates an engine malfunction
A buzzer also sounds.
→ Have the vehicle inspected by your Lexus dealer.
Indicates a malfunction in:
• The SRS airbag system;
• The front passenger occupa nt classification system;
or,
• The seat belt pretensioner system
A buzzer also sounds.
→ Have the vehicle inspected by your Lexus dealer.
Warning messageDetails/Actions
(U.S.A.) (Canada)
(U.S.A.) (Canada)
(U.S.A.) (Canada)

4287-2. Steps to take in an emergency
GS450h_OM_OM30G62U_(U)
Indicates a malfunction in the brake override systemA buzzer also sounds.
→ Have the vehicle inspecte d by your Lexus dealer
immediately.
Indicates that engine oil level is low
This message may ap pear if the vehicle is stopped on a
slope. Move the vehicle to a level surface and check to
see if the message disappears.
A buzzer also sounds.
→ Check the level of engine oil, and add if necessary.
Indicates that the hybrid system has overheated
This message may be disp layed when driving under
severe operating conditions. (For example, when driv-
ing up a long steep hill.)
A buzzer also sounds.
→ Stop and check. ( →P. 461)
Indicates a malfunction in:
• The Automatic High Beam system (if equipped);
• The AFS (Adaptive Front-lighting System) (if equipped); or
• The LED headlight system
A buzzer also sounds.
→ Have the vehicle inspected by your Lexus dealer.
Warning messageDetails/Actions
(Flashes)