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GS450h_300h_OM_OM30F92E_(EE)
6-3. Do-it-yourself maintenance
Do-it-yourself service
precautions ................................399
Hood ................................................ 401
Positioning a floor jack.............402
Engine compartment............... 403
12-volt battery............................... 412
Tires .................................................. 416
Tire inflation pressure...............429
Wheels............................................. 431
Air conditioning filter................433
Electronic key battery ..............435
Checking and replacing
fuses .............................................. 437
Light bulbs ..................................... 442
7-1. Essential information
Emergency flashers...................452
If your vehicle has to be
stopped in an
emergency.................................453
7-2. Steps to take in an
emergency
If your vehicle needs
to be towed ................................454
If you think something
is wrong .......................................459
If a warning light turns on
or a warning buzzer
sounds..........................................460
If a warning message
is displayed................................. 466
If you have a flat tire
(vehicles with spare tire) ..... 498
If you have a flat tire
(vehicles without spare
tire) ............................................... 509
If the hybrid system
will not start................................523
If the parking brake
cannot be released.................525
If the electronic key does
not operate properly ............. 527
If the 12-volt battery is
discharged ................................ 530
If your vehicle overheats .........535
If the vehicle becomes
stuck.............................................. 542
7When trouble arises

2154-1. Before driving
4
Driving
GS450h_300h_OM_OM30F92E_(EE)
■Passing other vehicles
Consider the total combined length of your vehicle and trailer and ensure that
the vehicle-to-vehicle distance is sufficient before executing lane changes.
■Transmission information
To maintain engine braking efficiency, when using engine braking, when driv-
ing on a long steep downgrade, do not use the transmission in D. (P. 227)
■If the engine overheats
Towing a loaded trailer up a long, steep incline in temperatures exceeding
30 C (85F) may result in the engine overheating. If the engine coolant tem-
perature gauge indicates that the engine is overheating, turn the air condition-
ing off immediately, leave the road and stop the vehicle in a safe place.
( P. 535)
■When parking the vehicle
Always place wheel chocks under the wheels of both the vehicle and trailer.
Firmly set the parking brake and shift the shift lever to P.
WARNING
Follow all the instructions described in this se ction. Failure to do so could cause an acci- dent resulting in death or serious injury.
■Trailer towing precautions
When towing, make sure that none of the weight limits are exceeded. ( P. 211)
■To avoid accident or injury
●Do not tow a trailer when the compact spare tire is installed on your vehicle.
●Do not tow a trailer when the tire installed is repaired with the emergency tire punc- ture repair kit.
●Do not use cruise control (if equipped) or dynamic radar cruise control with full-
speed range (if equipped) when trailer towing.
■Vehicle speed in towing
Observe the legal maximum speeds for trailer towing.
■Before descending hills or long declines
Reduce speed and downshift. However, never downshift suddenly while descending steep or long downhill grades.
■Operation of the brake pedal
Do not hold the brake pedal depressed often or for long periods of time.
Doing so may result in the brake ov erheating or reduce braking effects.

2724-5. Using the driving support systems
GS450h_300h_OM_OM30F92E_(EE)
WARNING
■Pre-crash braking*3
●When the pre-crash braking function is operating, a large amount of braking force will be applied.
●If the vehicle is stopped by the operation of the pre-crash braking function, the pre-crash braking function operation will be canceled after approximately 2 seconds.Depress the brake pedal as necessary.
●The pre-crash braking function may not operate if certain operations are performedby the driver. If the accelerator pedal is being depressed strongly or the steeringwheel is being turned, the system may determine that the driver is taking evasive
action and possibly prevent the pre-crash braking function from operating.
●In some situations, while the pre-crash braking function is operating, operation of thefunction may be canceled if the accelerator pedal is depressed strongly or the steer-
ing wheel is turned and the system determines that the driver is taking evasive action.
●If the brake pedal is being depressed, the system may determine that the driver is tak-ing evasive action and possibly delay the operation timing of the pre-crash braking
function.
*3: Depending on the region in which the vehicle was sold, the pre-crash braking func-
tion may not be available.
■When to disable the pre-crash safety system
In the following situations, disable the system, as it may not operate properly, possibly
leading to an accident resulting in death or serious injury:
●When the vehicle is being towed
●When your vehicle is towing another vehicle
●When transporting the vehicle via truck, boat, train or similar means of transportation
●When the vehicle is raised on a lift with the hybrid system on and the tires are allowed to rotate freely
●When inspecting the vehicle using a drum tester such as a chassis dynamometer orspeedometer tester, or when using an on vehicle wheel balancer
●When a strong impact is applied to the front bumper or front grille, due to an accident
or other reasons
●If the vehicle cannot be driven in a stable manner, such as when the vehicle has beenin an accident or is malfunctioning
●When the vehicle is driven in a sporty manner or off-road
●When the tires are not properly inflated
●When the tires are very worn
●When tires of a size other than specified are installed
●When tire chains are installed
●When a compact spare tire or an emergency tire puncture repair kit is used
●If equipment (snow plow, etc.) that may obstruct the radar sensor or camera sensor istemporarily installed to the vehicle

2854-5. Using the driving support systems
4
Driving
GS450h_300h_OM_OM30F92E_(EE)
WARNING
■Before using LKA system
Do not rely solely upon the LKA system. Th e LKA system does not automatically drive the vehicle or reduce the amount of attention that must be paid to the area in front of
the vehicle. The driver must always assume full responsibility for driving safely by pay- ing careful attention to the surrounding conditions and operating the steering wheel tocorrect the path of the vehicle. Also, the driver must take adequate breaks when
fatigued, such as from driving for a long period of time. Failure to perform appropriate driving operat ions and pay careful attention may lead to an accident, resulting in death or serious injury.
■To avoid operating LKA system by mistake
When not using the LKA system, use the LKA switch to turn the system off.
■Situations unsuitable for LKA system
Do not use the LKA system in the following situations. The system may not operate properly and le ad to an accident, resulting in death or serious injury.
●A spare tire, tire chains, etc. are equipped.
●When the tires have been excessively worn, or when the tire inflation pressure is low.
●Tires which differ by structure, manufacturer, brand or tread pattern are used.
●Objects or patterns that could be mistaken for white (yellow) lines are present on the side of the road (guardrails, cu rbs, reflective poles, etc.).
●Vehicle is driven on a snow-covered road.
●White (yellow) lines are difficult to see due to rain, snow, fog, dust, etc.
●Asphalt repair marks, white (yellow) line marks, etc. are present due to road repair.
●Vehicle is driven in a temporary lane or restricted lane due to construction work.
●Vehicle is driven on a road surface which is slippery due to rainy weather, fallen snow, freezing, etc.
●Vehicle is driven in traffic lanes other than on highways and freeways.
●Vehicle is driven in a construction zone.
●Vehicle is towing a trailer or another vehicle. (vehicles with towing package)
■Preventing LKA system malfunctions and operations performed by mistake
●Do not modify the headlights or place stickers, etc. on the surface of the lights.
●Do not modify the suspension etc. If the suspension etc. needs to be replaced, con- tact any authorized Lexus retailer or Le xus authorized repairer, or any reliable
repairer.
●Do not install or place anything on the hood or grille. Also, do not install a grille guard (bull bars, kangaroo bar, etc.).
●If your windshield needs repairs, contac t any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer.

431
6
6-3. Do-it-yourself maintenance
Maintenance and care
GS450h_300h_OM_OM30F92E_(EE)
Wheels
When replacing wheels, care should be taken to ensure that they are equivalent
to those removed in load capacity, diameter, rim width and inset*.
Replacement wheels are available at any authorized Lexus retailer or Lexus
authorized repairer, or any reliable repairer.
*: Conventionally referred to as “offset”.
Lexus does not recommend using the following:
●Wheels of different sizes or types
●Used wheels
●Bent wheels that have been straightened
●Steel wheels (except for vehicles with steel spare wheel)
●Use only Lexus wheel nuts and wrenches designed for use with your alumi-
num wheels.
●When rotating, repairing or changing your tires, check that the wheel nuts are
still tight after driving 1600 km (1000 miles).
●Be careful not to damage the aluminum wheels when using tire chains.
●Use only Lexus genuine balance weights or equivalent and a plastic or rubber
hammer when balancing your wheels.
■When replacing wheels (vehicles with the tire pressure warning system)
The wheels of your vehicle are equipped with tire pressure warning valves and transmit- ters that allow the tire pressure warning sy stem to provide advance warning in the event of a loss in tire inflation pressure. Whenever wheels are replaced, tire pressure warning
valves and transmitters must be installed. (P. 418)
If a wheel is bent, cracked or heavily corroded, it should be replaced. Other-
wise, the tire may separate from the wheel or cause a loss of handling control.
Wheel selection
Aluminum wheel precautions

4326-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30F92E_(EE)
WARNING
■When replacing wheels
●Do not use wheels that are a different size from those recommended in the Owner’s Manual, as this may result in a loss of handling control.
●Never use an inner tube in a leaking wheel which is designed for a tubeless tire. Doingso may result in an accident, causing death or serious injury.
●Except for vehicles with steel spare wheel: Do not install steel wheels.
The wheel contact surface could be damaged, and the wheel could come off while driving, which could lead to an accident re sulting in death or serious injury. (except for vehicles with steel spare wheel)
■Use of defective wheels prohibited
Do not use cracked or deformed wheels. Doing so could cause the tire to leak air during driving, possibly causing an accident.
NOTICE
■Replacing tire pressure warning valves and transmitters (vehicles with the tire pres-sure warning system)
●Because tire repair or replacement may affe ct the tire pressure warning valves and transmitters, make sure to have tires se rviced by any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer or other qualified service shop. In
addition, make sure to purchase your tire pressure warning valves and transmitters at any authorized Lexus retailer or Lexus auth orized repairer, or any reliable repairer.
●Ensure that only genuine Lexus wheels are used on your vehicle.
Tire pressure warning valves and transmitte rs may not work properly with non-genu- ine wheels.

4657-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30F92E_(EE)
WARNING
■If both the ABS and the brake system warning lights remain on
Stop your vehicle in a safe place immediately and contact any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer. The vehicle will become
extremely unstable during braking, and the ABS system may fail, which could cause an accident resulting in death or serious injury.
■When the electric power steering system warning light comes on
The steering wheel may become extremely heavy. If the steering wheel becomes heavier than us ual when operating, hold firmly and oper- ate using more force than usual.
■If the tire pressure warning light comes on
Be sure to observe the following precautions. Failure to do so could cause a loss of vehicle control and result in death or serious injury.
●Stop your vehicle in a safe place as soon as possible. Adjust the tire inflation pressureimmediately.
●If the tire pressure warning light comes on even after tire inflation pressure adjust-
ment, it is probable that you have a flat tire. Check the tires. If a tire is flat, change it with the spare tire and have the flat tire repaired by the nearest any authorized Lexusretailer or Lexus authorized repa irer, or any reliable repairer.
●Avoid abrupt maneuvering and braking. If the vehicle tires deteriorate, you could lose control of the steering wheel or the brakes.
■If a blowout or sudden air leakage should occur
The tire pressure warning syst em may not activate immediately.
NOTICE
■To ensure the tire pressure warning system operates properly
Do not install tires with different specifications or makers, as the tire pressure warning system may not operate properly.

4987-2. Steps to take in an emergency
GS450h_300h_OM_OM30F92E_(EE)
If you have a flat tire (vehicles with spare tire)
●Stop the vehicle in a safe place on a hard, flat surface.
●Set the parking brake.
●Shift the shift lever to P.
●Stop the hybrid system.
●Turn on the emergency flashers. ( P. 452)
Your vehicle is equipped with a spare tire. The flat tire can be replaced with
the spare tire.
For details about tires: P. 416
WARNING
■If you have a flat tire
Do not continue driving with a flat tire.
Driving even a short distance with a flat tire can damage the tire and the wheel beyond repair, which could result in an accident.
Before jacking up the vehicle