Page 430 of 600
4306-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30F92E_(EE)
NOTICE
■When inspecting and adjusting tire inflation pressure
Be sure to put the tire valve caps back on. If a valve cap is not installed, dirt or mois ture may get into the valve and cause an air
leak, resulting in decrease d tire inflation pressure.
Page 431 of 600

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
Page 451 of 600

451
7When trouble arises
GS450h_300h_OM_OM30F92E_(EE)
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
Page 459 of 600

459
7
7-2. Steps to take in an emergency
When trouble arises
GS450h_300h_OM_OM30F92E_(EE)
If you think something is wrong
●Fluid leaks under the vehicle.
(Water dripping from the air conditioning after use is normal.)
●Flat-looking tires or uneven tire wear
●Engine coolant temperature gauge needle continually points higher than nor-
mal.
●Changes in exhaust sound
●Excessive tire squeal when cornering
●Strange noises related to the suspension system
●Pinging or other noises related to the hybrid system
●Engine missing, stumbling or running roughly
●Appreciable loss of power
●Vehicle pulls heavily to one side when braking
●Vehicle pulls heavily to one side when driving on a level road
●Loss of brake effectiveness, spongy feeling, pedal almost touches the floor
If you notice any of the following sy mptoms, your vehicle probably needs
adjustment or repair. Contact any authorized Lexus retailer or Lexus autho-
rized repairer, or any reliable repairer as soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms
Page 463 of 600

4637-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30F92E_(EE)
*: Driver’s and front passenger’s seat belt buzzer:
The driver’s and front passenger’s seat belt buzzer sounds to alert the driver and front passenger that his or her seat belt is not fastened. The buzzer sounds intermittently for
30 seconds after the vehicle reaches a speed of 20 km/h (12 mph). Then, if the seat belt is still unfastened , the buzzer will sound in a different tone for 90 more seconds.
■Front passenger detection sensor, seat belt reminder and warning buzzer
●If luggage is placed on the front passenger seat, the front passenger detection sensor may cause the warning light to flash and the warning buzzer to sound even if a passen-
ger is not sitting in the seat.
●If a cushion is placed on the seat, the sensor may not detect a passenger, and the warn- ing light may not operate properly.
■If the malfunction indicator lamp comes on while driving
The malfunction indicator lamp will come on if the fuel tank becomes completely empty. If the fuel tank is empty, refuel the vehicle immediately. The malfunction indicator lamp
will go off after several trips.
If the malfunction indicator la mp does not go off, contact any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer as soon as possible.
■Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insufficient or the voltage temporarily drops, the electric power steering system warning light may come on and the warning buzzer
may sound.
(If equipped)
Tire pressure warning light When the light comes on:Low tire inflation pressure such as
• Natural causes ( P. 464) • Flat tire ( P. 498, 509) Adjust the tire inflation pressure to the specified level.
The light will turn off after a few minutes. In case the light does not turn off even if the tire inflation pressure is adjusted, have thesystem checked by any authorized Lexus retailer or Lexus
authorized repairer, or any reliable repairer. When the light comes on after blinking for 1 minute:Malfunction in the tire pressure warning system
Have the system checked by any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer.
(If equipped)
LKA warning lightThe warning light comes on and a warning message is displayed to
indicate that the LKA (Lane-Keepin g Assist) system is not available temporarily or has detected a malfunction. P. 478
Warning lightWarning light/Details/Actions
Page 464 of 600

4647-2. Steps to take in an emergency
GS450h_300h_OM_OM30F92E_(EE)
■When the tire pressure warning light comes on (if equipped)
Carry out the following procedure after the tire temperature has lowered sufficiently.
●Check the tire inflation pressure and adjust to the appropriate level.
●If the warning light does not go out even afte r several minutes, check that the tire infla- tion pressure is at the specifie d level and carry out initialization.
The warning light may come on again if the above operations are conducted without first
allowing the tire temperature to lower sufficiently.
■The tire pressure warning light may come on due to natural causes
The tire pressure warning light may come on due to natural causes such as natural air
leaks and tire inflation pressure changes caused by temperature. In this case, adjusting the tire inflation pressure will turn off the warning light (after a few minutes).
■When a tire is replaced with a spare tire
The compact spare tire is not equipped with a tire pressure warning valve and transmit- ter. If a tire goes flat, the tire pressure warning light will not turn off even though the flattire has been replaced with the spare tire.
■Conditions that the tire pressure warning system may not function properly
P. 420
■If the tire pressure warning light frequently comes on after blinking for 1 minute
If the tire pressure warning light frequently comes on after blinking for 1 minute when the power switch is turned to ON mode, have it checked by any authorized Lexus retailer orLexus authorized repairer, or any reliable repairer.
■Warning buzzer
In some cases, the buzzer may not be heard because of noisy place or an audio sound.
Page 465 of 600

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.
Page 485 of 600
4857-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30F92E_(EE)
Indicates that the accelerator and brake pedals are being depressed simultaneously, and the brake override
system is operating. Release the accelerator or brake pedal. (P. 201)
(If equipped)
Indicates that the tire inflation pressure is low
Check the tire inflation pressure, and adjust to the appropriate level.
Warning messageDetails/Actions
(Flashes)