2010 Lexus HS250h maintenance

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4-3. Do-it-yourself maintenance
■Before recharging
When recharging, the 12-volt battery produces hydrogen gas which is flammable
and
explosive. Therefore, observe the following precautions before recharging:
●If recharging with the 12-volt battery installed on the vehicle, be sure to discon -
nect the ground cable.
●Make sure the power switch on the charger is off when connecting and discon -
necting the charger cables to the 12-volt battery.
■After recharging/reconnecting the 12-volt battery
●Unlocking the doors using the smart ke y system may not be possible immedi-
ately after disconnecting the 12
-volt battery. If this happens, use the wireless
remote control or the mechanical key to lock/unlock the doors.
●Start the hybrid system with the “P OWER” switch in ACCESSORY mode. The
hybrid system may not start with the “POWER” switch turned OFF. However,
the hybrid system will operate normally from the second attempt.
●The “POWER” switch mode is recorded by the vehicle. If the battery is recon -
nected, the vehicle will return the “POWER” switch mode to the status it was in
be
fore the battery was disconnected. Make sure to turn off the power before
disconnect the battery. Take extra care when connecting the battery if the
“POWER” switch mode prior to discharge is unknown.
If the system will not start even after mult i
ple attempts, contact your Lexus dealer.
■Exterior
Make sure that the 12-volt ba ttery terminals are not corroded and
that there are no loose connect ions, cracks or loose clamps.
Terminals
Hold-down clamp

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4-3. Do-it-yourself maintenance
4
Maintenance and care
CAUTION
■Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid and may pro-
duce hydrogen gas which is flammable and explosive. To reduce the risk of death or
serious injury, take the following precautions while working on or near the 12-volt
battery:
●Do not cause sparks by touching the 12-volt battery terminals with tools.
●Do not smoke or light a match near the 12-volt battery.
●Avoid contact with eyes, skin and clothes.
●Never inhale or swallow electrolyte.
●Wear protective safety glasses when working near the 12-volt battery.
●Keep children away from the 12-volt battery.
■Where to safely charge the 12-volt battery
Always charge the 12-volt battery in an open area. Do not charge the 12-volt bat-
tery in a garage or closed room where there is insufficient ventilation.
■How to recharge the 12-volt battery
Only perform a slow charge (5 A or le ss). The 12-volt battery may explode if
charged at a quicker rate.
■Emergency measures regarding electrolyte
●If electrolyte gets in your eyes 
Flush your eyes with clean water for at least 15 minutes and get immediate medi-
cal attention. If possible, continue to apply water with a sponge or cloth while
traveling to the nearest medical facility.
●If electrolyte gets on your skin 
Wash the affected area thoroughly. If you feel pain or burning, get medical atten-
tion immediately.
●If electrolyte gets on your clothes 
It can soak through clothing on to your skin. Immediately take off the clothing and
follow the procedure above if necessary.
●If you accidentally swallow electrolyte 
Drink a large quantity of water or milk. Get emergency medical attention imme-
diately.

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4-3. Do-it-yourself maintenance
CAUTION
■When replacing the 12-volt battery
Use a 12-volt battery designed for this vehicle. Failure to do so may cause gas
(hydrogen) to enter the passenger compartment, causing a fire or explosion.
For replacement of the 12-volt battery, contact your Lexus dealer.
NOTICE
■When recharging the 12-volt battery
Never recharge the 12-volt battery while the hybrid system is operating. Also, be
sure all accessories are turned off.

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4-3. Do-it-yourself maintenance
4
Maintenance and care
Tires
Replace or rotate tires in accordance with maintenance schedules and
treadwear.
■Checking tires
New tread
Treadwear indicator
Worn tread
The location of treadwear indi-
cators is shown by the “TWI” or
“ ”

marks, etc., molded on the
sidewall of each tire.
Check spare tire condition and
pr
essure if not rotated.
■ Tire rotation
Rotate the tires in the order
sho
wn.
To equalize tire wear and extend
tire life, Lexus recommends that
tire rotation is carried out at the
same interval as tire inspection.
P225/45R18 91W tires: 
Do not fail to initialize the tire
pr
essure warning system after
tire rotation.
■ Tire pressure warning system
Your vehicle is equipped with a ti r
e pressure warning system that
uses tire pressure warning valves and transmitters to detect low tire
inflation pressure before serious problems arise. ( P. 4 9 5 , 504 ,
505)
Front

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4-3. Do-it-yourself maintenance
Installing tire pressure warning valves and transmitters
When replacing tires or wheels, tire pressure warning valves and trans-
mitters must also be installed.
When new tire pressure warning va lv
es and transmitters are installed,
new ID codes must be registered in the tire pressure warning computer
and the tire pressure warning system must be initialized. Have tire pres-
sure warning valve and transmitter ID codes r
egistered by your Lexus
dealer. ( P. 4 3 9 )
Initializing the tire pressure warning system
■The tire pressure warning system must be initialized in the following
circumstances:
● V
ehicles with P225/45R18 91W tires: When rotating front and rear
tires which have different tire inflation pressures
● When changing the tir
e size
When the tire pressure warning sys tem is initializ
ed, the current tire
inflation pressure is set as the benchmark pressure.

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4-3. Do-it-yourself maintenance
4
Maintenance and care
■How to initialize the tire pressure warning system
Park the vehicle in a safe place and turn the “POWER” switch off.
Initialization cannot be performed while the vehicle is moving.
Adjust the tire inflation pressure to the specified cold tire inflation
pressure level. ( P. 555 )
Make sure to adjust the tire pressure to the specified cold tire inflation
pressure level. The tire pressure warning system will operate based on
this pressure level.
Turn the “POWER” switch to ON mode.
Press and hold the tire pressure warning reset switch until the tire
pressure warning light flashes slo
wly 3 times and the message
“TIRE PRESSURE RESET PROC EEDING” appears on the
multi-information display.
Wait for a few minutes with th e “P
OWER” switch in ON mode
and then turn the “POWER” switch off.
Registering ID codes
The tire pressure warning valve and transmitter is equipped with a unique
ID code. When replacing a tire pressure warning valve and transmitter, it
is necessary to register the ID code. Ha ve the ID code registered by your
Lexus dealer.

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4-3. Do-it-yourself maintenance
■When to replace your vehicle’s tires
Tires should be replaced if:
●You have tire damage such as cuts, splits, cracks deep enough to expose the
fabric, and bulges indicating internal damage.
●A tire goes flat repeatedly or cannot be properly repaired due to the size or
location of a cut or other damage.
If you are not sure, consult with your Lexus dealer.
■Replacing tires and wheels
If the ID code of the tire pressure warning valve and transmitter is not registered,
the tir
e pressure warning system will not work properly. After driving for about 20
minutes, the tire pressure warning light flas hes for 1 minute and stays on to indicate a
system malfunction.
■Tire life
Any tire over 6 years old must be checked by a
qualified technician even if it has sel-
dom or never been used or damage is not obvious.
■Routine tire inflation pressure checks
The tire pressure warning system does not replace routine tire inflation pressure
ch
ecks. Make sure to check tire inflation pressure as part of your routine of daily
vehicle checks.
■Low profile tires (vehicles with P225/45R18 91W tires)
Generally, low profile tires will wear more rapidly and tire grip performance will be
r
educed on snowy and/or icy roads when co mpared to standard tires. Be sure to
use snow tires or tire chains on snowy and/or icy roads and drive carefully at a
speed appropriate for road and weather conditions.

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4-3. Do-it-yourself maintenance
4
Maintenance and care
■Maximum load of tire
Check that the maximum load of the replacement tire is greater than 1 /2 of the
Gross Axle Weight Ratings (GAWR) of either the front axle or the rear axle, which-
ever is greater.
■Tire types
●Summer tires
Summer tires are high-speed performance tires best suited to highway driving
under dry conditions. Since summer tires do not have the same traction perfor-
mance as snow tires, summer tires are in adequate for driving on snow-covered
or icy roads. For driving on snow-covered roads or icy roads, the use of snow tires
is recommended. When installing snow tires, be sure to replace all four tires.
●All season tires
All season tires are designed to provide better traction in snow and to be ade-
quate for driving in most winter conditions as well as for use year-round. All sea-
son tires, however, do not have adequate traction performance compared with
snow tires in heavy or loose snow. Also, al l season tires fall short in acceleration
and handling performance compared with summer tires in highway driving.
●Snow tires
For driving on snow-covered roads or icy roads, we recommend using snow tires.
If you need snow tires, select tires of the same size, construction and load capac-
ity as the originally installed tires. Since your vehicle has radial tires as original
equipment, make sure your snow tires also have radial construction. Do not install
studded tires without first checking local regulations for possible restrictions.
Snow tires should be installed on all wheels. ( P. 2 4 4 )
■Initializing the tire pressure warning system
Initialize the system with the tire inflatio n pressure adjusted to the specified level.
■If the tread on snow tires wears down below 0.16 in. (4 mm)
The effectiveness of the tires as snow tires is lost.
For the GAWR, see the Certification Label.
For the maximum load of the tire, see the load
limit at maximum cold tire inflation pressure
mentioned on the sidewall of the tire. 
( P. 5 6 0 )