Page 776 of 1014

7526-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30D53E_(EE)
CAUTION
Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid and may
produce hydrogen gas which is flammable and explosive. To reduce the
risk of death or serious injury, take the following precautions while work-
ing 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 battery in a garage or closed room where there is insufficient ventila-
tion.
How to recharge the 12-volt battery
Recharge at a current of 5 A or less and make sure that the recharging
period does not exceed a total of 12 hours.
Page 780 of 1014

7566-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30D53E_(EE)
Your vehicle is equipped with a tire pressure warning system that
uses tire pressure warning valves and transmitters to detect low tire
inflation pressure before serious problems arise.
Vehicles without the tire inflation pressure display function
If the tire pressure drops below a predetermined level, the driver is
warned by a warning light. (P. 834)
Vehicles with the tire inflation pressure display function
If the tire pressure drops below a predetermined level, the driver
is warned by a screen display and a warning light. (P. 859)
The tire pressure detected by the tire pressure warning system
can be displayed on the multi-information display. (P. 117)
Installing tire pressure warning valves and transmitters
When replacing tires or wheels, tire pressure warning valves and
transmitters must also be installed.
When new tire pressure warning valves 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 pressure warning valve and transmitter ID
codes registered by any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional. (P. 758)
Tire pressure warning system (if equipped)
Page 782 of 1014
7586-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30D53E_(EE)
Press and hold the tire pres-
sure warning reset switch
until the tire pressure warn-
ing light blinks slowly 3
times.
Wait for a few minutes with the power 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. Have the
ID code registered by any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
4
5
Page 783 of 1014

759 6-3. Do-it-yourself maintenance
6
Maintenance and care
GS450h_300h_OM_OM30D53E_(EE)
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 any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional.
Replacing tires and wheels (vehicles with the tire pressure warning system)
If the ID code of the tire pressure warning valve and transmitter is not regis-
tered, the tire pressure warning system will not work properly. After driving
for about 10 minutes, the tire pressure warning light blinks 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 seldom 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 pres-
sure checks. Make sure to check tire inflation pressure as part of your routine
of daily vehicle checks.
When rotating the tires (vehicles with the tire pressure warning system featur-
ing a tire inflation pressure display function)
Make sure that the power switch is off. If the tires are rotated while the power
switch is in ON mode, the tire position information will not be updated.
If this accidentally occurs, either turn the power switch to off and then to ON
mode, or initialize the system after checking that the tire pressure is properly
adjusted.
Page 785 of 1014

761 6-3. Do-it-yourself maintenance
6
Maintenance and care
GS450h_300h_OM_OM30D53E_(EE)
The initialization operation (vehicles with the tire pressure warning system)
Make sure to carry out initialization after adjusting the tire inflation pres-
sure.
Also, make sure the tires are cold before carrying out initialization or tire
inflation pressure adjustment.
If you have accidentally turned the power switch off during initialization, it
is not necessary to press the reset switch again as initialization will restart
automatically when the power switch has been turned to ON mode for the
next time.
If you accidentally press the reset switch when initialization is not neces-
sary, adjust the tire inflation pressure to the specified level when the tires
are cold, and conduct initialization again.
Warning performance of the tire pressure warning system (if equipped)
The warning of the tire pressure warning system will change in accordance
with the conditions under which it was initialized. For this reason, the system
may give a warning even if the tire pressure does not reach a low enough
level, or if the pressure is higher than the pressure that was adjusted to when
the system was initialized.
When initialization of the tire pressure warning system has failed (vehicles
with the tire pressure warning system)
Initialization can be completed in a few minutes. However, in the following
cases, the settings have not been recorded and the system will not operate
properly. If repeated attempts to record tire inflation pressure settings are
unsuccessful, have the vehicle inspected by any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
When operating the tire pressure warning reset switch, the tire pressure
warning light does not blink 3 times.
After carrying out the initialization procedure, the tire pressure warning
light blinks for 1 minute then stays on after driving for 20 minutes.
Registering ID codes (vehicles with the tire pressure warning system)
The ID codes of the tire pressure warning valve and transmitters for two sets
of wheels can be registered.
It is not necessary to register the ID codes when replacing normal tires with
snow tires, if the ID codes for the wheels of both normal tires and snow tires
are registered beforehand.
For information about changing ID codes, ask any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
Page 792 of 1014

7686-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30D53E_(EE)
CAUTION
When inspecting or replacing tires
Observe the following precautions to prevent accidents.
Failure to do so may cause damage to parts of the drive train as well as dan-
gerous handling characteristics, which may lead to an accident resulting in
death or serious injury.
Do not mix tires of different makes, models or tread patterns.
Also, do not mix tires of remarkably different treadwear.
Do not use tire sizes other than those recommended by Lexus.
Do not mix differently constructed tires (radial, bias-belted or bias-ply
tires).
Do not mix summer, all season and snow tires.
Do not use tires that have been used on another vehicle.
Do not use tires if you do not know how they were used previously.
Vehicles with a compact spare tire: Do not tow if your vehicle has a com-
pact spare tire installed.
Vehicles with an emergency tire puncture repair kit (if equipped): Do not
tow anything if a tire that has been repaired using the emergency tire
puncture repair kit is installed. The load on the tire may cause unexpected
damage to the tire.
When initializing the tire pressure warning system (vehicles with the tire
pressure warning system)
Do not operate the tire pressure warning reset switch without first adjusting
the tire inflation pressure to the specified level. Otherwise, the tire pressure
warning light may not come on even if the tire inflation pressure is low, or
it may come on when the tire inflation pressure is actually normal.
Page 812 of 1014

7886-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30D53E_(EE)
8F/PMP25Multiport fuel injection system/sequen-
tial multiport fuel injection system
9H-LP RH-LO20Right-hand headlight (low beam)*1
10H-LP LH-LO20Left-hand headlight (low beam)*1
11BATT FAN
(HV)*210Hybrid battery (traction battery) cooling
fan system
12ABS MAIN 210Brake system
13ABS MAIN 110Brake system
14IGCT NO.130IGCT NO.2, IGCT NO.3, IGCT NO.4,
IGCT NO.5
15ECU-B7.5VGRS, smart entry & start system
16INV W/P10Hybrid system
17ETCS10Multiport fuel injection system/sequen-
tial multiport fuel injection system
18EPS-B10Electric power steering system
19D/C CUT30DOME, MPX-B
20HORN10Horn
21ODS5No circuit
22TV7.5Remote Touch screen
23P/I-B NO.280IG2 MAIN, EFI MAIN, EDU, F/PMP,
A/F
24ABS NO.230Motor relay
25P/I-B NO.150H-LP HI RH, H-LP HI LH, DRL, emer-
gency brake signal
26H-LP LO30H-LP LO RH, H-LP LO LH
27LH J/B-B40Left-hand junction block
28RH J/B-B40Right-hand junction block
29VGRS40VGRS
30OIL PMP60Oil pump
FuseAmpereCircuit
Page 813 of 1014

789 6-3. Do-it-yourself maintenance
6
Maintenance and care
GS450h_300h_OM_OM30D53E_(EE)
31IGCT NO.57.5Power management system, shift posi-
tion sensor
32WIP-S7.5Windshield wipers, driver support sys-
tem
33WA S H - S5Windshield washer, driver support sys-
tem
34COMB SW5Windshield wipers
35DOME7.5
Personal lights, ornament lights, trunk
light,
footwell lights, door courtesy lights, van-
ity
lights, rear door inside handle illumina-
tions,
power trunk lid
36MPX-B10
Body ECU, smart entry & start system,
electric tilt and telescopic steering col-
umn, power seats, head-up display, front
door ECU, gauges and meters, steering
sensor, yaw rate and G sensor, overhead
module, RR CTRL SW, power trunk lid,
clock, CAN gateway ECU
37IGCT NO.410Power control unit
38IGCT NO.37.5Hybrid battery (traction battery), DC/DC
converter
39IGCT NO.25Hybrid system
40IG2 NO.15DCM, CAN gateway ECU
41GAUGE5Gauges and meters
42EPS*280Electric power steering
43DC/DC150RH-J/B DC/DC, P/I DC/DC,
LH-J/B DC/DC, LUG-J/B DC/DC
44P/I DC/DC100RR S/SHADE, DEFOG, FOG, TAIL,
PA N E L
45RH J/B DC/DC80Right-hand junction block
FuseAmpereCircuit