Page 633 of 860

GS450h_U (OM30D01U)
6336-3. Do-it-yourself maintenance
6
Maintenance and care
CAUTION
The engine compartment contains many mechanisms and fluids that may move sud-
denly, become hot, or become electrically energized. To avoid death or serious
injury, observe the following precautions.
■When working on the engine compartment
●Make sure that the “POWER ON” on the multi-information display and the
“READY” indicator are both off.
●Keep hands, clothing and tools away from the moving fan and engine drive belt.
●Be careful not to touch the engine, power control unit, radiator, exhaust manifold,
etc. right after driving as they may be hot. Oil and ot her fluids may also be hot.
●Do not leave anything that may burn easily, such as paper and rags, in the engine
compartment.
●Do not smoke, cause sparks or expose an open flame to fuel. Fuel fumes are flam-
mable.
■When working near the electric cooling fans or radiator grille
Be sure the power switch is off.
With the power switch in ON mode, the electric cooling fans may automatically
start to run if the air conditioning is on and/or the coolant temperature is high.
( P. 6 4 4 )
■Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc. from get-
ting in your eyes.
NOTICE
■If you remove the air cleaner filter
Driving with the air cleaner filter removed may cause excessive engine wear due to
dirt in the air. Also, a backfire could cause a fire in the engine compartment.
Page 662 of 860

662
GS450h_U (OM30D01U)
6-3. Do-it-yourself maintenance
Ti r e v a l v e
Tire pressure gauge
Remove the tire valve cap.
Press the tip of the tire pressure gauge onto the tire valve.
Read the pressure using the gauge gradations.
If the tire inflation pressure is not at the recommended level, adjust the
pressure.
If you add too much air, press the center of the valve to deflate.
After completing the tire inflation pressure measurement and adjust-
ment, apply soapy water to the valve and check for leakage.
Put the tire valve cap back on.
■Tire inflation pressure check interval
You should check tire inflation pressure every two weeks, or at least once a month.
Do not forget to check the spare.
■Effects of incorrect tire inflation pressure
Driving with incorrect tire inflation pressure may result in the following:
●Reduced fuel efficiency
●Reduced driving comfort and tire life
●Reduced safety
●Damage to the drive train
If a tire needs frequent inflating, have it checked by your Lexus dealer.
Inspection and adjustment procedure
1
2
1
2
3
4
5
6
Page 674 of 860
674
GS450h_U (OM30D01U)
6-3. Do-it-yourself maintenance
■Engine compartment
Fuse layout and amperage ratings
FuseAmpereCircuit
1IGN10Starting system
2INJ10Multiport fuel injection system/sequential
multiport fuel injection system
3EFI NO.210Air intake system, exhaust system
4IG2 MAIN20IGN, GAUGE, INJ, AIR BAG, IG2 NO.1,
LH-IG2
5EFI MAIN25Multiport fuel injection system/sequential
multiport fuel injection system, EFI NO.2
6A/F15Air flow sensor
7EDU20Multiport fuel injection system/sequential
multiport fuel injection system
8F/ P M P25Multiport fuel injection system/sequential
multiport fuel injection system
9H-LP RH-LO20Right-hand headlight (low beam)*
10H-LP LH-LO20Left-hand headlight (low beam)*
Page 675 of 860
GS450h_U (OM30D01U)
6756-3. Do-it-yourself maintenance
6
Maintenance and care
11ABS MAIN 210Brake system
12ABS MAIN 110Brake system
13IGCT NO.130IGCT NO.2, IGCT NO.3, IGCT NO.4,
IGCT NO.5
14ECU-B7. 5Smart access system with push-button start
15INV W/P10Hybrid system
16ETCS10Multiport fuel injection system/sequential
multiport fuel injection system
17EPS-B10Electric power steering system
18D/C CUT30DOME, MPX-B
19HORN10Horn
20ODS5Occupant classification system
21TV7. 5Remote Touch screen
22P/ I - B N O. 280IG2 MAIN, EFI MAIN, EDU, F/PMP, A/F
23ABS NO.230ECB
24P/ I - B N O.150H-LP HI RH, H-LP HI LH, DRL
25H-LP LO30H-LP LO RH, H-LP LO LH
26LH J/B-B40Left-hand junction block
27RH J/B-B40Right-hand junction block
28VGRS40No circuit
29OIL PMP60Oil pump
30IGCT NO.57. 5Power management system, shift position
sensor
31WIP-S7. 5Windshield wipers, driver support system
32WA S H - S5Windshield washer, driver support system
33COMB SW5Windshield wipers
FuseAmpereCircuit
Page 679 of 860
GS450h_U (OM30D01U)
6796-3. Do-it-yourself maintenance
6
Maintenance and care
11DOOR FL30Outside rear view mirror defoggers, power
window (front left-hand)
12CAPACITOR
(HV)10Capacitor
13STRG LOCK15Steering lock system
14D/L NO.225Power door lock system
15DOOR RL30Power window (rear left-hand)
16HAZ15Turn signal lights, emergency flashers
17LH-IG210
Multiport fuel injection system/sequential
multiport fuel injection system, stop lights,
smart access system with push-button start,
steering lock system, brake system, power
management system
18LH J/B-B7. 5Body ECU
19S/ROOF20Moon roof
20P/ S E AT 2 F/ L25Po w e r s e a t s
21TI & TE20Electric tilt and telescopic steering column
22A/C7. 5Air conditioning system
FuseAmpereCircuit
Page 714 of 860

7147-2. Steps to take in an emergency
GS450h_U (OM30D01U)After taking the specified steps to correct the suspected
problem, check
that the warning light goes off.
Brake system warning light Indicates a malfunction in:
• The electronically controlled brake system;
• The regenerative braking system; or
• The parking brake system
Follow the correction procedures.
Warning lightWarning light/Details
Warning lightWarning light/DetailsCorrection procedure
Open door warning light
(warning buzzer)
*1
Indicates that a door or the
trunk is not fully closed
Check that all the doors and
the trunk are closed.
Low fuel level warning lightIndicates remaining fuel is
approximately 2.6 gal. (10.0
L, 2.2 Imp.gal.) or less
Refuel the vehicle.
Seat belt reminder light (warn-
ing buzzer)
*2
Warns the driver and/or front
passenger to fasten their seat
belts
Fasten the seat belt. If the front passenger’s seat is
occupied, the front passen-
ger’s seat belt also needs to
be fastened to make the
warning light (warning
buzzer) off.
Master warning lightA buzzer sounds and the
warning light comes on and
flashes to indicate that the
master warning system has
detected a malfunction.
P. 7 2 1
Page 716 of 860

7167-2. Steps to take in an emergency
GS450h_U (OM30D01U)
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors,
side impact sensors (front door), side impact sensors (front), side impact sensors
(rear), driver’s seat position sensor, driver’s seat belt buckle switch, front passenger
occupant classification system, “AIR BAG ON” indicator light, “AIR BAG OFF” indi-
cator light, front passenger’s seat belt buckle switch, seat belt pretensioner assem-
blies, airbags, interconnectin g wiring and power sources. ( P. 4 0 )
■Front passenger detection sensor, seat belt reminder and warning buzzer
If luggage is placed on the front passen ger seat, the front passenger detection sen-
sor may cause the warning light to flash and the warning buzzer to sound even if a
passenger is not sitting in the seat.
■If the malfunction indicator lamp comes on while driving
First check the following:
●Is the fuel tank empty?
If it is, fill the fuel tank immediately.
●Is the fuel tank cap loose?
If it is, tighten it securely.
The light will go off after several driving trips.
If the light does not go off even after several trips, contact your Lexus dealer as soon
as possible.
■Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insufficient of the voltage temporarily
drops, the electric power steering system warning light may come on and the warn-
ing buzzer may sound.
■When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level. Pushing the tire
pressure warning reset switch will not turn off the tire pressure warning light.
Page 719 of 860

7197-2. Steps to take in an emergency
GS450h_U (OM30D01U)
7
When trouble arises
CAUTION
■Maintenance of the tires
Each tire, including the spare (if provided), should be checked monthly when cold
and inflated to the inflation pressure re commended by the vehicle manufacturer on
the vehicle placard or tire inflation pressu re label (tire and load information label).
(If your vehicle has tires of a different size than the size indicated on the vehicle
placard or tire inflation pressure label [t ire and load information label], you should
determine the proper tire inflation pressure for those tires.)
As an added safety feature, your vehicle has been equipped with a tire pressure
monitoring system (TPMS-tire pressure wa rning system) that illuminates a low tire
pressure telltale (tire pressure warning light ) when one or more of your tires is sig-
nificantly under-inflated. Accordingly, when the low tire pressure telltale (tire pres-
sure warning light) illuminates, you should stop and check your tires as soon as
possible, and inflate them to the proper pressure. Driving on a significantly under-
inflated tire causes the tire to overheat and can lead to tire failure. Under-inflation
also reduces fuel efficiency and tire tread life, and may affect the vehicle’s handling
and stopping ability.
Please note that the TPMS (tire pressure warning system) is not a substitute for
proper tire maintenance, and it is the driver’s responsibility to maintain correct tire
pressure, even if under-inflation has not re ached the level to trigger illumination of
the TPMS low tire pressure telltale (tire pressure warning light).
Your vehicle has also been equipped with a TPMS (tire pressure warning system)
malfunction indicator to indicate when th e system is not operating properly. The
TPMS (tire pressure warning system) malfunction indicator is combined with the
low tire pressure telltale (tire pressure warning light). When the system detects a
malfunction, the telltale will flash for approximately one minute and then remain
continuously illuminated. This sequence will continue upon subsequent vehicle
start-ups as long as the malfunction exists . When the malfunction indicator is illumi-
nated, the system may not be able to detect or signal low tire pressure as intended.