2010 Lexus HS250h belt

443
4-3. Do-it-yourself maintenance
4
Maintenance and care
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 dangerous handling characteristics,
which may lead to an accident resu lting in death or serious injury.
●Do not mix tires of different makes, mode ls or tread patterns. Also, do not mix
tires of remarkably different treadwear.
●Do not use tire sizes other th an 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.
■When initializing the tire pressure warning system
Do not operate the tire pressure warning re set 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.
NOTICE
■Repairing or replacing tires, wheels and tire pressure warning valves and trans-
mitters
When removing or fitting the wheels, tires or the tire pressure warning valves and
transmitters, contact your Lexus dealer as the tire pressure warning valves and
transmitters may be damage d if not handled correctly.
■To avoid damaging the tire pressu re warning valves and transmitters
Do not use liquid sealants on flat tires.
■Driving on rough roads
Take particular care when driving on roads with loose surfaces or potholes. 
These conditions may cause losses in tire inflation pressure, reducing the cushion-
ing ability of the tires. In addition, driv ing on rough roads may cause damage to the
tires themselves, as well as the vehicle’s wheels and body.

462
4-3. Do-it-yourself maintenance
Driver’s side instrument panel
FuseAmpereCircuit
1TA I L10 AParking lights, tail lights, license plate
lights, side maker lights, front fog lights
2PA N E L10 A
Navigation system, audio system, air
conditioning system, emergency
flashers switch, wiper de-icer switch,
seat heater switch, P position switch,
headlight cleaner switch, front pas-
senger’s seatbelt reminder light,
power window switch, VSC-OFF
switch, HUD switch, AFS-OFF switch,
POWER ·ECO· EV mode switch,
view select switch, trunk opener
switch, fuel lid opener switch, glove
box light, rear sun shade switch,
remote touch, rear view mirror switch

465
4-3. Do-it-yourself maintenance
4
Maintenance and care
21RR FOG7. 5 ANo circuit
22FUEL OPN7. 5 ATrunk opener switch, fuel filler door
opener switch
23OBD7. 5 AOn-board diagnosis
24PWR SEAT FL30 ADriver’s side power seat
25FR FOG15 AFront fog lights
26PWR SEAT FR30 APassenger’s side power seat
27PSB30 APre-collision seat belts system
28WELCAB30 ANo circuit
29DOOR NO.125 APower door lock system
30SEAT HTR FL10 ADriver’s side seat heater
31SEAT HTR FR10 APassenger’s side seat heater
32RAD NO.27. 5 A
Navigation system, audio system, air
conditioning system, HUD, remote
touch
33PWR OUTLET15 APo w e r o u t l e t
34ECU-ACC10 ARear view mirror, air conditioning sys-
tem, audio system, navigation system
FuseAmpereCircuit

490
5-1. Essential information
Event data recorder
In a crash or a near crash event
The SRS airbag sensor assembly contains the EDR. In a crash or near
crash event, this device may record some or all of the following informa-
tion:
● Engine speed
● Whether the br
ake pedal was applied or not
● V
ehicle speed
●T
o what extent the accelerator pedal was depressed
●Hybrid tr
ansmission shift position
●Whether the driv
er and front passenger wore seat belts or not
● D
river's seat position
●SRS airbag deplo
yment data
● SRS airbag s
ystem diagnostic data
● F
ront passenger’s occupant classification
The information abov e is intended to be used for the purpose of impr
ov-
ing vehicle safety performance. Unlike general da ta recorders, the EDR
does not record sound data such as conversation between passengers.
Your vehicle has computers that monitor and control certain aspects of
your vehicle. These computers assist in driving and maintaining optimal
vehicle performance.
Besides storing data usef ul for troubleshooting, there is an event data
recorder (EDR) that records data in a crash or near crash event.

5
When trouble arises
493
5-2. Steps to take in an emergency
Have the vehicle inspected by your Lexus dealer immediately.
Failing to investigate the cause of the following warnings may lead to the
system operating abnormally and possibly cause an accident. Have the
vehicle inspected by your Lexus dealer immediately.
High engine coolant temperatur e warning light (flashes or
comes on) Indicates that the engine is overheating P. 5 4 1
• Flashes: Engine is overheating. Drive carefully.
• Comes on: Engine is overheated. Stop the vehicle.
Warning lightWarning light/Details
Brake system warning light (yellow indicator) Indicates a malfunction in:
• The regenerative brake system; or
• The electronically controlled brake system
(U.S.A.)

(Canada)
Malfunction indicator lamp
Indicates a malfunction in:
• The hybrid system;
• The electronic engine control system;
• The electronic throttle control system; or
• The hybrid transmission control system
SRS warning lightIndicates a malfunction in:
• The SRS airbag system;
• The front passenger occupant classification system; or
• The seat belt pretensioner system
(U.S.A.)

(Canada)
“ABS” warning lightIndicates a malfunction in:
•The ABS; or
• The brake assist system
Warning lightWarning light/Details

5
When trouble arises
495
5-2. Steps to take in an emergency
Follow the correction procedures.
After taking the specified steps to correct the suspected problem, check
that the warning light goes off.
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 light
Indicates remaining fuel is
approximately 2.2 gal. (8.3
L, 1.8 Imp. gal.) or less
Refuel the vehicle.
Driver’s seat belt reminder
light (warning buzzer)
*2
Warns the driver to fasten
his/her seat belt.Fasten the seat belt.
(On the center panel)
Front passenger’s seat belt
reminder light 
(warning buzzer)
*2
Warns the front passenger to
fasten his/her seat belt.
Fasten the seat belt.
Master warning light A buzzer sounds and the
warning light comes on and
flashes to indicate that the
master warning system has
detected a malfunction.
 P. 5 0 1

496
5-2. Steps to take in an emergency
*1: Open door warning buzzer:
P. 5 0 5
*2: 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 inter-
mittently for 10 seconds after the vehicle
reaches a speed of 12 mph (20 km/h).
Then, if the seat belt is still unfastened, the buzzer will sound in a different tone
for 20 more seconds.
Tire pressure warning light
When the light comes on: 
Low tire inflation pressureAdjust the tire inflation pres-
sure.
When the light comes on after
blinking for 1 minute: 
Malfunction in the tire pres-
sure warning system
Have the system checked by
your Lexus dealer.
■SRS warning light
This warning light system monitors the airb ag
sensor assembly, front airbag sensors,
side and curtain shield airbag sensors, curtain shield and rear side airbag sensors,
driver’s seat position sensor , driver’s seat belt buckle switch, front passenger occu -
pant classification system, “AIR BAG ON” indicator light, “
AIR BAG OFF” indicator
light, front passenger’s seat belt buckle switch, seat belt pretensioner assemblies,
inflators, interconnecting wiring and power sources. ( P. 1 0 5)
■Front passenger detection sensor, passenger 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 passenger is not sitting in the seat.
●If a cushion is placed on the seat, the sensor may not detect a passenger, and the
warning light may not operate properly.
Warning lightWarning light/DetailsCorrection procedure

498
5-2. Steps to take in an emergency
The tire pressure warning system may be disabled in the following conditions:
(When the condition becomes normal, the system will work properly.)
●If electronic devices or facilities using similar radio wave frequencies are nearby.
●If a radio set at similar frequency is in use in the vehicle.
●If a window tint that affects the radio wave signals is installed.
●If there is a lot of snow or ice on the vehicle, particularly around the wheels or
wheel housings.
●If non-genuine Lexus wheels are used (Even if you use Lexus wheels, the tire
pressure warning system may not work properly with some types of tires.)
●If tire chains are used.
■If the tire pressure warning light comes on after flashing frequently for 1 minute
If the tire pressure warning light comes on after flashing frequently for 1 minute
when the “POWER” switch is turned to ON mode, have it checked by your Lexus
dealer.
■Customization that can be configured at Lexus dealer
The vehicle speed linked seat belt reminder buzzer can be disabled. 
(Customizable features P. 5 7 2 )
CAUTION
■When the electric power steering system warning light comes on
The steering wheel may become extremely heavy. 
If the steering wheel becomes heavier than usual when operating, hold firmly and
operate it 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 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 pres-
sure immediately.
●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 Lexus dealer.