ABS Lexus HS250h 2010 Hybrid System / LEXUS 2010 HS250H OWNERS MANUAL (OM75006U)

168
2-2. Instrument cluster
CAUTION
■If a safety system warning light does not come on
Should a safety system light such as the ABS and SRS airbag warning light not
come on when you start the hybrid system , this could mean that these systems are
not available to help protect you in an accid ent, which could result in death or seri-
ous injury. Have the vehicle inspected by your Lexus dealer immediately if this
occurs.
■ Warning lights
Warning lights inform the driver of malfunctions in any of the vehi-
cle’s systems. ( P. 4 9 2 )
*1: These lights turn on when the “POWER” switch is turned to ON mode
to indicate that a system check is being performed. They will turn off
after the hybrid system is on, or after a few seconds. There may be a
malfunction in a system if a light does not come on, or if the lights do not
turn off. Have the vehicle inspected by your Lexus dealer.
*2: The indicator flashes to indicate a malfunction.
(U.S.A.)(Canada)(U.S.A.)(Canada)
redyellow
(U.S.A.)(Canada)(if equipped)
(if equipped)(if equipped)(if equipped)
(if equipped)(for driver)(for front
passenger)
*1*1*1*1*1*1*1
*1*1*1*1*1, 2
*1*1, 2*2*2*2*1*1
*2

215
2-4. Using other driving systems
2
When driving
CAUTION
●Assisting the driver to judge proper following distance 
The dynamic radar cruise control determ ines whether the following distance
between the driver’s own vehicle and a designated vehicle travelling ahead is
appropriate or not. It is not capable of making any other type of judgement.
Therefore, it is absolutely necessary for the driver to remain vigilant and to deter-
mine whether or not there is a possibil ity of danger in any given situation.
●Assisting the driver to operate the vehicle 
The dynamic radar cruise control has no capability to prevent or avoid a collision
with a vehicle travelling ahead. Therefore, if there is ever any danger, the driver
must take immediate and direct control of the vehicle and act appropriately in
order to ensure the safety of all involved.
■To avoid inadvertent cruise control activation
Switch the cruise control off using the “ON-OFF” button when not in use.
■Situations unsuitable for dynamic radar cruise control
Do not use dynamic radar cruise contro l in any of the following situations.
Doing so may result in inappropriate sp eed control and could cause an accident
resulting in death or serious injury.
●In heavy traffic
●On roads with sharp bends
●On winding roads
●On slippery roads, such as thos e covered with rain, ice and snow
●On steep downhills, or where there are sudden changes between sharp up and
down gradients. 
Vehicle speed may exceed the set speed when driving down a steep hill.
●At entrances to expressways
●When weather conditions are bad enough that they may prevent the sensors
from functioning correctly (fog, sn ow, sandstorm, heavy rain, etc.)
●When an approach warning buzzer is heard often
■When the sensor may not be correctly detecting the vehicle ahead
Apply the brakes as necessary when any of the following types of vehicles are in
front of you. As the sensor may not be able to correctly detect these types of vehi-
cles, the approach warning (P. 210) will not be activated, and a fatal or serious
accident may result.

225
2-4. Using other driving systems
2
When driving
Driving assist systems
To help enhance driving safety and performance, the following systems
operate automatically in response to various driving situations. Be aware,
however, that these systems are supplementary and should not be relied
upon too heavily when operating the vehicle.
■ABS (Anti-lock Brake System)
Helps to prevent wheel lock when the brakes are applied suddenly, or if
the brakes are applied while driving on a slippery road surface
■ Brake assist
Generates an increased level of braking force after the brake pedal is
depressed when the system detects a panic stop situation
■VSC (Vehicle Stability Control)
Helps the driver to control skidding wh en swerving suddenly or turning on
slippery road surfaces
■ TRAC (Traction Control)
Helps to maintain drive power and prevents the drive wheels from spin -
ning when starting the vehicle or
accelerating on slippery roads
■EPS (Electric Power Steering)
Employs an electric motor to reduce the amount of effort needed to turn
the steering wheel
■Enhanced VSC (Enhanced vehicle stability control)
Provides cooperative control of the ABS, TRAC, VSC and EPS. 
Helps to maintain directional stability when swerving on slippery road sur -
faces by controlling steering performance.
■ PCS (Pre-Collision System) (if equipped)
 P. 2 3 3

227
2-4. Using other driving systems
2
When driving
■Turning off both TRAC and VSC systems
To turn the TRAC and VSC sys-
tems off, press and hold the button
for mor
e than 3 seconds while the
vehicle is stopped.
A message will be shown on the
multi-information display and
“VSC OFF” indicator will come on.
Press the button again to turn the
sy
stems back on.
■Sounds and vibrations caused by the ABS, brake assist, VSC and TRAC
●A sound may be heard from the engine compartment when the hybrid system is
started, just after the vehicle begins to move, if the brake pedal is depressed
repeatedly, or 1-2 minutes after the hybrid system is stopped. This sound does
not indicate that a malfunction has occurred in any of these systems.
●Any of the following conditions may occur when the above systems are operat -
ing. None of these indicates that a malfunction has occurred.
• Vibrations may be felt through the vehicle body and steering.
• A motor sound may be heard after the vehicle comes to a stop.
• The brake pedal may pulsate slightly after the ABS is activated.
• The brake pedal may move down s lightly af
ter the ABS is activated.
■EPS operation sound
When the steering wheel is operated, a motor soun
d (whirring sound) may be
heard. This does not indicate a malfunction.
■Reactivation of the TRAC /VSC systems
Turning off the hybrid system after turning off the TRAC/VSC systems will automat -
ically reactivate them.
■Reactivation of the TRAC sy stem linked to vehicle speed
When only the TRAC system is turned of
f, the TRAC system will turn on when vehi -
cle speed increases. However, when both TR
AC and VSC systems are turned off,
the systems will not turn on even when vehicle speed increases.

228
2-4. Using other driving systems
■Reduced effectiveness of the EPS system
The effectiveness of the EPS system is reduced to prevent the system from over-
heating when there is frequent steering input over an extended period of time. The
steering wheel may feel heavy as a result. Should this occur, refrain from excessive
steering input or stop the vehicle and turn the hybrid system off. The EPS system
should return to normal within 10 minutes.
CAUTION
■The ABS does not operate effectively when
●Tires with inadequate gripping ability are used (such as excessively worn tires on
a snow covered road).
●The vehicle hydroplanes while driving at high speed on wet or slick road.
■Stopping distance when the ABS is operating will exceed that of normal condi-
tions
The ABS is not designed to shorten the vehicle’s stopping dist ance. Always main-
tain a safe distance from the vehicle in front of you in the following situations:
●When driving on dirt, gravel or snow-covered roads
●When driving with tire chains
●When driving over bumps in the road
●When driving over roads with potholes or roads with uneven surfaces
■TRAC may not operate effectively when
Directional control and power may not be ac hievable while driving on slippery road
surfaces, even if the TRAC system is operating. 
Do not drive the vehicle in conditions where stability and power may be lost.
■When the VSC is activated
The slip indicator light flashes and a warning buzzer sounds. Always drive carefully.
Reckless driving may cause an accident. Exercise particular care when the indica-
tor light flashes and a buzzer sounds.
■When the TRAC/VSC systems are turned off
Be especially careful and drive at a speed appropriate to the road conditions. As
these are the systems to ensure vehicle stability and driving force, do not turn the
TRAC/VSC systems off unless necessary.

229
2-4. Using other driving systems
2
When driving
CAUTION
■Replacing tires
Make sure that all tires are of the specified size, brand, tread pattern and total load
capacity. In addition, make sure that the tires are inflated to the recommended tire
inflation pressure level.
The ABS and VSC systems will not function correctly if different tires are installed
on the vehicle. 
Contact your Lexus dealer for further info rmation when replacing tires or wheels.
■Handling of tires and the suspension
Using tires with any kind of problem or modifying the suspension will affect the driv-
ing assist systems, and may cause a system to malfunction.

431
4-3. Do-it-yourself maintenance
4
Maintenance and care
Brake fluid
■Checking fluid level
The brake fluid level should be
betw
een the “MAX” and “MIN”
lines on the tank.
■ A
dding fluid
Make sure to check the fluid type and prepare the necessary item.
Fluid typeFMVSS No.116 DOT 3 or SAE J1703 brake fluid
ItemsClean funnel
■Brake fluid can absorb moisture from the air
Excess moisture in the brake fluid can cause a dangerous loss of braking efficiency.
Use only newly opened brake fluid.
CAUTION
■When filling the reservoir
Take care as brake fluid can harm your hands and eyes and damage painted sur-
faces. 
If fluid gets on your hands or in your eyes, flush the affected area with clean water
immediately.
If you still experience discomfort, see a doctor.

458
4-3. Do-it-yourself maintenance
Fuse layout and amperage ratings
Engine compartment
FuseAmpereCircuit
1HTR50 AAir conditioning system
2RDI40 AElectric cooling fans
3OIL PMP10 AHybrid system, transmission
4S-HORN10 ANo circuit
5ABS MAIN NO.27. 5 AElectronically controlled brake system
6H-LP CLN30 AHeadlight cleaner
7AMP NO.130 AAudio system, back door opener
8IGCT30 APCU, IGCT NO.2, IGCT NO.3,
hybrid system
9P CON MAIN7. 5 A
P position control system, hybrid sys-
tem, smart access system with push-
button start

459
4-3. Do-it-yourself maintenance
4
Maintenance and care
10AM27. 5 A
Smart access system with push-button
start, hybrid system, multiport fuel
injection system/sequential multiport
fuel injection system, P position con-
trol system, cruise control system,
dynamic radar cruise control system
11ECU-B27. 5 A
Smart access system with push-button
start, multiport fuel injection system/
sequential multiport fuel injection sys-
tem, trunk opener switch
12MAYDAY10 ALexus link system
13ECU-B310 AAir conditioning system, rear window
defogger, mirror heater
14TURN & HAZ10 ATurn signal lights, emergency flashers
15ETCS10 A
Multiport fuel injection system/
sequential multiport fuel injection sys-
tem
16ABS MAIN NO.120 AElectronically controlled brake system
17P/I 240 A
P position control system, hybrid sys-
tem, transmission, smart access sys-
tem with push-button start, horn,
headlights (low beam), back-up lights
18ABS MTR 130 AElectronically controlled brake system
19ABS MTR 230 AElectronically controlled brake system
20H-LP HI MAIN20 AHeadlights (high beam)
21AMP NO.230 AAudio system, navigation system
22DOOR NO.225 ANo circuit
FuseAmpereCircuit

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