coolant temperature Lexus HS250h 2011 Hybrid system / LEXUS 2011 HS250H OWNERS MANUAL (OM75037U)

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2-2. Instrument cluster
2
When driving
NOTICE
■To prevent damage to the hybrid system and its components
A high engine coolant temperature warning light (P. 498) is installed instead of
an engine coolant temperature gauge. If the high engine coolant temperature
warning light illuminates or flashes, the vehicle may be overheating. Immediately
stop the vehicle in a safe area ( P. 5 4 8 ) .

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4-3. Do-it-yourself maintenance
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 indicator on the “POWER” switch and the “READY” indicator
are both off.
●Keep hands, clothing and tools away from the moving fans 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 other 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 automati-
cally start to run if the air conditioning is on and/or the coolant temperature is high.
(  P. 4 3 6 )
■Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc. from getting
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.

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4-3. Do-it-yourself maintenance
4
Maintenance and care
Power control unit coolant reservoirReservoir cap
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, add coolant up to the
“FULL” line. (P. 5 6 0 )
■Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality ethylene glycol
based non-silicate, non-amine, non-nitrite, and non-borate coolant with long-life
hybrid organic acid technology.
U.S.A.: “Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50%
deionized water. (Minimum temperature: -31 F [-35C])
Canada: “Toyota Super Long Life Coolant” is a mixture of 55% coolant and 45% deionized water. (Minimum temperature: -44 F [-42 C])
For more details about coolant, contact your Lexus dealer.
■If the coolant level drops within a short time of replenishing
Visually check the radiators, hoses, engine/power control unit coolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have your Lexus dealer test the cap and check for leaks in
the cooling systems.

5
When trouble arises
495
5-1. Essential information
If you think something is wrong
If you notice any of the following symptoms, your vehicle probably needs
adjustment or repair. Contact your Lexus dealer as soon as possible.
■Visible symptoms
●Fluid leaks under the vehicle
(Water dripping from the air conditioning after use is normal.)
● Flat-looking tires or uneven tire wear
● High engine coolant temperature warning light flashes or comes
on
■ Audible symptoms
●Changes in exhaust sound
● Excessive tire squeal when cornering
● Strange noises related to the suspension system
● Pinging or other noises related to the hybrid system
■ Operational symptoms
●Engine missing, stumbling or running rough
● Appreciable loss of power
● Vehicle pulls heavily to one side when braking
● Vehicle pulls heavily to one side when driving on a level road.
● Loss of brake effectiveness, sp ongy feeling, pedal almost touches
the floor

548
5-2. Steps to take in an emergency
If your vehicle overheats
Correction procedures■ If the engine coolant temperature warning light comes on or flashes
Stop the vehicle in a safe place and turn off the air conditioning
system.
Check to see if steam is coming out from the engine area.
If you see steam:
Stop the hybrid system. Carefully lift the hood after the steam
subsides and then restart the hybrid system.
If you do not see steam:
Leave the hybrid system operating and carefully lift the hood.
Check to see if the cooling fans are operating.
If the fans are operating:
Wait until the high engine coolant temperature warning light goes
off and then stop the hybrid system.
If the fans are not operating:
Stop the hybrid system immediately and call your Lexus dealer.
The following may indicate that your vehicle is overheating:
●The high engine coolant temperature warning light comes on or
flashes:
The engine may be overheating.
● “HYBRID SYSTEM OVERHEAT” is sh own on the multi-information
display:
The power control unit may be overheating.
Follow the correction procedure as described below.

550
5-2. Steps to take in an emergency
After the hybrid system has cooled
down, check the power control
unit coolant level and inspect the
cooling system for leaks.
If the engine compartment cover
needs to be removed. (P. 4 2 9 )
Add power control unit coolant if
necessary.
Water can be used in an emer-
gency if power control unit coolant
is unavailable. ( P. 5 6 0 )
Have the vehicle inspected at the ne arest Lexus dealer as soon as possi-
ble.
■Overheating
The following symptoms may occur wh en your vehicle is overheating:
●The high engine coolant temperature warn ing light comes on or flashes, or the
hybrid system output decreases.
●Steam comes out from the engine area.
●“HYBRID SYSTEM OVERHEAT” is displayed on the multi-information display.

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6-1. Specifications
Warning: The temperature grades of a tire assume that it is properly inflated
and not overloaded.
Excessive speed, underinflation, or excess ive loading, either separately or in
combination, can cause heat buildup and possible tire failure.
Glossary of tire terminology
Tire related termMeaning
Cold tire inflation pres-
sureTire pressure when the vehicle has been parked for
three hours or more, or has not been driven more
than 1 mile or 1.5 km under that condition
Maximum inflation pres-
sureThe maximum cold inflated pressure to which a tire
may be inflated, shown on the sidewall of the tire
Recommended inflation
pressureCold tire inflation pressure recommended by a man-
ufacturer
Accessory weight
The combined weight (in excess of those standard
items which may be replaced) of transmission, power
steering, power brakes, power windows, power seats,
radio and heater, to the extent that these items are
available as factory-installed equipment (whether
installed or not)
Curb weight
The weight of a motor vehicle with standard equip-
ment, including the maximum capacity of fuel, oil and
coolant, and if so equipp ed, air conditioning and
additional weight optional engine
Maximum loaded vehicle
weight
The sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight
(d) Production options weight
Normal occupant weight150 lb. (68 kg) times the number of occupants speci-
fied in the second column of Table 1
* that follows

622
Alphabetical index
Warning buzzersBrake system .......................................498
Open door ........................................... 501
Seat belt reminder.............................. 501
Warning lights AFS OFF................................................ 499
Anti-lock brake system................... 499
Brake assist system........................... 499
Brake system .......................................498
Charging system ...............................498
Cruise control ..................................... 499
Electric power steering warning light ..................................... 499
Electronic engine control system .................................................. 499
High coolant temperature ............498
Hybrid battery system ..................... 499
LKA........................................................... 499
Low fuel level ........................................ 501
Low tire pressure................................ 501
Malfunction indicator lamp........... 499
Master warning light ......................... 501
Open door ............................................ 501
Pre-collision system ......................... 499
Pretensioner ......................................... 499
Radar cruise control......................... 499
Seat belt reminder light ................... 501
Slip indicator ........................................ 499
SRS airbags .......................................... 499
Tire pressure warning light ............ 501 Warning messages
Cruise control .....................................508
Dynamic radar cruise control ........................................508, 511
Electric power steering system..................................................508
Engine oil maintenance......................511
Engine oil pressure........................... 507
EV drive mode .......................................511
Headlight ...............................................508
Hood ...........................................................511
Hybrid system..................................... 507
Intuitive parking assist ............508, 511
Key .............................................................. 519
Lane-Keeping Assist ...........................511
Moon roof.................................................511
Open door ...............................................511
Parking brake..........................................511
Pre-collision system................508, 511
Smart access system with push start.............................................. 519
Tire pressure warning system......................................................511
Trunk............................................................511
Washer fluid ............................................511
Washer Checking............................................... 438
Preparing and checking before winter.....................................249
Switch ........................................................198
Washing and waxing...........................408W

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What to do if...
What to do if...
A tire puncturesP. 5 2 7If you have a flat tire
The hybrid system does not start
P. 5 3 7If the hybrid system will not start
P. 9 8Immobilizer system
P. 5 4 3If the vehicle 12-volt battery is dis-
charged
The engine coolant temperature
warning light flashes or come on
Steam can be seen coming
from under the hood
P. 5 4 8If your vehicle overheats
The key is lostP. 5 3 9If you lose your keys
The 12-volt battery runs outP. 5 4 3If the vehicle 12-volt battery is dis-
charged
The doors cannot be lockedP. 5 8Doors
The horn begins to soundP. 1 0 0Alarm
The vehicle is stuck in mud or
sandP. 5 5 2If the vehicle becomes stuck
A warning light or indicator
light comes onP. 4 9 8If a warning light turns on or a warning
buzzer sounds...

626
What to do if...
■Warning lights
*: The light flashes to indicate a malfunction.
P. 5 0 0
or
P. 4 9 8P. 5 0 0
P. 4 9 8P. 5 0 0
P. 4 9 9P. 5 0 0
P. 4 9 9P. 5 0 0
P. 5 0 1
or
P. 4 9 9P. 5 0 1
P. 4 9 9P. 5 0 1
P. 5 0 1
or
P. 4 9 9P. 5 0 1
P. 5 0 0P. 5 0 2
P. 5 0 0P. 5 0 0
Brake system warning light“AFS OFF” indicator light*
Slip indicator light
Charging system warning
light“LKA” indicator light*
High engine coolant temperature
warning lightCruise control indicator
light*
Brake system warning lightRadar cruise control
indicator light*
Malfunction indicator lampOpen door warning light
Low fuel level warning light
SRS warning lightDriver’s seat belt reminder
light
“ABS” warning lightFront passenger’s seat belt
reminder light
Master warning light
Electric power steering system
warning lightTire pressure warning light
Pre-collision system warning
light*Automatic High Beam
Indicator light*