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

151
2-1. Driving procedures
2
When driving
■Situations in which EV drive mode cannot be turned on
It may not be possible to turn EV drive mode on in the following situations. If it can -
not be turned on, a buzzer will sound and a message will be shown on the multi-
info
rmation display.
●Engine coolant temperature is low.
●Vehicle speed is about 19mph (30km/h) or more.
●The hybrid battery (traction battery) is low. 
An “Energy Monitor” display of level 3 or lower may indicate a low battery level.
(  P. 3 2 )
● The temperature of the hybrid system is high. 
The vehicle has been left in the sun, driv en on a
hill, driven at high speeds, etc.
●The temperature of the hybrid system is low. 
The vehicle has been left in temperatures lower than about 32°F (0°C) for a
l
ong period of time etc.
●The gasoline engine is warming up.
●The accelerator pedal is depressed firmly or the vehicle is on a hill etc.
●The windshield defogger is in use.
■Automatic cancellation of EV drive mode
When driving in EV drive mode, the gasoline engine may automatically restart in
the
following situations. When EV drive mo de is canceled, a buzzer will sound and
the EV drive mode indicator will flash and go off.
●The hybrid battery (traction battery) becomes low. 
The remaining battery level indicated in the “Energy Monitor” display is level 2
or lo
wer. ( P. 3 2)
●Vehicle speed becomes more than about 19 mph (30 km/h).
●The accelerator pedal is depressed firmly or the vehicle is on a hill etc.
When it is possible to inform the driver o
f automatic cancellation in advance, a prior
notice screen will appear on the multi-information display.
■ Possible driving distance when driving in EV drive mode
In EV drive mode, it is possible to drive up to about several hundred yards if driving
at
a speed of about 19 mph (30 km/h) or less. (The distance that is possible
depends on the hybrid battery [traction battery] level and driving conditions.)

411
4-2. Maintenance
4
Maintenance and care
General maintenance
Engine compartment
Tr u n k
ItemsCheck points
Brake fluidIs the brake fluid at the correct level?
( P. 4 3 1 )
CoolantIs the engine coolant at the correct
level? ( P. 4 2 8 )
Engine oilIs the engine oil at the correct level? 
( P. 4 2 4 )
Exhaust systemThere should not be any fumes or
strange sounds.
Radiator/condenser
The radiator and condenser should
be free from foreign objects. 
( P. 4 3 0 )
Wa s h e r f l u i dIs there sufficient washer fluid? 
( P. 4 3 2 )
ItemsCheck points
12-volt batteryCheck the connections. ( P. 4 3 3 )
Listed below are the general maintenance items that should be performed
at the intervals specified in the “Warranty and Service Guide” or “Owner’s
Manual Supplement”. It is recommend ed that any problem you notice
should be brought to the attention of your Lexus dealer or qualified service
shop for advice.

416
4-3. Do-it-yourself maintenance
Do-it-yourself service precautions
If you perform maintenance by yourself, be sure to follow the correct pro-
cedure as given in these sections.
ItemsPa r t s a n d t o o l s
12-volt battery condition ( P. 4 3 3 )
•Grease
• Conventional wrench 
(for terminal clamp bolts)
Brake fluid level ( P. 4 3 1 )
• FMVSS No.116 DOT 3 or SAE
J1703 brake fluid
•Rag or paper towel
• Funnel (used only for adding brake
fluid)
Engine/power control unit coolant
level ( P. 4 2 8 )
• “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.
For the U.S.A.: 
“Toyota Super Long Life Coolant”
is pre-mixed with 50% coolant and
50% deionized water.
For Canada: 
“Toyota Super Long Life Coolant”
is pre-mixed with 55% coolant and
45% deionized water.
• Funnel (used only for adding cool- ant)

422
4-3. Do-it-yourself maintenance
Engine compartment
Engine coolant reservoir 
( P. 4 2 8 )
Engine oil filler cap 
( P. 425)
Engine oil level dipstick 
( P. 4 2 4 )
Power control unit coolant
reservoir ( P. 4 2 8 )
Brake fluid reservoir  (P. 4 3 1 )Fuse box ( P. 455)
Engine coolant radiator 
( P. 430)
Power control unit coolant
radiator ( P. 430)
Condenser ( P. 430)
Electric cooling fans
Washer fluid tank 
( P. 4 3 2 )

428
4-3. Do-it-yourself maintenance
Coolant
The coolant level is satisfactory if it is between the “FULL” and “LOW”
lines on the reservoir when the hybrid system is cold.
Engine coolant reservoir
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, add coolant up to the
“FULL” line. (P. 5 5 2 )

429
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 5 2 )
■Coolant selection
Only use “Toyota Super Long Life Coolant” or a s
imilar 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% d
eionized 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
ca
ps, drain cock and water pump. 
If you cannot find a leak, have your Lexus dealer test the cap and check for leaks in
the coo
ling systems.

5
When trouble arises
489
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 v
ehicle
(Water dripping from the air conditioning after use is normal.)
● Flat
-looking tires or uneven tire wear
●High engine coolant temper
ature warning light flashes or comes
on
■ A
udible symptoms
●Changes in e
xhaust sound
● Ex
cessive tire squeal when cornering
●Str
ange noises related to the suspension system
●P
inging or other noises related to the hybrid system
■ Oper
ational symptoms
●Engine mis
sing, stumbling or running rough
●A
ppreciable loss of power
●V
ehicle pulls heavily to one side when braking
●V
ehicle pulls heavily to one side when driving on a level road.
● L
oss of brake effectiveness, sp ongy feeling, pedal almost touches
the floor

542
5-2. Steps to take in an emergency
After the hybrid system has cooled
down sufficiently, check the engine
coolant level and inspect the cool-
ing system for leaks.
Add engine coolant if necessary.
Water can be used in an emer -
gency if engine coolant is unavail -
able. ( P. 5 5 2 )
Have the vehicle inspected at the ne arest Lexus dealer as soon as possi-
ble.
■ If “HYBRID S
YSTEM OVERHEAT” is shown on the multi-informa -
tion display
Stop the vehicle in a safe place an d turn of
f the air conditioning
system.
Leave the hybrid system operating and carefully lift the hood.
Remove the engine compartment covers. ( P. 4 2 3 )
Check if the cooling fans are operating.
If the fans are operating: 
Wait until the “HYBRID SYST EM O
VERHEAT” message disap-
pears and then stop the hybrid system. 
If the message does not disappear, call your Lexus dealer.
If the fans are not operating: 
Stop the hybrid system immediately and call your Lexus dealer.

5
When trouble arises
543
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.
Add power control unit coolant if
nec
essary.
Water can be used in an emer -
gency if power control unit coolant
is una
vailable. ( P. 5 5 2 )
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.

602
Alphabetical index
TowingDinghy towing ..................................... 248
Emergency towing ...........................483
Trailer towing........................................247
TRAC......................................................... 225
Traction control ..................................... 225
Trailer towing.......................................... 247
Trip meter ................................................. 162
Trunk Opener ...................................................... 60
Turn signal lights Replacing light bulbs........................ 469
Switch ........................................................ 162
Wattage..................................................556
Vanity lights Vanity lights .......................................... 372
Wattage..................................................556
Vanity mirrors ........................................ 372
Vehicle identification number ........ 548
Vehicle stability control...................... 225
Ventilators ............................................... 375
VSC ............................................................ 225
Warning buzzers Brake system ....................................... 492
Open door ..........................................495
Seat belt reminder.............................495 Warning lights
AFS OFF ............................................... 493
Anti-lock brake system .................. 493
Brake assist system .......................... 493
Brake system ........................................492
Charging system ................................492
Cruise control ..................................... 493
Electric power steering warning light..................................... 493
Electronic engine control 
system.................................................. 493
High coolant temperature .............492
Hybrid battery system .................... 493
LKA .......................................................... 493
Low fuel level....................................... 495
Low tire pressure .............................. 495
Malfunction indicator lamp .......... 493
Master warning light........................ 495
Open door ........................................... 495
Pre-collision system......................... 493
Pretensioner ........................................ 493
Radar cruise control ........................ 493
Seat belt reminder light .................. 495
Slip indicator ........................................ 493
SRS airbags .......................................... 493
Tire pressure warning light .......... 495
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