overheating Lexus HS250h 2012 Owner's Manual

34
1-1. Hybrid system
HS250h_U_75050U
CAUTION
●If your vehicle needs to be towed, do so with front wheels raised. If the wheels
connected to the electric motor (traction motor) are on the ground when towing,
the motor may continue to generate electricity. This may cause an electricity
leakage leading to a fire. (
→P. 4 9 5 )
●Carefully inspect the ground under the vehicle. If you find that liquid has leaked
onto the ground, the fuel system may have been damaged. Leave the vehicle as
soon as possible.
■Nickel-metal hydride battery
Your vehicle contains a sealed nickel-metal hydride battery. If disposed of improp-
erly, it is hazardous to the environment and there is a risk of severe burns and elec-
trical shock that may result in death or serious injury.
■Emergency shut off system
Carefully check to see if there are exposed high voltage parts or cables. Never
touch the parts or cables. (
→P. 3 0 )
NOTICE
■Hybrid battery air vent
●Do not put foreign objects near the air vent. The hybrid battery (traction battery)
may overheat and be damaged.
●Clean the air vent regularly to prevent the hybrid battery (traction battery) from
overheating.
●Do not wet or allow foreign substances to enter the air vent as this may cause a
short circuit and damage the hybrid battery (traction battery).
●Do not carry large amounts of water such as water cooler bottles in the vehicle. If
water spills onto the hybrid battery (traction battery), the battery may be dam-
aged. Have the vehicle inspected by your Lexus dealer.

149
2-1. Driving procedures
2
When driving
HS250h_U_75050U
CAUTION
■Exhaust gases
Exhaust gases include harmful carbon monoxide (CO), which is colorless and
odorless. Inhaling exhaust gases may lead to death or a serious health hazard.
●If the vehicle is in a poorly ventilated area, stop the hybrid system. In a closed
area, such as a garage, exhaust gases may collect and enter the vehicle. This may
lead to death or a serious health hazard.
●The exhaust system should be checked occasionally. If there is a hole or crack
caused by corrosion, damage to a joint or abnormal exhaust noise, be sure to
have the vehicle inspected and repaired by your Lexus dealer. Failure to do so
may allow exhaust gases to enter the vehicle, resulting in death or a serious health
hazard.
■When taking a nap in the vehicle
Always turn the hybrid system off. Otherwise, if you accidentally move the shift
lever or depress the accelerator pedal, this could cause an accident or fire due to
hybrid system overheating. Additionally, if the vehicle is parked in a poorly venti-
lated area, exhaust gases may collect and enter the vehicle, leading to death or a
serious health hazard.
■When braking
●When the brakes are wet, drive more cautiously.
Braking distance increases when the brakes are wet, and this may cause one side
of the vehicle to brake differently than the other side. Also, the parking brake may
not securely hold the vehicle.
●If the power brake assist function does not operate, do not follow other vehicles
closely and avoid downhill or sharp turns that require braking.
In this case, braking is still possible, but it will require more force on the pedal than
usual. Braking distance may also increase.
●The brake system consists of 2 individual hydraulic systems; if one of the systems
fails, the others will still operate. In this case, the brake pedal should be depressed
more firmly than usual and the braking distance will increase. If this happens, do
not continue to drive the vehicle. If the brake system warning light (red indicator)
comes on while driving, immediately stop the vehicle in a safe place and contact
your Lexus dealer.

172
2-2. Instrument cluster
HS250h_U_75050U
NOTICE
■To prevent damage to the hybrid system and its components
A high engine coolant temperature warning light (→P. 502) 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 5 2 ) .

390
3-7. Other interior features
HS250h_U_75050U
CAUTION
■Burns
●Use caution when seating the following persons in a seat with the seat heater on
to avoid the possibility of burns:
• Babies, small children, the elderly, the sick and the physically challenged
• Persons with sensitive skin
• Persons who are fatigued
• Persons who have taken alcohol or drugs that induce sleep (sleeping drugs,cold remedies, etc.)
●Do not cover the seat with anything when using the seat heater.
Using the seat heater with a blanket or cushion increases the temperature of the
seat and may lead to overheating.
●Do not use the seat heater more than necessary. Doing so may cause minor
burns or overheating.
NOTICE
■To prevent damage to the seat heaters/ventilators
Do not put heavy objects that have an uneven surface on the seat and do not stick
sharp objects (needles, nails, etc.) into the seat.
■To prevent 12-volt battery discharge
Turn the seat heaters/ventilators off when the hybrid system is off.

5
When trouble arises
503
5-2. Steps to take in an emergency
HS250h_U_75050U
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. 552
• Flashes: Engine is overheating. Drive carefully.
• Comes on: Engine is overheated. Stop the vehicle.
Warning lightWarning light/Details
Brake system warning light Indicates a malfunction in:
• The regenerative brake system; or
• The electronically controlled brake system
(U.S.A.)

(Canada)
Malfunction indicator lampIndicates a malfunction in:
• The hybrid system;
• The electronic engine control system;
• The electronic throttle control system; or
• The hybrid transmission control system
SRS warning light
Indicates 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

518
5-2. Steps to take in an emergency
HS250h_U_75050U
(U.S.A. only)
Indicates that all mainte-
nance is required to cor-
respond to the driven
distance on the mainte-
nance schedule*
1 .Pe r f o r m t h e n e c e s s a r y
maintenance.
Please reset the mainte-
nance data after the main-
tenance is performed
(→ P. 4 2 4 )
Comes on approximately
5000 miles (8000 km)
after the maintenance
data has been reset.
(The indicator will not
work properly unless the
maintenance data has
been reset.)
Indicates that the tire
inflation pressure is lowCheck the tire inflation
pressure, and adjust to the
appropriate level.
(If equipped)
Indicates that the pre-
collision system is not
currently functional
• The grille or the sensor is
dirty.
• The pre-collision system is not functional due to
overheating.
• Check the grille and the sensor and clean them if
they are dirty.
• Check that the system will become functional
after the system cools
down.
Wa r n i n g m e s s a g eDetailsCorrection procedure

552
5-2. Steps to take in an emergency
HS250h_U_75050U
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 immediat ely 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 shown on the multi-information
display:
The power control unit may be overheating.
Follow the correction procedure as described below.

554
5-2. Steps to take in an emergency
HS250h_U_75050UCheck that the coolant level of the
power control unit is between the
“FULL” and “LOW” lines of the
reservoir tank.
“FULL” line
“LOW” line
If the coolant level of the power
control unit is insufficient, add
more coolant.
If power control unit coolant is
unavailable, water can be used as
an emergency substitute.
Restart the hybrid system (depress and hold the brake pedal, and
press the “POWER” switch once). Check that the “HYBRID
SYSTEM OVERHEAT” message has gone off.
If the warning message remains on, stop the hybrid system and
contact your Lexus dealer.
Have the vehicle inspected at the nearest Lexus dealer as soon as possi-
ble.
■Overheating
The following symptoms may occur when your vehicle is overheating:
●The high engine coolant temperature warning 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.

616
Alphabetical index
HS250h_U_75050U
Cooling systemEngine overheating .......................... 552
Cruise control Cruise control ....................................... 212
Dynamic radar crui se control ....... 216
Cup holders ............................................. 381
Curtain shield airbags.......................... 109
Customizable features ...................... 584
Daytime running light system ........... 194
Defogger* Rear window.........................................274
Side mirrors ...........................................274
Dimensions............................................. 560
Dinghy towing ........................................ 262
Display
Dynamic radar cruise control.................................................... 216
Multi-information display................. 177
Trip information ................................... 180
Warning message............................... 512
Do-it-yourself maintenance .............. 431
Door courtesy lights Door courtesy lights......................... 374
Wattage................................................. 568
Doors
Door glasses ........................................... 90
Door lock.................................. 47, 58, 61
Rear door child protector ................ 62
Side doors .................................................. 61
Side mirrors ............................................. 87
Driver’s seat belt reminder light .... 505
Driver’s seat position memory ........... 72
Driving
Break-in tips ........................................... 143
Correct posture ................................... 107 Procedures............................................. 142
Winter driving tips ............................ 258
Driving position memory.......................72
Electric power steering...................... 238
Electronic key If the electronic key does not operate properly............................ 544
Emergency, in case of If the electronic key does not
operate properly............................ 544
If the engine will not start ................. 541
If the hybrid system will not start ......................................................... 541
If the 12-volt battery is discharged .........................................547
If the warning buzzer sounds...... 502
If the warning light turns on.......... 502
If the warning message is displayed .............................................. 512
If you have a flat tire ........................ 532
If you lose your keys ........................ 543
If you think something is wrong ....................................................501
If your electronic key does not operate properly ................... 544
If your vehicle becomes stuck .... 556
If your vehicle has to be stopped in an emergency ............................558
If your vehicle needs to be
towed ................................................... 495
If your vehicle overheats................ 552
Emergency flasher Switch ...................................................... 494
Engine Accessory mode ................................. 153
D
E

617
Alphabetical index
HS250h_U_75050U
Compartment ......................................437
Engine switch ........................................ 152
Hood ....................................................... 434
How to start the engine.................... 152
How to start the hybrid system.................................................... 152
Identification number.......................560
If the engine will not start ................. 541
If the hybrid system will not start.......................................................... 541
Ignition switch........................................ 152
Overheating......................................... 552
Power switch ......................................... 152
Engine compartment cover............. 438
Engine coolant Capacity................................................. 564
Checking ................................................442
Preparing and checking
before winter.................................... 258
Engine/power control unit coolant
Capacity................................................. 564
Checking ................................................442
Preparing and checking before winter.................................... 258
Engine immobilizer system ................. 101
Engine oil Capacity................................................. 563
Checking ............................................... 439
Preparing and checking before winter.................................... 258
Engine switch ........................................... 152
Enhanced VSC ..................................... 238
EPS............................................................. 238
EV drive mode switch .......................... 157
Event data recorder ............................... 20 Floor mat .................................................. 394
Fluid
Brake ....................................................... 566
Washer ...................................................446
Fog lights Replacing light bulbs ......................... 481
Switch.......................................................202
Wattage................................................. 568
Foot light................................................... 374
Foot well lighting ................................... 374
Front fog lights Replacing light bulbs ......................... 481
Switch.......................................................202
Wattage................................................. 568
Front passenger occupant classification system ............................ 121
Front passenger's seat belt reminder light..................................... 505
Front seats Adjustment ...............................................68
Driver’s seat position memory ....... 72
Front side marker light
Replacing light bulbs ......................... 481
Wattage................................................. 568
Front turn signal lights Replacing light bulbs ......................... 481
Switch........................................................ 166
Wattage................................................. 568
Fuel Capacity .................................................562
Fuel gauge.............................................. 169
Gas station information ................. 628
Information ........................................... 569
Refueling.................................................... 97
Type ......................................................... 569
*: For vehicles with a navigation system, refer to “Navigation System Owner’s Manual”.
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