2012 Lexus HS250h engine

512
5-2. Steps to take in an emergency
HS250h_U_75050U
If a warning message is displayed
Stop the vehicle immediately.
A buzzer sounds and a warning message is shown on the multi-informa-
tion display. The following warning indicates the possibility of damage to
the vehicle that may lead to an accident. Immediately stop the vehicle in a
safe place and contact your Lexus dealer.
Wa r n i n g m e s s a g eDetails
Indicates abnormal engine oil pressure A buzzer also sounds.
The warning message is displayed if the engine oil
pressure is too low.
Indicates a malfunction in the hybrid system
A buzzer also sounds.
If a warning is shown on the multi-information display, stay calm and per-
form the following actions:
Master warning light
The master warning light also
comes on or flashes in order to
indicate that a message is cur-
rently being displayed on the
multi-information display.
Multi-information display
If any of the warning light comes on again after the following actions
have been performed, contact your Lexus dealer.

5
When trouble arises
529
5-2. Steps to take in an emergency
HS250h_U_75050U

Po w e r w a s t u r n e d
off due to the
automatic power
off function.
Next time when
starting the hybrid
system, increase
the engine speed
slightly and main-
tain that level for
approximately 5
minutes to
recharge the 12-
volt battery.
OnceThe electronic key
has a low battery.Replace the elec-
tronic key battery.
(→ P. 4 6 7 )
Interior
buzzerExterior buzzerWa r n i n g m e s s a g eDetailsCorrection
procedure

548
5-2. Steps to take in an emergency
HS250h_U_75050U
Connect the jumper cables according to the following procedure:Connect a positive jumper cable clamp to the exclusive jump start-
ing terminal on your vehicle
Connect the clamp on the other end of the positive cable to the pos-
itive (+) battery terminal on the second vehicle
Connect a negative cable clamp to the negative (-) battery terminal
on the second vehicle
Connect the clamp at the other end of the negative cable to a solid,
stationary, unpainted metallic point away from the exclusive jump
starting terminal and any moving parts, as shown in the illustration. Start the engine of the second vehicle. Increase the engine
speed slightly and maintain that level for approximately 5 min-
utes to recharge the 12-volt battery of your vehicle.
Maintain the engine speed of th e second vehicle and start the
hybrid system of your vehicle by turning the “POWER” switch
to ON mode.

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.

5
When trouble arises
553
5-2. Steps to take in an emergency
HS250h_U_75050UAfter the hybrid system has cooled
down sufficiently, check the engine
coolant level and inspect the cool-
ing system for leaks.
If the engine compartment cover
needs to be removed. (
→P. 4 3 8 )
Add engine coolant if necessary.
Water can be used in an emer-
gency if engine coolant is unavail-
able. ( →P. 5 6 4 )
Have the vehicle inspected at the nearest Lexus dealer as soon as possi-
ble.
■If “HYBRID SYSTEM OVERHEAT” is shown on the multi-informa-
tion display
Stop the vehicle in a safe place.
Stop the hybrid system (press the “POWER” switch once), and
then carefully lift the hood.
Wait until the hybrid system has
fully cooled down. When the sys-
tem has fully cooled down, check if
coolant has leaked from the radia-
tor core.
If a large amount of coolant leak-
age is found, contact your Lexus
dealer immediately.

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.

5
When trouble arises
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5-2. Steps to take in an emergency
HS250h_U_75050U
CAUTION
■To prevent an accident or injury when inspecting under the hood of your vehicle
●If steam is seen coming from under the hood, do not open the hood until the
steam has subsided. The engine compartment may be very hot, causing serious
injuries such as burns.
●Check that the indicator on the “POWER” switch and the READY indicator are
off.
●For vehicles with a hybrid system, there are times when the gasoline engine auto-
matically starts to run or the cooling fans suddenly start to operate. Do not touch
or approach the rotating parts of the belt or fans. Doing so may lead to fingers,
clothes or tools getting caught, resulting in injury.
●Do not loosen the coolant reservoir cap while the hybrid system and radiator are
hot.
Serious injuries, such as burns, may result from hot coolant and steam released
under pressure.
NOTICE
■When adding engine/power control unit coolant
Wait until the hybrid system has cooled down before adding engine/power control
unit coolant.
When adding coolant, do so slowly. Adding cool coolant to a hot hybrid system too
quickly can cause damage to the hybrid system.
■To prevent damage to the cooling system
Observe the following precautions:
●Avoid contaminating the coolant with foreign matter (such as sand or dust etc.)
●Do not use commercially available coolant additives

561
6-1. Specifications
6
Vehicle specifications
HS250h_U_75050UThis number is also on the Certifi-
cation Label.
■ Engine number
The engine numbers is stamped on
the engine block as shown.
Engine
Model2AZ-FXE
Ty p e4-cylinder in line, 4-cycle, gasoline
Bore and stroke3.48 × 3.78 in. (88.5 × 96.0 mm)
Displacement144.1 cu.in. (2362 cm3)
Drive belt tensionAutomatic adjustment
Valve clearance
(engine cold)Intake: 0.007  0.011 in. (0.19  0.29 mm)
Exhaust: 0.015
 0.019 in. (0.38  0.48 mm)