2012 Lexus HS250h check engine

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4-3. Do-it-yourself maintenance
HS250h_U_75050U
Radiator and condenserCheck the radiator and condenser and clear away any foreign objects.
If either of the above parts is extremely dirty or you are not sure of their
condition, have your vehicle inspected by your Lexus dealer.
CAUTION
■When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps.
The cooling system may be under pressure and may spray hot coolant if the cap is
removed, causing serious injuries, such as burns.
NOTICE
■When adding coolant
Coolant is neither plain water nor straight antifreeze. The correct mixture of water
and antifreeze must be used to provide proper lubrication, corrosion protection
and cooling. Be sure to read the antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.
CAUTION
■When the hybrid system is hot
Do not touch the radiators or condenser as they may be hot and cause serious inju-
ries, such as burns.

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4-3. Do-it-yourself maintenance
4
Maintenance and care
HS250h_U_75050U
Checking and replacing fuses
If any of the electrical components do not operate, a fuse may have blown.
If this happens, check and replace the fuses as necessary.
Turn the “POWER” switch off.
Open the fuse box cover.
Engine compartment
Push the tab in and lift the lid off.
Driver’s side instrument panel Remove the lid.
After a system failure, see “Fuse layout and amperage ratings”
(→ P. 472) for details about which fuse to check.

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4-3. Do-it-yourself maintenance
4
Maintenance and care
HS250h_U_75050U
Light bulbs
You may replace the following bulbs by yourself. The difficulty level of
replacement varies depending on the bulb. If necessary bulb replacement
seems difficult to perform, contact your Lexus dealer.
For more information about replacing other light bulbs, contact your Lexus
dealer.
■ Preparing for light bulb replacement
Check the wattage of the light bulb to be replaced. ( →P. 568)
■ Remove the engine compartment covers
→ P. 4 3 8
■ Front bulb locations
Halogen headlights
Front side marker light Headlight low beam
Parking light
Front turn signal light
Front fog lightHeadlight high beam
and daytime running light

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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
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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.

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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

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6-1. Specifications
6
Vehicle specifications
HS250h_U_75050U
Lubrication system
*: The engine oil capacity is a reference quantity to be used when exchanging.Warm up the engine and turn off the hybrid system, wait more than 5 minutes,
and check the oil level on the dipstick.
■Engine oil selection
“Toyota Genuine Motor Oil” is used in your Lexus vehicle. Use Lexus
approved “Toyota Genuine Motor Oil” or equivalent to satisfy the follow-
ing grade and viscosity.
Oil grade: ILSAC multigrade engine oil
Recommended viscosity: SAE 0W-20
SAE 0W-20 is the best choice for
good fuel economy and good
starting in cold weather.
If SAE 0W-20 is not available,
SAE 5W-20 oil may be used.
However, it must be replaced with
SAE 0W-20 at the next oil
change.
Oil capacity
(Drain and refill
-reference*)
With filter
Without filter
4.5 qt. (4.3 L, 3.8 lmp.qt.)
4.3 qt. (4.1 L, 3.6 lmp.qt.)
Outside temperature