2010 Lexus HS250h check engine

430
4-3. Do-it-yourself maintenance
Radiator and condenser
Check the radiator and condenser and clear away any foreign objects. 
If either of the above parts is extremely dir
ty 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 burns or other injuries.
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 condense r as they may be hot and cause burns.

455
4-3. Do-it-yourself maintenance
4
Maintenance and care
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 la y
out and amperage ratings”
( P. 4 5 8 ) for details about which fuse to check.

469
4-3. Do-it-yourself maintenance
4
Maintenance and care
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.
5 5 6 )
■ R
emove the engine compartment covers
 P.
4 2 3
■ F
ront bulb locations
Halogen headlights
Front side marker lightHeadlight low beam
Parking light
Front turn signal light
Front fog light
Headlight high beam

506
5-2. Steps to take in an emergency
(Flashes)
(If equipped)
Indicates that the moon
roof is not fully closed A buzzer also sounds.
(With the “POWER”
switch off, and the
driver's door open)
Close the moon roof.
Indicates that the parking
brake is still engagedIf the vehicle reaches a
speed of 3 mph 
(5 km/h),
flashes and a buzzer
sounds to indicate that
the parking brake is still
engaged.
Release the parking
brake.
Indicates that the washer
fluid level is lowAdd washer fluid.
(U.S.A. only)
Indicates that the engine
oil is scheduled to be
changed
Check the engine oil, and
change if necessary.
Comes on approximately
4500 miles (7200 km)
after the engine oil is
changed. 
(The indicator will not
work properly unless the
oil maintenance data has
been reset.)
Wa r n i n g m e s s a g eDetailsCorrection procedure

5
When trouble arises
507
5-2. Steps to take in an emergency
(U.S.A. only)
Indicates that the engine
oil should be changedComes on approxi-
mately 5000 miles
(8000 km) after the
engine oil is changed
(and the oil maintenance
data has been reset)
Check and change the
engine oil.
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
because the grille or the
sensor is dirty.
This message also
appears when the pre-
collision system is not
functional due to over-
heating.
Check the grille and the
sensor and clean them if
they are dirty.In case of overheating,
the system will become
functional once the sys-
tem cools down.
(If equipped)
Indicates that intuitive
parking assist sensor is
dirty or covered with ice
A buzzer also sounds.
The site of the malfunc-
tion and the vehicle
image are flashing.
Clean the sensor.
Wa r n i n g m e s s a g eDetailsCorrection procedure

5
When trouble arises
541
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 an d turn of
f the air conditioning
system.
Check to see if steam is coming out from the engine area.
If you see steam: 
Stop the hybrid system. Carefu lly lif
t 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.
Remove the engine compartment cover. ( P. 4 2 3 )
Check to see if the cooling fans are operating.
If the fans are operating: 
Wait until the high engine coolant temperature warning light goes
of
f 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 S
YSTEM OVERHEAT” is sh own on the multi-information
display: 
The power control unit may be overheating.
Follow the correction procedure as described below.

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.