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4-3. Do-it-yourself maintenance
IS350/250_U
CAUTION
The engine compartment contains many mechanisms and fluids that may move sud-
denly, become hot, or become electrically energized. To avoid death or serious injury,
observe the following precautions.
■When working on the engine compartment
●Keep hands, clothing, and tools away from the moving fan and engine drive belt.
●Be careful not to touch the engine, radiator, exhaust manifold, etc. right after driv-
ing as they may be hot. Oil and other fluids may also be hot.
●Do not leave anything that may burn easily, such as paper or rags, in the engine
compartment.
●Do not smoke, cause sparks or expose an open flame to fuel or the battery. Fuel
and battery fumes are flammable.
●Be extremely cautious when working on the battery. It contains poisonous and
corrosive sulfuric acid.
■When working near the electric cooling fan or radiator grille
Be sure the “ENGINE START STOP” switch is OFF.
With the “ENGINE START STOP” switch in IGNITION ON mode, the electric
cooling fan may automatically start to run if the air conditioning is on and/or the
coolant temperature is high. (→P. 3 9 4 )
■Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc. from getting
in the eyes.
NOTICE
■If you remove the air cleaner filter
Driving with the air cleaner filter removed may cause excessive engine wear due to
dirt in the air. Also, a backfire could cause a fire in the engine compartment.
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4-3. Do-it-yourself maintenance
IS350/250_U
Air conditioning filter
The air conditioning filter must be cleaned or changed regularly to main-
tain air conditioning efficiency.
■ Removal method
Set the air conditioning system to recirculated mode.
The air conditioning filter case cannot be removed with the system in
the outside air mode.
Turn the “ENGINE START STOP” switch OFF.
Open the glove box. Lift and
remove the partition.
Remove the filter cover.
Remove the filter case.
STEP1
STEP2
STEP3
STEP4
STEP5
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4-3. Do-it-yourself maintenance
IS350/250_U■
Engine compartment (type B fuse box)
FuseAmpereCircuit
1SPARE30 ASpare fuse
2SPARE25 ASpare fuse
3SPARE10 ASpare fuse
4FR CTRL-B25 AH-LP UPR, HORN
5A/F15 A
Multiport fuel injection system/
sequential multiport fuel injection sys-
tem
6ETCS10 A
Multiport fuel injection system/
sequential multiport fuel injection sys-
tem
7ALT-S7. 5 ACharging system
8TEL10 ALexus Enform
9STR LOCK25 ASteering lock
10H-LP CLN30 AHeadlight cleaner
11A/C COMP7. 5 AAir conditioning system
12DEICER25 AWindshield wiper de-icer
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6-1. Specifications
IS350/250_U
■Gasoline quality
In very few cases, driveability problems may be caused by the brand of gasoline you
are using. If driveability problems persist, try changing the brand of gasoline. If this
does not correct the problem, consult your Lexus dealer.
■Gasoline quality standards
●Automotive manufacturers in the US, Europe and Japan have developed a
specification for fuel quality called World-Wide Fuel Charter (WWFC) that is
expected to be applied worldwide.
●The WWFC consists of four categories that are based on required emission
levels. In the US, category 4 has been adopted.
●The WWFC improves air quality by lowering emissions in vehicle fleets, and
customer satisfaction through better performance.
■Lexus recommends the use of gasoline containing detergent additives
●Lexus recommends the use of gasoline that contains detergent additives to
avoid build-up of engine deposits.
●All gasoline sold in the US contains detergent additives to clean and/or keep
clean intake systems.
■Lexus recommends the use of cleaner burning gasoline
Cleaner burning gasoline, including reformulated gasoline that contains oxygen-
ates such as ethanol or MTBE (Methyl Tertiary Butyl Ether) is available in many
areas.
Lexus recommends the use of cleaner burning gasoline and appropriately blended
reformulated gasoline. These types of gasoline provide excellent vehicle perfor-
mance, reduce vehicle emissions and improve air quality.
■Lexus does not recommend blended gasoline
●Lexus allows the use of oxygenate blended gasoline where the oxygenate con-
tent is up to 10% ethanol or 15% MTBE.
●If you use gasohol in your Lexus, be sure that it has an octane rating no lower
than 87.
●Lexus DOES NOT recommend the use of gasoline containing methanol.