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429
4-3. Do-it-yourself maintenance
4
Maintenance and care
IS350/250_U
Wheels
■When replacing wheels
The wheels of your Lexus are equipped with tire pressure warning valves and trans-
mitters that allow the tire pressure warning system to provide advanced warning in
the event of a loss in tire inflation pressure. Whenever wheels are replaced, the tire
pressure warning valves and transmitters must be installed. (→P.  4 1 6 )
If a wheel is bent, cracked or heavily corroded, it should be replaced. Oth-
erwise, the tire may separate from the wheel or cause loss of handling con-
trol.
■Wheel selection
When replacing wheels, care should be taken to ensure that they
are equivalent to those removed in load capacity, diameter, rim
width, and inset
*.
Replacement wheels are available at your Lexus dealer.
*: Conventionally referred to as “offset”.
Lexus does not recommend using:
● Wheels of different sizes or types
● Used wheels
● Bent wheels that have been straightened
■ Aluminum wheel precautions
●Use only Lexus wheel nuts and wrenches designed for use with
your aluminum wheels.
● When rotating, repairing or changing your tires, check that the
wheel nuts are still tight after driving 1000 miles (1600 km).
● Be careful not to damage the aluminum wheels when using tire
chains.
● Use only Lexus genuine balance weights or equivalent and a
plastic or rubber hammer when balancing your wheels. 
         
        
        
     
        
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4-3. Do-it-yourself maintenance
IS350/250_U
CAUTION
■When replacing wheels
●Do not use wheels that are a different size from those recommended in the
Owner’s Manual, as this may result in loss of handling control.
●Never use an inner tube in a leaking wheel which is designed for a tubeless tire.
Doing so may result in an accident, causing death or serious injury.
NOTICE
■Replacing tire inflation pressure warning valves and transmitters
●Because tire repair or replacement may affect the tire pressure warning valves
and transmitters, make sure to have tires serviced by your Lexus dealer or other
qualified service shop. In addition, make sure to purchase your tire pressure
warning valves and transmitters at your Lexus dealer.
●Ensure that only genuine Lexus wheels are used on your vehicle.
Tire pressure warning valves and transmitters may not work properly with non-
genuine wheels.  
         
        
        
     
        
        Page 446 of 578
445
4-3. Do-it-yourself maintenance
4
Maintenance and care
IS350/250_U■
Driver’s side instrument panel
FuseAmpereCircuit
1FR P/SEAT LH30 APo w e r  s e a t
2A/C7. 5  AAir conditioning system
3MIR HTR15 AOutside rear view mirror defoggers
4TV NO.110 ADisplay
5FUEL OPEN10 AFuel filler door opener
6TV NO.27. 5  A
7PSB30 APre-collision seat belt
8S/ROOF25 AMoon roof
9TA I L10 ATail lights, license plate lights, parking 
lights
10PA N E L7. 5  ASwitch illumination, air conditioning 
system, display
11RR FOG7. 5  A
12ECU-IG LH10 A
Cruise control, air conditioning sys-
tem, power steering, rain sensor, anti-
glare inside rear view mirror, shift lock 
system, moon roof, tire inflation pres-
sure warning system
13FR S/HTR LH15 ASeat heaters and ventilators 
         
        
        
     
        
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448
4-3. Do-it-yourself maintenance
IS350/250_U
FuseAmpereCircuit
13FR DOOR RH20 APower windows, outside rear view 
mirrors
14AM27. 5  ASmart access system with push-button 
start
15RH-IG7. 5  A
Seat belts, intuitive parking assist, 
automatic transmission, seat heater 
and ventilator
16FR S/HTR RH15 ASeat heaters and ventilators
17ECU-IG RH10 A
Power seats, smart access system with 
push-button start, AWD system, out-
side rear view mirrors, VDIM, air con-
ditioning system, pre-collision seat 
belt, electric tilt and telescopic steer-
ing, power windows, navigation sys-
tem
■After a fuse is replaced
●If the lights do not turn on even after the fuse has been replaced, a bulb may
need replacement. (→P.  4 5 2 )
●If the replaced fuse blows again, have the vehicle inspected by your Lexus
dealer.
■If there is an overload in the circuits
The fuses are designed to blow before the entire wiring harness is damaged. 
         
        
        
     
        
        Page 460 of 578

When trouble arises5
459
IS350/250_U
5-1. Essential informationEmergency flashers............... 460
If your vehicle needs to be towed..................................  461
If you think something  is wrong ..................................  467
Fuel pump shut off  system ..................................... 468
Event data recorder ..............  469 5-2. Steps to take in an 
emergency
If a warning light turns  on or a warning buzzer 
sounds... ................................... 471
If a warning message is  displayed................................ 480
If you have a flat tire...............  492
If the engine will not start .....  501
If the shift lever cannot be  shifted from P .......................  503
If you lose your keys ..............  504
If the electronic key does  not operate properly..........  505
If the vehicle battery is  discharged ............................  509
If your vehicle overheats ......  512
If the vehicle becomes  stuck.........................................  515 
         
        
        
     
        
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5
When trouble arises
467
5-1. Essential information
IS350/250_U
If you think something is wrong
If you notice any of the following symptoms, your vehicle probably needs
adjustment or repair. Contact your Lexus dealer as soon as possible.
■Visible symptoms
●Fluid leaks under the vehicle
(Water dripping from the air conditioning after use is normal.)
● Flat-looking tires or uneven tire wear
● Engine coolant temperature gauge needle continually points
higher than normal
■ Audible symptoms
●Changes in exhaust sound
● Excessive tire squeal when cornering
● Strange noises related to the suspension system
● Pinging or other noises related to the engine
■ Operational symptoms
●Engine missing, stumbling or running rough
● Appreciable loss of power
● Vehicle pulls heavily to one side when braking
● Vehicle pulls heavily to one side when driving on a level road
● Loss of brake effectiveness, sp ongy feeling, pedal almost touches
the floor 
         
        
        
     
        
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474
5-2. Steps to take in an emergency
IS350/250_U
*1:Open door warning buzzer:
→P.  4 8 3
*2:Driver's and front passenger’s seat belt reminders buzzer:
The driver’s and front passenger’s seat belts reminder sounds to alert the driver
and front passenger that his or her sear belt is not fastened. The buzzer sounds
intermittently for 10 seconds after the vehicle has reached a speed of at least 12
mph (20 km/h). Then, if the seat belt is still unfastened, the buzzer will sound in a
different tone for 20 more seconds.
Warning lightWarning light/DetailsCorrection procedure
(On the center 
panel)
Front passenger’s seat belt 
reminder light
(warning buzzer)
*2
Warns the front passenger to 
fasten his/her seat belt.
Fasten the seat belt.
Tire pressure warning light
When the light comes on: 
Low tire inflation pressureAdjust the tire inflation pres-
sure.
When the light comes on after 
blinking for 1 minute:
Malfunction in the tire pres-
sure warning system
Have the system checked by 
your Lexus dealer.
Master warning lightA buzzer sounds and the 
warning light comes on and 
flashes to indicate that the 
master warning system has 
detected a malfunction.
→ P.  4 8 0 
         
        
        
     
        
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5
When trouble arises
475
5-2. Steps to take in an emergency
IS350/250_U
■If the malfunction indicator lamp comes on while driving
First check the following:
●Is the fuel tank empty?
If it is, fill the fuel tank immediately.
●Is the fuel tank cap loose?
If it is, tighten it securely.
The lamp will go off after taking several driving trips.
If the lamp does not go off even after several trips, contact your Lexus dealer as
soon as possible.
■Electric power steering warning light
When the battery is low or when the voltage drops temporarily, the electric power
steering warning light may come on.
■Front passenger detection sensor and pass enger seat belt reminder and warning
buzzer
●If luggage is placed on the front passenger seat, the front passenger detection
sensor may cause the warning light to flash and the warning buzzer to sound,
even if a passenger is not sitting in the seat.
●If a cushion is placed on the seat, the sensor may not detect a passenger, and the
warning light may not operate properly.
■When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level. Pressing the
satellite switch does not turn off the tire pressure warning light.
■The tire pressure warning light may turn on due to natural causes
The tire pressure warning light may turn on due to natural causes such as natural air
leaks or tire inflation pressure changes caused by temperature. In this case, adjust-
ing the tire inflation pressure will turn off the warning light (after a few minutes).
■When a tire is replaced with a spare tire
The compact spare tire is not equipped with the tire pressure warning valve and
transmitter. If a tire goes flat, the tire pressure warning light will not turn off even
though the flat tire is replaced with the spare tire. Replace the spare tire with the
repaired tire and adjust the proper tire inflation pressure. The tire pressure warning
light will turn off after a few minutes.