check system Lexus IS250 2009 Owner's Guide

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5-2. Steps to take in an emergency
08_IS350/250_U_(L/O_0808)
*1:Open door warning buzzer:

P. 3 9 5
*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. 3 9 2

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5-2. Steps to take in an emergency
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■If the tire pressure warning system is inoperative
The tire pressure warning system will be disabled in the following conditions:
(When the condition becomes normal, the system will work properly.)
●If tires not equipped with tire pressure warning valves and transmitters are used
●If the ID code on the tire pressure warning valves and transmitters is not regis-
tered in the tire pressure warning computer
●If a different set of tires has been selected using the satellite switch.
●If the tire inflation pressure is 73 psi (500 kPa, 5.1 kgf/cm2 or bar) or higher
The tire pressure warning system may be disabled in the following conditions:
(When the condition becomes normal, the system will work properly.)
●If electronic devices or facilities using similar radio wave frequencies are nearby
●If a radio set at similar frequencies is in use in the vehicle
●If there is a lot of snow or ice on the vehicle, in particular around the wheels or
wheel housings
●If non-genuine Lexus wheels are used (Even if you use Lexus wheels, the tire
pressure warning system may not work properly with some types of tires.)
●If tire chains are used
■If the tire pressure warning light comes on after blinking for 1 minute frequently
If the tire pressure warning light comes on after blinking for 1 minute frequently
when the “ENGINE START STOP” switch is turned to IGNITION ON mode, have
it checked by your Lexus dealer.

5
When trouble arises
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5-2. Steps to take in an emergency
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CAUTION
■When the electric power steering warning light comes on
The steering wheel may become extremely heavy.
If the steering wheel becomes heavier than usual when operating, firmly hold and
operate it using more force than usual.
■If the tire pressure warning light comes on
Be sure to observe the following precautions. Failure to do so could cause loss of
vehicle control and result in death or serious injury.
●Stop your vehicle in a safe place as soon as possible. Adjust the tire inflation pres-
sure immediately.
●If the tire pressure warning light comes on even after tire inflation pressure adjust-
ment, it is probable that you have a flat tire. Check the tires. If the tire is flat,
change to the spare tire and have the flat tire repaired by the nearest Lexus
dealer.
●Avoid abrupt maneuvering and braking. If the vehicle tires deteriorate, you could
lose control of the steering wheel or the brakes.
■If a blowout or sudden air leakage should occur
The tire pressure warning system may not activate immediately.

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5-2. Steps to take in an emergency
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CAUTION
■Maintenance of the tires
Each tire, including the spare (if provided), should be checked monthly when cold
and inflated to the inflation pressure recommended by the vehicle manufacturer on
the vehicle placard or tire inflation pressure label (tire and loading information
label). (If your vehicle has tires of a different size than the size indicated on the vehi-
cle placard or tire inflation pressure label [tire and loading information label], you
should determine the proper tire inflation pressure for those tires.)
As an added safety feature, your vehicle has been equipped with a tire pressure
monitoring system (TPMS-tire pressure warning system) that illuminates a low tire
pressure telltale (tire pressure warning light) when one or more of your tires is sig-
nificantly under-inflated. Accordingly, when the low tire pressure telltale (tire pres-
sure warning light) illuminates, you should stop and check your tires as soon as
possible, and inflate them to the proper pressure. Driving on a significantly under-
inflated tire causes the tire to overheat and can lead to tire failure. Under-inflation
also reduces fuel efficiency and tire tread life, and may affect the vehicle's handling
and stopping ability.
Please note that the TPMS (tire pressure warning system) is not a substitute for
proper tire maintenance, and it is the driver's responsibility to maintain correct tire
pressure, even if under-inflation has not reached the level to trigger illumination of
the TPMS low tire pressure telltale (tire pressure warning light).
Your vehicle has also been equipped with a TPMS (tire pressure warning system)
malfunction indicator to indicate when the system is not operating properly. The
TPMS (tire pressure warning system) malfunction indicator is combined with the
low tire pressure telltale (tire pressure warning light). When the system detects a
malfunction, the telltale will flash for approximately one minute and then remain
continuously illuminated. This sequence will continue upon subsequent vehicle
start-ups as long as the malfunction exists. When the malfunction indicator is illumi-
nated, the system may not be able to detect or signal low tire pressure as intended.
TPMS (tire pressure warning system) malfunctions may occur for a variety of rea-
sons, including the installation of replacement or alternate tires or wheels on the
vehicle that prevent the TPMS (tire pressure warning system) from functioning
properly. Always check the TPMS (tire pressure warning system) malfunction tell-
tale after replacing one or more tires or wheels on your vehicle to ensure that the
replacement or alternate tires and wheels allow the TPMS (tire pressure warning
system) to continue to function properly.

5
When trouble arises
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5-2. Steps to take in an emergency
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Follow the correction procedures.A buzzer sounds and a warning message is shown on the multi-informa-
tion display. After taking the spec ified steps to correct the suspected
problem, check that the warning message turns off.
Wa r n i n g m e s s a g eDetailsCorrection procedure
Indicates that one or
more of the doors is not
fully closed.
The system also indi-
cates which doors are
not fully closed.
flashes and a
buzzer sounds to indi-
cate that one or more of
the doors is not fully
closed (with the vehicle
having reached a speed
of 3 mph [5 km/h]).
Make sure that all of the
doors are closed.
Indicates that the hood is
not fully closed.
flashes and a
buzzer sounds to indi-
cate that hood is not fully
closed (with the vehicle
having reached a speed
of 3 mph [5 km/h]).
Close the hood.

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5-2. Steps to take in an emergency
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Wa r n i n g m e s s a g eDetailsCorrection procedure
Indicates low tire inflation
pressure.Check the tire inflation
pressure, and adjust to the
appropriate level.
(Flashing)
(If equipped)
Indicates that the pre-
collision system is not
currently functional.
Clean the grille and the
sensor. This message appears
when the pre-collision
system is hot. In this case,
wait until the system
cools down.
(If equipped)
Indicates that intuitive
parking assist is dirty or
covered with ice.
Clean the sensor.
(Flashing)
(If equipped)
Indicates that the radar
cruise control sensor is
dirty or covered with ice.
Clean the sensor.

5
When trouble arises
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5-2. Steps to take in an emergency
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■The compact spare tire
●The compact spare tire is identified by the label “TEMPORARY USE ONLY”
on the tire sidewall.
Use the compact spare tire temporarily only in an emergency.
●Make sure to check the tire pressure of the compact spare tire. (
P. 4 3 9 )
■When using the compact spare tire
As the compact spare tire is not equipped with the tire pressure warning valve and
transmitter, low inflation pressure of the spare tire will not be warned. Also, if you
replace the compact spare tire after the tire pressure warning light comes on, the
light remains on.
■If you have a flat rear tire on a road covered with snow or ice
Install the compact spare tire on the front of the vehicle. Perform the following steps
and fit tire chains to the rear tires.Replace a front tire with the compact spare tire.
Replace the flat rear tire with the tire removed from the front of the vehi-
cle.
Fit tire chains to the rear tires.
■After completing the tire change
The tire pressure warning system must be reset. (

P. 3 2 7 )
STEP1
STEP2
STEP3

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5-2. Steps to take in an emergency
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Emergency start function
When the engine does not start, the following steps can be used as an
interim measure to start the engine if the “ENGINE START STOP” switch
is functioning normally.Vehicles with an automatic transmission Set the parking brake.
Put the shift lever in P.
Set the “ENGINE START STOP” switch to ACCESSORY mode.
Press and hold the “ENGINE START STOP” switch about 15 sec-
onds while depressing the brake pedal firmly.
Vehicles with a manual transmission Set the parking brake.
Put the shift lever in N.
Set the “ENGINE START STOP” switch to the ACCESSORY
mode.
Push and hold the “ENGINE START STOP” switch about 15 sec-
onds while depressing the brake pedal and clutch pedal firmly.
Even if the engine can be started using the above steps, the system may
be malfunctioning. Have the vehicle checked by your Lexus dealer.
STEP1
STEP2
STEP3
STEP4
STEP1
STEP2
STEP3
STEP4

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5-2. Steps to take in an emergency
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■Avoiding a discharged battery
●Turn off the headlights and the audio system while the engine is off.
●Turn off any unnecessary electrical components when the vehicle is running at a
low speed for an extended period, such as in heavy traffic, etc.
CAUTION
■Avoiding battery fires or explosions
Observe the following precautions to prevent accidentally igniting the flammable
gas that may be emitted from the battery.
●Make sure the jumper cable is connected to the correct terminal and that it is not
unintentionally in contact with any part other than the intended terminal.
●Do not allow the jumper cables to come into contact with the “+” and “-” termi-
nals.
●Do not allow open flame or use matches, cigarette lighters or smoke near the
battery.
Maintain the engine speed on the second vehicle and turn the
“ENGINE START STOP” switch to IGNITION ON mode,
then start the vehicle’s engine.
Once the vehicle’s engine has started, remove the jumper
cables in the exact reverse order in which they were con-
nected.
Once the engine starts, have the vehicle checked at your Lexus dealer
as soon as possible.STEP5
STEP6

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5-2. Steps to take in an emergency
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If your vehicle overheats
If your engine overheats:
Stop the vehicle in a safe place and turn off the automatic air
conditioning system.
Check to see if steam is coming out from under the hood.
If you see steam: Stop the engine. Carefully lift the hood after the steam sub-
sides and then restart the engine.
If you do not see steam: Leave the engine running and carefully lift the hood.
Remove the engine compartment cover. (
P. 312)
Check to see if the cooling fan is operating.
If the fan is operating: Wait until the temperature of the engine (shown on the
instrument cluster) begins to fall and then stop the engine.
If the fan is not operating: Stop the engine immediately and call your local Lexus
dealer.
After the engine has cooled
down sufficiently, check the
engine coolant level and inspect
the radiator core (radiator) for
any leaks.STEP1
STEP2
STEP3
STEP4
STEP5