Page 469 of 586

4688-2. Steps to take in an emergency
IS350/250_U (OM53C50U)
*1: Parking brake engaged warning buzzer:→ P. 4 7 5
*2: Open door warning buzzer:
→ P. 4 74
*3: Driver’s seat belt buzzer:
The driver’s seat belt buzzer sounds to alert the driver that his or her seat belt is not
fastened. Once the engine switch is turned to IGNITION ON mode, the buzzer
sounds for 6 seconds. If the vehicle reaches a speed of 12 mph (20 km/h), the buzzer
sounds once. If the seat belt is still unfastened after 24 seconds, the buzzer will sound
intermittently for 10 seconds. Then, if the seat belt is still unfastened, the buzzer will
sound in a different tone for 20 more seconds.
Front passenger’s seat belt buzzer:
The front passenger’s seat belt buzzer sounds to alert the front passenger that his or
her seat belt is not fastened. The buzzer sounds once if the vehicle reaches a speed of
12 mph (20 km/h). If the seat belt is still unfastened after 24 seconds, the buzzer will
sound intermittently for 10 seconds. Then, if the seat belt is still unfastened, the buzzer
will sound in a different tone for 20 more seconds.
Tire pressure warning light When the light comes on:
Low tire inflation pressure such as
• Natural causes ( →P. 4 6 9 )
•Flat tire ( →P. 4 8 6 )
→ Adjust the tire inflation pressure to the specified level.
The light will turn off after a few minutes. In case the light does
not turn off even if the tire inflation pressure is adjusted, have the
system checked by your Lexus dealer.
When the light comes on after blinking for 1 minute:
Malfunction in the tire pressure warning system
→ Have the system checked by your Lexus dealer.
Warning lightWarning light/Details/Actions
Page 470 of 586

4698-2. Steps to take in an emergency
8
When trouble arises
IS350/250_U (OM53C50U)
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors, side
impact sensors (front door), side impact sensors (front), side impact sensors (rear),
driver’s seat position sensor, driver’s seat belt buckle switch, front passenger occupant
classification system, “AIR BAG ON” indicat or light, “AIR BAG OFF” indicator light,
front passenger’s seat belt buckle switch, seat belt pret ensioner assemblies, airbags,
interconnecting wiring and power sources. ( →P. 3 8 )
■Front passenger detection sensor, 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 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 light will go off after several driving trips.
If the light does not go off even after several trips, contact your Lexus dealer as soon as
possible.
■Electric power steering system warning light (warning buzzer)
When the battery charge becomes insufficient of the voltage temporarily drops, the
electric power steering system warning light may come on and the warning buzzer may
sound.
■When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level. Pushing the tire
pressure warning reset switch will not turn off the tire pressure warning light.
■The tire pressure warning light may come on due to natural causes
The tire pressure warning light may come on due to natural causes such as natural air
leaks and tire inflation pressure changes caused by temperature. In this case, adjusting
the tire inflation pressure will turn off the warning light (after a few minutes).
■When a tire is replaced with the spare tire
The compact spare tire is not equipped with a tire pressure warning valve and transmit-
ter. If a tire goes flat, the tire pressure warning light will not turn off even though the flat
tire has been replaced with the spare tire.
■Conditions that the tire pressure warning system may not function properly
→ P. 4 2 8
■If the tire pressure warning light freque ntly comes on after blinking for 1 minute
If the tire pressure warning light frequently comes on after blinking for 1 minute when the
engine switch is turned to IGNITION ON mode, have it checked by your Lexus dealer.
■Warning buzzer
In some cases, the buzzer may not be heard due to being in a noisy location or audio
sound.
Page 485 of 586

4848-2. Steps to take in an emergency
IS350/250_U (OM53C50U)
Once
• When the doors were unlockedwith the mechanical key and then
the engine switch was pressed,
the electronic key could not be
detected in the vehicle.
• The electronic key could not be detected in the vehicle even after
the engine switch was pressed
two consecutive times.
→ Touch the electronic key to the
engine switch while depressing
the brake pedal.
Once
During an engine starting proce-
dure in the event that the electronic
key was not functioning properly
(→ P. 500), the engine switch was
touched with the electronic key.
→ Press the engine switch within
10 seconds of the buzzer sound-
ing.
Indicates that:
• With the engine switch off, the
doors were unlocked and then the
driver's door was opened and
closed
• The engine switch was turned to ACCESSORY mode without
starting the engine
• The shift lever was shifted to P or N from another shift position with
the engine switch in IGNITION
ON mode.
→ Press the engine switch while
depressing the brake pedal.
Once
The engine switch has been turned
off with the shift lever in a position
other than P or N.
→Shift the shift lever to P.
Once
After the engine switch has been
turned off with the shift lever in a
position other than P, the shift lever
has been shifted to P.
→Turn the engine switch off.
Interior
buzzerExteriorbuzzerWa r n i n g m e s s a g eDetails/Actions
(Flashes)
(Flashes)
(Flashes)
Page 486 of 586
4858-2. Steps to take in an emergency
8
When trouble arises
IS350/250_U (OM53C50U)
*: The engine may not be restarted depending on the vehicle condition.
■Wa r n i n g m e s s a g e s
→P. 4 8 1
■Warning buzzer
→P. 4 6 9
Power was turned off due to the
automatic power off function.
→ Next time when starting the
engine, increase the engine
speed slightly and maintain that
level for approximately 5 min-
utes to recharge the battery.
Con-
tinuous
Indicates that the engine was
stopped in an emergency while driv-
ing
→To restart the engine, shift the
shift lever to N and turn the
engine switch to IGNITION
ON mode.
*
Once
Indicates that the engine switch has
been pressed while driving
→Except when emergency stop-
ping of the vehicle is needed,
immediately release the engine
switch.
Interior
buzzerExteriorbuzzerWa r n i n g m e s s a g eDetails/Actions
(Flashes)
(Flashes)
Page 501 of 586
5008-2. Steps to take in an emergency
IS350/250_U (OM53C50U)
Ensure that the shift lever is in P and depress the brake pedal.
Touch the Lexus emblem side of the
electronic key to the engine switch.
When the electronic key is detected, a
buzzer sounds and the engine switch
will turn to IGNITION ON mode.
When the smart access system with
push-button start is deactivated in
customization setting, the engine switch
will turn to ACCESSORY mode.
Firmly depress the brake pedal and check that is shown on the multi-
information display.
Press the engine switch.
In the event that the engine still cannot be started, contact your Lexus dealer.
Starting the engine
1
2
3
4
Page 504 of 586

5038-2. Steps to take in an emergency
8
When trouble arises
IS350/250_U (OM53C50U)
Connect the jumper cables according to the following procedure:Connect a positive jumper cable clamp to the positive (+) battery terminal
on your vehicle.
Connect the clamp on the other end of the positive cable to the positive (+)
battery terminal on the second vehicle.
Connect a negative cable clamp to the negative (-) battery terminal on the
second vehicle.
Connect the clamp at the other end of the negative cable to a solid, station-
ary, unpainted metallic point away from the battery and any moving parts,
as shown in the illustration.
Start the engine of the second vehicle. Increase the engine speed slightly and
maintain at that level for approximately 5 minutes to recharge the battery of
your vehicle.
Open and close any of the doors of your vehicle with the engine switch off.
Maintain the engine speed of the second vehicle and start the engine of your
vehicle by turning the engine switch to IGNITION ON mode.
Once the vehicle’s engine has started, remove the jumper cables in the exact
reverse order from which they were connected.
Once the engine starts, have the vehicle inspected at your Lexus dealer as soon
as possible.3
1
2
3
4
4
5
6
7
Page 517 of 586
5169-1. Specifications
IS350/250_U (OM53C50U)
■Spark plug
Cooling system
IS250IS350
Capacity 11.1 qt. (10.5 L, 9.2 Imp. qt.) 9.8 qt. (9.3 L, 8.2 Imp. qt.)
Coolant type
Use either of the following:
• “Toyota Super Long Life Coolant”
• Similar high-quality ethylene glycol-based non-silicate,
non-amine, non-nitrite, and non-borate coolant with long-
life hybrid organic acid technology
Do not use plain water alone.
Ignition system
Make DENSO FK20HBR11
Gap0.043 in. (1.1 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.
Electrical system
Battery
Open voltage at 68°F
(20 °C):12.6 12.8 V Fully charged
12.2
12.4 V Half charged
11.8 12.0 V Discharged
(Check the voltage 20 minutes after the engine and all
lights are turned off.)
Charging rates5 A max.
Page 561 of 586

560
IS350/250_U (OM53C50U)What to do if... (Troubleshooting)
What to do if... (Troubleshooting)
●If you lose your mechanical keys, new genuine mechanical keys can be made
by your Lexus dealer. (
→P. 1 0 0 )
●If you lose your electronic keys, the risk of vehicle theft increases significantly.
Contact your Lexus dealer immediately. ( →P. 1 0 2 )
●Is the electronic key battery weak or depleted? ( →P. 4 3 9 )
●Is the engine switch in IGNITION ON mode?
When locking the doors, turn the engine switch off. ( →P. 1 6 0 )
●Is the electronic key left inside the vehicle?
When locking the doors, make sure that you have the electronic key on your
person.
●The function may not operate properly du e to the condition of the radio wave.
( → P. 116)
●Is the child-protector lock set?
The rear door cannot be opened from inside the vehicle when the lock is set.
Open the rear door from outside and then unlock the child-protector lock.
(→ P. 1 0 6 )
●The function to prevent the electronic key from being left inside the trunk will
operate and you can open the trunk as usual. Take the key out from the trunk.
(→ P. 111)
If you have a problem, check the following before contacting your Lexus
dealer.
The doors cannot be locked, unlocked, opened or closed
You lose your keys
The doors cannot be locked or unlocked
The rear door cannot be opened
The trunk lid is closed with the electronic key left inside