
5758-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
If a warning light turns on or a warning buzzer
sounds
Calmly perform the following actions if any of the warning lights comes on or
flashes. If a light comes on or flashes, bu t then goes off, this does not necessar-
ily indicate a malfunction in the system . However, if this continues to occur,
have the vehicle inspected by any au thorized Lexus retailer or Lexus autho-
rized repairer, or any reliable repairer.
Warning light and warning buzzer list
Warning lightWarning light/Details/Actions
Brake system warning light Indicates that:
• The brake fluid level is low; or
• The brake system is malfunctioning Immediately stop the vehicle in a safe place and contact any
authorized Lexus retailer or Lexus authorized repairer, or any
reliable repairer. Continuing to drive the vehicle may be dan- gerous.
Brake system warning light
Indicates a malfunction in:
• The regenerative braking system; or
• The electronically controlled brake system Have the vehicle inspected by any authorized Lexus retailer or
Lexus authorized repairer, or any reliable repairer immediately.
(If equipped)
Charging system warning light
Indicates a malfunction in the vehicle’s charging system Immediately stop the vehicle in a safe place and contact any
authorized Lexus retailer or Lexus authorized repairer, or any
reliable repairer.
Malfunction indicator lamp Indicates a malfunction in:
• The hybrid system;
• The emission control system (if equipped); • The electronic engine control system; or
• The electronic throttle control system
Have the vehicle inspected by any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer immediately.

5768-2. Steps to take in an emergency
IS300h_EE(OM53D89E)
SRS warning light Indicates a malfunction in:
• The SRS airbag system; or
• The seat belt pretensioner system Have the vehicle inspected by any authorized Lexus retailer or
Lexus authorized repairer, or any reliable repairer immediately.
ABS warning light
Indicates a malfunction in: • The ABS; or
• The brake assist system
Have the vehicle inspected by any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer immediately.
Parking brake warning light (warning buzzer)*1
Indicates that the parking brake is engaged
Release the parking brake.
Electric power steering system warning light (warning buzzer) Indicates a malfunction in the EPS (Electric Power Steering) sys-
tem
Have the vehicle inspected by any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer immediately.
(If equipped)
LDA (Lane Departure Alert) indicator
If the LDA indicato r is illuminated:
Indicates a malfunction in the LDA (Lane Departure Alert with
steering control) system. Check the warning message displayed on the multi-information
display. ( P. 581)
If the LDA indicator flashes:
Indicates that the vehicle has deviated from the lane (while the
LDA [Lane Departure Alert with stee ring control] system is oper- ating)
Check the area around the vehicle and return the vehicle to
between the lane lines.
Warning lightWarning light/Details/Actions

5788-2. Steps to take in an emergency
IS300h_EE(OM53D89E)
*1: Parking brake engaged warning buzzer:
P. 587
*2: Open door warning buzzer:
P. 583
*3: Seat belt warning buzzer:
The seat belt warning buzzer sounds to al ert the driver, front passenger and rear pas-
sengers that his or her seat belt is not fastened. The buzzer sounds for 30 seconds
after the vehicle reaches a speed of 20 km/h (12 mph). Then, if the seat belt is still unfastened, the buzzer w ill sound in a different tone for 90 more seconds.
■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 passen-
ger is not sitting in the seat.
●If a cushion is placed on the seat, the sens or may not detect a passenger, and the warn-
ing light may not operate properly.
■If the malfunction indicator lamp comes on while driving
The malfunction indicato r lamp will come on if the fuel tank becomes completely empty.
If the fuel tank is empty, refuel the vehi cle immediately. The malfunction indicator lamp
will go off after several trips.
If the malfunction indicator lamp does not go off, contact any authorized Lexus retailer or
Lexus authorized repairer, or any re liable repairer as soon as possible.
Rear passengers’ seat belt reminder lights (warning buzzer)*3
Warns the rear passengers to fasten their seat belts
Fasten the seat belt.
Master warning light
A buzzer sounds and the warning light comes on and flashes to indicate that the master warning system has detected a malfunc-
tion.
P. 581
Tire pressure warning light When the light comes on:
Low tire inflation pressure such as
• Natural causes ( P. 579) •Flat tire ( P. 610, 625)
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 inflat ion pressure is adjusted, have the
system checked by any authorized Lexus retailer or Lexus
authorized repairer, or any reliable repairer. When the light comes on after blinking for 1 minute:
Malfunction in the tire pressure warning system
Have the system checked by any authorized Lexus retailer or Lexus authorized repairer, or any reliable repairer.
Warning lightWarning light/Details/Actions

5808-2. Steps to take in an emergency
IS300h_EE(OM53D89E)
WARNING
■If both the ABS and the brake system warning lights remain on
Stop your vehicle in a safe place immediately and contact any authorized Lexus retailer
or Lexus authorized repairer, or any re liable repairer. The vehicle will become
extremely unstable during braking, and the ABS system may fail, which could cause an accident resulting in de ath or serious injury.
■When the electric power steering system warning light comes on
The steering wheel may become extremely heavy. When steering wheel operations are heavier than usual, grip the steering wheel firmly
and operate it using more force than usual.
■If the tire pressure warning light comes on
Be sure to observe the following precaution s. Failure to do so could cause a loss of
vehicle control and result in death or serious injury.
Vehicles with an emergency tire puncture repair kit
●Stop your vehicle in a safe place as soon as possible. Adjust the tire inflation pressure
immediately.
●If the tire pressure warning light comes on even after tire inflation pressure adjust- ment, it is probable that you ha ve a flat tire. Check the tires. If a tire is flat, repair the
flat tire by using emergency tire puncture repair kit.
●Avoid abrupt maneuvering and braking. If the vehicle tires deteriorate, you could lose control of the steering wheel or the brakes.
Vehicles with run-flat tires
●Decelerate to the lowest appropriate speed as soon as possible. Do not drive over 60 km/h (37 mph).
●Check and adjust the tire inflation pressure 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. Have the tire replaced by the nearest
authorized Lexus retailer or Lexus author ized repairer, or any reliable repairer.
●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 syst em may not activate immediately.
NOTICE
■To ensure the tire pressure warning system operates properly
Do not install tires with different specifications or makers, as the tire pressure warning system may not operate properly.

5968-2. Steps to take in an emergency
IS300h_EE(OM53D89E)
Indicates a malfunction in the brake override system
A buzzer also sounds.
Have the vehicle inspected by any authorized Lexus retailer or Lexus authorized repairer, or any reliable
repairer.
Indicates that engine oil level is low
This message may ap pear if the vehicle is stopped on a
slope. Move the vehicle to a level surface and check to see if the message disappears.
Check the level of engine oil, and add if necessary.
Indicates that the hybrid system has overheated This message may be disp layed when driving under
severe operating conditions. (For example, when driv-
ing up a long steep hill.) A buzzer also sounds.
Stop and check. (P. 636)
Indicates a malfunction in:
• The automatic headlight leveling system; or • The Automatic High Beam system (if equipped); or
• The LED headlight system
A buzzer also sounds. Have the vehicle inspected by any authorized Lexus
retailer or Lexus authorized repairer, or any reliable
repairer.
Warning messageDetails/Actions

6278-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D89E)
One of the following may be the cause of the problem:
●The 12-volt battery may be discharged. (P. 631)
●One or both of the 12-volt battery terminals may be disconnected.
( P. 522)
Contact any authorized Lexus retailer or Lexus authorized repairer, or any reliable
repairer if the problem canno t be repaired, or if repair procedures are unknown.
When the hybrid system does not start, the following steps can be used as an
interim measure to start the hybrid system if the power switch is functioning nor-
mally.
Do not use this starting procedur e except in cases of emergency.
Set the parking brake.
Shift the shift lever to P.
Turn the power switch to ACCESSORY mode.
Press and hold the power switch for ab out 15 seconds while depressing the
brake pedal firmly.
Even if the hybrid system can be starte d using the above steps, the system may
be malfunctioning. Have the vehicle insp ected by any authorized Lexus retailer
or Lexus authorized repairer , or any reliable repairer.
The interior lights and headlights do not turn on, or the horn does not
sound.
Emergency start function
1
2
3
4

670What to do if... (Troubleshooting)
IS300h_EE(OM53D89E)
●Is the window lock switch pressed?
The power window except for the one at the driver’s seat cannot be operated
if the window lock switch is pressed. ( P. 193)
●The auto power off function will be operated if the vehicle is left in ACCES-
SORY or ON mode (the hybrid system is not operating) for a period of time.
( P. 221)
●The seat belt reminder light is flashing
Are the driver and the front passenger wearing the seat belts? ( P. 577)
●The parking brake indicator is on
Is the parking brake released? ( P. 235)
Depending on the situation, other type s of warning buzzer may also sound.
( P. 575, 581)
●Did anyone inside the vehicle open a door or anything move inside the vehicle
during setting the alarm?
The sensor detects them and the alarm sounds. ( P. 92)
Do one of the following to deactivate or stop the alarm:
• Unlock the doors or open the trunk using the entry function or wireless
remote control.
• Start the hybrid system.
The windows do not open or close by operating the power window
switches
The power switch is turned off automatically
A warning buzzer sounds during driving
An alarm is activated and the horn sounds (if equipped)

672
IS300h_EE(OM53D89E)
Alphabetical index
Alphabetical index
A/C ............................................................ 466
Air conditioning filter........................ 547
Automatic air conditioning
system ..................................................466
S-FLOW mode..................................469
Blower customization ..................... 475
AAC disc ................................................. 396
ABS (Anti-lock Brake System) ....... 352
Warning light ....................................... 576
Adaptive Variable Suspension
system ....................................................353
Air conditioning filter .......................... 547
Air conditioning system ..................... 466
Air conditioning filter........................ 547
Automatic air conditioning
system ..................................................466
S-FLOW mode..................................469
Blower customization ..................... 475
Airbags ........................................................ 43
Airbag manual on-off system......... 53
Airbag operating conditions ...........49
Airbag precautions for
your child .............................................. 45
Correct driving posture.................... 36
Curtain shield airbag operating
conditions ..............................................49
Curtain shield airbag
precautions ........................................... 47
General airbag precautions ........... 45
Locations of airbags ............................43
Modification and disposal of
airbags.................................................... 48
Side airbag operating
conditions ..............................................49
Side airbag precautions .................... 45
Side and curtain shield airbags
operating conditions ........................49
Side and curtain shield airbags
precautions .......................................... 45
SRS airbags ..............................................43
SRS warning light .............................. 576
Airbag manual on-off system ............. 53
Alarm............................................................ 92
Anchor brackets .......................................67
Antennas (smart entry &
start system) ......................................... 157
A