
5638-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
■Doors
Use the mechanical key (→P. 131) in
order to perform the following oper-
ations:
Locks all the doors
Closes the windows and moon
roof (turn and hold)
*
Unlocks all the doors
Opens the windows and moon roof (turn and hold)
*
*
: This setting must be customized at any authorized Lexus dealer or repairer, or another duly qualified and equipped professional.
■Tr u n k
Turn the mechanical key clockwise
to open.
If the electronic key does not operate properly
If communication between the electronic key and vehicle is interrupted ( →P.
151) or the electronic key cannot be us ed because the battery is depleted, the
smart entry & start system and wireless remote control cannot be used. In
such cases, the doors and trunk can be opened and the hybrid system can be
started by following the procedure below.
Locking and unlocking the doors, unlocking the trunk and key linked
functions
1
2
3
4

5658-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53D56E)
■Stopping the hybrid system
Shift the shift lever to P and press the power switch as you normally do when stopping the
hybrid system.
■Replacing the key battery
As the above procedure is a temporary measure, it is recommended that the electronic
key battery be replaced immediately when the battery is depleted. ( →P. 4 8 8 )
■Alarm (if equipped)
Using the mechanical key to lock the doors will not set the alarm system.
If a door is unlocked using the mechanical key when the alarm system is set, the alarm
may be triggered.
■Changing power switch modes
Release the brake pedal and press the power switch in step above.
The hybrid system does not start and modes will be changed each time the switch is
pressed. ( →P. 2 1 3 )
■When the electronic key does not work properly
●Make sure that the smart entry & start syst em has not been deactivated in the customi-
zation setting. If it is off, turn the function on.
(Customizable features →P. 5 9 1 )
●Check if battery-saving mode is set. If it is set, cancel the function. (→P. 1 5 0 )
CAUTION
■When using the mechanical key and operating the power windows or moon roof
Operate the power window or moon roof after checking to make sure that there is no
possibility of any passenger having any of their body parts caught in the window or
moon roof.
Also, do not allow children to operate the mechanical key. It is possible for children and
other passengers to get caught in the power window or moon roof.
3

5668-2. Steps to take in an emergency
IS300h_EE(OM53D56E)
If you have a set of jumper (or booster) cables and a second vehicle with a 12-volt
battery, you can jump start your vehicle by following the steps below.Confirm that the electronic key is
being carried.
When connecting the jumper (or
booster) cables, depending on the situa-
tion, the alarm may activate and doors
locked. (
→P. 9 8 )
Open the hood ( →P. 4 5 3 ) a n d f u s e
box cover.
Remove the clips.
Push the tabs on either side to
detach the lock and lift the lid off
while pulling the lock plate.
If the 12-volt battery is discharged
The following procedures may be used to start the hybrid system if the 12-volt
battery is discharged.
You can also call any authorized Lexus dealer or repairer, or another duly
qualified and equipped professional.
1
2
1
2

5688-2. Steps to take in an emergency
IS300h_EE(OM53D56E)
Maintain the engine speed of the second vehicle and start the hybrid system
of your vehicle by turning the power switch to ON mode.
Make sure the “READY” indicator comes on. If the indicator does not come
on, contact any authorized Lexus dealer or repairer, or another duly qualified
and equipped professional.
Once the hybrid system has started, remove the jumper cables in the exact
reverse order from which they were connected.
Once the hybrid system starts, have the vehicle inspected at any authorized
Lexus dealer or repairer, or another duly qualified and equipped professional as
soon as possible.
■Starting the hybrid system when the 12-volt battery is discharged
The hybrid system cannot be started by push-starting.
■To prevent 12-volt battery discharge
●Turn off the headlights and the audio system while the hybrid system 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.
■Charging the 12-volt battery
The electricity stored in the 12-volt battery will discharge gradually even when the vehicle
is not in use, due to natural discharge and the draining effects of certain electrical appli-
ances. If the vehicle is left for a long time, the 12-volt battery may discharge, and the
hybrid system may be unable to start. (The 12-volt battery recharges automatically while
the hybrid system is operating.)
■When recharging or replacing the 12-volt battery
●In some cases, it may not be possible to un lock the doors using the smart entry & start
system when the 12-volt battery is discharged. Use the wireless remote control or the
mechanical key to lock or unlock the doors.
●The hybrid system may not start on the first attempt after the 12-volt battery has
recharged but will start normally after the second attempt. This is not a malfunction.
●The power switch mode is memorized by the vehicle. When the 12-volt battery is
reconnected, the system will return to the mo de it was in before the 12-volt battery was
discharged. Before disconnecting the 12-volt battery, turn the power switch off.
If you are unsure what mode the power switch was in before the 12-volt battery dis-
charged, be especially careful when reconnecting the 12-volt battery.
7
8
9

604
IS300h_EE(OM53D56E)What to do if... (Troubleshooting)
What to do if... (Troubleshooting)
●If you lose your mechanical keys, new genuine mechanical keys can be made
by any authorized Lexus dealer or repairer, or another duly qualified and
equipped professional. (
→P. 1 3 2 )
●If you lose your electronic keys, the risk of vehicle theft increases significantly.
Contact any authorized Lexus dealer or repairer, or another duly qualified
and equipped professional immediately. ( →P. 1 3 5 )
●Is the electronic key battery weak or depleted? ( →P. 4 8 8 )
●Is the power switch in ON mode?
When locking the doors, turn the power switch off. ( →P. 2 1 3 )
●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 due to the condition of the radio wave.
(→ P. 151)
●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 4 0 )
If you have a problem, check the foll owing before contacting any authorized
Lexus dealer or repairer, or another duly qualified and equipped professional.
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

605What to do if... (Troubleshooting)
IS300h_EE(OM53D56E)
●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. 1 4 6 )
●Did you press the power switch while firmly depressing the brake pedal?
(→ P. 212)
●Is the shift lever in P? ( →P. 2 1 4 )
●Is the electronic key anywhere detectable inside the vehicle? ( →P. 1 4 9 )
●Is the steering wheel unlocked? ( →P. 2 1 5 )
●Is the electronic key battery weak or depleted?
In this case, the hybrid system can be started in a temporary way. ( →P. 5 6 4 )
●Is the 12-volt battery discharged? ( →P. 566)
●Is the power switch in ON mode?
If you cannot release the shift lever by depressing the brake pedal with the
power switch in ON mode. ( →P. 5 6 2 )
●It is locked automatically to prevent theft of the vehicle. ( →P. 2 1 5 )
The trunk lid is closed with the electronic key left inside
If you think som
ething is wrong
The hybrid system does not start
The shift lever cannot be shifted from P even if you depress the brake
pedal
The steering wheel cannot be turned after the hybrid system is stopped

610Alphabetical index
IS300h_EE(OM53D56E)
BrakeFluid ......................................................... 585
Parking brake .......................................227
Regenerative braking ...........................81
Warning light .........................................521
Brake assist ............................................. 296
Break-in tips ............................................ 195
Brightness control
Instrument panel li ght control..........112
BSM (Blind Spot Monitor) ................. 310
Card key.................................................... 130
Care ................................................442, 446
Aluminum wheels .............................. 443
Exterior.................................................... 442
Interior .....................................................446
Seat belts................................................ 447
Cargo hooks ........................................... 432
Caution label .............................................83
CD player ................................................354
Chains ....................................................... 323 Child restraint system............................ 60
Baby seats, definition............................ 61
Baby seats, installation ........................70
Child seats, definition ........................... 61
Child seats, installation .......................70
Installing CRS with ISOFIX
rigid anchors ........................................ 73
Installing CRS with seat belts ..........70
Installing CRS with top strap ........... 74
Junior seats, definition .......................... 61
Junior seats, installation ...................... 72
Child safety ................................................ 59
12-volt battery precautions .......................... 465, 569
Airbag precautions ............................. 45
Child restraint system ........................ 60
How your child should wear the seat belt.............................. 40
Installing child restraints .................... 69
Moon roof precautions .................... 192
Power window lock switch ............185
Power window precautions........... 187
Rear door child-protectors ............140
Removed electronic key battery precautions....................... 490
Seat belt precautions...........................42
Seat heater precautions ..................423
Trunk precautions .............................. 147
C

612Alphabetical index
IS300h_EE(OM53D56E)
Doors .......................................................... 136Automatic door locking and
unlocking system............................. 140
Door lock.................................................139
Open door warning buzzer .......... 137
Open door warning
light ........................................................ 523
Outside rear view mirrors................ 181
Rear door child-protector ............ 140
Side windows........................................ 185
Drive information..................................... 116
Drive info 1/Drive info 2........................ 117
Driver’s and front passenger’s seat belt reminder light ...................523
Driver’s seat position memory ......... 169
Driving ........................................................ 194 Break-in tips .......................................... 195
Correct driving posture .................... 36
Driving mode select switch .......... 293
Hybrid vehicle driving tips ............320
Procedures .............................................194
Winter drive tips................................. 322
Dynamic radar cruise control.......... 254 E-mail ........................................................388
Eco drive mode ..................................... 293
Elapsed time .............................................. 116
Electric motor (traction motor) ..........79
Electric Power Steering (EPS) ....... 296
Function.................................................. 296
Warning light........................................522
Electronic key ......................................... 130 Battery-saving function ....................150
If the electronic key does not operate properly ............................ 563
Replacing the battery ......................488
Emergency, in case of
If a warning message is displayed .............................................527
If the 12-volt battery is discharged ........................................ 566
If the electronic key does not operate properly ............................ 563
If the hybrid system will not start .......................................................560
If the shift lever cannot be shifted from P................................... 562
If the warning buzzer sounds........ 521
If the warning light turns on ............ 521E