Page 478 of 608
478
ES300h_OM_OM33D45U_(U)7-3. Do-it-yourself maintenance
Electronic key battery
●Flathead screwdriver
●Small flathead screwdriver
●Lithium battery CR2032
Take out the mechanical key.
Remove the cover.
To prevent damage to the key, cover the
tip of the screwdriver with a rag.
Remove the depleted battery.
Insert a new battery with the “+” termi-
nal facing up.
Replace the battery with a new one if it is depleted.
You will need the following items:
Replacing the battery
1
2
3
Page 479 of 608

ES300h_OM_OM33D45U_(U)
4797-3. Do-it-yourself maintenance
7
Maintenance and care
■Use a CR2032 lithium battery
●Batteries can be purchased at your Lexus dealer, loca l electrical appliance shops or
camera stores.
●Replace only with the same or equivalent type recommended by the manufacturer.
●Dispose of used batteries according to local laws.
■If the electronic key battery is depleted
The following symptoms may occur:
●The smart access system with push-button start and wireless remote control will not
function properly.
●The operational rang e will be reduced.
WARNING
■Removed battery and other parts
These parts are small and if swallowed by a child, they can cause choking. Keep away
from children. Failure to do so coul d result in death or serious injury.
NOTICE
■For normal operation after replacing the battery
Observe the following precautions to prevent accidents:
●Always work with dry hands.
Moisture may cause the battery to rust.
●Do not touch or move any other co mponent inside the remote control.
●Do not bend either of the battery terminals.
Page 495 of 608
495
ES300h_OM_OM33D45U_(U)
8When trouble arises
8-1. Essential informationEmergency flashers .................. 496
If your vehicle has to be stopped in an emergency.... 497
8-2. Steps to take in an emergency If your vehicle needs to be towed................................498
If you think something is wrong ................502
If a warning light turns on or a warning buzzer sounds.....503
If a warning message is displayed ................................509
If you have a flat tire ................... 513
If the hybrid sy stem will not
start ............................................... 523
If the electronic key does not operate properly ..................... 525
If the 12-volt battery is discharged ................................. 527
If your vehicle overheats .......... 531
If the vehicle becomes stuck .............................................535
Page 523 of 608

523
ES300h_OM_OM33D45U_(U)8-2. Steps to take in an emergency
8
When trouble arises
If the hybrid system will not start
One of the following may be the cause of the problem:
●The electronic key may not be functioning properly. (
→P. 526)
●There may not be sufficient fuel in the vehicle’s tank.
Refuel the vehicle.
●There may be a malfunction in the immobilizer system. ( →P. 76)
●There may be a malfunction in the steering lock system.
●The hybrid system may be malfunctioni ng due to an electrical problem such
as electronic key battery depletion or a blown fuse. However, depending on
the type of malfunction, an interim meas ure is available to start the hybrid sys-
tem. ( →P. 524)
One of the following may be the cause of the problem:
●The 12-volt battery may be discharged. ( →P. 527)
●The 12-volt battery terminal connections may be loose or corroded.
(→ P. 457)
One of the following may be the cause of the problem:
●The 12-volt battery may be discharged. ( →P. 527)
●One or both of the 12-volt battery terminals may be disconnected. ( →P. 457)
Contact your Lexus dealer if the problem cannot be repaired, or if repair procedures
are unknown.
Reasons for the hybrid system not star ting vary depending on the situation.
Check the following and perform the appropriate procedure:
The hybrid system will not start even though the correct starting proce-
dure is being followed. ( →P. 168)
The interior lights and headlights are d im, or the horn does not sound or
sounds at a low volume.
The interior lights and headlights do not turn on, or the horn does not
sound.
Page 525 of 608

525
ES300h_OM_OM33D45U_(U)8-2. Steps to take in an emergency
8
When trouble arises
If the electronic key does not operate properly
■Doors
Use the mechanical key (
→P. 105)
in order to perform the following
operations:
Locks all the doors
Closes the windows and moon
roof (turn and hold)
*
Unlocks the door
Turning the key rearward unlocks the
driver’s door. Turning the key once
again within 5 seconds unlocks the
other doors.
Opens the windows and moon roof (turn and hold)*
*
: This setting must be custom ized at your Lexus dealer.
■Trunk
Turn the mechanical key clockwise
to open.
An alarm will sound if the alarm is set.
(→ P. 78)
If communication between the electronic key and vehicle is interrupted
(→ P. 123) or the electronic key ca nnot be used because the battery is
depleted, the smart access system with push-button start and wireless
remote control cannot be used. In su ch 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
Page 526 of 608

5268-2. Steps to take in an emergency
ES300h_OM_OM33D45U_(U)
Ensure that the shift lever is in P and depress the brake pedal.
Touch the Lexus emblem side of the
electronic key to the power switch.
The power switch will turn to ON mode.
When the smart access system with
push-button start is deactivated in cus-
tomization setting, the power switch will
turn to ACCESSORY mode.
Firmly depress the brake pedal and check that is shown on the multi-
information display.
Press the power switch.
In the event that the hybrid system st ill cannot be started, contact your Lexus
dealer.
■Stopping the hybrid system
Shift the shift lever to P and press the power sw itch 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. 478)
■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. 169)
■When the electronic key does not work properly
●Make sure that the smart access system wi th push-button start has not been deacti-
vated in the customization setting. If it is off, turn the function on.
(Customizable features →P. 560)
●Check if battery-saving mode is set. If it is set, cancel the function. (→P. 122)
Starting the hybrid system
1
2
WARNING
■When using the mechanical key and operating the power windows or moon roof
Operate the power window or moon roof afte r 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 op erate the mechanical key. It is possible for children and
other passengers to get caught in the power window or moon roof.
3
4
3
Page 527 of 608
527
ES300h_OM_OM33D45U_(U)8-2. Steps to take in an emergency
8
When trouble arises
If the 12-volt battery is discharged
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, depe nding on the situa-
tion, the alarm may activate and doors
locked. ( →P. 79)
Open the trunk lid and remove the 12-volt battery cover. (→ P. 457)
In the event that the trunk opener cannot be used, use the mechanical key to open the
trunk. ( →P. 525)
Connect the jumper cables accordin g to the following procedure:
The following procedures may be used to start the hybrid system if the 12-volt
battery is discharged.
You can also call your Lexus deal er or a qualified repair shop.
1
2
3
Page 529 of 608

5298-2. Steps to take in an emergency
ES300h_OM_OM33D45U_(U)
8
When trouble arises
■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 stopped.
●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 w ill 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 access system
with push-button start 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 retu rn to the mode it was in before the 12-volt battery was
discharged. Before disconne cting 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.