2018 LEXUS RX450h key battery

694 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U■
Stopping the hybrid system
Shift the shift lever to P, set the parking brake, 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. 630)■
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. 240)■
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. 740)●
Check if battery-saving mode is set. If it is set, cancel the function. ( → P. 160)
WARNING ■
When using the mechanical key and operating the power windows or the moon roof
or panoramic moon roof
Operate the power window or the moon roof or panoramic moon roof after checking
to make sure that there is no possibility of any passenger having an y of their body parts
caught in the window or the moon roof or panoramic 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 powe r window or the moon roof or panoramic
moon roof. 3

6958-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85UIf 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. 87)
Open the hood ( → P. 595) and fuse
box cover.
Open the exclusive jump starting
terminal cover.If the 12-volt battery is discharged The following procedures may be used to start the hybrid system if the vehi-
cle’s 12-volt battery is discharged.
You can also call your Lexus deal er or a qualified repair shop.1
2
3

698 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U■
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 the 12-volt battery is removed or discharged ●
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 be fore the 12-volt battery was
discharged. Before disconnect ing 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. ●
The power back door must be initialized. ( → P. 150)■
When replacing the 12-volt battery ●
RX450h: Use a Central Degassing type 12 -volt battery (European Regulations).
RX450hL: Use a 12-volt battery designed for this vehicle. ●
RX450h: Use a 12-volt battery that the case size is same as the previous one (LN2),
20 hour rate capacity (20HR) is equivalent (60Ah) or greater, and performance rating
(CCA) is equivalent (460A) or greater.
• If the sizes differ, the 12-volt battery cannot be properly secured.
• If the 20 hour rate capacity is low, even if the time period where the vehicle is not
used is a short time, the 12-volt battery may discharge and the hybrid system may
not be able to start.

766
RX450h_RX450hL _U_OM48F85UWhat to do if... (Troubleshooting)
What to do if... (Troubleshooting) ●
If you lose your mechanical keys, ne w genuine mechanical keys can be made
by your Lexus dealer. ( → P. 133)●
If you lose your electronic keys, the risk of vehicle theft increases significantly.
Contact your Lexus dealer immediately. ( → P. 135)●
Is the electronic key battery weak or depleted? ( → P. 630)●
Is the power switch in ON mode?
When locking the doors, turn the power switch off. ( → P. 240)●
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. 160)
●
Is the child-protector lock set?
The rear door cannot be opened from in side the vehicle when the lock is set.
Open the rear door from outside and then unlock the child-protector lock.
( → P. 139)If you have a problem, check the foll owing 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

767What to do if... (Troubleshooting)
RX450h_RX450hL _U_OM48F85U●
Did you press the power switch while firmly depressing the brake pedal?
( → P. 239)●
Is the shift lever in P? ( → P. 241)●
Is the electronic key anywhere detectable inside the vehicle? ( → P. 158)●
Is the steering wheel unlocked? ( → P. 242)●
Is the electronic key battery weak or depleted?
In this case, the hybrid system can be started in a temporary way. ( → P. 693)●
Is the 12-volt battery discharged? ( → P. 695)●
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. 250)●
It is locked automatically to prevent theft of the vehicle. ( → P. 242)
●
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. 196)
●
The auto power off function will be operated if the vehicle is left in
ACCESSORY or ON mode (the hybrid sy stem is not operating) for a period
of time. ( → P. 241)If you think something 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
The windows do not open or close by operating the power window
switches
The power switch is turned off automatically

773Alphabetical index
RX450h_RX450hL _U_OM48F85UCare
Aluminum wheels ............................... 581
Exterior................................................... 580
Interior .................................................... 584
Seat belts ............................................... 585
Self-restoring coat ............................ 580
Cargo capacity............................ 220, 710
Cargo hooks .......................................... 540
Cargo net hooks ................................... 540
Chains .........................................................391
Child restraint system............................ 55
Booster seats installation................... 64
Convertible seats
installation .............................................. 62
Front passenger occupant
classification system ......................... 47
Infant seats definition .............................61
Infant seats installation ........................ 57
Installing CRS with LATCH
anchors ................................................... 67
Installing CRS with seat
belts ............................................................61
Installing CRS with top tether
strap.......................................................... 70
LATCH anchors ................................... 67 Child safety .................................................... 54
12-volt battery
precautions .......................... 609, 700
Airbag precautions.............................. 39
Child restraint system......................... 55
How your child should
wear the seat belt .............................. 33
Installing child restraints .................... 55
Moon roof precautions .................. 203
Panoramic moon roof
precautions ....................................... 207
Power back door
precautions ......................................... 152
Power window lock switch.............196
Power window precautions ...........199
Rear door child-p rotectors ............139
Removed key battery
precautions .........................................631
Seat belt extender
precautions .......................................... 35
Seat belt precautions .......................... 35
Seat heater precautions ................. 525C

775Alphabetical index
RX450h_RX450hL _U_OM48F85UDrive information .................................. 105
Drive-start control ..................... 213, 249
Driver’s seat belt reminder light ..... 662
Driver’s seat position memory ........... 181
Driving
Break-in tips ...........................................214
Correct posture.....................................30
Driving mode select switch ..........379
Hybrid vehicle driving tips............ 388
Procedures ............................................. 212
Winter drive tips ................................ 390
Driving position memory...................... 181
Memory recall function.................... 184
Power easy access system .............. 181
Dynamic radar cruise control
with full-speed range ....................... 306 E-Four ....................................................... 383
ECB (Electronically Controlled
Brake System) .................................... 382
Eco drive mode......................................379
EDR (Event data recorder).....................11
Electric motor
Location .....................................................74
Specification ........................................... 712
Electric Power Steering (EPS) ....... 383
Warning light .........................................661
Electronic key .......................................... 132
Battery-saving function ....................159
If the electronic key does not
operate properly ............................ 692
Replacing the battery ......................630
Electronically Controlled
Brake System (ECB) ....................... 382
Emergency flashers ............................ 652 E

776 Alphabetical index
RX450h_RX450hL _U_OM48F85UEmergency, in case of
If a warning buzzer sounds.......... 660
If a warning light turns on.............. 660
If a warning message is
displayed.............................................667
If the 12-volt battery is
discharged ........................................ 695
If the electronic key does not
operate properly.............................692
If the hybrid system will
not start ............................................... 690
If you have a flat tire ..........................673
If you lose your keys ................ 133, 135
If you think something is
wrong .................................................. 659
If your vehicle becomes
stuck ..................................................... 706
If your vehicle has to
be stopped in an
emergency........................................ 653
If your vehicle needs to be
towed................................................... 654
If your vehicle overheats ................702
Energy monitor ....................................... 124 Engine
ACCESSORY mode ..................... 240
Compartment ..................................... 597
Engine switch ...................................... 239
Hood........................................................595
How to start the hybrid
system .................................................. 239
Identification number......................... 712
If your vehicle has to be
stopped in an emergency..........653
Ignition switch (power switch) .... 239
Overheating......................................... 702
Power switch ....................................... 239
Engine coolant
Capacity................................................... 715
Checking ................................................ 601
Preparing and checking
before winter ....................................390
Engine coolant temperature
gauge .........................................................96
Engine oil
Capacity................................................... 713
Checking .............................................. 598
Preparing and checking
before winter ....................................390
Engine oil maintenance data ........... 600
Engine switch ......................................... 239
Enhanced VSC ..................................... 382
EPS
(Electronic Power Steering) ........ 383
Warning light .........................................661
EV drive mode .......................................244
EV indicator ............................................... 76
Event data recorder (EDR).....................11