2018 LEXUS RX450h battery

630 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85U●
Flathead screwdriver ●
Lithium battery CR2032
Take out the mechanical key.
Remove the cover. To prevent damage to the key, cover the
tip of the flathead screwdriver with a
tape.
Remove the depleted battery. When removing the cover, the elec-
tronic key module may stick to the cover
and the battery may not be visible. In this
case, remove the el ectronic key module
in order to remove the battery.
Insert a new battery with the “+” termi-
nal facing up.Electronic key battery Replace the battery with a new one if it is depleted.
You will need the following items:
Replacing the battery 1
2
3

6317-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
Use a CR2032 lithium battery ●
Batteries can be purc hased 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 the 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.

6337-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
Luggage compartment (type A fuse box)
■
Luggage compartment (type B fuse box)
Remove the fuse with the pullout
tool.
Only some fuses can be removed
using the pullout tool. 
RX450h 
RX450hL
Remove the 12-volt battery cover.
( → P. 606) Remove the deck board and side aux-
iliary box cover and 12-volt battery
cover. ( → P. 606)
RX450h 
RX450hL
Remove the terminal cover. Remove the terminal cover. 3

651
8When trouble arises
RX450h_RX450hL _U_OM48F85U 8-1. Essential information
Emergency flashers .................. 652
If your vehicle has
to be stopped in
an emergency .......................... 653
8-2. Steps to take in
an emergency
If your vehicle needs
to be towed................................ 654
If you think something is
wrong ........................................... 659
If a warning light turns on
or a warning buzzer
sounds..........................................660
If a warning message is
displayed..................................... 667
If you have a flat tire .................. 673
If the hybrid system will
not start .......................................690
If the electronic key does
not operate properly ............. 692
If the 12-volt battery is
discharged ................................. 695
If your vehicle overheats ......... 702
If the vehicle becomes
stuck ............................................. 706

652
RX450h_RX450hL _U_OM48F85U8-1. Essential information
Press the switch. All the turn signal lights will flash. To turn
them off, press the switch once again.
■
Emergency flashers
If the emergency flashers are used for a long time while the hybrid system is not operat-
ing (while the “READY” indicator is not illu minated), the 12-volt battery may discharge.
Emergency flashers The emergency flashers are used to warn other drivers when the vehicle has
to be stopped on the road due to a breakdown, etc.

664 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U■
SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors, side
impact sensors (front door), side impact se nsors (rear), driver’s seat position sensor,
driver’s seat belt buckle sw itch, front passenger occupant classification system (ECU and
sensors), “AIR BAG ON” indicator light, “A IR BAG OFF” indicator light, front passen-
ger’s seat belt buckle switch, driver’s seat belt pretension er, front passenger’s seat belt
pretensioner and force limiter, airbags, in terconnecting wiring and power sources.
( → P. 36) ■
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 sittin g 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. ■
Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insu fficient or the voltage temporarily drops,
the electric power steering system warning light may come on and the warning buzzer
may sound. ■
If the malfunction indicator lamp comes on while driving
First check the following: ●
Is the fuel tank empty?
If it is, fill the fu el 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 severa l trips, contact your Lexus dealer as soon as
possible. ■
When the tire pressure warning light comes on
Inspect the tires to check if a tire is punctured.
If a tire is punctured: → P. 673
If none of the tires are punctured:
Turn the power switch off then turn it to ON mode. Check if the tire pressure warning
light comes on or blinks. 
If the tire pressure warning light comes on
After the temperature of the tires has lowere d sufficiently, check the inflation pressure
of each tire and adjust th em to the specified level.
If the warning light does not turn off even after several minutes have elapsed, check
that the inflation pressure of each tire is at the specified level an d perform initialization.
( → P. 613)
If the warning light does not turn off severa l minutes after the init ialization has been per-
formed, have the vehicle inspected by your Lexus dealer immediately. 
If the tire pressure wa rning light blinks for 1 minute then stays on
There may be a malfunction in the tire pressure warnin g system. Have the vehicle
inspected by your Lexus dealer immediately. 1
2

668 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U* : A buzzer sounds the first time a message is shown on the multi-information display.
●
If the following messages are shown, there may be a malfunction.
Immediately stop the vehicle in a safe place and contact your Lexus dealer.
Continuing to drive the vehicle may be dangerous.
• “Braking Power Low Stop in a Safe Place See Owner’s Manual”
• “Oil Pressure Low Stop in a Safe Place See Owner’s Manual”
• “Charging System Malfunction See Owner’s Manual” ●
If the following messages are shown, there may be a malfunction.
Immediately have the vehicle inspected by your Lexus dealer.
• “Hybrid System Malfunction”
•“Check Engine”
• “Hybrid Battery System Malfunction”
• “Accelerator System Malfunction”
• “Access System with Elec. Key Malfunction See Owner’s Manual” ●
If “Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” is
displayed, following the instructions, accordingly. ( → P. 702)Flashes ⎯ Sounds Indicates a situation, such as when
damage to the vehicle or danger may
result
Comes
on ⎯ Does not sound Indicates a condition, such as malfunc-
tion of electrical components, their
condition, or indicates the need for
maintenance
Flashes ⎯ Does not sound Indicates a situation, such as when an
operation has been performed incor-
rectly, or indicates how to perform an
operation correctly
If a message instructing to refer to the Owner’s Manual is displayed System
warning
light Warning buzzer
* Warning

6698-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85UTake the appropriate actions as in structed in the message displayed.
If any of the following messages are displa yed, also refer to this Owner’s Manual.■
If “Hybrid System Overheated Reduced Output Power” is shown
This message may be displayed when driving under severe operating condi-
tions.
(For example, when driving up a long steep hill.)
Handling method: → P. 702■
If “Hybrid Battery Low Shift Ou t of N to Recharge” is shown
Message is displayed when the remainin g charge for the hybrid battery (trac-
tion battery) is low.
As the hybrid battery (traction battery) cannot be charged when the shift
lever is in N, when stopped for long periods of time shift the shift lever to P. ■
If “Hybrid Battery Low Hybrid System Stopped Shift to P and Restart” is
shown
Message is displayed when the remainin g charge for the hybrid battery (trac-
tion battery) is low, because vehicle has been shifted N for a long period of
time.
When operating the vehicle, restart the hybrid system. ■
If “Shift to P Before Exiting Vehicle” is shown
Message is displayed when the driver’s door is opened without turning the
power switch off with the shift lever in any position other than P.
Shift the shift lever to P.Other messages displayed on the multi-information display