battery LEXUS RX450h 2016 Repair Manual

4856-3. Do-it-yourself maintenance
6
Maintenance and care
RX450h_U_OM0E013U ●
The power switch mode is recorded by the vehicle. If the 12-volt battery is reconnected,
the vehicle will return the power switch mode to the status it was in before the 12-volt
battery was disconnected. Make sure to turn off the power before disconnect the 12-
volt battery. Take extra care when connecting the 12-volt battery if the power switch
mode prior to discharge is unknown.
If the system will not start even after multiple attempts at all methods above, contact your
Lexus dealer.
WA R N I N G ■
Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid and may produce
hydrogen gas which is flammable and explosive. To reduce the risk of death or serious
injury, take the following precautions while working on or near the 12-volt battery: ●
Do not cause sparks by touching the 12-volt battery terminals with tools. ●
Do not smoke or light a match near the 12-volt battery. ●
Avoid contact with eyes, skin and clothes. ●
Never inhale or swallow electrolyte. ●
Wear protective safety glasses when working near the 12-volt battery.●
Keep children away from the 12-volt battery. ■
Where to safely charge the 12-volt battery
Always charge the 12-volt battery in an open area. Do not charge the 12-volt battery in
a garage or closed room where th ere is insufficient ventilation.■
How to recharge the 12-volt battery
Only perform a slow charge (5 A or less). The 12-volt battery may explode if charged
at a quicker rate. ■
Emergency measures regarding electrolyte ●
If electrolyte gets in your eyes
Flush your eyes with clean water for at least 15 minutes and get immediate medical
attention. If possible, continue to apply water with a sponge or cloth while traveling to
the nearest medical facility. ●
If electrolyte gets on your skin
Wash the affected area thoroughly. If you fe el pain or burning, get medical attention
immediately. ●
If electrolyte gets on your clothes
It can soak through clothing on to your skin. Immediately take off the clothing and fol-
low the procedure above if necessary. ●
If you accidentally swallow electrolyte
Drink a large quantity of water or milk. Get emergency medica l attention immedi-
ately. ■
When handling the 12-volt battery
 P. 5 7 2

486 6-3. Do-it-yourself maintenance
RX450h_U_OM0E013U WA R N I N G ■
When disconnecting the 12-volt battery
NOTICE ■
When recharging the 12-volt battery
Never recharge the 12-volt battery while the hybrid system is operating. Also, be sure
all accessories are turned off.Do not disconnect the negative (-) terminal on
the body side as shown. The disconnected neg-
ative (-) terminal may to uch the positive (+) ter-
minal, which may cause a short and result in
death or serious injury.

506 6-3. Do-it-yourself maintenance
RX450h_U_OM0E013U ●
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. 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

5076-3. Do-it-yourself maintenance
6
Maintenance and care
RX450h_U_OM0E013U ■
Use a CR2032 lithium battery ●
Batteries can be purchased at your Lexus dealer, local 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 range will be reduced.
WA R N I N G ■
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 could result in death or serious injury.
NOTICE ■
For normal operation afte r 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 component inside the remote control. ●
Do not bend either of the battery terminals.

5096-3. Do-it-yourself maintenance
6
Maintenance and care
RX450h_U_OM0E013U 
Luggage compartment (type A fuse box)
Remove the 12-volt battery cover.
(  P. 4 8 3 ) 
Luggage compartment (type B fuse box)
Remove the terminal cover.
Remove the fuse with the pullout
tool.
Only some fuses can be removed
using the pullout tool.
Check if the fuse is blown.
Normal fuse
Blown fuse Replace the blown fuse with a new
fuse of an appropriate amperage rat-
ing. The amperage rating can be
found on the fuse box lid.
Many types of fuse are used on this
vehicle. This illustration shows a com-
mon type of fuse used on this vehicle. 3
4
1
2

527
7When trouble arises
RX450h_U_OM0E013U 7-1. Essential information
Emergency flashers .................. 528
If your vehicle has to be
stopped in an
emergency................................. 529
7-2. Steps to take in an
emergency
If your vehicle needs to be
towed ...........................................530
If you think something is
wrong ........................................... 535
If a warning light turns
on or a warning buzzer
sounds.......................................... 536
If a warning message is
displayed..................................... 543
If you have a flat tire................... 549
If the hybrid system will not
start .................................................561
If the shift lever cannot be
shifted from P............................ 563
If the electronic key does
not operate properly ............. 564
If the 12-volt battery is
discharged .................................568
If your vehicle overheats .......... 574
If the vehicle becomes
stuck ............................................. 578

528
RX450h_U_OM0E013U 7-1. 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 in the road due to a breakdown, etc.

5397-2. Steps to take in an emergency
7
When trouble arises
RX450h_U_OM0E013U * : Driver’s and front passenger’s seat belt warning buzzer:
The driver’s seat belt warning buzzer sounds to alert the driver that his or her seat belt
is not fastened. Once the power switch is turned to ON mode, the buzzer sounds for
6 seconds. If the vehicle reaches a speed of 12 mph (20 km/h), the buzzer sounds
once. If the seat belt is st ill unfastened after 24 second s, the buzzer will sound inter-
mittently for 10 seconds. Then, if the seat be lt is still unfastened, the buzzer will sound
in a different tone for 20 more seconds.
The front passenger’s seat belt warning buzzer sounds to alert the front passenger
that his or her seat belt is not fastened. The buzzer sounds once if the vehicle reaches
a speed of 12 mph (20 km/h). If the seat belt is still unfastened after 24 seconds, the
buzzer will sound intermittently for 10 seconds. Then, if the seat belt is still unfastened,
the buzzer will sound in a different tone for 20 more seconds. ■
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 swit ch, 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 pretensioner, front passenger’s seat belt
pretensioner and force limiter, airbags, in terconnecting wiring and power sources.
(  P. 3 8 ) ■
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 th e seat, the sensor 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 insufficient of the voltage temporarily drops,
the electric power steering system warnin g 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 fuel 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.

544 7-2. Steps to take in an emergency
RX450h_U_OM0E013U * : 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
shown, following the instructions, accordingly. (  P. 5 74 )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 Wa r n i n g b u z z e r
* Wa r n i n g

5457-2. Steps to take in an emergency
7
When trouble arises
RX450h_U_OM0E013U Take 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. 5 74■
If “Hybrid Battery Low Shift Ou t of N to Recharge” is shown
Message is displayed when the remaining charge for the hybrid battery (trac-
tion battery) is low.
As the hybrid battery (traction batter y) 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 remaining charge for the hybrid battery (trac-
tion battery) is low, because vehicle ha s 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