2018 LEXUS RX450h charging

6097-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
Before recharging
When recharging, the 12-volt battery produc es hydrogen gas which is flammable and
explosive. Therefore, observe the following precautions before recharging: ●
If recharging with the 12-volt battery installed on the vehicle, be sure to disconnect the
ground cable. ●
Make sure the power switch on the charge r is off when connecting and disconnecting
the charger cables to the 12-volt battery. ■
After recharging/reconnecting the 12-volt battery ●
The hybrid system may not start. Follow the procedure below to initialize the system.
Shift the shift lever to P.
Open and close any of the doors.
Restart the hybrid system. ●
Unlocking the doors using the smart access system with push-button start may not be
possible immediately after reconnecting the 12-volt battery. If this happens, use the
wireless remote control or the mechan ical key to lock/unlock the doors.●
Start the hybrid system with the power sw itch in ACCESSORY mo de. The hybrid sys-
tem may not start with the power switch turned off. However, the hybrid system will
operate normally from the second attempt.●
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 connec ting the 12-volt battery if the power switch
mode prior to discharge is unknown.
If the system will not start even after multip le attempts at all methods above, contact your
Lexus dealer.
WARNING ■
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 matc h 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. 1
2
3

610 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85UWARNING ■
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 s kin. 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 emergenc y medical attention immedi-
ately. ■
When handling the 12-volt battery
→ P. 700 ■
When disconnecting the 12-volt battery (RX450h)
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 touch the positive (+) ter-
minal, which may cause a short and result in
death or serious injury.

660 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85UIf a warning light turns on or a warning buzzer
sounds Calmly perform the following actions if any of the warning lights comes on or
flashes. If a light comes on or flashes, but then goes off, this does not necessar-
ily indicate a malfunction in the system . However, if this continues to occur,
have the vehicle inspecte d by your Lexus dealer.
Warning light and warning buzzer list Warning light Warning light/Details/Actions(U.S.A.)
(Canada)
Brake system warning light
Indicates that:
• The brake fluid level is low; or
• The brake system is malfunctioning
→ Immediately stop the vehicle in a safe place and contact your
Lexus dealer. Continuing to drive the vehicle may be dangerous.
Brake system warning light
Indicates a malfunction in:
• The regenerative braking system;
• The electronically controlled brake system; or
• The electric parking brake
→ Have the vehicle inspected by your Lexus dealer immediately. (If equipped)
Charging system warning light
Indicates a malfunction in the vehicle’s charging system
→ Immediately stop the vehicle in a safe place and contact your
Lexus dealer. Continuing to drive the vehicle may be dangerous. (U.S.A.)
(Canada)
Malfunction indicator lamp
Indicates a malfunction in:
• The hybrid system;
• The electronic engine control system; or
• The electronic throttle control system
→ Have the vehicle inspected by your Lexus dealer immediately.
SRS warning light
Indicates a malfunction in:
• The SRS airbag system;
• The front passenger occupant classification system; or
• The seat belt pretensioner system
→ Have the vehicle inspected by your Lexus dealer immediately.

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

672 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U■
If “Maintenance Required Visit Your Dealer” is displayed (U.S.A. only)
Indicates that all maintenance is requir ed to correspond to the driven distance
on the maintenance schedule
* .
Comes on approximately 5000 miles (8000 km) after the message has
been reset.
(The indicator will not work properly unless the message has been reset.)
Perform the necessary maintenance. Please reset the message after the main-
tenance is performed. ( → P. 588)
* : Refer to the separate “Scheduled Mainte nance” or “Owner’s Manual Supplement”
for the maintenance interval applicable to your vehicle. ■
System warning lights
The master warning light does not come on or flash in the following cases. Instead, a sep-
arate system warning light will come on along with a message shown on the multi-infor-
mation display. ●
“Braking Power Low Visit Your Dealer”:
The brake system warning light (yellow) come on. ( → P. 660)●
“Antilock Brake System Malfunction Visit Your Dealer”:
The ABS warning light comes on. ( → P. 661)●
“Charging System Malfunction See Ow ner's Manual” (F SPORT models):
The charging system wa rning light comes on. ( → P. 660)■
Warning buzzer
→ P. 665
NOTICE ■
“High Power Consumption Partial Limit On AC/Heater Operation” is frequently
shown
There is a possible malfunction relating to the charging system or the 12-volt battery
may be deteriorating. Have the vehicle inspected by your Lexus dealer.

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.

700 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85UWARNING ■
Avoiding 12-volt battery fires or explosions
Observe the following precautions to preven t accidentally igniting the flammable gas
that may be emitted from the 12-volt battery: ●
Make sure each jumper cable is connected to the correct terminal and that it is not
unintentionally in contact with any other than the intended terminal.●
Do not allow the other end of the jumper cab le connected to the “+” terminal to come
into contact with any other parts or metal surfaces in the area, such as brackets or
unpainted metal. ●
Do not allow the + and - clamps of the jump er cables to come in to contact with each
other. ●
Do not smoke, use matches, cigarette light ers or allow open flame near the 12-volt
battery. ■
12-volt battery precautions
The 12-volt battery contains poisonous and co rrosive acidic electr olyte, while related
parts contain lead and lead compounds. Ob serve the following precautions when han-
dling the 12-volt battery: ●
When working with the 12-volt battery, always wear safety glasses and take care not
to allow any battery fluids (acid) to come in to contact with skin, clothing or the vehicle
body. ●
Do not lean over the 12-volt battery. ●
In the event that battery fluid comes into contact with the skin or eyes, immediately
wash the affected area with water and seek medical attention.
Place a wet sponge or cloth over the affected area until medical attention can be
received. ●
Always wash your hands after handling the 12-volt battery support, terminals, and
other battery-related parts. ●
Do not allow children near the 12-volt battery. ■
After recharging the 12-volt battery
Have the 12-volt battery inspected at yo ur Lexus dealer as soon as possible.
If the 12-volt battery is deteriorating, continued use may cause the 12-volt battery to
emit a malodorous gas, which may be de trimental to the health of passengers.■
When replacing the 12-volt battery ●
When the vent plug and indicator are close to the hold down clamp, the battery fluid
(sulfuric acid) may leak. ●
For information regarding 12-volt battery replacement, contact your Lexus dealer.●
Make sure to replace the 12-volt battery with one designed for this vehicle. Other-
wise, hydrogen gas may enter the vehicle, possibly causing a fire or explosion. ●
After replacing, securely attach the exhaust hose and exhaust hole plug to the
exhaust hole of the replaced 12-volt battery. If not properly installed, gases (hydro-
gen) may leak into the vehicle interior, an d there is the possible danger of the gas
igniting and exploding.

7018-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85UNOTICE ■
When handling jumper cables
When connecting the jumper cables, ensure that they do not become entangled in the
cooling fans or belt. ■
To prevent damaging the vehicle
The exclusive jump starting te rminal is to be used when charging the 12-volt battery
from another vehicle in an emergency. It cannot be used to jump start another vehicle.