2018 LEXUS RX450h battery

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RX450h_RX450hL _U_OM48F85U 7
Maintenance and care 7-3. Do-it-yourself maintenance
Do-it-yourself service precautions If you perform maintenance by yourself, be sure to follow the correct proce-
dure as given in these sections. Items Parts and tools
12-volt battery con-
dition ( → P. 605) •Grease
• Conventional wrench (for terminal clamp bolts)
Brake fluid level
( → P. 603) • FMVSS No.116 DOT 3 or SAE J1703 brake fluid
• Rag or paper towel
• Funnel (used only for adding brake fluid)
Engine/power con-
trol unit coolant level
( → P. 601) • “Toyota Super Long Life Coolan t” or a similar high quality
ethylene glycol-based non-silicate, non-amine, non-nitrite
and non-borate coolant with long-life hybrid organic acid
technology
For the U.S.A.:
“Toyota Super Long Life Coolant” is pre-mixed with 50%
coolant and 50% deionized water.
For Canada:
“Toyota Super Long Life Cool ant” is pre-mixed with 55%
coolant and 45% deionized water.
• Funnel (used only for adding coolant)
Engine oil level
( → P. 598) • “Toyota Genuine Motor Oil” or equivalent
• Rag or paper towel
• Funnel (used only for adding engine oil)
Fuses ( → P. 632) • Fuse with same amperage rating as original
Headlight aim
*( → P. 635) • Phillips-head screwdriver
Light bulbs
( → P. 637) • Bulb with same number and wattage rating as original
• Flathead screwdriver •Wrench
Radiator and con-
denser ( → P. 602) ⎯
Tire inflation pres-
sure ( → P. 620) • Tire pressure gauge • Compressed air source

5977-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
12-volt battery
→ P. 605Engine compartment
Washer fluid tank ( → P. 604)
Brake fluid reservoir ( → P. 603)
Engine oil level dipstick
( → P. 598)
Engine coolant reservoir
( → P. 601)
Power control unit coolant reservoir
( → P. 601) Fuse boxes ( → P. 632)
Radiator ( → P. 602)
Power control unit coolant
radiator ( → P. 602)
Condenser ( → P. 602)
Electric cooling fans
Engine oil filler cap ( → P. 599)1
2
3
4
5 6
7
8
9
10
11

6057-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U 
RX450h
The 12-volt battery is located in the
left-hand side of luggage compart-
ment. 
RX450hL
The 12-volt battery is located in the
left-hand side of luggage compart-
ment.12-volt battery Location

606 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85U 
RX450h
Lift the deck board and attach the hook. ( → P. 544)
Remove the cover after removing
the clips.
Press
Pull out 
RX450hL
Remove the deck board and side auxiliary box cover. ( → P. 545)
Remove the 12-volt battery cover.
Remove the deck side trim cover.Removing the 12-volt battery cover 1
2
1
2
1
2
3

6077-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U 
RX450h
Make sure that the 12-volt battery terminals are not corroded and that there are
no loose connections, cracks, or loose clamps.
Terminals
Hold-down clamp 
RX450hL
Make sure that the 12-volt battery terminals are not corroded and that there are
no loose connections, cracks, or loose clamps.
Terminals
Hold-down clampExterior 1
2
1
2

608 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85U 
RX450h
Install the 12-volt battery cover with the
clips.
Push up center position
Insert
Press 
RX450hL
Install the deck side trim cover.
Install the 12-volt battery cover.Installing the 12-volt battery cover 1
2
3
1
2

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.