2007 Lexus GS450h battery

371
4-3. Do-it-yourself maintenance
4
Maintenance and care
12 volt battery
■Location
The 12 volt battery is located in the
lef
t-hand side of luggage compart-
ment.
■ Ex
terior
Make sure that the battery terminals ar
e not corroded and that there
are no loose connections, cracks, or loose clamps.
Terminals
Hold-down clamp
NOTICE
■If the fluid level is low or high
It is normal for the brake fluid level to go down slightly as the brake pads wear or
when the fluid level in the accumulator is high. 
If the reservoir needs frequent refilli ng, it may indicate a serious problem.

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4-3. Do-it-yourself maintenance
■Before recharging
When recharging, the 12 volt battery produces hydrogen gas which is flammable
and
explosive. Therefore, before recharging:
●If recharging with the 12 volt battery installed on the vehicle, be sure to discon -
nect the ground cable.
●Make sure the power switch on the charger is off when connecting and discon -
necting the charger cables to the battery.
■After recharging/reconnecting the 12 volt battery
In some cases, the hybrid sy stem may
not start. Follow one or both of the following
procedures:
●After opening and closing the driver's door, wait 10 seconds then attempt to
start the hybrid system. (If the system does not start first time, repeat the proce -
dure.)
●With the shift lever in “P” and the powe r switch in the “OFF” mode, open and
close any door, then attempt to start the hybrid system.
If the system will not start even after mult i
ple attempts at both methods, contact
your Lexus dealer.

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4-3. Do-it-yourself maintenance
4
Maintenance and care
CAUTION
■Chemicals in the 12 volt battery
A battery contains poisonous and corrosive sulfuric acid and may produce hydro-
gen gas which is flammable and explosive. To reduce the risk of death or serious
injury, take the following precautions while working on or near battery:
●Do not cause sparks by touching the battery terminals with tools.
●Do not smoke or light a match near the battery.
●Avoid contact with eyes, skin and clothes.
●Never inhale or swallow electrolyte.
●Wear protective safety glasses when working near the battery.
●Keep children away from the battery.
■Where to safety charge the 12 volt battery
Always charge the battery in an open area. Do not charge the battery in a garage or
closed room where there is not sufficient ventilation.
■How to recharge the 12 volt battery
Only perform a slow charge (5A or less). The 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 medi-
cal 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 feel pain or a burning sensation, seek
medical attention immediately.
●If electrolyte gets on your clothes 
It can soak through clothing on to your skin. Immediately take off the clothing and
follow the procedure above if necessary.
●If you accidentally swallow electrolyte 
Drink a large quantity of water or milk. Fo llow with milk of magnesia, beaten raw
egg or vegetable oil. Get emergency medical attention immediately.

374
4-3. Do-it-yourself maintenance
Washer fluid
If any washer does not work or the
warning message appears on the
multi-information display, the
washer tank may be empty. Add
washer fluid.
NOTICE
■When recharging the 12 volt battery
Never recharge the battery while the hybrid system is on. Also, be sure all accesso-
ries are turned off.
NOTICE
■Do not use any fluid other than washer fluid
Do not use soapy water or engine antifreeze instead of washer fluid.
Doing so may cause streaking on the vehicle’s painted surfaces.
■Diluting washer fluid
Dilute washer fluid with water as necessary. 
Refer to the freezing temperatures listed on the washer fluid tank.

393
4-3. Do-it-yourself maintenance
4
Maintenance and care
Electronic key battery
Replace the battery with a new one if it is discharged.
■You will need the following items:
●F
lathead screwdriver
●Small Phillips-head sc rewd
river
● Lithium batter
y (CR1632)
■ R
eplacing the battery
Take out the mechanical key.
Remove the cover.
Remove the depleted battery.
Insert a new battery with the “+”
terminal facing up.
STEP1
STEP2
STEP3

394
4-3. Do-it-yourself maintenance
■If the electronic key battery is discharged
The following symptoms may occur.
●The smart access system with push-button start and wireless remote control will
not function properly.
●The operational range is reduced.
■Use a CR1632 lithium battery
●Batteries can be purchased at your Lexus dealer, jewelers, or camera stores.
●Replace only with the same or equivalent type recommended by a Lexus dealer.
●Dispose of used batteries according to the local laws.
CAUTION
■Removed battery and other parts
Keep away from children. 
These parts are small and if swallowed by a child they can cause choking.
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 comp onents inside the electronic key.
●Do not bend the battery terminals.

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4-3. Do-it-yourself maintenance
4
Maintenance and care
FuseAmpereCircuit
8IG210
Multiport fuel injection system/
sequential multiport fuel injection
system, noise filter
9EFI No.210Fuel system, exhaust system
10H-LP R LWR15Headlight low beam (right)
11H-LP L LWR15Headlight low beam (left)
12D/C CUT30DOME, MPX-B
13IGCT No.37. 5Hybrid battery (traction battery)
14IGCT No.27. 5Hybrid system
15MPX-B7. 5
Power windows, door control system,
power seat, electronically controlled
brake system, combination switch,
electric tilt and telescopic steering,
gauges and meters
16DOME7. 5Interior lights, foot lights, vanity light,
gauges and meters
17ABS MAIN110Electronically controlled brake sys-
tem
18ABS MOTOR30ABS
19ABS MAIN210Electronically controlled brake sys-
tem
20F/ P M P25Fuel system
21EFI25
EFI2, multiport fuel injection system/
sequential multiport fuel injection
system
22INJ20
Multiport fuel injection system/
sequential multiport fuel injection
system

When trouble arises5
419
5-1. Essential information ........... 420If your vehicle needs to be 
towed........................................... 420
If you think something is 
wrong .......................................... 427
Event data recorder ................. 428 5-2. Steps to take in an

emergency............................ 430
If a warning light turns on or a 
warning buzzer sounds............ 430
If a warning message is 
displayed.................................... 436
If you have a flat tire 
(Vehicles with run-flat 
tires) ............................................. 455
If you have a flat tire 
(Vehicles with standard 
tires) ............................................. 456
If the hybrid system will not 
start .............................................. 466
If the shift lever cannot be 
shifted from P........................... 467
If you lose your keys ................. 468
When the electronic key  battery is discharged ............ 469
If the 12 volt battery is 
discharged .................................. 471
If your vehicle overheats ........ 475
If the vehicle becomes 
stuck ............................................ 478