2010 Lexus GS450h battery

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4-2. Maintenance
4
Maintenance and care
GS_HV_U (OM30C81U)
January 28, 2010 10:42 am
Emission inspection and maintenance (I/M) programs
Some states have vehicle emission inspection programs which include
OBD (On Board Diagnostics) checks. The OBD system monitors the oper-
ation of the emission control system.
■If the malfunction indicator lamp comes on
The OBD system determines that a problem exists somewhere in
the emission control system. Your vehicle may not pass the I/M test
and may need to be repaired. Contact your Lexus dealer to service
the vehicle.
■Your vehicle may not pass the I/M test:
●When the 12 volt battery is disconnected or discharged
Readiness codes that are set during ordinary driving are erased.
Also, depending on your driving habits, the readiness codes may
not be completely set.
●When the fuel tank cap is loose
The malfunction indicator lamp comes on as a temporary mal-
function and your vehicle may not pass the I/M test.
■When the malfunction indicator lamp goes off after several driv-
ing trips
The error code in the OBD system will not be cleared unless the
vehicle is driven 40 or more times.
■If your vehicle does not pass the I/M test
Contact your Lexus dealer to prepare the vehicle for re-testing.

454
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
4-3. Do-it-yourself maintenance
Do-it-yourself service precautions
If you perform maintenance yourself, be sure to follow the correct proce-
dure given in these sections.
ItemsPa r t s a n d t o o l s
12 volt battery condition (P. 4 7 0)
•Grease
• Conventional wrench
(for terminal clamp bolts)
Brake fluid level (P. 4 6 8 )
• FMVSS No.116 DOT 3 or SAE
J1703 brake fluid
•Rag or paper towel
• Funnel (used only for adding brake
fluid)
Engine/power control unit coolant
level (P. 4 6 6 )
• “Toyota Super Long Life Coolant”
or similar high quality ethylene gly-
col 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 Coolant”
is pre-mixed with 55% coolant and
45% deionized water.
• Funnel (used only for adding cool-
ant)

460
4-3. Do-it-yourself maintenance
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
Engine compartment
■12 volt battery
P. 4 7 0
Engine oil level dipstick
(P. 4 6 2 )
Engine oil filler cap
(P. 463)
Brake fluid reservoir
(P. 468)
Fuse box (P. 4 9 6 )Washer fluid tank
(P. 4 74 )
Gasoline engine/power 
control unit coolant 
reservoir (P. 466)
Electric cooling fans
Condenser (P. 468)
Radiator (P. 468)

470
4-3. Do-it-yourself maintenance
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
12 volt battery
The 12 volt battery is located in the left-hand side of luggage compart-
ment.
■Removing the cover

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4-3. Do-it-yourself maintenance
4
Maintenance and care
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
■Exterior
Make sure that the 12 volt battery
terminals are not corroded and
that there are no loose connec-
tions, cracks, or loose clamps.
Terminals
Hold-down clamp
■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 12 volt battery.
■After recharging/reconnecting the 12 volt battery
In some cases, the hybrid system 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 “POWER” switch is OFF, open and close any
door, then attempt to start the hybrid system.
If the system will not start even after multiple attempts at both methods, contact
your Lexus dealer.

472
4-3. Do-it-yourself maintenance
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
CAUTION
■Chemicals in the 12 volt battery
A 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 seri-
ous injury, take the following precautions while working on or near 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 there is not sufficient ventilation.
■How to recharge the 12 volt battery
Only perform a slow charge (5A or less). The 12 volt battery may explode if
charged at a quicker rate.

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4-3. Do-it-yourself maintenance
4
Maintenance and care
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
CAUTION
■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. Get emergency medical attention imme-
diately.
■When replacing the 12-volt battery
Use a 12-volt battery designed for this vehicle. Failure to do so may cause gas
(hydrogen) to enter the passenger compartment, causing a fire or explosion.
For replacement of the 12-volt battery, contact your Lexus dealer.
NOTICE
■When recharging the 12 volt battery
Never recharge the 12 volt battery while the hybrid system is on. Also, be sure all
accessories are turned off.

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4-3. Do-it-yourself maintenance
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
Electronic key battery
Replace the battery with a new one if it is discharged.
■You will need the following items:
●Flathead screwdriver
●Small Phillips-head screwdriver
●Lithium battery (CR1632)
■Replacing 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