Page 558 of 784
558
ES350_300h_OM_OM33B99U_(U)
7-3. Do-it-yourself maintenance
■Adding distilled waterRemove the vent plug.
Add distilled water.
If the “UPPER LEVEL” line cannot
be seen, check the fluid level by
looking directly at the cell.
Put the vent plug back on and close it securely.
■Before recharging
When recharging, the 12-volt battery prod uces hydrogen gas which is flammable
and explosive. Therefore, observe the following 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 charger is off when connecting and discon-
necting the charger cables to the 12-volt battery.
1
Low O.K.2
3
Page 559 of 784

ES350_300h_OM_OM33B99U_(U)
5597-3. Do-it-yourself maintenance
7
Maintenance and care
■After recharging/reconnecting the 12-volt battery
The engine 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 engine.
●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 me chanical key to lock/unlock the doors.
●Start the engine with the “START STOP ENGINE” switch in ACCESSORY mode.
The engine may not start with the “START STOP ENGINE” switch turned off. How-
ever, the engine will operate normally from the second attempt.
●The “START STOP ENGINE” switch mode is recorded by the vehicle. If the 12-volt
battery is reconnected, the vehicle will return the “START STOP ENGINE” switch
mode to the status it was in before the 12-volt battery was disconnected. Make sure
to turn off the engine before disconnect the 12-volt battery. Take extra care when
connecting the 12-volt battery if the “START STOP ENGINE” switch mode prior to
discharge is unknown.
If the engine will not start even after mu ltiple attempts, contact your Lexus dealer.
CAUTION
■Chemicals in the 12-volt battery
Batteries contain 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 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.
1
2
3
Page 560 of 784

560
ES350_300h_OM_OM33B99U_(U)
7-3. Do-it-yourself maintenance
CAUTION
■Where to safely charge the 12-volt battery
Always charge the 12-volt battery in an open area. Do not charge the 12-volt bat-
tery in a garage or closed room where there 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 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 burning, get medical atten-
tion 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.
NOTICE
■When recharging the 12-volt battery
Never recharge the 12-volt battery while th e engine is running. Also, be sure all
accessories are turned off.
■When adding distilled water
Avoid overfilling. Water spilled during 12-volt battery recharging may cause corro-
sion.
Page 563 of 784

ES350_300h_OM_OM33B99U_(U)
5637-3. Do-it-yourself maintenance
7
Maintenance and care
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
■Before recharging
When recharging, the 12-volt battery prod uces 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 charger is off when connecting and discon-
necting 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 me chanical key to lock/unlock the doors.
●Start the hybrid system with the “POWER” switch in ACCESSORY mode. The
hybrid system 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 recon-
nected, the vehicle will return the “POWER” switch mode to the status it was in
before the 12-volt battery was disconnect ed. Make sure to turn off the “POWER”
switch 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 mult iple attempts at all methods above, contact
your Lexus dealer.
Exterior
1
2
1
2
3
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ES350_300h_OM_OM33B99U_(U)
5657-3. Do-it-yourself maintenance
7
Maintenance and care
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 burning, get medical atten-
tion 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 ve hicle. 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 th e hybrid system is operating. Also, be
sure all accessories are turned off.
Page 590 of 784
590
ES350_300h_OM_OM33B99U_(U)
7-3. Do-it-yourself maintenance
FuseAmpereCircuit
1WIP-S5Driver support system, windshield wipers
2FA N50Electric cooling fan
3H-LP CLN30No circuit
4ENG W/PMP*130Cooling system
5PTC HTR NO.250PTC heater
6PTC HTR NO.150PTC heater
7HTR50Air conditioning system
8ALT*2140Charging system
DC/DC*1120Hybrid system
9ABS NO.2*230VSC, ABS
10ST/AM2*230Starting system
ABS NO.1*130VSC, ABS
11H-LP-MAIN30H-LP RH-LO, H-LP LH-LO
12ABS MTR NO.2*150VSC, ABS
13ABS NO.1*250VSC, ABS
ABS MTR NO.1*150VSC, ABS
14R/B NO.2*150IGCT MAIN, INV W/PMP
15EPS80Electric power steering
16S-HORN7. 5S-HORN
17DEICER15Windshield wiper de-icer
18HORN10Horn
19TV15
Multi-information display, audio display,
Remote Touch, audio system, gauges and
meters
20AMP NO.230Audio system
21EFI NO.215
Multiport fuel injection system, sequential
multiport fuel system, electronic controlled
transmission
Page 591 of 784

ES350_300h_OM_OM33B99U_(U)
5917-3. Do-it-yourself maintenance
7
Maintenance and care
22EFI NO.3
10*2Multiport fuel injection system, sequential
multiport fuel system, air intake system,
exhaust system
7. 5*1Multiport fuel injection system, sequential
multiport fuel system, air intake system
23INJ7. 5Multiport fuel injection system, sequential
multiport fuel system
24ECU-IG2 NO.37. 5
Multiport fuel injection system, sequential
multiport fuel system, electronic controlled
transmission, power management system,
steering lock system, cruise control system
25IGN15Starting system
26D/L-AM225Power door lock system
27IG2-MAIN25INJ, IGN
28ALT-S*27. 5Charging system
DC/DC-S*17. 5Hybrid system
29MAYDAY5MAYDAY
30TURN&HAZ15Turn signal lights, emergency flashers
31STRG LOCK10Steering lock system
32AMP30Audio system
33H-LP LH-LO15Left-hand headlight
34H-LP RH-LO15Right-hand headlight
35EFI-MAIN NO.130EFI NO.2, EFI NO.3, fuel system
36SMART5Smart access system with push-button start,
occupant classification system
37ETCS10Multiport fuel injection system, sequential
multiport fuel system
38ABS NO.2*17. 5VSC, ABS
39EFI NO.17. 5
Multiport fuel injection system, sequential
multiport fuel system, electronic controlled
transmission
FuseAmpereCircuit
Page 594 of 784

594
ES350_300h_OM_OM33B99U_(U)
7-3. Do-it-yourself maintenance
■Driver’s side instrument panel
FuseAmpereCircuit
1ECU-IG1 NO.210
Main body ECU, audio system, shift lock sys-
tem, outside mirror control ECU, tension
reducer, windshield wipers, heated steering
wheel, multi-information display, audio dis-
play, intuitive parking assist, tire pressure
warning system, moon roof, auto anti-glare
inside rear view mirror, raindrop sensor, rear
sunshade, wireless door lock system, power
trunk opener and closer ECU
2ECU-IG1 NO.110
Electric cooling fan, windshield wiper de-
icer, VSC, ABS, charging system, steering
sensor, electronic controlled transmission,
electric power steering, gateway ECU, elec-
tric tilt and telescopic steering column
3PA N E L N O. 25Clock
4TA I L15Parking lights, side marker lights, license
plate lights
5DOOR F/R20Power window, outside mirror control ECU
6DOOR R/R20Po w e r w i n d o w
7DOOR F/L20Power window, outside mirror control ECU
8DOOR R/L20Po w e r w i n d o w
9H-LP LVL7. 5Automatic headlight leveling system
10WA S H E R10Windshield washer
11A/C-IG17. 5Air conditioning system, PTC heater, gauges
and meters, seat heaters and ventilators