2013 Lexus GS450h cooling

637
GS450h_U (OM30D01U)6-3. Do-it-yourself maintenance
6
Maintenance and care
Engine compartment
■12-volt battery
 P. 6 4 7
Engine oil level dipstick
(P. 6 3 9 )
Engine coolant reservoir (P. 6 4 2 )
Engine oil filler cap (P. 640)
Power control unit coolant res-
ervoir ( P. 6 4 2 )Brake fluid reservoir
(P. 645)
Fuse box ( P. 670)
Washer fluid tank ( P. 646)
Electric cooling fans
Condenser ( P. 644)
Radiator ( P. 644)1
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3
4
5
6
7
8
9
10

GS450h_U (OM30D01U)
6436-3. Do-it-yourself maintenance
6
Maintenance and care
■Coolant selection
Only use “Toyota Super Long Life Coolant” 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.
U.S.A.:
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deionized
water. (Minimum temperature: -31 F [-35C])
Canada:
“Toyota Super Long Life Coolant” is a mixture of 55% coolant and 45% deionized
water. (Minimum temperature: -44 F [-42C])
For more details about coolant, contact your Lexus dealer.
■If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit coolant reservoir caps,
drain cock and water pump.
If you cannot find a leak, have your Lexus dealer test the cap and check for leaks in
the cooling system.
CAUTION
■When the hybrid system is hot
Do not remove the engine/power control un it coolant reservoir caps or the radia-
tor cap.( P. 777)
The cooling system may be under pressure and may spray hot coolant if the cap is
removed, causing serious injuries, such as burns.
NOTICE
■When adding coolant
Coolant is neither plain water nor straight antifreeze. The correct mixture of water
and antifreeze must be used to provide proper lubrication, corrosion protection
and cooling. Be sure to read the antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.

676
GS450h_U (OM30D01U)
6-3. Do-it-yourself maintenance
34DOME7. 5
Personal lights, ornament lights, trunk light,
footwell lights, door courtesy lights, vanity
lights, rear door inside handle illuminations,
power trunk opener and closer
35MPX-B10
Body ECU, smart access system with push-
button start, electric tilt and telescopic steer-
ing column, power seats, head-up display,
front door ECU, gauges and meters, steer-
ing sensor, yaw rate and G sensor, overhead
module, RR CTRL SW, power trunk opener
and closer, clock, CAN gateway ECU
36IGCT NO.410Po w e r c o n t r o l u n i t
37IGCT NO.37. 5Hybrid battery (traction battery), DC/DC
converter
38IGCT NO.25Hybrid system
39IG2 NO.15DCM, CAN gateway ECU
40GAUGE5Gauges and meters
41DC/DC150RH-J/B DC/DC, P/I DC/DC
42P/ I D C / D C100RR S/SHADE, DEFOG, FOG, TAIL,
PA N E L
43RH J/B DC/DC80Right-hand junction block
44LH J/B DC/DC50Left-hand junction block
45H-LP CLN30Headlight cleaner
46FAN NO.240Electric cooling fans
47LUG J/B DC/DC80Luggage compartment junction block
48FAN NO.180Electric cooling fans
49PTC NO.150PTC heater
50PTC NO.250PTC heater
51HTR50Air conditioning system
FuseAmpereCircuit

682
GS450h_U (OM30D01U)
6-3. Do-it-yourself maintenance
■Trunk
FuseAmpereCircuit
1PSB30Pre-collision seat belts
2PTL25Power trunk opener and closer
3RR J/B-B10Smart access system with push-button start
4RR S/HTR20Seat heaters (rear)
5FR S/HTR10Seat heaters/ventilators (front)
6RR FOG10No circuit
7DC/DC-S (HV)7. 5DC/DC converter
8BATT FAN (HV)20Hybrid battery (traction battery) cooling fan
system
9SECURITY7. 5SECURITY
10ECU-B NO.37. 5Parking brake
11TRK OPN7. 5Power trunk opener and closer
12DCM (HV)7. 5DCM
13AC INV (HV )20Po w e r o u t l e t ( 1 2 0 V AC )
14RR-IG15Radar sensor, Blind Spot Monitor
15RR ECU-IG10
Power trunk opener and closer, parking
brake, tension reducer (rear left-hand), RR
CTRL SW, tire pressure warning system
16EPS-IG5Electric power steering system
17BACK UP7. 5Back-up lights

774
GS450h_U (OM30D01U)
7-2. Steps to take in an emergency
If your vehicle overheats
●The needle of the engine coolant temperature gauge enters the red
zone:
The engine may be overheating.
●“Hybrid System Overheat” is shown on the multi-information display:
The power control unit may be overheating.
■If the needle of the engine coolant temperature gauge enters the red
zone
Stop the vehicle in a safe place an d turn off the air conditioning sys-
tem.
Check to see if steam is coming out from the engine area.
If you see steam:
Stop the hybrid system. Carefull y lift the hood after the steam sub-
sides and then restart the hybrid system.
If you do not see steam:
Leave the hybrid system operating and carefully lift the hood.
Check to see if the cooling fans are operating.
If the fans are operating:
Wait until the engine coolant temperature ga uge begins to fall and
then stop the hybrid system.
If the fans are not operating:
Stop the hybrid system immediately and call your Lexus dealer.
The following may indicate that your vehicle is overheating:
Correction procedures
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2
3

7757-2. Steps to take in an emergency
GS450h_U (OM30D01U)
7
When trouble arises
After the hybrid system has
cooled down sufficiently,
check the engine coolant level
and inspect the cooling sys-
tem for leaks.
If the engine compartment cover
needs to be removed: P. 6 3 8
Add engine coolant if neces-
sary.
Water can be used in an emer-
gency if engine coolant is unavail-
able. ( P. 7 8 7 )
Have the vehicle inspected at the nearest Lexus dealer as soon as pos-
sible.
■If “Hybrid System Overheat” is shown on the multi-information dis-
play
Stop the vehicle in a safe place an d turn off the air conditioning sys-
tem.
Leave the hybrid system operating and carefully lift the hood.
Check if the cooling fans are operating.
If the fans are operating:
Wait until the “Hybrid System Overheat” message disappears and
then stop the hybrid system.
If the message does not disapp ear, call your Lexus dealer.
If the fans are not operating:
Stop the hybrid system immediately and call your Lexus dealer.
4
5
1
2
3

7767-2. Steps to take in an emergency
GS450h_U (OM30D01U)After the hybrid system has
cooled down, check the power
control unit coolant level and
inspect the cooling system for
leaks.
If the engine compartment cover
needs to be removed:
P. 6 3 8
Add power control unit cool-
ant if necessary.
Water can be used in an emer-
gency if power control unit coolant
is unavailable. ( P. 7 8 7 )
Have the vehicle inspected at the nearest Lexus dealer as soon as pos-
sible.
■Overheating
If you observe the following, your vehicle may be overheating:
●The engine coolant temperature gauge enters the red zone or a loss of power is
experienced.
●“Hybrid System Overheat” is shown on the multi-information display.
●Steam comes out from under the hood.
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5

7777-2. Steps to take in an emergency
GS450h_U (OM30D01U)
7
When trouble arises
CAUTION
■When inspecting under the hood of your vehicle
Observe the following precautions.
Failure to do so may result in serious injury such as burns.
●If steam is seen coming from under the hood, do not open the hood until the
steam has subsided. The engine compartment may be very hot.
●Keep hands and clothing away from the fans , etc. while the hybrid system is oper-
ating.
●For vehicles with a hybrid system, there are times when the gasoline engine auto-
matically starts to run or the cooling fans suddenly start to operate. Do not touch
or approach the rotating parts of the belt or fans. Doing so may lead to fingers,
clothes or tools getting caught, resulting in injury.
NOTICE
■When adding engine/power control unit coolant
Add coolant slowly after the hybrid syst em has cooled down sufficiently. Adding
cool coolant to a hot hybrid system too quickly can cause da mage to the hybrid
system.
■To prevent damage to the cooling system
Observe the following precautions:
●Avoid contaminating the coolant with foreign matter (such as sand or dust etc.).
●Do not use commercially available coolant additives.
●Do not loosen the radiator cap or the cool-
ant reservoir caps while the hybrid system
and radiator are hot.
High temperature steam or coolant could
spray out.