engine Lexus GS450h 2008 Do-it-yourself maintenance / LEXUS 2008 GS450H (OM30A96U) Service Manual

488
5-1. Essential information
GS_HV_U
December 12, 2007 3:50 pm
If you think something is wrong
If you notice any of the following symptoms, your vehicle probably needs
adjustment or repair. Contact your Lexus dealer as soon as possible.
■ Visible symptoms
●Fluid leaks under the vehicle 
(Water dripping from the air conditioning after use is normal.)
● Flat-looking tires or uneven tire wear
● Engine coolant temper ature gauge needle continually points
higher than normal
■ Audible symptoms
●Changes in exhaust sound
● Excessive tire squeal when cornering
● Strange noises related to the suspension system
● Pinging or other noises related to the hybrid system
■ Operational symptoms
●Engine missing, stumbling or running rough
● Appreciable loss of power
● Vehicle pulls heavily to one side when braking
● Vehicle pulls heavily to one side when driving on a level road
● Loss of brake effectiveness, sp ongy feeling, pedal almost touches
the floor

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When trouble arises
489
5-1. Essential information
GS_HV_U
December 12, 2007 3:50 pm
Event data recorder
In a crash or a near car crash eventThe SRS airbag sensor ass embly contains the EDR. In a crash or a near
car crash event, this devic e may record some or all of the following infor-
mation:
● Gasoline engine speed
● Whether the brake pedal was applied or not
● Vehicle speed
● To what extent the accelerator pedal was depressed
● Position of the transmission shift lever
● Whether the driver and front passenger wore seat belts or not
● Driver’s seat position
● SRS airbag deployment data
● SRS airbag system diagnostic data
● Front passenger’s occupant classification
Your vehicle has computers that monitor and control certain aspects of
your vehicle. These computers assist in driving and maintaining optimal
vehicle performance.
Besides storing data useful for troublesh ooting, there is a system to record
data in a crash or a near car crash event. This is called an Event Data
Recorder (EDR).

492
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
Have the vehicle inspected immediately.Failing to investigate the cause of the following warnings may lead to the
system operating abnormally and possibly cause an accident. Have the
vehicle inspected by your Lexus dealer immediately.
*2: Electronically Controlled Brake System
Warning lightWarning light/Details
(U.S.A.)

(Canada)
Malfunction indicator lamp
Malfunction in:
• The electronic engine control system;
• The hybrid system;
• The electronic throttle control system; or
• The transmission control system.
SRS warning lightMalfunction in:
• The SRS airbag system;
• The front passenger occupant classification system; or
• The seat belt pretensioner system.
(U.S.A.)

(Canada)
ABS warning lightMalfunction in:
•The ABS; or
• The brake assist system.
ECB*2/VSC warning light
Malfunction in:
• The electronically controlled brake system; or
• The VSC.
Electric power steering system warning light Malfunction in the EPS.
“PCS” warning light (if equipped)Malfunction in the pre-collision system.

500
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
If a warning message is displayed
Stop the vehicle immediately.A buzzer sounds and a warning message is shown on the multi-informa-
tion display. The following warnings indicate the possibility of damage to
the vehicle that may lead to an acci dent. Immediately stop the vehicle in a
safe place and contact your Lexus dealer.
Wa r n i n g m e s s a g eDetails
(Flashing)
Abnormal engine oil pressure.
The warning light may turn on if the engine oil pres-
sure is too low.
Malfunction in the hybrid system.
If a warning is shown on the multi-information display, stay calm and per-
form the following actions:
Multi-information display
Master warning light
The master warning light also
comes on or flashes in order to
indicate that a message is cur-
rently being displayed on the
multi-information display.
If any of the warning li ght turns on again after pe rforming the following
actions, contact your Lexus dealer.

5
When trouble arises
507
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
Wa r n i n g m e s s a g eDetailsCorrection procedure
The engine oil level is low.Check the engine oil level,
and add if necessary.

Low tire inflation pres-
sure.Check the tire inflation
pressure, and adjust to the
appropriate level.
(U.S.A. only)
The engine oil should be
changed.
Check and change the
engine oil.
Comes on approximately
5000 miles (8000 km)
after the engine oil is
changed (and the oil
maintenance data has
been reset).

510
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
Wa r n i n g m e s s a g eDetailsCorrection procedure
(Flashing)
The gasoline engine can-
not operate or the shift
lever is in “N” for a long
time.
Stop the vehicle and shift
the shift lever to “P”.
(Flashing)
The transmission is out of
“P” when attempting to
start the hybrid system.Shift the shift lever to “P”
before pressing the power
switch.
(Flashing)
The driver’s door is
opened when the trans-
mission is out of “P” with
the hybrid system on.
Shift the shift lever to “P”.
■After changing the engine oil (U.S.A. only)
Make sure to reset the oil maintenance data. (P. 4 2 5 )
■Approach warning message
In the following instances, there is the poss ibility that the approach warning will not
activate even when the vehicle-to-vehicle distance decreases.
●When your vehicle and the vehicle ahead are traveling at the same speed or the
vehicle ahead is traveling more quickly than your vehicle.
●When the vehicle ahead is traveling at very low speed.
●Immediately after cruise control speed is set.
●At the instant the accelerator pedal is depressed.

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When trouble arises
535
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
Positive (+) battery terminal on your vehicle.
Positive (+) battery terminal on the second vehicle.
Negative (-) battery terminal on the second vehicle.
Negative (-) battery terminal on your vehicle.
Start the engine of the second vehicle. Increase the engine
speed slightly and maintain at that level for approximately 5
minutes to recharge the 12 volt battery of your vehicle.
Open and close any of the door s with the “POWER” switch is
OFF.
Maintain the engine speed on th e second vehicle and turn the
“POWER” switch to the ON mo de, then start the vehicle’s
hybrid system.
Make sure the “READY” light co mes on. If the light does not
come on, contact your Lexus dealer.
Once the vehicle’s hybrid system has started, remove the
jumper cables in the exact reverse order in which they were
connected.
Once the hybrid system starts, have the vehicle checked at your Lexus
dealer as soon as possible.
STEP3
STEP4
STEP5
STEP6
STEP7

538
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
If your vehicle overheats
If your hybrid system overheats:
Stop the vehicle in a safe place and turn off the air conditioning
system.
Check to see if steam is coming out from under the hood.
If you see steam: 
Stop the hybrid system and carefully lift the hood.
If you do not see steam: Leave the hybrid system running and carefully lift the hood.
Remove the engine compartment cover. ( P. 421)
Check to see if the cooling fan is operating.
If the fan is operating: 
Wait until the engine coolant temperature gauge begins to
fall and then stop the hybrid system.
If the fan is not operating: 
Stop the hybrid system immed iately and call your local
Lexus dealer.
After the hybrid system has
cooled down sufficiently, check
the coolant level and inspect the
radiator core (radiator) for any
leaks.STEP1
STEP2
STEP3
STEP4
STEP5

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When trouble arises
539
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
■Overheating
In the following situations, your vehicle may be overheating.
●The engine coolant temperature gauge enters the red zone or a loss of power is
experienced.
●Steam is coming from under the hood.
●The message “HYBRID SYSTEM OVERHEAT” is displayed on the multi-infor-
mation display.
CAUTION
■To prevent an accident or injury when in specting under the hood of your vehicle
●Keep hands and clothing away from the fan and engine drive belt while the hybrid
system is running.
●Do not loosen the radiator cap while the hybrid system and radiator are hot. 
Serious injury, such as burns, may resu lt from hot coolant and steam released
under pressure.
Add coolant if necessary.
Water can be used in an emer-
gency measure if coolant is
unavailable. ( P. 5 4 8 )
Have the vehicle checked at your nearest Lexus dealer as soon as pos-
sible.
STEP6

545
6-1. Specifications
6
Vehicle specifications
GS_HV_U
December 12, 2007 3:50 pm
Vehicle identificationThe vehicle identification number (VIN ) is the legal identifier for your
vehicle. This is the primary identification number for your Lexus. It is used
in registering the ownership of your vehicle.
This number is stamped on the top left of the instrument panel and in the
engine compartment.
This number is also on the Certifi-
cation Label.
■ The engine number and electric motor (traction motor) number
These numbers are stamped on the locations shown in the above illustration.