2008 Lexus GS450h ECU

466
4-3. Do-it-yourself maintenance
GS_HV_U
December 27, 2007 1:38 pm
■Right side instrument panel
FuseAmpereCircuit
1ECU-IG RH10
Electric tilt and telescopic steering,
combination switch, power seat,
smart access system with push-but-
ton start, air conditioning system,
touch screen, shift lock system, tire
pressure warning system, front/rear
stabilizer system
2FR S/HTR RH15Seat heaters, seat heaters and venti-
lators
3RH-IG7. 5
Front right door control system, rear
right door control system, seat belt
pretensioners, transmission, seat
heaters, seat heaters and ventilators
4AM27. 5Starting system
5FR DOOR RH20Front right door control system
6RR DOOR RH20Rear right door control system

467
4-3. Do-it-yourself maintenance
4
Maintenance and care
GS_HV_U
December 27, 2007 1:38 pm
FuseAmpereCircuit
7AIR SUS20AV S
8PWR OUTLET15Po w e r o u t l e t
9CIG15Cigarette lighter
10ACC7. 5
Audio system, smart access system
with push-button start, touch screen,
rear view monitor system, Lexus Link
System ECU
11IGN10
Smart access system with push-but-
ton start, SRS airbag system, stop-
lights, hybrid system, steering lock
system, electronically controlled
brake system, Lexus Link System
ECU, front passenger occupant clas-
sification system ECU
12GAUGE7. 5Gauges and meters
13STR LOCK25Steering lock system
14SECURITY7. 5Smart access system with push-but-
ton start
15TI & TE20Electric tilt and telescopic steering
16AM17. 5
17STOP SW7. 5Stoplights, shift lock system
18OBD7. 5On-board diagnosis system
19FR P/SEAT RH30Po w e r s e a t

479
4-3. Do-it-yourself maintenance
4
Maintenance and care
GS_HV_U
December 27, 2007 1:38 pm
■High-intensity discharge (HID) headlights
If voltage to the high-intensity discharge bulbs is insufficient, the light may not come
on, or may go out temporarily. The high-i ntensity discharge bulbs will come on
when normal power is restored.
CAUTION
■Replacing light bulbs
●Turn off the headlights. Do not attempt to replace the bulb immediately after turn-
ing off the headlights. 
The bulbs become very hot and may cause burns.
●Do not touch the glass portion of the light bulb with bare hands. Hold the bulb by
the plastic or metal portion. 
If the bulb is scratched or dropped it may blow out or crack.
●Fully install light bulbs and any parts used to secure them. Failing to do so may
result in heat damage, fire, or water ente ring the headlight unit. This may damage
the headlights or cause condensation to build up on the lens.
●Do not attempt to take apart or repair the low beam discharge headlight bulbs,
connectors, power supply circuits, or related components. 
Doing so could result in electric shock and death or serious injury.
■High-intensity discharge (HID) headlights
●Contact your Lexus dealer before replac ing high-intensity discharge headlights
(including light bulbs).
●Do not touch the high-intensity discharge headlight’s high voltage socket when
the headlights are turned on. 
An extremely high voltage of 20000 V wi ll be discharged and could result in
death or serious injury by electric shock.
■To prevent damage or fire
Make sure bulbs are fully seated and locked.

482
GS_HV_U
December 12, 2007 3:50 pm
5-1. Essential information
If your vehicle needs to be towed
Before towingThe following may indicate a problem with your transmission. Contact
your Lexus dealer before towing.
● The hybrid system is running, but the vehicle will not move.
● The vehicle makes an abnormal sound.
Emergency towing
If a tow truck is not available, in an emergency your vehicle may be tem-
porarily towed using a cable or ch ain secured to the emergency towing
eyelet. This should only attempted on hard, surfaced roads for short dis-
tances below 18 mph (30 km/h). 
A driver must be in the vehicle to s teer and operate the brakes. The vehi-
cle’s wheels, drive train, axles, steering and brakes must be in good condi-
tion.
If towing is necessary, we recommen d having your vehicle towed by your
Lexus dealer or a commercial towing service, using a lift-type truck or a flat
bed truck. 
Use a safety chain system for all towing , and abide by all state/provincial
and local laws.
If towing from the rear, the wheels and axle on the ground must be in good
condition.
If they are damaged, use a to wing dolly or flat bed truck.

484
5-1. Essential information
GS_HV_U
December 12, 2007 3:50 pm
Installing towing eyeletRemove the eyelet cover using a
flathead screwdriver.
To protect the bodywork, place a
rag between the screwdriver and
the vehicle body, as shown in the
illustration.
Insert the towing eyelet into the
hole and tighten partially by hand.
Tighten down the towing eyelet
securely using a wheel nut wrench.
STEP1
STEP2
STEP3
■Location of the emergency towing eyelet
P. 5 1 7

5
When trouble arises
485
5-1. Essential information
GS_HV_U
December 12, 2007 3:50 pm
Towing with a sling-type truck
CAUTION
■Installing towing eyelet to the vehicle
Make sure that towing eyelet is installed securely.
If not securely installed, towing eyelet ma y come loose during towing. This may lead
to accidents that cause serious injury or even death.
NOTICE
■To prevent body damage
Do not tow with a sling-type truck, either from the front or rear.

494
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
*3: Open door warning buzzer:
P. 5 0 5
*
4: Driver’s and front passenger’s seat belt reminder buzzer:
The driver’s and front passenger’s seat belts reminder sounds to alert the driver
and front passenger that his or her seat belt is not fastened. The buzzer sounds
intermittently for 10 seconds after the vehicle has reached a speed of at least 12
mph (20 km/h). Then, if the seat belt is still unfastened, the buzzer will sound in
a different tone for 20 more seconds.
Warning lightWarning light/DetailsCorrection procedure
Master warning light
A buzzer sounds and the
warning light comes on and
flashes to indicate that the
master warning system has
detected a malfunction.
Take appropriate action in
accordance with the message
displayed on the multi-infor-
mation display.
■If the malfunction indicator lamp comes on while driving
First check the following:
●Is your vehicle low on gas? 
If it is, refuel the vehicle immediately.
●Is the fuel tank cap loose? 
If it is, tighten it securely.
The light will go off after taking several driving trips. 
If the light does not go off even after several trips, contact your Lexus dealer as soon
as possible.

5
When trouble arises
495
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
■Front passenger detection sensor and passenger seat belt reminder
●If luggage is placed on the front passenger seat, the front passenger detection
sensor may cause the warning light to flash, even if a passenger is not sitting in
the seat.
●If a cushion is placed on the seat, the sensor may not detect a passenger, and the
warning light may not operate properly.
■SRS warning light
This warning light system monitors the following:
●The airbag sensor assembly
●Front airbag sensors
●The curtain shield and rear side airbag sensors
●The side and curtain shield airbag sensors
●The front passenger occupant classification ECU
●“AIR BAG ON” and “AIR BAG OFF” indicator lights
●The pressure sensor
●The belt tension sensor
●The seat belt buckle switches
●The driver’s seat position sensor
●The inflators
●The warning light
●The interconnecting wiring and power sources
■If the tire pressure warning light comes on after blinking for 1 minute frequently
If the tire pressure warning light comes on after blinking for 1 minute frequently
when the “POWER” switch is turned to ON mode, have it checked by your Lexus
dealer.