traction control Lexus GX470 2003 Basic Functions / LEXUS 2003 GX470 (OM60A45U) User Guide

STARTING AND DRIVING
327
If the indicator light does not come on when the switch is
pushed, contact your Lexus dealer.

Slip indicator light
With the vehicle traveling at a speed of 25 km/h (15 mph) or
less, release your foot from the accelerator or brake pedal to
activate the system. The vehicle will descend the hill at a low
speed. While the system is operating, the slip indicator light on
the instrument panel will flash and the stop lights and high
mounted stoplight will be lit.
If you push the “DAC” switch to turn the system off while it is
in operation, the system will stop operating gradually. The
downhill assist control system indicator light will flash to alert
the driver. To continue driving at a low speed, push the “DAC”
switch to turn the system on.
The slip indicator light and downhill assist control system
indicator light come on for a few seconds when the ignition key
is turned to “ON”. If any of the indicator lights does not come
on when the ignition is turned on, contact your Lexus dealer. If the system is used frequently, the brake actuator
temperature
may become too high and a buzzer will sound
intermittently.
If this happens, the downhill assist control system indicator
light will flash and a buzzer will sound intermittently. When the
temperature of the brake actuator goes down, the system will
begin to operate again. Until it restarts, the active traction
control system and hill−start assist control system will not
operate; however, the conventional brake can be operated.

STARTING AND DRIVING
328
“VSC TRAC” warning light
If there is any abnormality in the system, the “VSC TRAC”
warning light will come on. When the “DAC” switch is
pushed, the downhill assist control system indicator light
also flash.
If the “VSC TRAC” warning light comes on, there may be an
abnormality in any of the following systems in addition to the
downhill assist control system.
Hill− start assist control system
 Active traction control system
 Vehicle skid control system
When the system is normal and the ignition key is turned to
“ON”, the warning light will come on and will go off after a few
seconds. It is not a malfunction that the warning light may stay
on for 60 seconds after the ignition key is turned to the “ON”
position. Depressing the brake pedal repeatedly may turn on the light.
It is normal if it goes out after a few seconds.
The brake actuator temperature increases during continuous
operation of
the above mentioned system on such as slippery
roads. If the brake actuator temperature becomes too high
while any of the systems is operating, a buzzer will start to
sound intermittently to indicate that the downhill assist control
system can no longer operate. In this case, stop your vehicle
immediately at a safe place.
If the system continues to operate, the buzzer sound changes
from intermittent to continuous. (The continuous buzzer
sounds for about 3 seconds.) At this time, the “VSC TRAC”
warning light will come on and the downhill assist control
system stops operating temporarily in order to protect the
brake actuator. (Although the downhill assist control system
does not operate, it is no problem to continue your driving.) The
system will be automatically restored after a short time and the
“VSC TRAC” warning light goes out.
If the warning light comes on while driving, the system does not
work. However, as normal braking operates when being
applied, it is no problem to continue your driving.
In the following cases, contact your Lexus dealer:
 The warning light does not come on after the ignition key is
turned to “ON”.
 The warning light remains on after the ignition key is turned
to “ON”.
 The warning light comes on while driving.

STARTING AND DRIVING
330The slip indicator light comes on for a few seconds when the
ignition key is turned to “ON”. If the indicator light does not
come on when the ignition is turned on, contact your Lexus
dealer.
Keep in mind the following when driving.

The hill −start assist control system operates for 5 seconds
maximally. If both the brake and accelerator pedals remain
undepressed for longer than 5 seconds, the buzzer will
sound at more frequent intervals and the system will
gradually stop operating.
 The hill −start assist control system is not designed as a
function for stopping the vehicle on a uphill slope. When
stopping the vehicle, be sure to depress the brake pedal.
If the system is used frequently, the brake actuator
temperature may become too high and a buzzer will sound
intermittently.
In this case, a buzzer will sound intermittently. When the
temperature of the brake actuator goes down, the system will
begin to operate again. Until it restarts, the active traction
control system and downhill assist control system will not
operate; however, the conventional brake can be operated.
“VSC TRAC” warning light
If there is any abnormality in the system, the “VSC TRAC”
warning light will come on.
If the system malfunctions, the “VSC TRAC” warning light will
come on.
If the “VSC TRAC” warning light comes on, there may be an
abnormality in any of the following systems in addition to the
hill −start assist control system.
 Downhill assist control system
 Active traction control system
 Vehicle skid control system
When the system is normal and the ignition key is turned to
“ON”, the warning light will come on and will go off after a few
seconds. It is not a malfunction that the warning light may stay
on for 60 seconds after the ignition key is turned to the “ON”
position.

STARTING AND DRIVING
334“ABS” warning light
The light comes on when the ignition key is turned to the “ON”
position. If the anti−lock brake system and the brake assist
system work properly, the light turns off after a few seconds.
Thereafter, if either of the systems malfunctions, the light
comes on again.
When the “ABS” warning light is on (and the brake system
warning light is off), the anti
−lock brake system, the brake
assist system, the active traction control system and the
vehicle skid control system do/does not operate, but the brake
system still operates conventionally.
When the “ABS” warning light is on (and the brake system
warning light is off), the anti −lock brake system does not
operate so that the wheels could lock up during a sudden
braking or braking on slippery road surfaces. If either of the following conditions occurs, this indicates
a malfunction somewhere in the components monitored
by the warning light system. Contact your Lexus dealer as
soon as possible to service the vehicle.

The light does not come on when the ignition key is turned
to the “ON” position, or remains on.
 The light comes on while you are driving.
A warning light turning on briefly during operation does not
indicate a problem.
CAUTION
If the “ABS” warning light remains on together with the
brake system warning light, immediately stop your
vehicle at a safe place and contact your Lexus dealer.
In this case, not only the antilock brake system will fail
but also the vehicle will become extremely unstable
during braking.
Either of the following conditions may occur, but do not
indicate a malfunction:
 The light may stay on for about 60 seconds after the ignition
key is turned to the “ON” position. It is normal if it turns off
after a while.
 Depressing the brake pedal repeatedly may turn on the
light. It is normal if it turns off after a few seconds.

CHASSIS
435
If you have tire damage such as cuts, splits, cracks deep
enough to expose the fabric, or bulges indicating internal
damage, the tire should be replaced.
If a tire often goes flat or cannot be properly repaired due to the
size or location of a cut or other damage, it should be replaced.
If you are not sure, consult with your Lexus dealer.
If an air loss occurs while driving, do not continue driving with
a deflated tire. Driving even a short distance can damage a tire
beyond repair.
Any tires which are over 6 years old must be checked by
a qualified technician even if damage is not obvious.
Tires deteriorate with age even if they have never or seldom
been used.
This also applies to the spare tire and tires stored for future use.
Uniform tire quality grading
This information has been prepared in accordance with
regulations issued by the National Highway T
raffic Safety
Administration of the U.S. Department of Transportation.
It provides the purchasers and/or prospective purchasers
of Lexus vehicles with information on uniform tire quality
grading.
Your Lexus dealer will help answer any questions you may
have as you read this information.
DOT quality grades All passenger vehicle tires must
conform to Federal Safety Requirements in addition to
these grades. Quality grades can be found where
applicable on the tire sidewall between tread shoulder and
maximum section width. For example: Treadwear 200
Traction AA Temperature A
Treadwear − The treadwear grade is a comparative rating
based on the wear rate of the tire when tested under controlled
conditions on a specified government test course. For
example, a tire graded 150 would wear one and a half (1 − 1/2)
times as well on the government course as a tire graded 100.
The relative performance of tires depends upon the actual
conditions of their use, however, and may depart significantly
from the norm due to variations in driving habits, service
practices and differences in road characteristics and climate.
Traction AA, A, B, C − The traction grades, from highest to
lowest, are AA, A, B and C, and they represent the tire’s ability
to stop on wet pavement as measured under controlled
conditions on specified government test surfaces of asphalt
and concrete. A tire marked C may have poor traction
performance.

CHASSIS
436Warning: The traction grade assigned to this tire is based on
braking (straight ahead) traction tests and does not include
cornering (turning) traction.
Temperature A, B, C − The temperature grades are A (the
highest), B, and C, representing the tire’s resistance to the
generation of heat and its ability to dissipate heat when tested
under controlled conditions on a specified indoor laboratory
test
wheel. Sustained high temperature can cause the material
of the tire to degenerate and reduce tire life, and excessive
temperature can lead to sudden tire failure. The grade C
corresponds to a level of performance which all passenger car
tires must meet under the Federal Motor Vehicle Safety
Standard No. 109. Grades B and A represent higher levels of
performance on the laboratory test wheel than the minimum
required by law.
Warning: The temperature grades for this tire are established
for a tire that is properly inflated and not overloaded. Excessive
speed, underinflation, or excessive loading, either separately
or in combination, can cause heat buildup and possible tire
failure.
Tire selection
When replacing a tire, use a tire of the same size and
construction, and the same or greater load capacity as the
originally installed tires. Also, all the tires must be the
same brand and have the same tread patterns.
Using any other size or type of tire may seriously affect
handling, ride, speedometer/odometer calibration, ground
clearance, and clearance between the body and tires or snow
chains.
CAUTION
Observe the following instructions. Otherwise, an
accident may occur resulting in death or serious
injuries.
 Do not mix radial, bias belted, or biasply tires on
your vehicle, as this may cause dangerous handling
characteristics resulting in loss of control.
 Do not use tires other than the manufacturer’s
recommended size, as this may cause dangerous
handling characteristics resulting in loss of control.
 Do not use tires of different brands, sizes,
construction or tread patterns, as this may cause
dangerous handling characteristics result ing in loss
of control.

CHASSIS
437
INSTALLING SNOW TIRES ANDCHAINS
When to use snow tires or chains
Snow tires or chains are recommended when driving on
snow or ice.
On wet or dry roads, conventional or radial tires provide better
traction than snow or studded tires.
Snow tire selection
If you need snow tires, select tires of the same size,
construction and load capacity as the originally installed
tires. Also, all the tires must be the same brand and have
the same tread patterns.
Do not use tires other than stated above. Since your vehicle
has radial tires as original equipment, make sure your snow
tires also have radial construction. Do not install studded tires
without first checking local regulations for possible restrictions.
CAUTION
Observe the following instructions. Otherwise, an
accident may occur resulting in death or serious
injuries.
Do not use snow tires other than the manufacturer’s
recommended size, as this may cause dangerous
handling characteristics resulting in loss of control.
 Do not use snow tires of different brands, sizes,
construction or tread patterns, as this may cause
dangerous handling characteristics resulting in loss
of control.
Snow tire installation
Snow tires should be installed on all wheels.
Installing snow tires on the rear wheels only can lead to an
excessive difference in road grip capability between the front
and rear tires which could cause loss of vehicle control.
CAUTION
 Do not drive with the snow tires incorrectly inflated.
 Never drive over 105 km/h (65 mph) with any type of
snow tires.

ELECTRICAL COMPONENTS
445
No.FUSEAMPERECIRCUIT
13 MIR
HEATER10Outside rear view mirror defog-
ger
14 STOP10
Stop lights, high m ounted
stoplight, shift lock control
system, vehicle skid control
system, electronic m odulated
suspension, rear height control
air suspension, multiport fuel
injection system/sequential
multiport fuel injection system
15 AC115V
INV15Power outlet (115 VAC)
16 FR FOG15Front fog lights
17 OBD7.5On −board diagnosis system
18 HEAD
(LO RH)10Right− hand headlight (low beam)
19 HEAD
(LO LH)10Left− hand headlight (low beam)
20 HEAD
(HI RH)10Right− hand headlight (high
beam)
21 HEAD
(HI LH)10Left− hand headlight (high beam)
22 EFI NO.210Multiport fuel injection system/
sequential multiport fuel injection
system
23 HEATER
NO.27.5Air conditioning system
24 DEFOG30Rear window defogger
No.FUSEAMPERECIRCUIT
25 AIRSUSNO.210Rear height control air suspen-
sion
26 SEAT
HEATER20Seat heaters
27 DOME10
Ignition switch light, interior
lights, personal lights, foot
lights, running board lights,
door courtesy lights, inside
door handle lights,
multi− information display
28 RADIO
NO.120Car audio system, navigation
system
29 ECUB10
Multiplex communication
system, vehicle skid control
system, wireless remote
control system, inside rear
view mirror, air conditioning
system, electronic modulated
suspension, driving position
memory system, power
windows, moon roof
30 ECUB NO.210Theft deterrent system
31 ABS
MTR40
Anti −lock brake system,
vehicle skid control system,
active traction control system,
brake assist system
32 AM230Starting system, all components
in “IGN”, “SRS”, “GAUGE” and
“ST2” fuses

ELECTRICAL COMPONENTS
446
No.FUSEAMPERECIRCUIT
33 ABSSOL50
Anti −lock brake system,
vehicle skid control system,
active traction control system,
brake assist system
34 ALTS7.5Charging system
35 MAYDAY7.5Lexus link system
36 HORN10Horns
37 TRNHAZ15Turn signal lights
38 ETCS10Electronic throttle control system
39 EFI20Multiport fuel injection
system/sequential multiport fuel
injection system
40 D FR P/W20Power window
41 DR/LCK25Power door lock
42 TOWING30Towing converter
43 RADIO
NO.230Car audio system, navigation
system
44 IGN10
Multiport fuel injection
system/sequential multiport fuel
injection system, vehicle skid
control system
45 SRS10SRS airbag system
46 GAUGE7.5Gauges and meters
47 ST27.5Multiport fuel injection
system/sequential multiport fuel
injection system
No.FUSEAMPERECIRCUIT
48 FR
WIPWSH30Windshield wipers, windshield
washer
49 TEMS20Electronic modulated suspen-
sion
50 DIFF20Four−wheel drive system
51 RR WIP15Rear window wiper
52 D P/SEAT30Driver’s power seats
53 P P/SEAT30Front passenger’s power seats
54 PWR
OUTLET15Power outlet (12 VDC)
55 IG1 NO.210Rear air conditioning system, in-
side rear view mirror
56 RR WSH15Rear window washer
57 ECUIG10
Shift lock control system, power
windows, outside rear view
mirror defogger, anti −lock brake
system, active traction control
system, vehicle skid control
system, air conditioning system,
navigation system, power
windows, moon roof, Lexus link
system, tilt and telescopic
steering, multi −information
display, driving position
memory system
58 IG110
Air conditioning system, back −up
lights, rear window defogger,
seat heaters, vehicle skid control
system