2006 Lexus GS430 ABS

STARTING AND DRIVING
428
Antilock brake system
The antilock brake system is designed to automatically
help prevent lockup of the wheels during a sudden
braking or braking on slippery road surfaces. This assists
in providing directional stability and steering
performance of the vehicle under these circumstances.
Effective way to press the ABS brake pedal: When the
anti−lock brake system function is in action, you may feel the
brake pedal pulsating and hear a noise. In this situation, to
let the anti−lock brake system work for you, just hold the
brake pedal down more firmly. Do not pump the brake in a
panic stop. This will result in reduced braking performance.
The anti −lock brake system becomes operative after the
vehicle has accelerated to a speed in excess of approximately
10 km/h (6 mph). It stops operating when the vehicle
decelerates to a speed below approximately 5 km/h (3 mph).
Depressing the brake pedal on slippery road surfaces such as
on a manhole cover, a steel plate at a construction site, joints
in a bridge, etc. on a rainy day tends to activate the anti −lock
brake system.
You may hear a click or motor sound in the engine
compartment for a few seconds when the engine is started or
just after the vehicle begins to move. This means that the
anti−lock brake system is in the self− check mode, and does not
indicate a malfunction. When the antilock brake system is activated, the
following conditions may occur. They do not indicate a
malfunction of the system:

You may hear the anti− lock brake system operating and feel
the brake pedal pulsating and the vibrations of the vehicle
body and steering wheel. You may also hear the motor
sound in the engine compartment even after the vehicle is
stopped.
 At the end of the anti−lock brake system activation, the
brake pedal may move a little forward.

STARTING AND DRIVING
430“ABS” warning light
G31080
 1
U.S.A. 2Canada
GS430—The light comes on when the engine switch is
selected in “IG −ON” mode. If the anti −lock brake system and
the brake assist system work properly, the light turns off in a
few seconds after the engine is started.
GS300—The light comes on for a few seconds when the
engine switch is selected in “IG −ON” mode. It indicates the
anti− lock brake system and the brake assist system work
properly.
If either system malfunctions, the light comes on again.
When the “ABS” warning light is on, the anti− lock brake system
and the brake assist system do not operate, but the brake
system still operates conventionally. If either of the following conditions occur, 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 engine switch is selected
in “IG− ON” mode.
 The light remains on after the engine is started (GS430), or
remains on after the engine switch is selected in “IG −ON”
mode (GS300).
 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 (red), 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.
GS430 only—Either of the following conditions may
occur, but does not indicate a malfunction:
 The light may stay on for about 60 seconds after the engine
is started. 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.

STARTING AND DRIVING
431
Drumindisc type parking brake system
Your vehicle has a drum−in−disc type parking brake system.
This type of brake system needs bedding−down of the brake
shoes periodically or whenever the parking brake shoes
and/or drums are replaced.
Have your Lexus dealer perform the bedding −down.
Brake assist system
When you slam the brakes on, the brake assist system
judges as an emergency stop and provides more powerful
braking for a driver who cannot hold down the brake pedal
firmly.
When you slam the brakes on, more powerful braking will be
applied. At this time, you may hear a sound in the engine
compartment and feel the vibrations of the brake pedal. This
does not indicate a malfunction.
The brake assist system becomes operative after the vehicle
has accelerated to a speed in excess of approximately 10 km/h
(6 mph). It stops operating when the vehicle decelerates to a
speed below approximately 5 km/h (3 mph).
The brake assist system may not work for about 60 seconds
after the engine is started.
For an explanation of this system’s warning light, see “ABS”
warning light on page 78 or 430.
BRAKE PAD WEAR LIMIT
INDICATORS
G31006
The brake pad wear limit indicators on your disc brakes
give a warning noise when the brake pads are worn to the
extent that replacement is required.
If you hear a squealing or scraping noise while driving, have
the brake pads checked and replaced by your Lexus dealer as
soon as possible. Expensive rotor damage can result if the
pads are not replaced when needed.
GS430 front brake only—
The high brake performance is achieved by proper wear of
brake pads and discs. As a result, the brake discs may wear
earlier than the ones on the conventional brake system.
When brake pads are replaced, brake disc thickness is
required to be measured.
It is dangerous to continue driving when brake pads and discs
have exceeded the wear limit.

STARTING AND DRIVING
446
Adaptive variable suspension control (GS430
only)
When the precollision sensor detects an object or
vehicle with which your vehicle may collide, and
determines that a collision may be unavoidable, the
adaptive variable suspension adjusts the damping effect
on the shock absorbers and regulates the vehicle not to
pitch forward so much.
The adaptive variable suspension will operate in the following
conditions:
When the vehicle speed is about 5 km/h (3 mph) or over.
 When the approaching speed in regard to the object or the
vehicle exceeds about 30 km/h (18 mph).
Precollision system failure warning
G31079
Precollision system warning light
The light warns that there is a problem somewhere in the
precollision system.
The light comes on when the engine switch is selected in
“IG−ON” mode. If the system works properly, the light goes off
after a few seconds.
If the light does not come on when the engine switch is selected
in “IG−ON” mode, have your vehicle checked by your Lexus
dealer.
If the system has a problem, the pre− collision system warning
light comes on or blinks. At this time, the master warning light
comes on, a warning tone sounds, and either of the following
messages appears on the multi−information display.
 PCS DISABLED NOW
 CHECK PCS

ELECTRICAL COMPONENTS
568
No.FUSEAMPERECIRCUIT
28 ECUIG LH10
Vehicle stability control system,
Electronic control brake system,
Yaw rate and G sensor,
Steering sensor, Cruise control
system, Dynamic radar cruise
control system, Electronic
power steering system, Variable
gear ratio steering system,
Rear view monitor system,
Four−wheel drive system, Front
controller, Moon roof, Rain
sensor
29 FR S/HTR
LH15Seat heater, Heated and
ventilated seats
30 FR P/SEAT LH30Power seat system
31 A/C7.5Air conditioning system
32 TV7.5Audio system, Air conditioning
system, Rear view monitor
system
33 TRK OPN10Trunk lid opener
34 LHB10Theft deterrent system
35 S/ROOF25Moon roof
36 ECUB10
Variable gear ratio steering
system, Electronic power
steering system, Driver’s seat
switch module
37 ABS
MAIN310Electronic control brake system
No.FUSEAMPERECIRCUIT
38 TURNHAZ15Turn signal lights, Emergency
flashers
39 IG2 MAIN20“IG2”, “GAUGE” and “IGN”
40 RAD NO.230Audio system
41 D/C CUT20“DOME “ and “MPX− B”
42 RAD NO.130Audio system
43 MPXB10
Multiplex communication
system, Front controller, Door
control system (Power door
lock system, Door courtesy
lights, Power windows, Power
rear view mirror control system,
Outside rear view mirror
heaters), Power seat system,
Steering sensors, Electronic
control brake system, Power tilt
and telescopic steering system,
Gauges and meters,
Combination switch
44 DOME10
Foot lights, Vanity lights,
Gauges and meters, Steering
spot light, Steering switch
illumination, Rear personal
lights, Automatic transmission
selector lever spot light, Front
personal lights
45 ABS
MAIN210Electronic control brake system
46 ABS
MOTOR30Anti− lock brake system

ELECTRICAL COMPONENTS
569
No.FUSEAMPERECIRCUIT
47 ABS
MAIN110Capacitor
48 E/GB60“FR CTRL BATT”, “ETCS” and
“ALT−S”
49 ABS150Vehicle stability control system,
“ABS MAIN1”, “ABS MAIN2”
and “ABS MTR”
50 RH J/BB30“AM2”, “DOOR FR” and “DOOR
RR”
51 VGRS40Variable gear ratio steering
system
52 MAIN30“H− LP R LWR” and “H −LP L
LWR”
53 STARTER30Starting system
54 LH J/BB30“FL DOOR”, “RL DOOR” and
“RAD No.3”
55 P/IB60Multi− port fuel injection
system/sequential multiport fuel
injection system
56 EPS80Electronic power steering
system
57 ALT150
“RH J/B− AM”, “LH J/B −AM”,
“E/G− AM”, “RR JB”, “HEATER”,
“DEFOG”, “FAN1”, “FAN2”,
“ABS2”, “ABS MOTOR”, “ABS
MAIN1”, and “ABS MAIN2”
No.FUSEAMPERECIRCUIT
58 RR J/B80
“STOP LP R”, “STOP LP L”,
“RR− B”, “RR TAIL”, “RR FOG”,
“RR− IG1”, “PSB”, and “RR
S/SHADE”
59 GLW PLG150Glow plug heater
60 RH J/BAM80
“AM1”, “OBD”, “STOP SW”, “TI
&TE”, “PWR OUTLET”, “FR
P/SEAT RH”, “STR LOCK”,
“ECU− IG RH”, “RH− IG”, “ACC”,
“CIG”, “SECURITY”, “FR
S/HTR RH”, and “AIR SUS”
61 ABS230Vehicle stability control system,
Anti− lock brake system
62 DEFOG50Rear window defogger, Noise
filter
63 FAN140Electric cooling fans
64 HEATER50Air conditioning system
65 GLW PLG250Glow plug heater
66 E/GAM60“H−LMP CLN”, “FR CTRL −AM”
and “A/C COMP”
67 LH J/
BAM80
“S/ROOF”, “FR P/SEAT LH”,
“TV”, “FR S/HTR LH”, “ECU− IG
LH”, “FR WIP”, “H −LP LVL”,
“LH− IG”, “FUEL OPEN”, “A/C”,
“PANEL”, and “LH− B”
68 FAN260No circuit
69 FR
CTRLB25“H− LP UPR” and “HORN”