ABS LEXUS GS400 2000 Service Owner's Manual

F02832
± BRAKEHYDRAULIC BRAKE BOOSTER
BR±47
2155 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(r) Inspect the left rear ABS solenoid.
(1) Turn the selector switch to ºLHº position.
(2) Depress the brake pedal several times and release
the brake pedal when the pump begins rotating.
Wait until the pump stops.
(3) Turn the ignition switch OFF.
(4) Depress the brake pedal with a force of 343 N (35
kgf, 77 lbf), record the fluid surface in the reservoir
tank of the hydraulic brake booster.
(5) Press the MAIN push switch for 10 sec., and check
that the fluid surface in the reservoir tank of the hy-
draulic brake booster does not rise up at this time.
If the fluid surface level rises up, replace the hydraulic brake
booster.
NOTICE:
Do not press MAIN push switch for more than 10 sec. When
operating the switch continuously, do it an interval of more
than 20 seconds.
(6) Start the engine and run it at idle.
(7) Depress the brake pedal.
(8) Release the parking brake pedal and shift the shift
lever to ºLº position.
(9) Once, release the brake pedal. After depressing the
brake pedal with stable force, then push and hold
MAIN push switch.
(10) Check that the left rear wheel rotates.
If the left rear wheel stops, replace the hydraulic brake booster.
(s) Stop the engine and lower the vehicle.
(t) Remove the ºSHEET Gº (SST) and disconnect the actua-
tor checker (SST) and sub±wire harness S (SST) from the
hydraulic brake booster.
(u) Connect the 2 connectors to the actuator.
(v) Clear the DTC (See page DI±389).

F06049
± BRAKEBRAKE FLUID
BR±5
2113 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(g) Bleed right front brake line.
(1) Select ºFR LINEº on the LEXUS hand±held tester.
(2) With ºFR LINEº turned ON with the LEXUS hand±
held tester, depress the brake pedal and hold it to
bleed the right front brake caliper.
(3) Repeat step (2) until there are no more air bubbles
in the fluid.
(h) Bleed left front brake line.
(1) Select ºFL LINEº on the LEXUS hand±held tester.
(2) With ºFL LINEº turned ON with the LEXUS hand±
held tester, depress the brake pedal and hold it to
bleed the left front brake caliper.
(3) Repeat step (2) until there are no more air bubbles
in the fluid.
(i) Bleed rear brake line.
(1) Select ºRR LINEº on the LEXUS hand±held tester.
(2) With ºRR LINEº turned ON with the LEXUS hand±
held tester, bleed the left and right rear brake cali-
per.
(j) Disconnect the LEXUS hand±held tester from DLC3.
(k) Clear the DTC (See page DI±389).
3. IN CASE OF USING ABS ACTUATOR CHECKER
(SST):
BLEED HYDRAULIC BRAKE BOOSTER
HINT:
If the hydraulic brake booster has been disassembled, discon-
nect the brake line from the hydraulic brake booster or if the res-
ervoir becomes empty, bleed the hydraulic brake booster.
(a) Disconnect the 2 connectors from the hydraulic brake
booster.

± INTRODUCTIONFOR ALL OF VEHICLES
IN±17
17 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. FOR VEHICLES EQUIPPED WITH A CATALYTIC CONVERTER
CAUTION:
If large amount of unburned gasoline flows into the converter, it may overheat and create a fire haz-
ard. To prevent this, observe the following precautions and explain them to your customer.
(a) Use only unleaded gasoline.
(b) Avoid prolonged idling.
Avoid running the engine at idle speed for more than 20 minutes.
(c) Avoid spark jump test.
(1) Perform spark jump test only when absolutely necessary. Perform this test as rapidly as possible.
(2) While testing, never race the engine.
(d) Avoid prolonged engine compression measurement.
Engine compression tests must be done as rapidly as possible.
(e) Do not run engine when fuel tank is nearly empty.
This may cause the engine to misfire and create an extra load on the converter.
(f) Avoid coasting with ignition turned off.
(g) Do not dispose of used catalyst along with parts contaminated with gasoline or oil.
3. IF VEHICLE IS EQUIPPED WITH MOBILE COMMUNICATION SYSTEM
For vehicles with mobile communication systems such as two±way radios and cellular telephones, observe
the following precautions.
(1) Install the antenna as far as possible away from the ECU and sensors of the vehicle's electronic
system.
(2) Install the antenna feeder at least 20 cm (7.87 in.) away from the ECU and sensors of the ve-
hicle's electronic systems. For details about ECU and sensors locations, refer to the section on
the applicable component.
(3) Avoid winding the antenna feeder together with other wiring as much as possible, and also avoid
running the antenna feeder parallel with other wire harnesses.
(4) Check that the antenna and feeder are correctly adjusted.
(5) Do not install powerful mobile communications system.
4. FOR USING OBD II SCAN TOOL OR LEXUS HAND±HELD TESTER
CAUTION:
Observe the following items for safety reasons:

Before using the OBD II scan tool or LEXUS hand±held tester, the OBD II scan tool's instruction
book or LEXUS hand±held tester's operator manual should be read thoroughly.

Be sure to route all cables securely when driving with the OBD II scan tool or LEXUS hand±held
tester connected to the vehicle. (i.e. Keep cables away from feet, pedals, steering wheel and
shift lever.)

Two persons are required when test driving with the OBD II scan tool or LEXUS hand±held tes-
ter, one person to drive the vehicle and the other person to operate the OBD II scan tool or LEX-
US hand±held tester.

IN04S±10
IN±20± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
20 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS
GENERAL INFORMATION
A large number of ECU controlled systems are used in the LEXUS GS400/GS300. In general, the ECU con-
trolled system is considered to be a very intricate system requiring a high level of technical knowledge and
expert skill to troubleshoot. However, the fact is that if you proceed to inspect the circuits one by one, trouble-
shooting of these systems is not complex. If you have adequate understanding of the system and a basic
knowledge of electricity, accurate diagnosis and necessary repair can be performed to locate and fix the
problem. This manual is designed through emphasis of the above standpoint to help service technicians
perform accurate and effective troubleshooting, and is compiled for the following major ECU controlled sys-
tems:
The troubleshooting procedure and how to make use of it are described on the following pages.
SystemPage
1. Engine 2JZ ± GEDI±1
2. Engine 1UZ ± FEDI±156
3. Automatic TransmissionDI±316
4. ABS & Hydraulic Brake Booster Power Supply SystemDI±387
5. Vehicle Skid Control (VSC) & Brake Assist (BA) SystemDI±473
6. Power Tilt and Power Telescopic Steering ColumnDI±517
7. Supplemental Restraint SystemDI±550
8. Power Seat Control SystemDI±683
9. Cruise Control SystemDI±704
10.Engine Immobiliser SystemDI±726
11. Combination Meter SystemDI±744
12.Sliding Roof SystemDI±764
13.Body No. 1 Control SystemDI±776
14.Body No. 2 Control SystemDI±820
15.Driver Door Control SystemDI±856
16.Passenger Door Control SystemDI±889
17.Rear Left Door Control SystemDI±921
18.Rear Right Door Control SystemDI±938
19.Multiplex Communication SystemDI±955
20.LEXUS Navigation SystemDI±1022
21.Air Conditioning SystemDI±1059
FOR USING OBDII SCAN TOOL OR LEXUS HAND±HELD TESTER

Before using the scan tool or tester, the scan tool's instruction book or tester's operator manual should
be read thoroughly.

If the scan tool or tester cannot communicate with ECU controlled systems when you have connected
the cable of the scan tool or tester to DLC3, turned the ignition switch ON and operated the scan tool,
there is a problem on the vehicle side or tool side.
(1) If communication is normal when the tool is connected to another vehicle, inspect the diagnosis
data link line (Bus
line) or ECU power circuit of the vehicle.
(2) If communication is still not possible when the tool is connected to another vehicle, the problem
is probably in the tool itself, so perform the Self Test procedures outline in the Tester Operator's
Manual.

DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE
Diagnostic Trouble
Code Check (Make a
note of and then clear)Confirmation
of SymptomsDiagnostic Trouble
Code CheckProblem Condition
Diagnostic Trouble
Code DisplayProblem symptoms
existSame diagnostic
trouble code is
displayedProblem is still occurring in the diagnostic
circuit
Normal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit
(The diagnostic trouble code displayed
first is either for a past problem or it is a
secondary problem)
No problem
symptoms existThe problem occurred in the diagnostic
circuit in the past
Normal Code DisplayProblem symptoms
existNormal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit
No problem
symptoms existNormal code is
displayedThe problem occurred in a place other
than in the diagnostic circuit in the past
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±23
23 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the LEXUS GS400/GS300 fulfills various functions. The first function is the Diag-
nostic Trouble Code Check in which a malfunction in the signal circuits to the ECU is stored in code in the
ECU memory at the time of occurrence, to be output by the technician during troubleshooting. Another func-
tion is the Input Signal Check which checks if the signals from various switches are sent to the ECU correctly.
By using these check functions, the problem areas can be narrowed down quickly and troubleshooting can
be performed effectively. Diagnostic functions are incorporated in the following systems in the LEXUS
GS400/GS300.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Diagnostic Test
Mode (Active Test)
Engine (2JZ±GE)
Engine (1UZ±FE)
Automatic Transmission
ABS & Hydraulic Brake Booster Power Supply System
Vehicle Skid Control (VSC) & Brake Assist (BA) System
Power Tilt and Power Telescopic Steering Column
Supplemental Restraint System
Cruise Control System
Engine Immobiliser System
Multiplex Communication System
LEXUS Navigation System
Air Conditioning System(with check Mode)
(with check Mode)
(with check Mode)















In diagnostic trouble code check, it is very important to determine whether the problem indicated by the diag-
nostic trouble code is still occurring or occurred in the past but returned to normal at present. In addition,
it must be checked in the problem symptom check whether the malfunction indicated by the diagnostic
trouble code is directly related to the problem symptom or not. For this reason, the diagnostic trouble codes
should be checked before and after the symptom confirmation to determine the current conditions, as shown
in the table below. If this is not done, it may, depending on the case, result in unnecessary troubleshooting
for normally operating systems, thus making it more difficult to locate the problem, or in repairs not pertinent
to the problem. Therefore, always follow the procedure in correct order and perform the diagnostic trouble
code check.

IN04Q±07
IN±36
± INTRODUCTIONTERMS
36 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
TERMS
ABBREVIATIONS USED IN THIS MANUAL
AbbreviationsMeaning
ABSAnti±Lock Brake System
ACAlternating Current
ACCAccessory
ACISAcoustic Control Induction System
ACSDAutomatic Cold Start Device
A.D.D.Automatic Disconnecting Differential
A/FAir±Fuel Ratio
AHCActive Height Control Suspension
ALRAutomatic Locking Retractor
ALTAlternator
AMPAmplifier
ANTAntenna
APPROX.Approximately
A/TAutomatic Transmission (Transaxle)
AT FAutomatic Transmission Fluid
AUTOAutomatic
AUXAuxiliary
AV GAverage
AV SAdaptive Variable Suspension
BABrake Assist
BACSBoost Altitude Compensation System
BATBattery
BDCBottom Dead Center
B/LBi±Level
B/SBore±Stroke Ratio
BTDCBefore Top Dead Center
BVSVBimetallic Vacuum Switching Valve
Calif.California
CBCircuit Breaker
CCoCatalytic Converter For Oxidation
CDCompact Disc
CFCornering Force
CGCenter Of Gravity
CHChannel
COMB.Combination
CPECoupe
CPSCombustion Pressure Sensor
CPUCentral Processing Unit
CRSChild Restraint System
CTRCenter
C/VCheck Valve
CVControl Valve

IN0253
WRONG CORRECT
IN0252
WRONG CORRECT IN±6
± INTRODUCTIONREPAIR INSTRUCTIONS
6 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(k) Care must be taken when jacking up and supporting the
vehicle. Be sure to lift and support the vehicle at the prop-
er locations (See page IN±8).
Cancel the parking brake on the level place and
shift the transmission in Neutral (or N position).
When jacking up the front wheels of the vehicle, at
first place stoppers behind the rear wheels.
When jacking up the rear wheels of the vehicle, at
fitst place stoppers before the front wheels.
When either the front or rear wheels only should be
jacked up, set rigid racks and place stoppers in front
and behind the other wheels on the ground.
After the vehicle is jacked up, be sure to support it
on rigid racks. It is extremely dangerous to do any
work on a vehicle raised on a jack alone, even for
a small job that can be finished quickly.
(l) Observe the following precautions to avoid damage to the
following parts:
(1) Do not open the cover or case of the ECU unless
absolutely necessary. (If the IC terminals are
touched, the IC may be destroyed by static electric-
ity.)
(2) To disconnect vacuum hoses, pull off the end, not
the middle of the hose.
(3) To pull apart electrical connectors, pull on the con-
nector itself, not the wires.
(4) Be careful not to drop electrical components, such
as sensors or relays. If they are dropped on a hard
floor, they should be replaced and not reused.
(5) When steam cleaning an engine, protect the elec-
tronic components, air filter and emission±related
components from water.
(6) Never use an impact wrench to remove or install
temperature switches or temperature sensors.
(7) When checking continuity at the wire connector, in-
sert the tester probe carefully to prevent terminals
from bending.
(8) When using a vacuum gauge, never force the hose
onto a connector that is too large. Use a step±down
adapter for adjustment. Once the hose has been
stretched, it may leak air.

IN0002
Example
± INTRODUCTIONREPAIR INSTRUCTIONS
IN±7
7 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(m) Installation and removal of vacuum hose:
(1) When disconnecting vacuum hoses, use tags to
identify where they should be reconnected to.
(2) After completing a job, double check that the vacu-
um hoses are properly connected. A label under the
hood shows the proper layout.
(n) Bleeding of hydraulic brake booster:
When repairing the hydraulic brake booster or ABS,
TRAC and VSC system, bleeding the air out of the hy-
draulic brake booster (See page BR±4).
(o) Unless otherwise stated, all resistance is measured at an
ambient temperature of 20°C (68°F). Because the resis-
tance may be outside specifications if measured at high
temperatures immediately after the vehicle has been run-
ning, measurement should be made when the engine has
cooled down.

IN±42
± INTRODUCTIONTERMS
42 Author: Date:
2000 LEXUS GS300/GS400 (RM718U) HO2S
Heated Oxygen SensorHeated Oxygen Sensor (HO2S)
IACIdle Air ControlIdle Speed Control (ISC)
IATIntake Air TemperatureIntake or Inlet Air Temperature
ICMIgnition Control Module±
IFIIndirect Fuel InjectionIndirect Injection (IDL)
IFSInertia Fuel±Shutoff±
ISCIdle Speed Control±
KSKnock SensorKnock Sensor
MAFMass Air FlowAir Flow Meter
MAPManifold Absolute PressureManifold Pressure
Intake Vacuum
MCMixture Control
Electric Bleed Air Control Valve (EBCV)
Mixture Control Valve (MCV)
Electric Air Control Valve (EACV)
MDPManifold Differential Pressure±
MFIMultiport Fuel InjectionElectronic Fuel Injection (EFI)
MILMalfunction Indicator LampCheck Engine Lamp
MSTManifold Surface Temperature±
MVZManifold Vacuum Zone±
NVRAMNon±Volatile Random Access Memory±
O2SOxygen SensorOxygen Sensor, O2 Sensor (O2S)
OBDOn±Board DiagnosticOn±Board Diagnostic System (OBD)
OCOxidation Catalytic ConverterOxidation Catalyst Convert (OC), CCo
OPOpen LoopOpen Loop
PAIRPulsed Secondary Air InjectionAir Suction (AS)
PCMPowertrain Control Module±
PNPPark/Neutral Position±
PROMProgrammable Read Only Memory±
PSPPower Steering Pressure±
PTOXPeriodic Trap OxidizerDiesel Particulate Filter (DPF)
Diesel Particulate Trap (DPT)
RAMRandom Access MemoryRandom Access Memory (RAM)
RMRelay Module±
ROMRead Only MemoryRead Only Memory (ROM)
RPMEngine SpeedEngine Speed
SCSuperchargerSupercharger
SCBSupercharger BypassE±ABV
SFISequential Multiport Fuel InjectionElectronic Fuel Injection (EFI), Sequential Injection
SPLSmoke Puff Limiter±
SRIService Reminder Indicator±
SRTSystem Readiness Test±
STScan Tool±
TBThrottle BodyThrottle Body
TBIThrottle Body Fuel InjectionSingle Point Injection
Central Fuel Injection (Ci)
TCTurbochargerTurbocharger
TCCTorque Converter ClutchTorque Converter

PP1Z3±01
PP±76
± PREPARATIONBRAKE
128 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
BRAKE
SST (Special Service Tools)
09023±00100Union Nut Wrench 10 mm
09318±12010Transfer Bearing Adjusting Nut
Wrench
09630±00014Power Steering Gear Housing
Overhaul Tool Set
(09631±00142)Overhaul Stand
09709±29018LSPV Gauge Set
09843±18020Diagnosis Check Wire
09950±60010Replacer Set
(09951±00180)Replacer 18
(09951±00190)Replacer 19
09990±00150ABS Actuator Checker and
Sub±harness
09990±00240ABS Actuator Checker Sheet ºGº
09990±00480ABS Actuator Checker
Sub±harness ºSº