2000 LEXUS GS400 ABS

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

SS0FE±01
± SERVICE SPECIFICATIONSSUSPENSION AND AXLE
SS±53
209 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
TORQUE SPECIFICATION
Part tightenN´mkgf´cmft´lbf
FRONT
Hub nut1031,05076
Brake caliper x Steering knuckle11 81,20087
ABS speed sensor x Steering knuckle7.88069 in.´lbf
Steering knuckle x Upper suspension arm8789064
Lower ball joint x Steering knuckle11 31,15083
Brake dust cover x Steering knuckle8.38574 in.´lbf
ABS speed sensor wire harness x Shock absorber5.05548 in.´lbf
Stabilizer bar x Stabilizer bar link5556041
Shock absorber bracket x Shock absorber1571,60011 6
Piston rod x Suspension support No.22728020
Suspension support No.1 x Body5657041
Upper suspension arm x Body5354039
Stabilizer bar link x No.2 lower suspension arm11 31,15083
Height control link x Shock absorber bracket5.45548 in.´lbf
No.2 lower suspension arm x No.1 lower suspension arm2452,500180
No.2 lower suspension arm x Lower ball joint1621,65011 9
Strut bar bracket x Body A
B58
152590
1,55043
11 2
No.2 lower suspension arm x Body9597070
Shock absorber bracket x No.2 lower suspension arm2525018
Tie rod end x Lower ball joint8789064
Stabilizer bar bracket x Body2829021
Tie rod end lock nut5657041
Axle hub lock nut1992,030147

SS±54
± SERVICE SPECIFICATIONSSUSPENSION AND AXLE
210 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)Part tighten
N´mkgf´cmft´lbf
REAR
Hub nut1031,05076
Brake caliper x Axle carrier1041,06577
Axle carrier x Upper suspension arm1081,10080
Backing plate x Axle carrier5960043
Drive shaft x Axle hub2892,950213
No.2 lower suspension arm x Axle carrier11 01,12081
No.1 lower suspension arm x Axle carrier7576555
Drive shaft x Differential side gear shaft6869550
Differential drain plug4950039
Differential filler plug4950039
Differential mounting boltFront
Rear123
1421,250
1,45090
105
Ring gear set boltSee page SA±73
Companion flange lock nutSee page SA±73
Differential carrier retainer set bolt2222516
Differential carrier cover set bolt4747534
Breather plug2121015
Suspension support x Body Upper side
Lower side64
18650
18547
13
Piston rod x Suspension support2728020
Upper suspension arm x Body8890065
No.1 lower suspension arm x Body7576555
No.2 lower suspension arm x Stabilizer bar link x Height control sensor link3030522
No.2 lower suspension arm x Shock absorber11 01,12081
No.2 lower suspension arm x Body11 01,12081
ABS speed sensor wire harness x Toe control link5.45548 in.´lbf
Toe control link x Axle carrier5960044
Toe control link x Body5960044
Stabilizer bar x Stabilizer bar link6566048
Stabilizer bar bracket x Body1818513
ABS speed sensor x Axle carrier7.88069 in.´lbf
Parking brake cable x Backing plate7.88069 in.´lbf
Suspension member brace x Body5051037
Differential x Propeller shaft7980558
Oil deflector x Differential carrier cover7.07062 in.´lbf