ECU LEXUS GS400 2000 Service Repair Manual

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.

IN0D6±01
± INTRODUCTIONTERMS
IN±41
41 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
GLOSSARY OF SAE AND LEXUS TERMS
This glossary lists all SAE±J1930 terms and abbreviations used in this manual in compliance with SAE rec-
ommendations, as well as their LEXUS equivalents.
SAE
ABBREVIATIONSSAE TERMSLEXUS TERMS
( )±±ABBREVIATIONS
A/CAir ConditioningAir Conditioner
ACLAir CleanerAir Cleaner, A/CL
AIRSecondary Air InjectionAir Injection (AI)
APAccelerator Pedal±
B+Battery Positive Voltage+B, Battery Voltage
BAROBarometric PressureHAC
CACCharge Air CoolerIntercooler
CARBCarburetorCarburetor
CFIContinuous Fuel Injection±
CKPCrankshaft PositionCrank Angle
CLClosed LoopClosed Loop
CMPCamshaft PositionCam Angle
CPPClutch Pedal Position±
CTOXContinuous Trap Oxidizer±
CTPClosed Throttle PositionLL ON, Idle ON
DFIDirect Fuel Injection (Diesel)Direct Injection (DI)
DIDistributor Ignition±
DLC1
DLC2
DLC3Data Link Connector 1
Data Link Connector 2
Data Link Connector 31: Check Connector
2: Total Diagnosis Comunication Link (TDCL)
3: OBD II Diagnostic Connector
DTCDiagnostic Trouble CodeDiagnostic Code
DTMDiagnostic Test Mode±
ECLEngine Control Level±
ECMEngine Control ModuleEngine ECU (Electronic Control Unit)
ECTEngine Coolant TemperatureCoolant Temperature, Water Temperature (THW)
EEPROMElectrically Erasable Programmable Read Only Memory
Electrically Erasable Programmable Read Only Memory
(EEPROM),
Erasable Programmable Read Only Memory (EPROM)
EFEEarly Fuel EvaporationCold Mixture Heater (CMH), Heat Control Valve (HCV)
EGRExhaust Gas RecirculationExhaust Gas Recirculation (EGR)
EIElectronic IgnitionTOYOTA Distributorless Ignition (TDI)
EMEngine ModificationEngine Modification (EM)
EPROMErasable Programmable Read Only MemoryProgrammable Read Only Memory (PROM)
EVAPEvaporative EmissionEvaporative Emission Control (EVAP)
FCFan Control±
FEEPROMFlash Electrically Erasable Programmable Read Only
Memory±
FEPROMFlash Erasable Programmable Read Only Memory±
FFFlexible Fuel±
FPFuel PumpFuel Pump
GENGeneratorAlternator
GNDGroundGround (GND)

± INTRODUCTIONTERMS
IN±43
43 Author: Date:
2000 LEXUS GS300/GS400 (RM718U) TCM
Transmission Control ModuleTransmission ECU, ECT ECU
TPThrottle PositionThrottle Position
TRTransmission Range±
TVVThermal Vacuum ValveBimetallic Vacuum Switching Valve (BVSV)
Thermostatic Vacuum Switching Valve (TVSV)
TWCThree±Way Catalytic Converter
Three±Way Catalytic (TWC)
Manifold Converter
CC
RO
TWC+OCThree±Way + Oxidation Catalytic ConverterCCR + CCo
VA FVolume Air FlowAir Flow Meter
VRVoltage RegulatorVoltage Regulator
VSSVehicle Speed SensorVehicle Speed Sensor
WOTWide Open ThrottleFull Throttle
WU±OCWarm Up Oxidation Catalytic Converter±
WU±TWCWarm Up Three±Way Catalytic Converter±
3GRThird Gear±
4GRFourth Gear±

MA001±07
± MAINTENANCEOUTSIDE VEHICLE
MA±1
44 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
OUTSIDE VEHICLE
GENERAL MAINTENANCE
These are maintenance and inspection items which are considered to be the owner's responsibility.
They can be done by the owner or they can have them done at a service shop.
These items include those which should be checked on a daily basis, those which, in most cases, do not
require (special) tools and those which are considered to be reasonable for the owner to do.
Items and procedures for general maintenance are as follows.
1. GENERAL NOTES

Maintenance items may vary from country to country. Check the owner's manual supplement in which
the maintenance schedule is shown.

Every service item in the periodic maintenance schedule must be performed.

Periodic maintenance service must be performed according to whichever interval in the periodic main-
tenance schedule occurs first, the odometer reading (miles) or the time interval (months).

Maintenance service after the last period should be performed at the same interval as before unless
otherwise noted.

Failure to do even one item an cause the engine to run poorly and increase exhaust emissions.
2. TIRES
(a) Check the pressure with a gauge. If necessary, adjust.
(b) Check for cuts, damage or excessive wear.
3. WHEEL NUTS
When checking the tires, check the nuts for looseness or for missing nuts. If necessary, tighten them.
4. TIRE ROTATION
Check the owner's manual supplement in which the maintenance schedule is shown.
5. WINDSHIELD WIPER BLADES
Check for wear or cracks whenever they do not wipe clean. If necessary, replace.
6. FLUID LEAKS
(a) Check underneath for leaking fuel, oil, water or other fluid.
(b) If you smell gasoline fumes or notice any leak, have the cause found and corrected.
7. DOORS AND ENGINE HOOD
(a) Check that all doors and the tailgate operate smoothly, and that all latches lock securely.
(b) Check that the engine hood secondary latch secures the hood from opening when the primary latch
is released.

MA002±06
MA±2
± MAINTENANCEINSIDE VEHICLE
45 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSIDE VEHICLE
GENERAL MAINTENANCE
These are maintenance and inspection items which are considered to be the owner's responsibility.
They can be done by the owner or they can have them done at a service shop.
These items include those which should be checked on a daily basis, those which, in most cases, do not
require (special) tools and those which are considered to be reasonable for the owner to do.
Items and procedures for general maintenance are as follows.
1. GENERAL NOTES

Maintenance items may vary from country to country. Check the owner's manual supplement in which
the maintenance schedule is shown.

Every service item in the periodic maintenance schedule must be performed.

Periodic maintenance service must be performed according to whichever interval in the periodic main-
tenance schedule occurs first, the odometer reading (miles) or the time interval (months).

Maintenance service after the last period should be performed at the same interval as before unless
otherwise noted.

Failure to do even one item an cause the engine to run poorly and increase exhaust emissions.
2. LIGHTS
(a) Check that the headlights, stop lights, taillights, turn signal lights, and other lights are all working.
(b) Check the headlight aiming.
3. WARNING LIGHTS AND BUZZERS
Check that all warning lights and buzzers function properly.
4. HORN
Check that it is working.
5. WINDSHIELD GLASS
Check for scratches, pits or abrasions.
6. WINDSHIELD WIPER AND WASHER
(a) Check operation of the wipers and washer.
(b) Check that the wipers do not streak.
7. WINDSHIELD DEFROSTER
Check that air comes out from the defroster outlet when operating the heater or air conditioner.
8. REAR VIEW MIRROR
Check that it is mounted securely.
9. SUN VISORS
Check that they move freely and are mounted securely.
10. STEERING WHEEL
Check that it has the specified freeplay. Be alert for changes in steering condition, such as hard steering,
excessive freeplay or strange noises.
11. SEATS
(a) Check that all front seat controls such as seat adjusters, seatback recliner, etc. operate smoothly.
(b) Check that all latches lock securely in any position.
(c) Check that the locks hold securely in any latched position.
(d) Check that the head restraints move up and down smoothly and that the locks hold securely in any
latches position.
(e) For folding±down rear seat backs, check that the latches lock securely.
12. SEAT BELTS
(a) Check that the seat belt system such as the buckles, retractors and anchors operate properly and
smoothly.
(b) Check that the belt webbing is not cut, frayed, worn or dameged.

± MAINTENANCEINSIDE VEHICLE
MA±3
46 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
13. ACCELERATOR PEDAL
Check the pedal for smooth operation and uneven pedal effort or catching.
14. BRAKE PEDAL (See page BR±9)
(a) Check the pedal for smooth operation.
(b) Check that the pedal has the proper reserve distance and freeplay.
(c) Check the brake booster function.
15. BRAKES
At a safe place, check that the brakes do not pull to one side when applied.
16. PARKING BRAKE (See page BR±11)
(a) Check that the lever has the proper travel.
(b) On a safe incline, check that the vehicle is held securely with only the parking brake applied.
17. AUTOMATIC TRANSMISSION ºPARKº MECHANISM
On a safe incline, check that the vehicle is held securely with the selector lever in ºPº position and all brakes
released.

B01983
37 N´m
B01657
127 N´m127 N´m
MA01T±01
B01658
98 N´m
MA±8
± MAINTENANCEBODY
51 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
BODY
INSPECTION
1. TIGHTEN BOLTS AND NUTS ON CHASSIS AND BODY
Tighten these parts:

Front seat mounting bolts
Torque: 37 N´m (375 kgf´cm, 27 ft´lbf)

Front suspension member±to±body mounting nuts
Torque: 98 N´m (1,000 kgf´cm, 72 ft´lbf)

Rear suspension member±to±body mounting bolts
Torque: 127 N´m (1,300 kgf´cm, 94 ft´lbf)
2. BODY INSPECTION
(a) Check the body exterior for dents, scratches and rust.
(b) Check the underbody for rust and damage.
If necessary, replace or repair.
3. ROAD TEST
(a) Check the engine and chassis for abnormal noises.
(b) Check that the vehicle does not wander or pull to one
side.
(c) Check that the brakes work properly and do not drag.
(d) Do setting of the parking brake shoes and drum.
4. FINAL INSPECTION
(a) Check the operation of the body parts:

Hood
Auxiliary catch operates properly
Hood locks securely when closed

Front and rear doors
Door locks operate properly
Doors close properly

Luggage compartment door
Door lock operates properly

Seat adjusts easily and locks securely in any posi-
tion
Front seat back locks securely in any position
Folding±down rear seat backs lock securely

SS0CN±02
SS±60
± SERVICE SPECIFICATIONSBODY ELECTRICAL
216 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
BODY ELECTRICAL
SERVICE DATA
DAYTIME RUNNING LIGHT RELAY (MAIN) (Wire Harness Side)
1 ± Ground (Ignition switch position LOCK or ACC)No voltage
1 ± Ground (Ignition switch position ON or START)Battery positive voltage
5 ± Ground (Engine Stop)No voltage
5 ± Ground (Engine Running)Battery positive voltage
7 ± Ground (Constant)Battery positive voltage
9 ± Ground (Constant)Battery positive voltage
AUTOMATIC LIGHT CONTROL SENSOR
(Connector disconnected)
4 ± Ground (Ignition switch position LOCK or ACC)No voltage
4 ± Ground (Ignition switch position ON)5.2 ± 9.0 V
(Connector connected)
1 ± Ground (Ignition switch position LOCK or ACC)No voltage
1 ± Ground (Ignition switch position ON)9.5 V or more
HEADLIGHT BEAM LEVEL CONTROL ECU
(Connector disconnected)
A1 ± A5 (Ignition switch position OFF)26 ± 30 W
A1 ± A6 (Ignition switch position OFF)26 ± 30 W
A1 ± A7 (Ignition switch position OFF)26 ± 30 W
A1 ± A8 (Ignition switch position OFF)26 ± 30 W
A4 ± B4 (Ignition switch position ON and light control switch HEAD)Below 1.5 V
B1 ± B3 (Ignition switch position OFF)3.5 k ± 6.5 kW
B5 ± B7 (Ignition switch position OFF)3.5 k ± 6.5 kW
(Connector disconnected)
B2 ± B3 (Ignition switch position ON)Approx. 2.5 V
B6 ± B7 (Ignition switch position ON)Approx. 2.5 V
B1 ± B3 (Ignition switch position ON)5V
B5 ± B7 (Ignition switch position ON)5V
TURN SIGNAL FLASHER
1 ± Ground (Ignition switch position LOCK or ACC)No voltage
1 ± Ground (Ignition switch position ON)Battery positive voltage
4 ± Ground (Constant)Battery positive voltage
LIGHT FAILURE RELAY (Wire Harness Side)
5 ± Ground (Light control switch position OFF)No voltage
5 ± Ground (Light control switch position TAIL or HEAD)Battery positive voltage
8 ± Ground (Ignition switch position LOCK or ACC)No voltage
8 ± Ground (Ignition switch position ON)Battery positive voltage
9 ± Ground (Stop light switch position OFF)No voltage
9 ± Ground (Stop light switch position ON)Battery positive voltage
10 ± Ground (Stop light switch position OFF)No voltage
10 ± Ground (Stop light switch position ON)Battery positive voltage
SPEEDOMETER (ON±VEHICLE)
USA:

SF0N1±03
± SFI (2JZ±GE)SFI SYSTEM
SF±1
1467 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
SFI SYSTEM
PRECAUTION
1. BEFORE WORKING ON FUEL SYSTEM, DISCON-
NECT NEGATIVE (±) TERMINAL CABLE FROM BAT-
TERY
HINT:
Any diagnostic trouble code retained by the ECM will be erased
when the battery negative (±) terminal cable is removed from
the battery.
Therefore, if necessary, read the diagnostic trouble code(s) be-
fore removing the negative (±) terminal cable from the battery.
2. DO NOT SMOKE OR WORK NEAR AN OPEN FLAME
WHEN WORKING ON FUEL SYSTEM
3. KEEP GASOLINE AWAY FROM RUBBER OR LEATH-
ER PARTS
4. MAINTENANCE PRECAUTIONS
(a) Precaution when the connecting gauge.
Use battery as the power source for the timing light, etc.
(b) In the event of engine misfire, these precautions should
be taken.
(1) Check proper connection of battery terminals, etc.
(2) Handle high±tension cords carefully.
(3) After repair work, check that the ignition coil termi-
nals and all other ignition system lines are recon-
nected securely.
(4) When cleaning the engine compartment, be espe-
cially careful to protect the electrical system from
water.
(c) Precautions when the handling heated oxygen sensors.
(1) Do not allow oxygen sensor to drop or hit against an
object.
(2) Do not allow the sensor to come into contact with
water.
5. IF VEHICLE IS EQUIPPED WITH MOBILE RADIO SYS-
TEM (HAM, CB, ETC.)
If the vehicle is equipped with a mobile communication system,
refer to the precaution in the IN section.
6. AIR INDUCTION SYSTEM
(a) Separation of the engine oil dipstick, oil filler cap, PCV
hose, etc. may cause the engine to run out of tune.
(b) Disconnection, looseness or cracks in the parts of the air
induction system between the throttle body and cylinder
head will cause air suction and cause the engine to run
out of tune.

FI2553
SST
SF±2
± SFI (2JZ±GE)SFI SYSTEM
1468 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
7. ELECTRONIC CONTROL SYSTEM
(a) Before removing SFI wiring connectors, terminals, etc.,
first disconnect the power by either turning the ignition
switch OFF or disconnecting the negative (±) terminal
cable from the battery.
HINT:
Always check the diagnostic trouble code before disconnecting
the negative (±) terminal cable from the battery.
(b) When installing the battery, be especially careful not to in-
correctly connect the positive (+) and negative (±) cable
terminals.
(c) Do not permit parts to receive a severe impact during re-
moval or installation. Handle all SFI parts carefully, espe-
cially the ECM.
(d) Do not be careless during troubleshooting as there are
numerous transistor circuits and even slight terminal con-
tact can further troubles.
(e) Do not open the ECM cover.
(f) When inspecting during rainy weather, take care to pre-
vent entry of water. Also, when washing the engine
compartment, prevent water from getting on the SFI parts
and wiring connectors.
(g) Parts should be replaced as an assembly.
(h) Care is required when pulling out and inserting wiring con-
nectors.
(1) Release the lock and pull out the connector, pulling
on the connectors.
(2) Fully insert the connector and check that it is locked.
(i) When inspecting a connector with a volt/ohmmeter.
(1) Carefully take out the water±proofing rubber if it is
a water±proof type connector.
(2) Insert the test probe into the connector from wiring
side when checking the continuity, amperage or
voltage.
(3) Do not apply unnecessary force to the terminal.
(4) After checking, install the water±proofing rubber on
the connector securely.
(5) Use SST for inspection or test of the injector or its
wiring connector.
SST 09842±30070