Page 514 of 1111
EM±2
± ENGINE MECHANICAL (2JZ±GE)CO/HC
1356 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
If the CO/HC concentration does not comply with regulations,
troubleshoot in the order given below.
(a) Check heated oxygen sensors operation.
(See page DI±44)
(b) See the table below for possible causes, and then inspect
and correct the applicable causes if necessary.
HCCOPhenomenonCauses
HighNormalRough idle1. Faulty ignitions:
Incorrect timing
Fouled, shorted or improperly gapped plugs
Open or crossed high±tension cords
2. Incorrect valve clearance
3. Leaky intake and exhaust valves
4. Leaky cylinder
HighLowRough idle
(Fluctuating HC reading)1. Vacuum leaks:
PCV hose
Intake manifold
Throttle body
Cylinder head gasket
2. Lean mixture causing misfire
HighHighRough idle
(Black smoke from exhaust)1. Restricted air filter
2. Plugged PCV valve
3. Faulty SFI systems:
Faulty pressure regulator
Faulty ECM
Faulty injector
Faulty throttle position sensor
Faulty mass air flow meter
Page 518 of 1111

A11128
Accelerator Pedal Position Sensor Connector
Throttle Control Motor Connector
Throttle Body and Intake Air Connector Assembly
Water Bypass HoseVSV Connector
for EVAP
EVAP Hose
Gasket Air Assist Hose Engine Wire
Oil Filler Cap
No.3 Timing Belt Cover
Gasket
No.2 Timing Belt Cover
GasketThrottle
Position
Sensor
Connector
Vacuum Hose
(from Actuator for ACIS)
Water Bypass Hose
Engine Wire Protector
High±Tension
Cord w/ Clamp
No.1 Cylinder
Head Cover
Gasket
Timing Belt
x 6
Timing Belt Guide
Gasket
x 5 No.1 Timing Belt Cover
Crankshaft
Pulley
21 (210, 15)
Drive Belt Tensioner
330 (3,300, 243)
Camshaft
Timing Pulley
(VVT±i Pulley)81 (810, 60)
Straight
Screw Plug
15 (150, 11)Seal Washer
Camshaft
Timing Oil
Control Valve
Camshaft Timing
Oil Control
Valve Connector Gasket
Oil Control Valve Filter
O±Ring
No.1 Oil PipeUnion Bolt
55 (550, 41)
Idler Pulley
Crankshaft Timing Pulley
Timing Belt Plate
Timing Belt Tensioner
N´m (kgf´cm, ft´lbf) : Specified torque
35 (350, 26)
8.0 (80, 71 in.´lbf)
27 (270, 20)
Non±reusable part
Precoated part
Dust Boot
Engine Wire ClampPCV Hose
Vacuum Hose
(from No.2
Vacuum Pipe)
± ENGINE MECHANICAL (2JZ±GE)TIMING BELT
EM±15
1369 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Page 521 of 1111

P11002
A11127
SST
A11126
5 mm
Hexagon
Wrench
A02662
Gasket
Union Bolt
Oil Control
Valve Filter
EM±18
± ENGINE MECHANICAL (2JZ±GE)TIMING BELT
1372 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(a) Alternately loosen the 2 bolts, and remove them, the ten-
sioner and dust boot.
(b) Disconnect the timing belt from the camshaft timing pul-
leys.
12. REMOVE EXHAUST CAMSHAFT TIMING PULLEY
Using SST, remove the bolt and timing pulley.
SST 09960±10010 (09962±01000, 09963±01000)
13. REMOVE ENGINE COVER
Remove the 4 nuts and engine cover.
14. REMOVE THROTTLE BODY AND INTAKE AIR
CONNECTOR ASSEMBLY (See page EM±5)
15. REMOVE NO.1 CYLINDER HEAD COVER
(a) Using a 5 mm hexagon wrench, remove the bolts, and dis-
connect the engine wire protector from the No.2 cylinder
head cover.
(b) Remove the nut, and disconnect the engine wire protec-
tor from the intake manifold.
(c) Remove the 2 bolts, and disconnect the high±tension
cords with the clamp from the No.2 cylinder head.
(d) Remove the 6 bolts, 2 nuts, No.1 cylinder head cover and
gasket.
16. REMOVE CAMSHAFT TIMING OIL CONTROL VALVE
(See page SF±43)
17. DISCONNECT NO.1 OIL PIPE
Remove the bolt, union bolt, oil control valve filter and 2 gas-
kets, and disconnect the No.1 oil pipe from the No.3 camshaft
bearing cap.
Page 528 of 1111

A02726
Seal WasherSet BoltHold
Straight
Screw
Plug
A02722
Mesh Part
Frame Part
A11126
5 mm
Hexagon
Wrench
A02661
Front MarkSST
± ENGINE MECHANICAL (2JZ±GE)TIMING BELT
EM±25
1379 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(c) Holding the hexagon portion of the camshaft with a
wrench.
(d) Using a 10 mm hexagon wrench, and the set bolt.
Torque: 81 N´m (810 kgf´cm, 60 ft´lbf)
(e) Using a 14 mm hexagon wrench, install the straight screw
plug with the seal washer to the set bolt.
Torque: 15 N´m (150 kgf´cm, 11 ft´lbf)
(f) Align the dot mark on the camshaft timing pulley with the
timing mark of the No.4 timing belt cover.
(g) Remove the wrench.
8. CONNECT NO.1 OIL PIPE
(a) Install the union bolt to the oil control valve filter.
NOTICE:
In case of touching the filter, avoid holding the mesh part
and holding the frame part.
(b) Install the oil pipe with 2 new gasket and the union bolt to
the No.3 camshaft bearing cap.
Torque: 55 N´m (550 kgf´cm, 41 ft´lbf)
9. INSTALL CAMSHAFT TIMING OIL CONTROL VALVE
(See page SF±43)
10. INSTALL NO.1 CYLINDER HEAD COVER
(a) Install the cylinder head and gasket with the 6 bolts and
2 nuts.
Torque: 8.5 N´m (85 kgf´cm, 75 in.´lbf)
(b) Install the high±tension cords and clamps with the 2 bolts.
Torque: 8.0 N´m (80 kgf´cm, 71 in.´lbf)
(c) Using a 5 mm hexagon wrench, install the engine wire
protector with the bolt and nut.
11. INSTALL THROTTLE BODY AND INTAKE AIR
CONNECTOR ASSEMBLY (See page EM±5)
12. INSTALL ENGINE COVER
Install the engine cover with the 4 nuts.
13. INSTALL EXHAUST CAMSHAFT TIMING PULLEY
(a) Align the camshaft knock pin with the groove on the
pulley, and slide on the timing pulley.
(b) Slide the timing pulley on the camshaft, facing the front
mark forward.
(c) Using SST, install the pulley bolt.
SST 09960±10010 (09962±01000, 09963±01000)
Torque: 81 N´m (810 kgf´cm, 60 ft´lbf)
Page 646 of 1111

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.
Page 649 of 1111

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
Page 672 of 1111

MA004±04
B01384
± MAINTENANCEENGINE
MA±5
48 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
ENGINE
INSPECTION
HINT:
Inspect these items when the engine is cold.
1. REPLACE TIMING BELT
(2JZ±GE ENGINE: See page EM±16)
(1UZ±FE ENGINE: See page EM±14)
2. INSPECT DRIVE BELT
(2JZ±GE ENGINE: See page CH±1)
(1UZ±FE ENGINE: See page CH±1)
3. REPLACE SPARK PLUGS
(2JZ±GE ENGINE: See page IG±1)
(1UZ±FE ENGINE: See page IG±1)
4. INSPECT AIR FILTER
(a) Remove the air filter.
(b) Visually check that the air filter is not excessively dam-
aged or oily.
If necessary, replace the air filter.
(c) Clean the filter with compressed air.
First blow from the inside thoroughly, then blow the out-
side of the filter.
(d) Reinstall the air filter.
5. REPLACE AIR FILTER
Replace the air filter with a new one.
6. REPLACE ENGINE OIL AND OIL FILTER
(2JZ±GE ENGINE: See page LU±2)
(1UZ±FE ENGINE: See page LU±3)
7. REPLACE ENGINE COOLANT
(2JZ±GE ENGINE: See page CO±2)
(1UZ±FE ENGINE: See page CO±2)
8. REPLACE GASKET IN FUEL TANK CAP
(2JZ±GE ENGINE: See page EC±7)
(1UZ±FE ENGINE: See page EC±7)
9. INSPECT FUEL LINES AND CONNECTIONS
Visually check the fuel lines for cracks, leakage, loose connec-
tions, deformation or tank band looseness.
10. INSPECT EXHAUST PIPES AND MOUNTINGS
Visually check the pipes, hangers and connections for severe
corrosion, leaks or damage.
11. ADJUST VALVE CLEARANCE
(2JZ±GE ENGINE: See page EM±5)
(1UZ±FE ENGINE: See page EM±4)
Page 824 of 1111
SF151±01
B08999
N´m (kgf´cm, ft´lbf) : Specified torque
Non±reusable part
21 (210, 15)
21 (210, 15)
VSV Connector for EVAP
Camshaft Position Sensor Connector
No.2 Vacuum Pipe
Accelerator Cable
EVAP Hose
Noise Filter
Connector
Vacuum
Hose
Throttle Position
Sensor Connector
Gasket
PS Air Hose
Engine Wire Clamp
Gasket
Oil Dipstick and
Guide for A/T
Engine Wire
Clamp
42 (420, 31)
Fuel Pressure Pulsation Damper
Gasket
O±Ring
Fuel Inlet Pipe Delivery Pipe
21 (210, 15)
Spacer
Injector Connector O±Ring O±Ring
Injector
Insulator
Grommet
28 (280, 21)
Engine Cover
SF±20
± SFI (2JZ±GE)INJECTOR
1486 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
COMPONENTS