LEXUS GS400 2000 Service Repair Manual

B00924
No.1 Cooling
Fan RelayCO0AL±01
B00021
Ohmmeter
Continuity
OhmmeterContinuity
41
3
2
B00022
No Continuity Ohmmeter
41
3
2
Battery
B01373
No.2 Cooling
Fan Relay
A00970
Continuity
Ohmmeter
No Continuity Continuity4
1
32
Ohmmeter
5
Ohmmeter
± COOLING (2JZ±GE)COOLING FAN RELAY
CO±33
1571 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
COOLING FAN RELAY
INSPECTION
1. INSPECT NO.1 COOLING FAN RELAY
(a) Remove the relay box cover.
(b) Remove the No.1 cooling fan relay. (Marking: FAN NO.1)
(c) Inspect the No.1 cooling fan relay continuity.
(1) Using an ohmmeter, check that there is continuity
between terminals 1 and 2.
If there is no continuity, replace the relay.
(2) Check that there is continuity between terminals 3
and 4.
If there is no continuity, replace the relay.
(d) Inspect the No.1 cooling fan relay operation.
(1) Apply battery positive voltage across terminals 1
and 2.
(2) Using an ohmmeter, check that there is no continu-
ity between terminals 3 and 4.
If there is continuity, replace the relay.
(e) Reinstall the No.1 cooling fan relay.
(f) Reinstall the relay box cover.
2. INSPECT NO.2 COOLING FAN RELAY
(a) Remove the relay box cover.
(b) Remove the No.2 cooling fan relay. (Marking: FAN NO.2)
(c) Inspect the No.2 cooling fan relay continuity.
(1) Using an ohmmeter, check that there is continuity
between terminals 1 and 2.
If there is no continuity, replace the relay.
(2) Check that there is continuity between terminals 3
and 4.
If there is no continuity, replace the relay.
(3) Check that there is no continuity between terminals
3 and 5.
If there is continuity, replace the relay.

A00971
Ohmmeter
No ContinuityOhmmeter
Continuity 4
1
32
5
Battery
B01375
No.3 Cooling
Fan Relay
A00968No ContinuityContinuity 12 Ohmmeter
5Ohmmeter
3
A00969
Ohmmeter
Continuity1
32
5
Battery
CO±34
± COOLING (2JZ±GE)COOLING FAN RELAY
1572 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(d) Inspect the No.2 cooling fan relay operation.
(1) Apply battery positive voltage across terminals 1
and 2.
(2) Using an ohmmeter, check that there is no continu-
ity between terminals 3 and 4.
If there is continuity, replace the relay.
(3) Using an ohmmeter, check that there is continuity
between terminals 3 and 5.
If there is no continuity, replace the relay.
(e) Reinstall the No.2 cooling fan relay.
(f) Reinstall the relay box cover.
3. INSPECT NO.3 COOLING FAN RELAY
(a) Remove the relay box cover.
(b) Remove the No.3 cooling fan relay. (Marking: FAN NO.3)
(c) Inspect the No.3 cooling fan relay continuity.
(1) Using an ohmmeter, check that there is continuity
between terminals 1 and 2.
If there is no continuity, replace the relay.
(2) Check that there is no continuity between terminals
3 and 5.
If there is continuity, replace the relay.
(d) Inspect the No.3 cooling fan relay operation.
(1) Apply battery positive voltage across terminals 1
and 2.
(2) Using an ohmmeter, check that there is continuity
between terminals 3 and 5.
If there is no continuity, replace the relay.
(e) Reinstall the No.3 cooling fan relay.
(f) Reinstall the relay box cover.

CO09Z±03
A02725Turn
Loosen
B01614
Water Bypass Outlet
No.1 Water Bypass Hose
B01638
Clamp Bracket
Connector Bracket
B01572No.2 Water Bypass Pipe
± COOLING (2JZ±GE)WATER PUMP
CO±5
1543 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
1. REMOVE RADIATOR ASSEMBLY
(See page CO±18)
2. REMOVE DRIVE BELT AND WATER PUMP PULLEY
(a) Loosen the 4 nuts holding the water pump pulley to the
water pump.
(b) Loosen the drive belt tension by turning the drive belt ten-
sioner clockwise, and remove the drive belt.
(c) Remove the 4 nuts and water pump pulley.
3. REMOVE TIMING BELT AND IDLER PULLEY
(See page EM±16)
4. REMOVE WATER BYPASS OUTLET AND NO.1
WATER BYPASS PIPE
(a) Remove the 2 bolts, water bypass outlet and No.1 water
bypass pipe.
(b) Remove the 3 O±rings from the water bypass outlet and
No.1 water bypass pipe.
5. REMOVE WATER INLET AND THERMOSTAT
(See page CO±11)
6. REMOVE WATER PUMP
(a) Loosen the nut and remove the bolt, slide the generator
away from the water pump.
(b) Remove the bolt, and disconnect the clamp bracket (for
engine wire).
(c) Remove the bolt, and disconnect the connector bracket
(for crankshaft position sensor connector).
(d) Remove the 2 nuts, and disconnect the No.2 water by-
pass pipe from the water pump.

B01941
Drain Hose
CO±6
± COOLING (2JZ±GE)WATER PUMP
1544 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(e) Remove the 6 bolts, water pump and gasket.
(f) Remove the drain hose.
(g) Remove the O±ring from the cylinder block.

CO0A0±01
B01574
± COOLING (2JZ±GE)WATER PUMP
CO±7
1545 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
INSPECT WATER PUMP
Turn the pulley seat, and check that the water pump bearing is
not rough or noisy.
If necessary, replace the water pump.

CO0A1±03
P03945
New
O±Ring
P02574
New Gasket
A02801
AB A
B
A
B
B
B
B01614
New O±Ring
CO±8
± COOLING (2JZ±GE)WATER PUMP
1546 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSTALLATION
1. INSTALL WATER PUMP
(a) Install a new O±ring to the cylinder block.
(b) Install the drain hose.
(c) Install a new gasket to the water pump.
(d) Connect the water pump to the water bypass pipe. Do not
install the nut yet.
(e) Install the water pump with the 2 bolts (A) and 4 bolts (B).
Torque: 21 N´m (210 kgf´cm, 15 ft´lbf)
HINT:
Hand tighten the (A) bolts first.
(f) Install the 2 nuts holding the No.2 water bypass pipe to
the water pump.
Torque: 21 N´m (210 kgf´cm, 15 ft´lbf)
(g) Install the connector bracket (for crankshaft position sen-
sor connector) with the bolt.
(h) Install the clamp bracket (for engine wire) with the bolt.
(i) Install the generator with the bolt and nut.
Torque: 40 N´m (400 kgf´cm, 30 ft´lbf)
2. INSTALL THERMOSTAT AND WATER INLET
(See page CO±13)
3. INSTALL NO.1 WATER BYPASS PIPE AND WATER
BYPASS OUTLET
(a) Install 2 new O±rings to the No.1 water bypass pipe.
(b) Install a new O±ring and the water bypass outlet with the
2 bolts.
Torque: 9.0 N´m (90 kgf´cm, 80 in.´lbf)
4. INSTALL IDLER PULLEY AND TIMING BELT
(See page EM±23)
5. INSTALL WATER PUMP PULLEY AND DRIVE BELT
Torque: 14 N´m (140 kgf´cm, 10 ft´lbf)

± COOLING (2JZ±GE)WATER PUMP
CO±9
1547 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
6. INSTALL RADIATOR ASSEMBLY
(See page CO±23)

EC00B±05
± EMISSION CONTROL (2JZ±GE)EMISSION CONTROL SYSTEM
EC±1
1452 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
EMISSION CONTROL SYSTEM
PURPOSE
The emission control systems are installed to reduce the amount of CO, HC and NOx exhausted from the
engine (3) and (4)), to prevent the atmospheric release of blow±by gas±containing HC (1) and evaporated
fuel containing HC being released from the fuel tank (2).
The function of each system is shown in these table.
SystemAbbreviationFunction
(1) Positive Crankcase Ventilation
(2) Evaporative Emission Control
(3) Three±Way Catalytic Converter
(4) Sequential Multiport Fuel Injection *PCV
EVAP
TWC
SFIReduces blow±by gas (HC)
Reduces evaporated HC
Reduces CO, HC and NOx
Injects a precisely timed, optimum amount of fuel for reduced exhaust
emissions
Remark: * For inspection and repair of the SFI system, refer to the SF section this manual.

EC0DF±01
B01589
Air Cleaner, MAF Meter
and Intake Air Resonator
AssemblyPCV Hose
PS Air Hose
Air Cleaner Inlet MAF Meter Connector
Heated Oxygen Sensor
(Bank 1 Sensor 1)EVAP Hose

Gasket
Exhaust Manifold (with Front TWC)
Pipe Support Bracket
N´m (kgf´cm, ft´lbf)

Non±reusable partWire Grommet
Front Exhaust Pipe
: Specified torque
Heated Oxygen Sensor
(Bank 2 Sensor 1)
Heated Oxygen Sensor
(Bank 1 Sensor 2)

Gasket
40 (408, 30)
x 8
45 (450, 32)
44 (440, 32)
Engine Wire Clamp
Case Clamp

Clamp
44 (440, 32)
EC±12± EMISSION CONTROL (2JZ±GE)THREE±WAY CATALYTIC CONVERTER (TWC)
SYSTEM
1463 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
THREE±WAY CATALYTIC CONVERTER (TWC) SYSTEM
COMPONENTS

B08609
N´m (kgf´cm, ft´lbf) : Specified torque

Non±reusable part
44 (440, 32)
Gasket


Gasket

Front Exhaust Pipe
(with Rear TWC)
44 (440, 32)
44 (440, 32)
Pipe Support Bracket Floor Carpet Under CoverHeated Oxygen
Sensor Connector
TWC
± EMISSION CONTROL (2JZ±GE)THREE±WAY CATALYTIC CONVERTER (TWC)
SYSTEMEC±13
1464 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)