ignition LEXUS GS400 2000 Service Manual PDF

I01272
2
1
I04077
Wire Harness Side
± BODY ELECTRICALWIPER AND WASHER SYSTEM
BE±79
2380 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
7. INSPECT WASHER MOTOR OPERATION
Connect the positive (+) lead from the battery to terminal 2 and
the negative (±) lead to terminal 1, check that the motor oper-
ates.
NOTICE:
These tests must be performed quickly (within 20 seconds) to
prevent the coil from burning out.
If operation is not as specified, replace the motor.
8. INSPECT WASHER MOTOR CIRCUIT
Connector disconnected:
Disconnect the connector from the motor and inspect the con-
nector on the wire harness side, as shown.
Tester connectionConditionSpecified condition
2 ± GroundIgnition switch ONBattery positive voltage
If circuit is not as specified, inspect the power source, wire har-
ness and wiper switch.

BE0HH±07
I01359
Brake Master Cylinder

Brake Fluid Level
Warning Switch
Combination Meter
and Telltale Light
Assembly
Airbag Sensor Assembly Parking Brake Switch
Driver Side
Junction Block

GAUGE Fuse

SRS±B FuseIgnition Switch
ECM
Washer Tank

Washer Level
Warning Switch Engine Room No.1
Junction Block

MPX±B Fuse
Seat Belt Buckle Switch
Rheostat Light Control
ABS, TRAC and VSC ECU
Clock Assembly

Passenger Seat Belt
Waning Light
BE±80
± BODY ELECTRICALCOMBINATION METER
2381 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
COMBINATION METER
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.

I04078
Connector ºBº Connector ºAº
BE0HL±03
BE±92
± BODY ELECTRICALCOMBINATION METER
2393 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT COMBINATION METER CIRCUIT
Connector disconnected:
Disconnect connector ºAº and ºBº from the combination meter
and inspect the connectors on the wire harness side as shown
in the table.
Tester connectionConditionSpecified condition
A1 ± GroundIgnition switch ONBattery positive voltage
A3 ± A4ConstantContinuity
A7 ± GroundLight control switch HEAD and headlight dimmer
switch HIContinuity
A8 ± Ground
B22 ± GroundConstantContinuity
A10 ± GroundWindow washer level warning switch Float downContinuity
B1 ± GroundIgnition switch ONBattery positive voltage
B4 ± B6ConstantApprox. 10 kW
B13 ± GroundConstantBattery positive voltage
B14 ± GroundConstantBattery positive voltage
B15 ± GroundLight control switch in HEADBattery positive voltage
If circuit is not as specified, wiring diagram and inspect the cir-
cuits connected to other parts.

I04085
AD
C
B
I04086
Fuel Receiver Gauge
Battery Ignition
Switch
Main
Sender
Gauge Wire Harness
Side
I04087
Battery Ignition
SwitchFuel Receiver Gauge
Wire Harness
SideSub
Sender
Gauge12
I04089
AD
C
B
I04090
F
1/2
E32
± BODY ELECTRICALCOMBINATION METER
BE±97
2398 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
9. INSPECT TACHOMETER RESISTANCE
Measure the resistance between terminals with fixing pointer to
the stopper.
Tester connectionResistance (W)
A ± B140 ± 185
C ± D130 ± 175
If resistance value is not as specified, replace the meter.
10. INSPECT FUEL RECEIVER GAUGE OPERATION
(See page DI±752)
(a) Disconnect the connector from the main sender gauge.
(b) Turn the ignition switch ON, check that the receiver gauge
needle indicates EMPTY.
(c) Connect the main sender gauge.
(d) Disconnect the connector from the sub sender gauge.
(e) Turn the ignition switch ON, check that the receiver gauge
needle indicates EMPTY.
HINT:
Because of the silicon oil in the gauge, it will take a short time
for needle to stabilize.
If operation is not as specified, inspect the receiver gauge resis-
tance.
11. INSPECT FUEL RECEIVER GAUGE RESISTANCE
Measure the resistance between terminals with fixing pointer to
the stopper.
Tester connectionResistance (W)
A ± B140 ± 185
C ± D130 ± 175
If resistance value is not as specified, replace the receiver
gauge.
12. INSPECT FUEL MAIN SENDER GAUGE RESISTANCE
Measure the resistance between terminals 1 and 2 for each
float position.
Float position mm (in.)Resistance (W)
F: Approx. 34.6 (1.36) ± 3 (0.12)Approx. 2.0 ± 1.0
1/2: Approx. 52.4 (2.06) ± 3 (0.12)Approx. 26.1 ± 3.0
E: Approx. 134.9 (5.31) ± 3 (0.12)Approx. 48.7 ± 1.0
If resistance value is not as specified, replace the main sender
gauge.

I04091
F
E1
2
1/2
I04094
A
D
C
B
I01277
Battery Ignition
SwitchWarning Light
Wire Harness Side
1 BE±98
± BODY ELECTRICALCOMBINATION METER
2399 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
13. INSPECT FUEL SUB SENDER GAUGE RESISTANCE
Measure the resistance between terminals 1 and 2 for each
float position.
Float position mm (in.)Resistance (W)
F: Approx. 9.5 (0.37) ± 3 (0.12)Approx. 2.0 ± 1.0
1/2: Approx. 110.5 (4.35) ± 3 (0.12)Approx. 33.0 ± 3.0
E: Approx. 206.5 (8.13) ± 3 (0.12)Approx. 61.3 ± 1.0
If resistance value is not as specified, replace the sub sender
gauge.
14. INSPECT ENGINE COOLANT TEMPERATURE RE-
CEIVER GAUGE OPERATION (See page DI±754)
15. INSPECT ENGINE COOLANT TEMPERATURE RE-
CEIVER GAUGE RESISTANCE
Measure the resistance between terminals with fixing pointer to
the stopper.
Tester connectionResistance (W)
A ± B140 ± 185
C ± D130 ± 175
If resistance value is not as specified, replace the receiver
gauge.
HINT:
This circuit includes the diode.
If resistance value is not as specified, replace the receiver
gauge.
16. INSPECT LOW OIL PRESSURE WARNING LIGHT
(a) Disconnect the connector from the warning switch and
ground terminal on the wire harness side connector.
(b) Turn the ignition switch ON and check that the warning
light lights up.
If the warning light does not light up, test the bulb.

I01278
I01279
Battery Ignition
SwitchWarning Light
I04095
OFF
ON
I04096
± BODY ELECTRICALCOMBINATION METER
BE±99
2400 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
17. INSPECT LOW OIL PRESSURE SWITCH CONTINUITY
(a) Disconnect the connector from the switch.
(b) Check that continuity exists between terminal and ground
with the engine stopped.
(c) Check that no continuity exists between terminal and
ground with the engine running.
HINT:
Oil pressure should be over 24.5 kPa (0.25 kgf/cm
2, 3.55 psi).
If operation is not as specified, replace the switch.
18. INSPECT BRAKE WARNING LIGHT
(a) Disconnect the connector from the brake fluid warning
switch.
(b) Release the parking brake pedal.
(c) Connect the terminals on the wire harness side of the lev-
el warning switch connector.
(d) Start the engine, check that the warning light lights up.
If the warning light does not light up, test the bulb or wire har-
ness.
19. INSPECT BRAKE FLUID LEVEL WARNING SWITCH
CONTINUITY
(a) Remove the reservoir tank cap and strainer.
(b) Disconnect the connector.
(c) Check that no continuity exists between the terminals with
the switch OFF (float up).
(d) Use siphon, etc. to take fluid out of the reservoir tank.
(e) Check that continuity exists between the terminals with
the switch ON (float down)
(f) Pour the fluid back in the reservoir tank.
If operation is not as specified, replace the switch.
20. INSPECT BRAKE FLUID LEVEL WARNING SWITCH
CIRCUIT (See page DI±835)
21. INSPECT PARKING BRAKE SWITCH CONTINUITY
(a) Check that continuity exists between the terminal and
switch body with the switch ON (switch pin released).
(b) Check that no continuity exists between the terminal and
switch body with the switch OFF (switch pin pushed in).
If operation is not as specified, replace the switch or inspect
ground point.
22. INSPECT PARKING BRAKE SWITCH CIRCUIT
(See page DI±796)

I04097
Battery Ignition
SwitchWarning Light
Wire Harness Side
I04098
Wire Harness Side
I04099
BatteryIgnition
SwitchWarning Light
Wire Harness Side BE±100
± BODY ELECTRICALCOMBINATION METER
2401 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
23. INSPECT REAR LIGHTS WARNING LIGHT
(See page DI±841)
(a) Disconnect the connector from the light failure sensor and
ground terminal 3 on the wire harness side connector.
(b) Start the engine, check that the warning light lights up.
If the warning light does not light up, inspect the bulb or wire har-
ness.
24. INSPECT LIGHT FAILURE SENSOR CIRCUIT
Disconnect connector from the light failure sensor and inspect
the connectors on the wire harness side as follows.
Tester connectionConditionSpecified condition
1 ± GroundConstantContinuity *
2 ± GroundConstantContinuity *
6 ± GroundConstantContinuity *
7 ± GroundConstantContinuity *
11 ± GroundConstantContinuity
12 ± GroundConstantContinuity *
5 ± GroundLight control switch OFFNo voltage
5 ± GroundLight control switch in TAIL or HEADBattery positive voltage
8 ± GroundIgnition switch in LOCK or ACCNo voltage
8 ± GroundIgnition switch ONBattery positive voltage
9, 10 ± GroundStop light switch OFFNo voltage
9, 10 ± GroundStop light switch ONBattery positive voltage
*: There is resistance because this circuit is grounded through
the bulb.
If circuit is as specified, replace the relay.
If circuit is not as specified, wiring diagram and inspect the cir-
cuits connected to other parts.
25. INSPECT ENGINE OIL LEVEL WARNING LIGHT
(a) Disconnect the connector from the switch.
(b) Run the engine.
(c) Turn the ignition switch ON, check that the warning light
lights up approximatery 40 seconds later.
If the warning light does not light up, inspect bulb or wire har-
ness.

I04105
Dark
(10k W)Bright
(0W)
4
5
I01322
Battery Ignition
SwitchWarning Light
2 1 Wire Harness Side
I01323
1 2 OFF
ON
I01328
Battery Ignition
SwitchWarning Light
2 1 Wire Harness Side
I04107
12
4
OFF
ON BE±102
± BODY ELECTRICALCOMBINATION METER
2403 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
30. INSPECT LIGHT CONTROL RHEOSTAT OPERATION
Gradually, turn the rheostat knob from the bright side to dark
side and check that the resistance decreases from 10 kW to 0
W between terminal 4 and 5. (Rheostat knob turned to clock-
wise)
If operation is not as specified, replace the rheostat light control.
31. INSPECT WINDOW WASHER LEVEL WARNING
LIGHT
(a) Disconnect the connector from the warning switch and
ground terminal on the wire harness side connector.
(b) Engine running and check that the warning light lights up.
If the warning light does not light up, inspect the bulb or wire har-
ness.
32. INSPECT WINDOW WASHER LEVEL WARNING
SWITCH CONTINUITY
(a) Check that no continuity exists between the terminals with
the switch OFF (float up).
(b) Check that continuity exists between the terminals with
the switch ON (float down).
If operation is not as specified, replace the switch or inspect
ground point.
33. INSPECT SEAT BELT WARNING LIGHT
(a) Disconnect the connector from the retractor switch and
ground terminal on the wire harness side connector.
(b) Turn the ignition switch ON and check that the warning
light lights up.
If the warning light does not light up, inspect the bulb or wire har-
ness.
34. INSPECT SEAT BELT BUCKLE SWITCH CONTINUITY
(a) Check that continuity exists between the terminals 1 and
4 on the switch side connector with the switch ON (belt
fastened).
(b) Check that continuity exists between the terminals 2 and
4 on the switch side connector with the switch OFF (belt
unfastened).
If operation is not as specified, replace the switch.

F02911
SST
Effort Gauge
SST
BR0K7±04
BR±38
± BRAKEHYDRAULIC BRAKE BOOSTER
2146 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
HYDRAULIC BRAKE BOOSTER
ON±VEHICLE INSPECTION
1. CHECK HYDRAULIC BRAKE BOOSTER FLUID PRES-
SURE CHANGE
(a) Inspect the battery positive voltage.
Battery positive voltage: 10 ± 14 V
(b) Turn the ignition switch OFF, depress the brake pedal
more than 40 times.
(c) Install LSPV gauge (SST) and brake pedal effort gauge,
bleed air.
SST 09709±29018
(d) When booster does not operate.
Depress the brake pedal and check fluid pressure.
At 245 N (25 kgf, 55 lbf):
Front brake pressureRear brake pressure
1,470 kPa (15 kgf/cm2, 213 psi)
or more0 kPa (0 kgf/cm2, 0 psi)
At 343 N (35 kgf, 77 lbf):
Front brake pressureRear brake pressure
2,059 kPa (21 kgf/cm2, 299 psi)
or more0 kPa (0 kgf/cm2, 0 psi)
(e) When booster operates.
(1) Turn the ignition switch ON and wait until the pump
motor has stopped.
(2) Depress the brake pedal and check fluid pressure.
At 49 N (5 kgf, 11 lbf):
Front brake pressureRear brake pressure
794 ± 1,814 kPa
(8.1 ± 18.5 kgf/cm2, 115 ± 263 psi)
961 ± 2,148 kPa
(9.8 ± 21.9 kgf/cm2, 139 ± 311 psi)
At 98 N (10 kgf, 22 lbf):
Front brake pressureRear brake pressure
3,442 ± 5,011 kPa
(35.1 ± 51.1 kgf/cm2, 499 ± 727 psi)
3,923 ± 5,698 kPa
(40 ± 58.1 kgf/cm2, 569 ± 826 psi)
At 147 N (15 kgf, 33 lbf):
Front brake pressureRear brake pressure
5,629 ± 7,845 kPa
(57.4 ± 80 kgf/cm2, 816 ± 1,138 psi)
6,237 ± 8,640 kPa
(63.6 ± 88.1 kgf/cm2, 905 ± 1,253 psi)
At 196 N (20 kgf, 44 lbf):
Front brake pressureRear brake pressure
8,002 ± 10,591 kPa
(81.6 ± 108 kgf/cm2, 1,161± 1,536 psi)
8,718 ± 11,572 kPa
(88.9 ± 118 kgf/cm2, 1,264 ± 1,678 psi)

D01827
± BRAKEHYDRAULIC BRAKE BOOSTER
BR±39
2147 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. IN CASE OF USING LEXUS HAND±HELD TESTER:
INSPECT HYDRAULIC BRAKE BOOSTER OPERA-
TION
(a) Inspect the battery positive voltage.
Battery positive voltage: 10 ± 14 V
(b) Turn the ignition switch OFF, depress the brake pedal
more than 40 times.
(c) Check that the brake pedal becomes heavy to depress.
If the pedal does not become to be heavy to depress, check and
replace the brake line and hydraulic brake booster.
(d) Turn the ignition switch ON, check the pump motor opera-
tion noise.
If the pump motor does not operate, check and replace the wire
harness and pump motor (See page BR±53).
(e) Connect the LEXUS hand±held tester.
(1) Connect the LEXUS hand±held tester to the DLC3.
(2) Turn the ignition switch ON.
(3) Select the ºACTIVE TESTº mode on the LEXUS
hand±held tester.
HINT:

Please refer to the LEXUS hand±held tester operator's
manual for further details.

To protect the solenoids, hand±held tester turns OFF au-
tomatically 2 secs. after every solenoid has been turned
ON.
(f) Inspect the front TRAC & VSC solenoid operation.
(1) Select ºSA1º and ºSA2º on the LEXUS hand±held
tester.
(2) With ºSA1º and ºSA2º turned ON simultaneously
with the LEXUS hand±held tester, depress the
brake pedal with stable force and check that the
pedal cannot be depressed.
HINT:
To protect the solenoids, LEXUS hand±held tester turns OFF
automatically 2 sec. after every solenoid has been turned ON.
If the pedal can be depressed, replace the hydraulic brake
booster.
NOTICE:
When operating it continuously, set the interval of more
than 20 seconds.
(3) Once, release the brake pedal.