2000 LEXUS GS400 check engine light

I04080
Connector
ºOº, ºPº, ºQº, ºRº BE±94
± BODY ELECTRICALCOMBINATION METER
2395 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)F5 (±) ± F12 (+)
A/T shift indicator light (R)Continuity
F2 (±) ± F12 (+)A/T shift indicator light (N)Continuity
F1 (±) ± F12 (+)A/T shift indicator light (D)Continuity
G1 (+) ± G5 (±)Left turn signal indicator lightContinuity
G6 (+) ± G5 (±)Right turn signal indicator lightContinuity
If circuit is not as specified, replace the bulb or circuit plate.
3. INSPECT COMBINATION METER CIRCUIT PLATE
From combination meter ECU to gauges:
TerminalResistance (W)
O1 ± O3
(Engine coolant temperature receiver gauge)Approx. 164.2
O2 ± O4
(Engine coolant temperature receiver gauge)Approx. 151.8
P1 ± P4 (Tachometer)Approx. 164.2
P2 ± P3 (Tachometer)Approx. 151.8
Q1 ± Q4 (Speedometer)Approx. 164.2
Q2 ± Q3 (Speedometer)Approx. 151.8
R1 ± R4 (Fuel receiver gauge)Approx. 164.2
R2 ± R3 (Fuel receiver gauge)Approx. 151.8
If circuit is not as specified, inspect the gauge or meter.
Then recheck system.
If circuit is not as specified, replace the circuit plate.

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.

I04102
ON OFF
I04103
ON OFF
I04104
Wire Harness Side
I01286
BatteryWarning Light
± BODY ELECTRICALCOMBINATION METER
BE±101
2402 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
26. INSPECT ENGINE OIL LEVEL WARNING SENSOR
(a) Check that continuity exists between terminals with the
switch to below 40 °C (104 °F). (Warning switch ON)
(b) Heat the switch to above 60 °C (140 °F) in an oil bath.
(c) Check that there is continuity between terminals with the
switch ON (float up).
(d) Check that there is no continuity between terminals with
the switch OFF (float down).
If operation is not as specified, replace the switch.
27. INSPECT ENGINE OIL LEVEL WARNING SENSOR
CIRCUIT
Disconnect the switch connector and inspect the connector on
wire harness side, as shown.
Tester connectionConditionSpecified condition
2 ± GroundConstantContinuity
If continuity is not as specified, inspect the wire harness or
ground point.
28. INSPECT OPEN DOOR WARNING LIGHT
Disconnect the connector from the door courtesy switch and
ground terminal 1 on the wire harness side, and check that the
warning light lights up.
If the warning light does not light up, inspect the bulb or wire har-
ness.
29. INSPECT DOOR COURTESY SWITCH CONTINUITY
AND CIRCUIT (See page BE±60)

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.

F02847
Stop Light Switch
Push Rod
Pedal HeightBR0JB±07
F02849
Pedal Freeplay
± BRAKEBRAKE PEDAL
BR±9
2117 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
BRAKE PEDAL
ON±VEHICLE INSPECTION
1. CHECK PEDAL HEIGHT
Pedal height from asphalt sheet:
150.0 ± 160.0 mm (5.906 ± 6.299 in.)
2. IF NECESSARY, ADJUST PEDAL HEIGHT
(a) Remove the No. 1 under cover, end pad, No. 1 safety pad
and No. 7 heater to register duct (See page BO±88).
(b) Disconnect the connector from the stop light switch.
(c) Loosen the stop light switch lock nut and remove the stop
light switch.
(d) Loosen the push rod lock nut.
(e) Adjust the pedal height by turning the pedal push rod.
(f) Tighten the push rod lock nut.
Torque: 25 N´m (260 kgf´cm, 19 ft´lbf)
(g) Install the stop light switch.
(h) Push in the brake pedal 5 ± 15 mm (0.20 ± 0.59 in.), turn
the stop light switch to lock the nut in the position where
the stop light goes off.
(i) Connect the connector to the stop light switch.
(j) After installation, push in the brake pedal 5 ± 15 mm (0.20
± 0.59 in.), check that stop light lights up.
(k) After adjusting the pedal height, check the pedal freeplay.
(l) Install the No. 7 heater to register duct, No. 1 safety pad,
end pad and No. 1 under cover.
3. CHECK PEDAL FREEPLAY
(a) Stop the engine and depress the brake pedal more than
40 times until there is no more pressure left in the booster.
(b) Push in the pedal by hand until the second point of resis-
tance begins to be felt, then measure the distance, as
shown.
Pedal freeplay: 0.2 ± 2.0 mm (0.008 ± 0.079 in.)
If incorrect, check the stop light switch clearance. If the clear-
ance is OK, then troubleshoot the brake system.
Stop light switch clearance:
0.5 ± 2.4 mm (0.020 ± 0.094 in.)
HINT:
The freeplay to the 1st point of resistance is due to the play be-
tween the clevis and pin. It is 0.2 ± 2.0 mm (0.008 ± 0.079 in.)
on the pedal.

CH043±01
B01372
Except Maintenance±Free Battery
B01888
Maintenance±Free BatteryVoltmeter
± CHARGING (2JZ±GE)CHARGING SYSTEM
CH±1
1603 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
CHARGING SYSTEM
ON±VEHICLE INSPECTION
CAUTION:

Check that the battery cables are connected to the
correct terminals.

Disconnect the battery cables when the battery is giv-
en a quick charge.

Do not do tests with a high voltage insulation resis-
tance tester.

Never disconnect the battery while the engine is run-
ning.
1. CHECK BATTERY ELECTROLYTE LEVEL
Check the electrolyte quantity of each cell.
Maintenance±Free Battery:
If under the lower level, replace the battery (or add distilled wa-
ter if possible). Check the charging system.
Except Maintenance±Free Battery:
If under the lower level, add distilled water.
2. Except Maintenance±Free Battery:
CHECK BATTERY SPECIFIC GRAVITY
Check the specific gravity of each cell.
Standard specific gravity: 1.25 ± 1.29 at 20°C (68°F)
If the specific gravity is less than specification, charge the bat-
tery.
3. Maintenance±Free Battery:
CHECK BATTERY POSITIVE VOLTAGE
(a) After having driven the vehicle and in the case that 20
minutes have not passed after having stopped the en-
gine, turn the ignition switch ON and turn on the electrical
system (headlight, blower motor, rear defogger etc.) for
60 seconds to remove the surface charge.
(b) Turn the ignition switch OFF and turn off the electrical sys-
tems.
(c) Measure the battery positive voltage between the nega-
tive (±) and positive (+) terminals of the battery.
Standard voltage: 12.5 ± 12.9 V at 20°C (68°F)
If the voltage is less than specification, charge the battery.
4. CHECK BATTERY TERMINALS AND FUSES
(a) Check that the battery terminals are not loose or cor-
roded.
If the terminals are corroded, clean the terminals.
(b) Check the fusible link and fuses for continuity.