LEXUS GS400 2000 Service Repair Manual

BE±14
± BODY ELECTRICALTROUBLESHOOTING
2315 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
w/o Driving Position Memory System:
SymptomSuspect AreaSee page
Mirror does not operate.
1. Mirror Switch
2. Wire Harness
3. Body No.2 ECU
4. Driver and Passenger Door ECUBE±176
±
DI±820
DI±856
DI±889
Mirror operates abnormally.
1. Mirror Switch
2. Mirror Motor
3. Wire Harness
4. Body No.2 ECU
5. Driver and Passenger Door ECUBE±176
BE±176
±
DI±820
DI±856
DI±889
ELECTRO CHROMIC MIRROR SYSTEM
SymptomSuspect AreaSee page
Electro Chromic Inner Mirror does not operate.
1. ECU±IG Fuse
2. Electro Chromic Inner Mirror
3. Wire HarnessBE±21
BE±182
±
Electro Chromic Outer Mirror does not operate.
1. ECU±IG Fuse
2. Electro Chromic Outer Mirror
3. Electro Chromic Inner Mirror
4. Wire HarnessBE±21
BE±182
BE±182
±
SEAT HEATER SYSTEM
SymptomSuspect AreaSee page
Seat heaters do not operate.
(Driver's and Passenger's)
1. SEAT HTR Fuse
2. Seat Heater Switch (D, P)
3. Wire Harness
4. Seat HeaterBE±21
BE±185
±
BE±185
Driver's seat heater does not operate.1. Seat Heater Switch (D, P)
2. Wire HarnessBE±185
±
Passenger's seat heater does not operate.1. Seat Heater Switch (D, P)
2. Wire HarnessBE±185
±
Seat heater temperature is too hot.Seat HeaterBE±185
FUEL LID OPENER SYSTEM
SymptomSuspect AreaSee page
Fuel lid opener system does not operate.
1. FUEL OPN Fuse
2. Fuel Lid Opener Switch
3. Fuel Lid Opener Motor
4. Wire HarnessBE±21
BE±188
BE±188
±
AUDIO SYSTEM
SymptomSuspect AreaSee page
Audio system abnormal operation.TROUBLESHOOTINGSBE±196
CLOCK SYSTEM
SymptomSuspect AreaSee page
Passenger seat belt warning system does not light up.TROUBLESHOOTING NO.1BE±227
Clock will not operate.TROUBLESHOOTING NO.1BE±227
Clock loses or gains time.TROUBLESHOOTING NO.2BE±227

± BODY ELECTRICALTROUBLESHOOTING
BE±15
2316 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
GARAGE DOOR OPENER SYSTEM
SymptomSuspect AreaSee page
The equipment of which code has been registered does not oper-
ate.1. Garage Door Opener Switch
2. Wire Harness
3. *BE±235
±
±
LED does not light up. (Even though either switch is pressed.)1. Garage Door Opener Switch
2. Wire HarnessBE±235
±
LED does not light up. (Only one switch is pressed.)Garage Door Opener SwitchBE±235
* As the GARAGE DOOR OPENER on the vehicle side seems to be normal, check the OPENER on the
equipment side, of which code has been registered.
ENGINE IMMOBILIZER SYSTEM
SymptomSuspect AreaSee page
Engine immobilizer system does not operate.See DIAGNOSIS SYSTEMDI±726
HORN SYSTEM
SymptomSuspect AreaSee page
Horn system does not operate.
1. HORN Fuse
2. Horn Relay
3. Horn Switch
4. Horn
5. Wire HarnessBE±21
BE±250
BE±250
BE±250
±
Horns blow all the time.
1. Horn Relay
2. Horn Switch
3. Wire HarnessBE±250
BE±250
±
One horn operates but the other horn does not operate.1. Horn
2. Wire HarnessBE±250
±
Horns operate abnormally.
1. Horn Relay
2. Horn
3. Wire HarnessBE±250
BE±250
±

BE01L±11
I01349
Ignition SwitchKey Unlock Warning Switch
BE±30± BODY ELECTRICALIGNITION SWITCH AND KEY UNLOCK WARNING
SWITCH
2331 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
IGNITION SWITCH AND KEY UNLOCK WARNING SWITCH
LOCATION

BE0H4±04
I01256
1 2 3 4
5 6 7 8 LOCKACC
ON
START
I04031
From Back Side
± BODY ELECTRICALIGNITION SWITCH AND KEY UNLOCK WARNING
SWITCHBE±31
2332 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT IGNITION SWITCH CONTINUITY
Switch positionTester connectionSpecified condition
LOCK±No continuity
ACC2 ± 3Continuity
ON2 ± 3 ± 4
6 ± 7Continuity
START1 ± 2 ± 4
6 ± 7 ± 8Continuity
If continuity is not as specified, replace the switch.
2. INSPECT IGNITION SWITCH CIRCUIT
Connect the switch connector and inspect the connector on
wire harness side from the back side, as shown.
Tester connectionConditionSpecified condition
2 ± GroundConstantBattery positive voltage
3 ± GroundIgnition switch ACC or ONBattery positive voltage
4 ± GroundIgnition switch ONBattery positive voltage
6 ± GroundIgnition switch ON or STARTBattery positive voltage
7 ± GroundConstantBattery positive voltage
8 ± GroundIgnition switch STARTBattery positive voltage
If circuit is not as specified, inspect the circuits connected to oth-
er parts.

I04265
I01663
1 2 OFF
ON
3 4
I04032
Wire Harness Side BE±32
± BODY ELECTRICALIGNITION SWITCH AND KEY UNLOCK WARNING
SWITCH
2333 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. INSPECT IGNITION KEY ILLUMINATION OPERATION
Connect the positive (+) lead from the battery to terminal 1 and
the negative (±) lead to terminal 2, and check that the indicator
light lights up.
If operation is not as specified, replace the switch.
4. INSPECT IGNITION KEY ILLUMINATION CIRCUIT
(See page DI±843)
5. INSPECT KEY UNLOCK WARNING SWITCH CONTI-
NUITY
Switch positionTester connectionSpecified condition
OFF (Key removed)±No continuity
ON (Key set)1 ± 2Continuity
If continuity is not as specified, replace the switch.
6. INSPECT KEY UNLOCK WARNING SWITCH CIRCUIT
(See page DI±828)
Connect the switch connector and inspect the connector on
wire harness side from the back side, as shown.
Tester connectionConditionSpecified condition
1 ± GroundConstantContinuity
If circuit is not as specified, inspect the circuits connected to oth-
er parts.

BE0H8±04
I10257
Driver Side Junction Block

GAUGE Fuse

TAIL Fuse

Taillight Control Relay

Body ECU No.2
Combination Switch

Light Control Switch

Headlight Dimmer SwitchIgnition Switch
Daytime Running
Light Main Relay
(w/ D.R.L. System) HeadlightsEngine Room No.1 Junction Block

H±LP L LWR Fuse

H±LP R LWR Fuse

H±LP L UPR Fuse (w/o D.R.L System)

H±LP R UPR Fuse (w/o D.R.L System)

Headight Control Relay D.R.L.: Daytime Running Light
Automatic Light Control Sensor
Headlights
Taillights
Engine Room No.2 Junction Block

Headight Dimmer (D.R.L. No.2) Relay

H±LP R UPR Fuse (w/ D.R.L System)

H±LP L UPR Fuse (w/ D.R.L System)
Light Control ECU Light Control ECU
Daytime Running Light No.3 and No.4 Relay
(w/ D.R.L. System)
Daytime Running Light Resister
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
BE±33
2334 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
HEADLIGHT AND TAILLIGHT SYSTEM
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.

BE0H9±05
I04239
Switch BodyWiper and Washer Switch
Light Control Switch and
Headlight Dimmer Switch
Steering Angle Sensor
Steering Position DiscSpiral Cable
Tilt and Telescopic Switch
Compression Spring
Cancel Cam
BE±34
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
2335 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
COMPONENTS

I04240
BE0K2±02
I04241
I04242
I04243
I04244
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
BE±35
2336 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
1. REMOVE SPIRAL CABLE
Remove the 4 screws and the spiral cable.
2. REMOVE WIPER AND WASHER SWITCH
Remove the 2 screws and the wiiper and washer switch.
3. REMOVE TILT AND TELESCOPIC SWITCH
Remove a screw and the tilt and telescopic switch.
4. REMOVE STEERING ANGLE SENSOR
Disengage the 2 claws and the steering angle sensor.
5. REMOVE LIGHT CONTROL SWITCH
Remove the 2 screws and the light control switch.

I04245
I04246
I04247
BE±36
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
2337 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
6. REMOVE STEERING POSITION DISC
7. REMOVE CANCEL CAM
Turn the cancel cam with pressing it and pull it out.
8. REMOVE COMPRESSION SPRING

BE0HA±02
I04033
HI
Flash OFFTAIL HEAD AUTO
LO
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
BE±37
2338 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. FAIL±SAFE FUNCTION
(Light Control ECU)
When input error is inspected.
When input voltage is not within the range of operation voltage (9 to 16 V),
lighting of the headlight stops. As soon as the voltage comes within the range,
it lights up again.
However if the input voltage becomes low after lighting up,
sufficient voltage is maintained until light of bulb completely goes off.
When output error is inspected (Open or short).
When light flushing is inspected.
When an error occurs in the output voltage (open or short) or flushing symptom
occurs on the bulb, lighting of the headlight stops, the condition is maintained
until power is turned ON again (headlight dimmer switch OFF " ON).
In this case, it can not be judged whether lighting malfunction is caused by an
output error or other reasons (fuse blown out, etc.).
Check that there is no error in fuse and wiring (including power source) and
replace the bulb in the first place, when the error still appears, replace the light
control ECU.
2. INSPECT LIGHT CONTROL SWITCH CONTINUITY
Switch positionTester connectionSpecified condition
OFF±No continuity
TAIL15 ± 16Continuity
HEAD14 ± 15 ± 16Continuity
AUTO13 ± 16Continuity
If continuity is not as specified, replace the switch.
3. INSPECT HEADLIGHT DIMMER SWITCH CONTINU-
ITY
Switch positionTester connectionSpecified condition
Low beam17 ± 18Continuity
High beam8 ± 17Continuity
Flash8 ± 9 ± 17Continuity
If continuity is not as specified, replace the switch.