LEXUS GS400 2000 Service Repair Manual

Will you register the
next key?
No Ye s
Insert already registered master key in the key
cylinder
Depress and release the acceleration pedal 4
times.
Depress and release the brake pedal 5 times,
and remove the master key.
Insert key to be registered in key cylinder.
Depress and release the acceleration pedal 1
time. (Security indicator blinks.)
Within 10 sec.Within 15 sec.
Within 20 sec.
Within 10 sec.
Within 10 sec.
After 60 sec. additional sub±key is registered.
(Security indicator is OFF.)
The registration mode completes when pulling
out the key and depressing and releasing the
brake pedal once or more within 10 secs. after
indicator has been OFF or 10 sec. have passed.
± BODY ELECTRICALENGINE IMMOBILISER SYSTEM
BE±243
2544 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. REGISTRATION OF ADDITIONAL SUB±KEY
There are 2 ways for registration of additional sub±key, one way is depressing brake pedal and acceleration
pedal and the other way is using LEXUS hand±held tester.
HINT:

It is possible to register up to 3 sub±key codes including the already registered key code.

When any operation time described below is over, registration mode completes.

When the next procedure is performed while the timer is working, the timer completes counting time,
then next timer starts.
(1) Depressing brake pedal and acceleration pedal:

Will you register the
next key?
Insert already registered master key in the key cylinder.
Using LEXUS hand±held tester select sub±key registra-
tion.
Remove the master key.
Insert key to be registered in key cylinder.
(Security indicator blinks.)
After 60 sec., additional sub±key is registered.
(Security indicator OFF.)
No Ye s Within
10 sec.Within 120 sec.
Within 20 sec.
Within 10 sec.
The registration mode completes when pulling
out the key and depressing and releasing the
brake pedal once or more within 10 secs. after
indicator has been OFF or 10 sec. have passed.
BE±244
± BODY ELECTRICALENGINE IMMOBILISER SYSTEM
2545 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(2) Using LEXUS hand±held tester:

1. Insert master key in the key cylinder.
2. Depress and release the acceleration pedal 6 times.
3. Depress and release the brake pedal 7 times.
4. Remove the master key.
HINT:
If the key cannot be pulled out within 30 sec. from the first brake
depression in the step 3, the key code deletion is canceled.(Key code erased)
Within 15 sec.
Within 20 sec.
Within 10 sec.
END
5. Leave the vehicle more than 20 sec. without any
operation.
± BODY ELECTRICALENGINE IMMOBILISER SYSTEM
BE±245
2546 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
4. ERASURE OF TRANSPONDER KEY CODE
There are 2 ways for erasure of transponder key code, one way is depressing brake pedal and acceleration
pedal and the other way is using LEXUS hand±held tester.
NOTICE:
Delete all other master and sub±key codes leaving the master key code to use the operation. When
using the key which was used before deletion, it is necessary to register the code again.
HINT:

When any operation time described below is over, registration mode completes.

When the next procedure is performed while the timer is working, the timer completes counting time,
then next timer starts.
(1) Depressing brake pedal and acceleration pedal:

1. Insert master key in the key cylinder.
2. Require key code deletion from hand±held tester.
(Security indicator blinks)
3. Remove the master key.
HINT:
When the key cannot be pulled out in the step 3, key code deletion is canceled.
(Security indicator is OFF.) END
(Key code erased.)
Within 120 sec.
Within 10 sec.
BE±246
± BODY ELECTRICALENGINE IMMOBILISER SYSTEM
2547 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(2) Using LEXUS hand±held tester:

BE02Q±15
I01376
ECM
Transponder Key Coil
Driver Side Junction Block

IGN Fuse Transponder Key Amplifier
± BODY ELECTRICALENGINE IMMOBILISER SYSTEM
BE±247
2548 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.

BE0G8±09
I04266
1 2
BE±248
± BODY ELECTRICALENGINE IMMOBILISER SYSTEM
2549 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
INSPECTION TRANSPONDER KEY COIL CONTINUITY
Check that continuity exists between terminals 1 and 2.
If continuity is not as specified, replace the coil.

BE0FY±09
I01377
Horn
Horn Switch Engine Room No.1
Junction Block

HORN Fuse
Theft Deterrent Horn
Engine Room No.2
Junction Block

Horn Relay
± BODY ELECTRICALHORN SYSTEM
BE±249
2550 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
HORN 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.

BE0FZ±08
I04195
I04196
6
I04197
BE±250
± BODY ELECTRICALHORN SYSTEM
2551 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT HORN SWITCH
(a) Disconnect the negative (±) terminal from the battery.
(b) Remove the left and right covers from the steering wheel.
(c) Using a torx socket wrench, loosen the 2 bolts.
(d) Pull up the horn pad and place it on the steering column,
as shown.
HINT:
Do not disconnect the connector from the horn pad.
(e) Disconnect the connector from the slip ring.
(f) Check that no continuity exists between terminal 6 of the
connector and body ground.
(g) Check that continuity exists between terminal 6 of the
connector and body ground when the horn contact plate
is pressed against the steering spoke assembly.
If continuity is not as specified, repair or replace the steering
wheel or wire harness as necessary.
(h) Install the horn pad in place and using a torx socket
wrench, torque the 2 bolts.
Torque:
7.1 N´m (72 kgf´cm, 62 in.´lbf)
(i) Install the left and right covers.
(j) Connect the negative (±) terminal to the battery.
2. INSPECT HORN OPERATION
Connect the positive (+) lead from the battery to the terminal
and negative (±) lead to the horn body and check that the horn
blows.
If operation is not as specified, replace the horn.
3. INSPECT HORN SWITCH CIRCUIT
(See page DI±806)

I01200
2 1
35
2 5
1 3
± BODY ELECTRICALHORN SYSTEM
BE±251
2552 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
4. INSPECT HORN RELAY CONTINUITY
ConditionTester connectionSpecified condition
Constant1 ± 2Continuity
Apply B+ between
terminals 1 and 2.3 ± 5Continuity
If continuity is not as specified, replace the relay.
5. INSPECT HORN RELAY CIRCUIT
(See page BE±21)

BE19B±01
± BODY ELECTRICALTROUBLESHOOTING
BE±3
2304 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
TROUBLESHOOTING
PROBLEM SYMPTOMS TABLE
IGNITION SWITCH AND KEY UNLOCK WARNING SWITCH
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
Ignition Switch:
SymptomSuspect AreaSee page
Ignition switch is not set to each position.4. Ignition switch
5. Power source circuitBE±31
±
Key Unlock Warning Switch:
SymptomSuspect AreaSee page
Key unlock warning system does not operate.
(The buzzer does not sound when the driver's door is opened with
the ignition OFF and key inserted)1. Key Unlock Warning Switch
2. Door Courtesy Switch
3. Wire HarnessBE±31
BE±60
±
Key unlock warning system does not operate.
(The buzzer sounds when the ignition key is ACC or ON)1. Ignition Switch
2. Wire HarnessBE±31
±
HEADLIGHT AND TAILLIGHT SYSTEM:
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
HINT:
To inspect the bulb and light control ECU, replace them with the ones working normally and judge whether
they work normally or not.
SymptomSuspect AreaSee page
ºAutomatic light control systemº does not operate.
1. Automatic Light Control Sensor
2. Light Control Switch
3. Door Courtesy Switch
4. Wire Harness
5. Body No.2 ECUBE±37
BE±37
BE±60
±
DI±820
Auto turn±off system does not operate when the driver's door is
opened.1. Drivers Door Courtesy SwitchBE±60
Auto turn±off system:
Headlight and taillight do not come on.1. Body ECU No.2
2. Wire HarnessDI±820
±
Auto turn±off system:
Headlight and taillight stay on.1. Body ECU No.2
2. Wire HarnessDI±820
±
USA:
SymptomSuspect AreaSee page
Only one headlight comes on.
1. Bulb
2. *Light Control ECU
3. Wire Harness±
±
±
ºLO±Beamº does not light (All).
1. Headlight Control Relay
2. *Light Control ECU
3. Wire HarnessBE±37
±
±
ºLO±Beamº does not light (One side).
1. Bulb
2. H±LP L±LWR Fuse
3. H±LP R±LWR Fuse
4. *Light Control ECU
5. Wire Harness±
BE±21
BE±21
±
±
ºHI±Beamº does not light (All).1. Headlight Dimmer Switch
2. Wire HarnessBE±37
±