light LEXUS GS400 2000 Service Repair Manual

F02853
B01549
F02853
IN±18
± INTRODUCTIONFOR ALL OF VEHICLES
18 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
5. FOR VEHICLES EQUIPPED WITH VEHICLE SKID
CONTROL (VSC) SYSTEM
NOTICE:
When using a 2±wheel drum tester such as a speedometer
tester or chassis dynamometer, etc., or jacking up the rear
wheels and driving the wheels, always push in the TRAC &
VSC cut switch and turn the TRAC & VSC system OFF.
(a) Press the VSC OFF switch.
(b) Check that the VSC OFF indicator light comes ON.
HINT:
The VSC OFF indicator light should be always OFF when the
engine is restarted.
(c) Begin measurements.
(d) Press the VSC OFF switch again to change the TRAC &
VSC system to operational condition and check that the
VSC OFF indicator light goes off.
HINT:
The SLIP indicator light blinks when the TRAC system is opera-
tional.

V07268
VIBRATION METHOD: When vibration seems to be the major cause.
CONNECTORS
WIRE HARNESS
PARTS AND SENSOR1
Slightly shake the connector vertically and horizontally.
Slightly shake the wire harness vertically and horizontally.
The connector joint, fulcrum of the vibration, and body
through portion are the major areas to be checked thorough-
ly.
Apply slight vibration with a finger to the part of the sensor
considered to be the problem cause and check that the mal-
function occurs.Shake Slightly
Swing Slightly
Vibrate Slightly
HINT:
Applying strong vibration to relays may result in open relays.
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±25
25 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. SYMPTOM SIMULATION
The most difficult case in troubleshooting is when there are no problem symptoms occurring. In such cases,
a thorough customer problem analysis must be carried out, then simulate the same or similar conditions and
environment in which the problem occurred in the customer's vehicle. No matter how much experience a
technician has, or how skilled he may be, if he proceeds to troubleshoot without confirming the problem
symptoms he will tend to overlook something important in the repair operation and make a wrong guess
somewhere, which will only lead to a standstill. For example, for a problem which only occurs when the en-
gine is cold, or for a problem which occurs due to vibration caused by the road during driving, etc., the prob-
lem can never be determined so long as the symptoms are confirmed with the engine hot condition or the
vehicle at a standstill. Since vibration, heat or water penetration (moisture) is likely cause for problem which
is difficult to reproduce, the symptom simulation tests introduced here are effective measures in that the ex-
ternal causes are applied to the vehicle in a stopped condition.
Important Points in the Symptom Simulation Test:
In the symptom simulation test, the problem symptoms should of course be confirmed, but the problem area
or parts must also be found out. To do this, narrow down the possible problem circuits according to the symp-
toms before starting this test and connect a tester beforehand. After that, carry out the symptom simulation
test, judging whether the circuit being tested is defective or normal and also confirming the problem symp-
toms at the same time. Refer to the problem symptoms table for each system to narrow down the possible
causes of the symptom.

B02389
B02390
HEAT METHOD: When the problem seems to occur when the suspect area is heated. 2
NOTICE:3 WATER SPRINKLING METHOD:
(1)
(2)
4 OTHER: When a malfunction seems to occur when electrical load is excessive.When the malfunction seems to occur on a rainy day or in a
high±humidity condition. Heat the component that is the likely cause of the malfunction
with a hair dryer or similar object. Check to see if the malfunction
occurs.
Sprinkle water onto the vehicle and check to see if the malfunc-
tion occurs.
Turn on all electrical loads including the heater blower, head
lights, rear window defogger, etc. and check to see if the mal-
function occurs.ON HINT:
If a vehicle is subject to water leakage, the leaked water may
contaminate the ECU. When testing a vehicle with a water leak-
age problem, special caution must be taken.
Malfunc-
tion
Do not heat to more than 60 °C (140 °F). (Temperature
is limited not to damage the components.)
Do not apply heat directly to parts in the ECU. (1)
(2)
Never sprinkle water directly into the engine compart-
ment, but indirectly change the temperature and hu-
midity by applying water spray onto the radiator front
surface.
Never apply water directly onto the electronic compo-
nents. NOTICE: IN±26
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
26 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

V08423 Knock Sensor 1
GRECM
KNK
E1 12
E6
WIRING DIAGRAM
Wiring Diagram
This shows a wiring diagram of the circuit.
Use this diagram together with ELECTRICAL
WIRING DIAGRAM to thoroughly understand the
circuit.
Wire colors are indicated by an alphabetical code.
B = Black, L = Blue, R = Red, BR = Brown,
LG = Light Green, V = Violet, G = Green,
O = Orange, W = White, GR = Gray, P = Pink,
Y = Yellow, SB = Sky Blue
The first letter indicates the basic wire color and
the second letter indicates the color of the stripe.
DTC P0325Knock Sensor 1 Circuit Malfunction
CIRCUIT DESCRIPTION
Knock sensor is fitted to the cylinder block to detect engine knocking. This sensor contains a piezoelectric element which
generates a voltage when it becomes deformed, which occurs when the cylinder block vibrates due to knocking. If engine
knocking occurs, ignition timing is retarded to suppress it.
DTC No. DTC Detecting Condition Trouble Area
P0325No knock sensor 1 signal to ECM with engine speed,
1,200 rpm or more.
Open or short in knock sensor1 circuit

Knock sensor 1 (looseness)

ECM
If the ECM detects the above diagnosis conditions, it operates the fall safe function in which the corrective retard angle
value is set to the maximum value.

Diagnostic Trouble Code No. and Detection Item

Circuit Description
The major role and operation, etc. of the circuit
and its component parts are explained.

Indicates the diagnostic trouble code, diagnostic
trouble code set parameter and suspect area of
the problem.


± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±29
29 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
6. CIRCUIT INSPECTION
How to read and use each page is shown below.

FI7187
IN0379
Sensor Side
ECU Side
IN0378
Sensor SideECU Side
IN0380
Sensor SideECU Side
IN0381
Pull Lightly
Looseness of Crimping
IN±32± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMS
32 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. CONNECTOR HANDLING
When inserting tester probes into a connector, insert them from
the rear of the connector. When necessary, use mini test leads.
For water resistant connectors which cannot be accessed from
behind, take good care not to deform the connector terminals.
3. CONTINUITY CHECK (OPEN CIRCUIT CHECK)
(a) Disconnect the connectors at both ECU and sensor
sides.
(b) Measure the resistance between the applicable terminals
of the connectors.
Resistance: 1 W or less
HINT:
Measure the resistance while lightly shaking the wire harness
vertically and horizontally.
4. RESISTANCE CHECK (SHORT CIRCUIT CHECK)
(a) Disconnect the connectors on both ends.
(b) Measure the resistance between the applicable terminals
of the connectors and body ground. Be sure to carry out
this check on the connectors on both ends.
Resistance: 1 MW or higher
HINT:
Measure the resistance while lightly shaking the wire harness
vertically and horizontally.
5. VISUAL CHECK AND CONTACT PRESSURE CHECK
(a) Disconnect the connectors at both ends.
(b) Check for rust or foreign material, etc. in the terminals of
the connectors.
(c) Check crimped portions for looseness or damage and
check that the terminals are secured in lock portion.
HINT:
The terminals should not come out when pulled lightly from the
back.

IN±38
± INTRODUCTIONTERMS
38 Author: Date:
2000 LEXUS GS300/GS400 (RM718U) H±FUSE
High Current Fuse
HIHigh
HIDHigh Intensity Discharge (Head Lamp)
HSGHousing
HTHard Top
HWSHeated Windshield System
IACIdle Air Control
ICIntegrated circuit
IDIIndirect Diesel Injection
IFSIndependent Front Suspension
IGIgnition
IIAIntegrated Ignition Assembly
INIntake (Manifold, Valve)
INTIntermittent
I/PInstrument Panel
IRSIndependent Rear Suspension
J/BJunction Block
J/CJunction Connector
KDKick±Down
LANLocal Area Network
LBLiftback
LCDLiquid Crystal Display
LEDLight Emitting Diode
LHLeft±Hand
LHDLeft±Hand Drive
L/H/WLength, Height, Width
LLCLong±Life Coolant
LNGLiquified Natural Gas
LOLow
LPGLiquified Petroleum Gas
LSDLimited Slip Differential
LSP & PVLoad Sensing Proportioning And Bypass Valve
LSPVLoad Sensing Proportioning Valve
MAX.Maximum
MICMicrophone
MILMalfunction Indicator Lamp
MIN.Minimum
MPMultipurpose
MPXMultiplex Communication System
M/TManual Transmission
MTMount
MTGMounting
NNeutral
NANatural Aspiration
No.Number
O/DOverdrive

MA002±06
MA±2
± MAINTENANCEINSIDE VEHICLE
45 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSIDE VEHICLE
GENERAL MAINTENANCE
These are maintenance and inspection items which are considered to be the owner's responsibility.
They can be done by the owner or they can have them done at a service shop.
These items include those which should be checked on a daily basis, those which, in most cases, do not
require (special) tools and those which are considered to be reasonable for the owner to do.
Items and procedures for general maintenance are as follows.
1. GENERAL NOTES

Maintenance items may vary from country to country. Check the owner's manual supplement in which
the maintenance schedule is shown.

Every service item in the periodic maintenance schedule must be performed.

Periodic maintenance service must be performed according to whichever interval in the periodic main-
tenance schedule occurs first, the odometer reading (miles) or the time interval (months).

Maintenance service after the last period should be performed at the same interval as before unless
otherwise noted.

Failure to do even one item an cause the engine to run poorly and increase exhaust emissions.
2. LIGHTS
(a) Check that the headlights, stop lights, taillights, turn signal lights, and other lights are all working.
(b) Check the headlight aiming.
3. WARNING LIGHTS AND BUZZERS
Check that all warning lights and buzzers function properly.
4. HORN
Check that it is working.
5. WINDSHIELD GLASS
Check for scratches, pits or abrasions.
6. WINDSHIELD WIPER AND WASHER
(a) Check operation of the wipers and washer.
(b) Check that the wipers do not streak.
7. WINDSHIELD DEFROSTER
Check that air comes out from the defroster outlet when operating the heater or air conditioner.
8. REAR VIEW MIRROR
Check that it is mounted securely.
9. SUN VISORS
Check that they move freely and are mounted securely.
10. STEERING WHEEL
Check that it has the specified freeplay. Be alert for changes in steering condition, such as hard steering,
excessive freeplay or strange noises.
11. SEATS
(a) Check that all front seat controls such as seat adjusters, seatback recliner, etc. operate smoothly.
(b) Check that all latches lock securely in any position.
(c) Check that the locks hold securely in any latched position.
(d) Check that the head restraints move up and down smoothly and that the locks hold securely in any
latches position.
(e) For folding±down rear seat backs, check that the latches lock securely.
12. SEAT BELTS
(a) Check that the seat belt system such as the buckles, retractors and anchors operate properly and
smoothly.
(b) Check that the belt webbing is not cut, frayed, worn or dameged.

P09958
MA01R±01
MA±6
± MAINTENANCEBRAKE
49 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
BRAKE
INSPECTION
1. INSPECT BRAKE LINE PIPES AND HOSES
HINT:
Check in a well lighted area. Check the entire circumference
and length of the brake hoses using a mirror as required. Turn
the front wheels fully right or left before checking the front brake.
(a) Check all brake lines and hoses for.

Damage

Wear

Deformation

Cracks

Corrosion

Leaks

Bends

Twists
(b) Check all clamps for tightness and connections for leak-
age.
(c) Check that the hoses and lines are clear of sharp edges,
moving parts and the exhaust system.
(d) Check that the lines install in grommets pass through the
center of the grommets.
2. INSPECT FRONT AND REAR BRAKE PADS AND
DISCS
(FRONT PADS: See page BR±16)
(REAR PADS: See page BR±25)
(FRONT DISCS: See page BR±21)
(REAR DISCS: See page BR±30)
3. INSPECT PARKING BRAKE LININGS AND DRUMS
(See page BR±35)
4. INSPECT OR CHANGE BRAKE FLUID
(See page BR±4)
Fluid: SAE J1703 or FMVSS No.116 DOT3

PP0O2±02
± PREPARATIONBODY ELECTRICAL
PP±93
145 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
EQUIPMENT
Voltmeter
Ammeter
Ohmmeter
Test lead
ThermometerEngine coolant temperature sender gauge, Engine oil level warn-
ing switch, Seat heater
SyphonBrake fluid level warning switch
Oil bathEngine oil level warning switch
Bulb (1.4 W)Defogger switch
Bulb (3.4 W)Fuel sender gauge, Engine coolant temperature receiver gauge,
Seat belt warning relay
Dry cell batteryFuel sender gauge, Power mirror
Heat lightSeat heater
Hexagon wrench (6 mm)Power seat
Torque wrench
Clip removerFor removing cowl louver
Masking tapeRear window defogger wire
Tin foilRear window defogger wire

SS0CN±02
SS±60
± SERVICE SPECIFICATIONSBODY ELECTRICAL
216 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
BODY ELECTRICAL
SERVICE DATA
DAYTIME RUNNING LIGHT RELAY (MAIN) (Wire Harness Side)
1 ± Ground (Ignition switch position LOCK or ACC)No voltage
1 ± Ground (Ignition switch position ON or START)Battery positive voltage
5 ± Ground (Engine Stop)No voltage
5 ± Ground (Engine Running)Battery positive voltage
7 ± Ground (Constant)Battery positive voltage
9 ± Ground (Constant)Battery positive voltage
AUTOMATIC LIGHT CONTROL SENSOR
(Connector disconnected)
4 ± Ground (Ignition switch position LOCK or ACC)No voltage
4 ± Ground (Ignition switch position ON)5.2 ± 9.0 V
(Connector connected)
1 ± Ground (Ignition switch position LOCK or ACC)No voltage
1 ± Ground (Ignition switch position ON)9.5 V or more
HEADLIGHT BEAM LEVEL CONTROL ECU
(Connector disconnected)
A1 ± A5 (Ignition switch position OFF)26 ± 30 W
A1 ± A6 (Ignition switch position OFF)26 ± 30 W
A1 ± A7 (Ignition switch position OFF)26 ± 30 W
A1 ± A8 (Ignition switch position OFF)26 ± 30 W
A4 ± B4 (Ignition switch position ON and light control switch HEAD)Below 1.5 V
B1 ± B3 (Ignition switch position OFF)3.5 k ± 6.5 kW
B5 ± B7 (Ignition switch position OFF)3.5 k ± 6.5 kW
(Connector disconnected)
B2 ± B3 (Ignition switch position ON)Approx. 2.5 V
B6 ± B7 (Ignition switch position ON)Approx. 2.5 V
B1 ± B3 (Ignition switch position ON)5V
B5 ± B7 (Ignition switch position ON)5V
TURN SIGNAL FLASHER
1 ± Ground (Ignition switch position LOCK or ACC)No voltage
1 ± Ground (Ignition switch position ON)Battery positive voltage
4 ± Ground (Constant)Battery positive voltage
LIGHT FAILURE RELAY (Wire Harness Side)
5 ± Ground (Light control switch position OFF)No voltage
5 ± Ground (Light control switch position TAIL or HEAD)Battery positive voltage
8 ± Ground (Ignition switch position LOCK or ACC)No voltage
8 ± Ground (Ignition switch position ON)Battery positive voltage
9 ± Ground (Stop light switch position OFF)No voltage
9 ± Ground (Stop light switch position ON)Battery positive voltage
10 ± Ground (Stop light switch position OFF)No voltage
10 ± Ground (Stop light switch position ON)Battery positive voltage
SPEEDOMETER (ON±VEHICLE)
USA: