2000 LEXUS GS400 air condition

DIAGNOSTIC TROUBLE CODE CHECK PROCEDURE
Diagnostic Trouble
Code Check (Make a
note of and then clear)Confirmation
of SymptomsDiagnostic Trouble
Code CheckProblem Condition
Diagnostic Trouble
Code DisplayProblem symptoms
existSame diagnostic
trouble code is
displayedProblem is still occurring in the diagnostic
circuit
Normal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit
(The diagnostic trouble code displayed
first is either for a past problem or it is a
secondary problem)
No problem
symptoms existThe problem occurred in the diagnostic
circuit in the past
Normal Code DisplayProblem symptoms
existNormal code is
displayedThe problem is still occurring in a place
other than in the diagnostic circuit
No problem
symptoms existNormal code is
displayedThe problem occurred in a place other
than in the diagnostic circuit in the past
± INTRODUCTIONHOW TO TROUBLESHOOT ECU CONTROLLED
SYSTEMSIN±23
23 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE CHECK
The diagnostic system in the LEXUS GS400/GS300 fulfills various functions. The first function is the Diag-
nostic Trouble Code Check in which a malfunction in the signal circuits to the ECU is stored in code in the
ECU memory at the time of occurrence, to be output by the technician during troubleshooting. Another func-
tion is the Input Signal Check which checks if the signals from various switches are sent to the ECU correctly.
By using these check functions, the problem areas can be narrowed down quickly and troubleshooting can
be performed effectively. Diagnostic functions are incorporated in the following systems in the LEXUS
GS400/GS300.
SystemDiagnostic Trouble
Code CheckInput Signal Check
(Sensor Check)Diagnostic Test
Mode (Active Test)
Engine (2JZ±GE)
Engine (1UZ±FE)
Automatic Transmission
ABS & Hydraulic Brake Booster Power Supply System
Vehicle Skid Control (VSC) & Brake Assist (BA) System
Power Tilt and Power Telescopic Steering Column
Supplemental Restraint System
Cruise Control System
Engine Immobiliser System
Multiplex Communication System
LEXUS Navigation System
Air Conditioning System(with check Mode)
(with check Mode)
(with check Mode)















In diagnostic trouble code check, it is very important to determine whether the problem indicated by the diag-
nostic trouble code is still occurring or occurred in the past but returned to normal at present. In addition,
it must be checked in the problem symptom check whether the malfunction indicated by the diagnostic
trouble code is directly related to the problem symptom or not. For this reason, the diagnostic trouble codes
should be checked before and after the symptom confirmation to determine the current conditions, as shown
in the table below. If this is not done, it may, depending on the case, result in unnecessary troubleshooting
for normally operating systems, thus making it more difficult to locate the problem, or in repairs not pertinent
to the problem. Therefore, always follow the procedure in correct order and perform the diagnostic trouble
code check.

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)

IN0D6±01
± INTRODUCTIONTERMS
IN±41
41 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
GLOSSARY OF SAE AND LEXUS TERMS
This glossary lists all SAE±J1930 terms and abbreviations used in this manual in compliance with SAE rec-
ommendations, as well as their LEXUS equivalents.
SAE
ABBREVIATIONSSAE TERMSLEXUS TERMS
( )±±ABBREVIATIONS
A/CAir ConditioningAir Conditioner
ACLAir CleanerAir Cleaner, A/CL
AIRSecondary Air InjectionAir Injection (AI)
APAccelerator Pedal±
B+Battery Positive Voltage+B, Battery Voltage
BAROBarometric PressureHAC
CACCharge Air CoolerIntercooler
CARBCarburetorCarburetor
CFIContinuous Fuel Injection±
CKPCrankshaft PositionCrank Angle
CLClosed LoopClosed Loop
CMPCamshaft PositionCam Angle
CPPClutch Pedal Position±
CTOXContinuous Trap Oxidizer±
CTPClosed Throttle PositionLL ON, Idle ON
DFIDirect Fuel Injection (Diesel)Direct Injection (DI)
DIDistributor Ignition±
DLC1
DLC2
DLC3Data Link Connector 1
Data Link Connector 2
Data Link Connector 31: Check Connector
2: Total Diagnosis Comunication Link (TDCL)
3: OBD II Diagnostic Connector
DTCDiagnostic Trouble CodeDiagnostic Code
DTMDiagnostic Test Mode±
ECLEngine Control Level±
ECMEngine Control ModuleEngine ECU (Electronic Control Unit)
ECTEngine Coolant TemperatureCoolant Temperature, Water Temperature (THW)
EEPROMElectrically Erasable Programmable Read Only Memory
Electrically Erasable Programmable Read Only Memory
(EEPROM),
Erasable Programmable Read Only Memory (EPROM)
EFEEarly Fuel EvaporationCold Mixture Heater (CMH), Heat Control Valve (HCV)
EGRExhaust Gas RecirculationExhaust Gas Recirculation (EGR)
EIElectronic IgnitionTOYOTA Distributorless Ignition (TDI)
EMEngine ModificationEngine Modification (EM)
EPROMErasable Programmable Read Only MemoryProgrammable Read Only Memory (PROM)
EVAPEvaporative EmissionEvaporative Emission Control (EVAP)
FCFan Control±
FEEPROMFlash Electrically Erasable Programmable Read Only
Memory±
FEPROMFlash Erasable Programmable Read Only Memory±
FFFlexible Fuel±
FPFuel PumpFuel Pump
GENGeneratorAlternator
GNDGroundGround (GND)

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.

PP0SN±01
PP±100
± PREPARATIONAIR CONDITIONING
152 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
AIR CONDITIONING
SST (Special Service Tools)
07110±58060Air Conditioner Service Tool Set
(07117±58060)Refrigerant Drain Service Valve
(07117±58070)T±Joint
(07117±58080)Quick Disconnect AdapterHigh pressure side
(07117±58090)Quick Disconnect AdapterLow pressure side
(07117±88060)Refrigerant Charging HoseHigh pressure side
(Color: Red)
(07117±88070)Refrigerant Charging HoseLow pressure side
(Color: Blue)
(07117±88080)Refrigerant Charging HoseUtility
(Color: Green)
07110±61050Wrench SetExpansion valve
(07111±21020)Holder
(07111±32020)Hexagon Wrench5 mm (0.20 in.)
07112±66040Magnetic Clutch Remover

± PREPARATIONAIR CONDITIONING
PP±101
153 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
07112±76060Magnetic Clutch Stopper
07114±84010Snap Ring Pliers
07114±84020Snap Ring Pliers
07116±38360Gas Leak Detector Assembly

PP0SO±01
PP±102
± PREPARATIONAIR CONDITIONING
154 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
RECOMMENDED TOOLS
09044±00020Torx Socket E10 .Compressor (GS300)
09082±00040TOYOTA Electrical Tester.