2003 LEXUS LS430 diagram

Fig. 65: Driver'S Seat Belt Warning Lamp Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
HINT:
If there is an open in the ground circuit (Airbag sensor assy center), the airbag sensor assy center outputs DTCs.
Perform troubleshooting with the "Supplemental Restraint System" 05-1026.
1.PERFORM ACTIVE TEST BY HAND-HELD TESTER
a. Operate the hand-held tester according to the steps on the display and select the "ACTIVE TEST".
METER:
ACTIVE TEST REFERENCE
OK:
Switch condition (ON/OFF) can be switched by ACTIVE TEST.
NG: REPLACE COMBINATION METER ASSY (SEE OVERHAUL
)
OK: GO TO NEXT STEP
ItemTest DetailsDiagnostic Note
D-BELT
REMINDIndicat. Lamp D-SEAT BELT
(OFF/ON)Confirm that the vehicle is stopped and engine
idling

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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE AIRBAG SENSOR ASSY CENTER (SEE HOW TO PROCEED WITH
TROUBLESHOOTING )
WIRING DIAGRAM
Fig. 70: Passenger'S Seat Belt Warning Lamp Wiring Diagram

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INSPECTION PROCEDURE
HINT:
Displa
y except for the seat belt warning indicator are shown in the navigation system (see HOW TO

Fig. 79: Identifying M4 And C12 Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE COMBINATION METER ASSY (SEE OVERHAUL
)
WIRING DIAGRAM
Fig. 80: ODO/TRIP Switch Wiring Diagram

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INSPECTION PROCEDURE
1.READ VALUE OF HAND-HELD TESTER
a. Operate the hand-held tester according to the steps on the display and select the "DATA LIST".
METER:
DATA LIST REFERENCE
ItemMeasurement Item/ Range (Display)Normal ConditionDiagnostic Note
ODO/TRIP SWODO/TRIP switch is ON / OFFON: Switch is pushed
OFF: Switch is released-
TRIP RESET SWTRIP RESET switch is ON / OFFON: Switch is pushed
OFF: Switch is released-

Fig. 82: Identifying C12 And T10 Connector Terminals
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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE COMBINATION METER ASSY (SEE OVERHAUL
)
WIRING DIAGRAM
Fig. 83: Light Control Rheostat Wiring Diagram

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INSPECTION PROCEDURE
1.READ VALUE OF HAND-HELD TESTER (LIGHT RHEOSTAT SIGNAL)
a. Operate the hand-held tester according to the steps on the display and select the "DATA LIST".
METER:
DATA LIST REFERENCE
ItemMeasurement Item/ Range
(Display)Normal ConditionDiagnostic
Note
LIGHT
RHEOSTATLight control rheostat / Min.: 0,
Max.: 255Light control rheostat switch is Dark
(0) --> Bright (255)-

Fig. 6: Identifying Cooling Fan System Component Location
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SYSTEM DIAGRAM
Fig. 7: System Diagram

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Fig. 3: System Diagram - Cruise Control System
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.CRUISE CONTROL SYSTEM

Fig. 18: DTC P0500 And P0503 Problem Symptom Diagnostic Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM
See WIRING DIAGRAM

INSPECTION PROCEDURE
See INSPECTION PROCEDURE
.
CIRCUIT DESCRIPTION
When the brake pedal is depressed, the stop lamp switch assy sends a signal to the ECM. When the ECM
receives this signal, it cancels the cruise control.
Fail-safe function operates to enable normal driving even if there is a malfunction in the stop lamp signal
circuit.
The cancel condition occurs when positive battery voltage is applied to terminal STP.
When the brake is applied, battery positive voltage is normally applied to terminal STP of the ECM through the
STOP fuse and the stop lamp switch assy, and the ECM turns the cruise control off.
Fig. 19: DTC P0571 Problem Symptom Diagnostic Chart

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WIRING DIAGRAM

Fig. 20: Wiring Diagram - Stop Light Switch Circuit Malfunction
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.READ VALUE ON HAND-HELD TESTER
a. Connect the han
d-held tester to the DLC3.