sensor LEXUS LS430 2003 Factory Repair Manual

Fig. 63: Identifying Fuel Sender Gauge Assy And Luggage Room Junction Block Assy Connector
Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE LUGGAGE ROOM JUNCTION BLOCK ASSY
WIRING DIAGRAM
Fig. 64: Water Temperature Receiver Gauge Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
HINT:
If there is an open or short in the engine coolant temperature sensor circuit, the ECM outputs DTCs. Perform
troubleshooting with the "SFI System 10-2".
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:
Needle indication is normal.
NG: REPLACE COMBINATION METER ASSY (SEE OVERHAUL
)
OK: GO TO NEXT STEP
2.READ VALUE OF HAND-HELD TESTER (ENGINE COOLANT)
a. Operate the hand-held tester according to the steps on the display and select the "DATA LIST".
ENGINE:
DATA LIST REFERENCE
OK:
Coolant temperature displayed on the tester is between 80°C (176°F) and 95°C (203°F) after
warning up.
NG: GO TO ENGINE CONTROL SYSTEM (SEE REPLACEMENT
)
OK: GO TO NEXT STEP
3.REPLACE COMBINATION METER ASSY
OK:
Normal operation
NG: GO TO ENGINE CONTROL SYSTEM (SEE REPLACEMENT
)
OK: END
WIRING DIAGRAM
ItemTest DetailsDiagnostic Note
COOLANT TEMPLOW /NORMAL /HI-
ItemMeasurement Item/ Range
(Display)Normal ConditionDiagnostic Note
COOLANT
TEMPCoolant Temperature / Min.: -
40°C (-40°F), Max.: 140°C
(284 °F)After warming up: 80
to 95°C (176 to 203°
F)If the value is "-40°C (-40°F)" or
"140°C (284°F)", sensor circuit is
open or shorted.

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

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
HINT:
Displa
y except for the seat belt warning indicator are shown in the navigation system (see HOW TO

4.CHECK HARNESS AND CONNECTOR (FRONT SEAT INNER BELT ASSY - BODY
GROUND) (SEE HOW TO PROCEED WITH TROUBLESHOOTING
)
a. Disconnect the connector from the front seat inner belt assy (FR Passenger Side).
b. Measure the resistance according to the value (s) in the table below.
Standard
RESISTANCE SPECIFICATIONS
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Fig. 72: Identifying Front Seat Inner Belt Assy (Passenger Side) Connector Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: GO TO NEXT STEP
5.CHECK HARNESS AND CONNECTOR (FRONT SEAT INNER BELT ASSY - AIRBAG
SENSOR ASSY CENTER) (SEE HOW TO PROCEED WITH TROUBLESHOOTING
)
Tester ConnectionConditionSpecified Condition
B5-5 - Body groundAlwaysBelow 1 ohms

Fig. 73: Identifying B5 And A25 Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE AIRBAG SENSOR ASSY CENTER (SEE HOW TO PROCEED WITH
TROUBLESHOOTING )
6.INSPECT COMBINATION METER ASSY
a. Disconnect the clock assy connector.
b. Measure the voltage according to the value (s) in the table below.
Standard
VOLTAGE SPECIFICATIONS
NG: Go to step 8
Fig. 74: Identifying C12 Connector Terminals
Terminal NoConditionSpecified condition
C12-9 - Body groundIgnition switch ON, Passenger seat belt is unfastened10 to 14 V

ON-VEHICLE INSPECTION
1.CHECK COOLING FAN SYSTEM
a. Look at the chart below. Check that when the cooling fan is in the condition on the left, its
operation is what is written on the right.
Standard when engine coolant temperature is below 82°C (180°F):
CONDITION AND OPERATION SPECIFICATION
If the fan does not operate as specified, proceed to next step.
2.INSPECT COOLING FAN MOTOR
a. Remove the air cleaner inlet No. 1.
b. Disconnect the 2 connectors.
c. Connect the battery and ammeter.
d. Check that the fan rotates smoothly, and then check the amperage on the ammeter.
Standard: 9.2 to 11.0 A at 20° C (68° F)
If the result is not as specified, replace the fan motor.
If the fan operates, proceed to the next step.
ConditionOperation (Fan Speed)
Ignition ON at engine stoppingNot rotating
A/C switch OFF at idle speedNot rotating
A/C switch ON at idle speedRotating (Low speed)
Disconnect ECT sensor connector at idle speedRotating (High speed)

The computer which controls the cruise control system is combined with the ECM, and the actuator uses
the throttle position sensor and motor. A microcomputer is built into the ECM to control functions
including: ON-OFF, SET/COAST, RESUME/ACCEL, CANCEL, vehicle speed operation, motor output
control, and overdrive control.
The ECM compares the driving vehicle speed from the speed sensor with the stored vehicle speed
set through the cruise control main switch assy. The ECM instructs the throttle valve motor of the
throttle position sensor and motor to close the valve when the driving vehicle speed is greater than
the stored vehicle speed, and instructs it to open the valve when the driving speed is less than the
stored speed.
The ECM receives signals such as ON-OFF, SET/COAST, RESUME/ACCEL, and CANCEL from
the cruise control main switch assy and executes them.
The ECM turns on the indicator in the combination meter based upon the ON signal from the cruise
control main switch assy.
The ECM cancels the cruise control system when it detects that the brake pedal is depressed, based
on the stop lamp switch signal.
The ECM cancels the cruise control system when it detects that the shift position is changed from
D (6th, 5th or 4th gear) to N (3rd, 2nd or 1st gear), based on the park/neutral position switch assy
signal.
2.LIMIT CONTROL
a. Low speed limit
The lowest possible limit of the speed setting range is set at approximately 40 km/h (25 mph). The
cruise control system cannot be set when the driving vehicle speed is below the low speed limit.
Cruise control operation will be automatically canceled and the stored vehicle speed will be erased
when the vehicle speed goes below the low speed limit while the cruise control is in operation.
b. High speed limit
The highest possible limit of the speed setting range is set at approximately 200 km/h (125 mph).
The cruise control system cannot be set when the driving vehicle speed is over the high speed limit.
Speed up using RESUME/ACCEL with the cruise control main switch assy also cannot be set
beyond the high speed limit.
3.OPERATION OF CRUISE CONTROL
The cruise control main switch operates seven functions: SET, COAST, TAP-DOWN, RESUME,
ACCEL, TAP-UP, and CANCEL. The SET, TAP-DOWN and COAST functions, and the RESUME,
TAP-UP and ACCEL functions are operated with the same switch. The cruise control main switch assy is
an automatic return type switch which turns on only while operating it in each arrow direction and turns
off after releasing it.
a. SET CONTROL
Vehicle speed is stored and constant speed control is maintained when pushing the switch to SET/
COAST while drivin
g with the cruise control main switch ON-OFF button on (the CRUISE main

indicator light is on), and the vehicle speed is within the set speed range (between the low and high
speed limits).
b. COAST CONTROL
The ECM makes the cruise control demanding throttle opening angle zero degrees and decelerates
the vehicle (the throttle valve is not fully closed due to idle speed control, etc.) when SET/COAST
on the cruise control main switch is pressed and held while the cruise control system is in
operation. Vehicle speed, when the cruise control main switch is released from SET/COAST, is
stored and constant speed control is maintained.
c. TAP-DOWN CONTROL
When tapping down on the cruise control main switch to SET/COAST (for approximately 0.5
second) while the cruise control system is in operation, the stored vehicle speed decreases each
time by approximately 1.6 km/h (1.0 mph). However, when the difference between the driving and
the stored vehicle speed is more than 5 km/h (approximately 3.1 mph), the vehicle speed, when the
cruise control main switch is released from SET/COAST, will be stored and constant speed control
is maintained.
d. ACCELERATION CONTROL
The throttle valve motor of the throttle position sensor and motor is instructed by the ECM to open
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500044004c005100030056005a004c00570046004b0003004c[s pressed and held while the
cruise control system is in operation. Vehicle speed, when the cruise control main switch is
released from RESUME/ACCEL, is stored and the vehicle is controlled at a constant speed.
e. TAP-UP CONTROL
When tapping up on the cruise control main switch to RESUME/ACCEL (for approximately 0.5
second) while the cruise control system is in operation, the stored vehicle speed increases each time
by approximately 1.6 km/h (1.0 mph). However, when the difference between the driving and the
stored vehicle speed is more than 5 km/h (approximately 3.1 mph), the stored vehicle speed will not
be changed.
f. RESUME CONTROL
If cruise control operation was cancelled with the stop lamp switch or the CANCEL switch, and if
driving speed is within the limit range, pushing the cruise control main switch to
RESUME/ACCEL restores vehicle speed memorized at the time of cancellation, and maintains
constant speed control.
g. MANUAL CANCEL CONTROL
Doing any of the following cancels the cruise control system while in operation. (The stored vehicle
speed in the ECM is maintained.)
Depressing the brake pedal

TROUBLE CODE (GO TO STEP 8)
NORMAL SYSTEM CODE (GO TO STEP 9)
8.(SEE DIAGNOSTIC TROUBLE CODE CHART
)
GO TO STEP 12
9.PROBLEM SYMPTOM SIMULATION
SYMPTOM DOES NOT OCCUR (GO TO STEP 10)
SYMPTOM OCCURS (GO TO STEP 11)
10.SYMPTOM SIMULATION (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
11.(SEE PROBLEM SYMPTOMS TABLE
)
12.CIRCUIT INSPECTION (SEE DTC P0500 VEHICLE SPEED SENSOR CIRCUIT
MALFUNCTION, DTC P0503 VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION -
DIAGNOSIS CIRCUIT
)
13.(SEE TERMINALS OF ECM
)
14.IDENTIFICATION OF PROBLEM
15.REPAIR OR REPLACE
16.CONFIRMATION TEST
END