LEXUS LS430 2003 Factory Repair Manual

a. Measure the voltage according to the value(s) in the table below.
Fig. 25: Identifying Driver Side Junction Block ECU Connectors

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DRIVER SIDE JUNCTION BLOCK ECU TERMINALS VOLTAGE SPECIFICATION
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LAMP SWITCH - DRIVER
SIDE J/B ECU)
OK: REPLACE DRIVER SIDE J/B
CIRCUIT DESCRIPTION
Pedal conditionTester connectionSpecification
DepressedD3-12 (STPI) - Body ground10 to 14 V
ReleasedD3-12 (STPI) - Body groundBelow 1 V

This DTC indicates the internal abnormalities of the ECM.
DTC P0607 PROBLEM SYMPTOM DIAGNOSTIC
HINT:
The ECM receives signals from each sensor to control all the functions of the cruise control with the
microcomputer.
When a trouble code is detected, fail-safe remains on until the ignition switch is turned off.
INSPECTION PROCEDURE
1.REPLACE ECM (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
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 respectively. The cruise control main switch is an
automatic return type switch which turns on only while operating it in each arrow direction and turns off after
releasing it. The internal contact point of the cruise control main switch is turned on with the switch operation.
Then the ECM reads the resistance value that has been changed by the switch operation to control SET,
COAST, RESUME, ACCEL and CANCEL.
WIRING DIAGRAM
DTC No.Detection ItemTrouble Area
P0607The ECM has a supervisory CPU and a control ECU inside. When
each input STP signal is different for 0.15 sec. or more, this trouble
code is output. This trouble code is output after 0.4 sec. has passed
from the time the cruise cancel input signal (STP input) is input into
the ECM.ECM

Fig. 26: Wiring Diagram - Cruise Control Switch Circuit
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INSPECTION PROCEDURE
1.READ VALUE ON HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. Accordin
g to the display on the tester, read the "DATA LIST".

Fig. 27: Identifying Cruise Control Main Switch Positions
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HAND-HELD TESTER VALUE (ECM)
OK: When cruise control main switch operation is performed the standard values will be above.
RESULT DETAIL
Item
Measurement Item /
Display (Range)
Normal ConditionDiagnostic Note
MAIN SW (MAIN)Main SW signal (Main
CPU) / ON or OFFON: Main SW ON (Pushed on)
OFF Main SW OFF (Pushed off)-
MAIN SW (SUB)Main SW signal (Main
CPU) / ON or OFFON: Main SW ON (Pushed on)
OFF Main SW OFF (Pushed off)-
CANCEL SWCANCEL SW signal / ON or
OFFON: CANCEL SW ON OFF:
CANCEL SW OFF-
SET/COAST SWSET/COAST SW signal / ON
or OFFON: SET/COAST SW ON OFF:
SET/COAST SW OFF-
RES/ACC SWRES/ACC SW signal / ON or
OFFON: RES/ACC SW ON OFF:
RES/ACC OFF-

B: Go to step 2
C: REPLACE CRUISE CONTROL MAIN SWITCH ASSY (SEE REPLACEMENT
)
A: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
2.INSPECT CRUISE CONTROL MAIN SWITCH ASSY
a. Disconnect the cruise control main switch connector.
Fig. 28: Checking Cruise Control Main Switch Assy

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b. Measure the resistance according to the value(s) in the table below.
CRUISE CONTROL MAIN SWITCH CONNECTOR TERMINALS RESISTANCE
SPECIFICATION
NG: REPLACE CRUISE CONTROL MAIN SWITCH ASSY (SEE REPLACEMENT
)
OK: Go to next step
OKA
NG (All items are defective.)B
NG (One to Four items are defective.)C
Switch conditionTester connectionResistance(ohms)
NeutralA-2 - A-310 kohms or higher
RES/ACCA-2 - A-3210 to 270
SET/COASTA-2 - A-3560 to 700
CANCELA-2 - A-31,380 to 1,700
Main Switch OFFA-2 - A-310 kohms or higher
Main Switch ONA-2 - A-3Below 1 ohms

3.INSPECT SPIRAL CABLE SUB-ASSY
a. Disconnect the spiral cable connector.
b. Measure the resistance according to the value(s) in the table below.
SPIRAL CABLE CONNECTOR TERMINALS RESISTANCE SPECIFICATION
Tester connectionSpecification
A-2 - C13-2Below 1 ohms
A-3 - C13-3Below 1 ohms

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Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE SPIRAL CABLE SUB-ASSY (SEE REPLACEMENT
)

OK: Go to next step
4.CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSY - ECM, BODY GROUND)
a. Measure the resistance according to the value(s) in the table below.
SPIRAL CABLE CONNECTOR TERMINALS RESISTANCE SPECIFICATION
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Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Tester connectionConditionSpecification
Spiral cable (C13-2) - CCS (E2-31)AlwaysBelow 1 ohms
CCS (E2-31) - Body groundAlways10 kohms or higher
Spiral cable (C13-3) - Body groundAlwaysBelow 1 ohms

Fig. 31: [Disconnecting ECM Connector]
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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE ECM (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The ECM detects a cruise control switch signal and sends it to the combination meter via CAN and
BEAN. Then the CRUISE main indicator light comes on.
The CRUISE main indicator light circuit uses CAN and BEAN for communication. If there are any
malfunctions in this circuit, check for DTCs in the CAN communication system and multiplex
communication system.
INSPECTION PROCEDURE
1.PERFORM ACTIVE TEST BY HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Check the CRUISE main indicator light by using ACTIVE TEST.
ACTIVE TEST DETAIL (COMBINATION METER ASSY)
OK: Indicator light comes on/goes off.
NG: GO TO COMBINATION METER SYSTEM (SEE HOW TO PROCEED WITH
TROUBLESHOOTING )
OK: Go to next step
2.READ VALUE ON HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position and turn the hand-held tester main switch on.
c. Select the item below in the "DATA LIST", and read the display on the hand-held tester.
DATA LIST (CC (ECM))
ItemVehicle Condition / Test DetailsDiagnostic Note
CRUISE INDIC"CRUISE" indicator is ON / OFF-
ItemMeasurement Item / Display
(Range)Normal ConditionDiagnostic
Note
CCS INDICATOR
MCruise indicator signal (Main
CPU) /ON or OFFON: "CCS READY" ON OFF:
"CCS READY" OFF-