2003 LEXUS LS430 replacement

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A: REPLACE ECM (SEE REPLACEMENT
)
5.INSPECT DRIVER SIDE J/B
a. Measure the voltage according to the value(s) in the table below.
Fig. 24: Identifying Driver Side Junction Block ECU Connectors

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DRIVER SIDE JUNCTION BLOCK ECU TERMINALS VOLTAGE SPECIFICATION
NG: Go to step 6
OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVER SIDE J/B ECU - ECM)
6.INSPECT DRIVER SIDE J/B
Pedal conditionTester connectionSpecification
DepressedD3-12 (STPO) - Body ground10 to 14 V
ReleasedD3-12 (STPO) - 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

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

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NG: REPLACE SPIRAL CABLE SUB-ASSY (SEE REPLACEMENT
)

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-

OK: When cruise control main switch operation is performed the standard values will be above.
NG: REPLACE ECM (SEE REPLACEMENT
)
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS
TABLE
CIRCUIT DESCRIPTION
Making a short circuit between terminals TC and CG of the DLC3 will output DTCs from the DLC3.
WIRING DIAGRAM
Fig. 32: [Wiring Diagram
- Diagnosis Circuit]
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HINT:
When a particular warning light stays blinking, a ground short in the wiring of terminal TC of the DLC3 or an
internal ground short in the relevant ECU is suspected.
INSPECTION PROCEDURE
CCS
INDICATORSCruise indicator signal (Sub
CPU) /ON or OFFON: "CCS READY" ON OFF:
"CCS READY" OFF-

3.CHECK HARNESS AND CONNECTOR (TC of DLC3 - BODY GROUND)
a. Measure the resistance according to the value(s) in the table below.
DLC3 CONNECTOR TERMINALS RESISTANCE SPECIFICATION
NG: REPAIR OR REPLACE WIRE HARNESS AND EACH ECU
Fig. 36: Identifying DLC3 Connector (TC) Terminals

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OK: REPLACE ECM (SEE REPLACEMENT
)
Tester connectionConditionSpecified condition
TC (D1-13) - Body groundAlways10 kohms or higher

PRECAUTION
REPLACEMENT
1.SEPARATE BATTERY NEGATIVE TERMINAL
2.REMOVE INSTRUMENT PANEL UNDER COVER SUB-ASSY NO. 2 (See step 21 in
REPLACEMENT
)
3.REMOVE INSTRUMENT PANEL GARNISH SUB-ASSY (See step 22 in REPLACEMENT
)
4.REMOVE GLOVE COMPARTMENT PLATE (See step 23 in REPLACEMENT
)
5.REMOVE CHOKE KNOB HOLE COVER (See REPLACEMENT
)
6.REMOVE INSTRUMENT PANEL FINISH PANEL (See step 26 in REPLACEMENT
)
7.REMOVE CRUISE CONTROL ECU ASSY
a. Disconnect the connector.
b. Remove the nut and cruise control ECU (distance control ECU) assy.