LEXUS LS430 2003 Factory Repair Manual

The dynamic laser cruise control system has two cruise control modes: the constant speed control mode and
vehicle-to-vehicle distance control mode.
The vehicle-to-vehicle distance control mode is always selected when starting up the dynamic radar
cruise control system.
The operation of the constant speed control mode is the same as that for the conventional type cruise
control system.
WIRING DIAGRAM
Fig. 82: Wiring Diagram
- Cruise Control Switch Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.READ VALUE OF 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. 83: Identifying Cruise Control Main Switch Position
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
CC (ECM):
DATA LIST (CC (ECM))
OK: When cruise control main switch operation is performed, the standard values will be above.
Item
Measurement Item / Display
(Range)
Normal ConditionDiagnostic Note
MAI NSW
(MAIN)Main SW signal (Main CPU) /
ON or OFFON: Main SW ON (Pushed
on) OFF: Main SW OFF
(Pushed off)-
MAI NSW (SUB)Main SW signal (Sub 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-

Result:
RESULT DETAIL
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. 84: Checking Cruise Control Main Switch Assy

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
b. Measure the resistance according to the value(s) in the table below.
Standard:
CRUISE CONTROL MAIN SWITCH CONNECTOR TERMINALS RESISTANCE
OKA
NG (All items are defective)B
NG (One to four items are defective)C
Switch conditionTester connectionResistance (ohms)
NeutralA-2 - A-3, A-3 - A-410 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

NG: REPLACE CRUISE CONTROL MAIN SWITCH ASSY (SEE REPLACEMENT )
OK: Go To Next Step.
3.INSPECT SPIRAL CABLE SUB-ASSY
a. Disconnect the spiral cable sub-assy connector.
b. Measure the resistance according to the value(s) in the table below.
Standard:
SPIRAL CABLE SUB-ASSY CONNECTOR TERMINALS RESISTANCE
MODEA-3 - A-4Below 1 ohms
Terminal No.Specified value
A-2 - C13-2Below 1 ohms
A-3 - C13-3Below 1 ohms
A-4 - C13-4Below 1 ohms

Fig. 85: Identifying Spiral Cable Sub-Assy Connector
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)
a. Measure the resistance according to the value(s) in the table below.
Standard:
SPIRAL CABLE SUB-ASSY AND ECM TERMINALS RESISTANCE
Fig. 86: Identifying Spiral Cable Sub
-Assy Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Tester connectionConditionSpecified value
C13-2 - E2-31 (CCS)AlwaysBelow 1 ohms
C13-4 - E3-20 (CCHG)AlwaysBelow 1 ohms
C13-2 - Body groundAlways10 kohms or higher
C13-4 - Body groundAlways10 kohms or higher

Fig. 87: Disconnecting ECM Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go To Next Step.
5.CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSY - BODY GROUND)
a. Measure the resistance according to the value(s) in the table below.
Standard:
SPIRAL CABLE SUB-ASSY CONNECTOR TERMINALS RESISTANCE
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Fig. 88: Identifying Spiral Cable Sub
-Assy Connector Terminals
Tester connectionConditionSpecified value
C13-3 - Body groundAlwaysBelow 1 ohms

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: REPLACE ECM (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The distance control switch sets the vehicle-to-vehicle distance mode.
The distance control switch (DISP2 button) is installed in the steering pad switch modulator. The vehicle-to-
vehicle distance set value can be changed by operating the distance control switch (DISP2 button) while the
dynamic radar cruise control system is in operation.
The steering pad switch modulator uses BEAN to communicate with each ECU. Therefore it does not have a
direct connection with the ECM. If there are any malfunctions in the communication line of the steering pad
switch modulator, one or more DTCs in the multiplex communication system is/are output.
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. Select the item "DISP2 (MULTI MODE SW)" in the DATA LIST, and read its value on the hand-
held tester.
d. Check the indication displayed on the hand-held tester, when the steering pad switch (DISP2) is
ON and when it is OFF.
MULTI-INFORMATION DISPLAY CONTROL SWITCH (STEERING PAD SWITCH
MODULATOR):
DATA LIST (MULTI-INFORMATION DISPLAY CONTROL SWITCH (STEERING PAD
SWITCH MODULATOR))
OK: When switch operation is performed the standard values will be above.
NG: REPLACE STEERING PAD SWITCH MODULATOR
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
ItemMeasurement Item / Display
(Range)Normal ConditionDiagnostic
Note
MULTI
DSP2 SWSteering pad switch (DISP2)
signal / ON or OFFON <=> OFF: Change ON/OFF each time
steering pad switch (DISP2) SW is pushed.-

CIRCUIT DESCRIPTION
When the cruise control main switch is on, CRUISE main indicator light and READY indicator light come on.
This indicates the control condition (presence or absence of a vehicle in front, vehicle-to-vehicle distance, and
set vehicle speed) and fail-safe state through the multiplex communication system and CAN communication
system.
The master warning light and CRUISE main indicator light come on and vehicle-to-vehicle distance
information is displayed on the combination meter as the alarm buzzer sounds.
Items such as "Clean Radar Sensor", "Cruise not Available", "Check Cruise System" and "Radar Cruise Ready"
are displayed in the multi-information display on the combination meter when the ECM detects signals from
each sensor and actuator and sends them to the combination meter via CAN and BEAN.
HINT:
If the vehicle in front in the same lane significantly decreases vehicle speed or another vehicle pulls in front of
your vehicle, adequate deceleration cannot be applied and the vehicle-to-vehicle distance will shorten. At this
time, the system sounds the buzzer and the master warning light blinks to warn the driver.
Each indicator in the dynamic laser cruise control uses CAN and BEAN for communication. Therefore if there
are any malfunctions in this circuit, check for DTCs in the CAN communication and multiplex communication
systems.
INSPECTION PROCEDURE
1.PERFORM ACTIVE TEST BY HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Check the cruise control switch by using ACTIVE TEST.
COMBINATION METER:
ACTIVE TEST DETAIL (COMBINATION METER)
OK: Indicator light comes on.
NG: GO TO COMBINATION METER SYSTEM (SEE HOW TO PROCEED WITH
TROUBLESHOOTING )
DescriptionTester displayCheck condition
"CRUISE" indicator is ON / OFFCRUISE INDICON - OFF
Graphic area is ON / OFFL-CRUISE DISPON - OFF
"CHECK CRUISE SYSTEM" indicator is ON / OFFL-CRS CHECK INDON - OFF
"RADAR READY" indicator is ON / OFFL-CRS READY INDON - OFF