2003 LEXUS LS430 Ecm

a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. According to the display on the tester, read the "DATA LIST".
Fig. 78: Identifying Cruise Control Main Switch Position

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
CC (ECM):
DATA LIST (CC (ECM))
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 (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-

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 SPECIFICATION
Fig. 81: Identifying Spiral Cable Sub
-Assy Connectors
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. 82: Disconnecting ECM Connector Terminals
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
SPECIFICATION
Fig. 83: Identifying Spiral Cable Sub
-Assy Connectors
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Tester connectionConditionSpecified value
C13-3 - Body groundAlwaysBelow 1 ohms

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
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 laser 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 (SEE REPLACEMENT
)
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN DIAGNOSTIC TROUBLE
CODE CHART
Item
Measurement 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

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 "CCS INDICATOR M", "CCS INDICATOR S", "CCS READY M" or "CCS
READY S" in the DATA LIST, and read its value on the hand-held tester.
d. Check the CRUISE main indicator light and READY indicator light, when the cruise control main
switch is ON and when it is OFF.
CC (ECM):
DATA LIST (CC (ECM))
OK: When cruise control main switch operation is performed the standard values will be above.
HINT:
*1 is OK, but *2 is NG --> DTC output or ECM failure
NG: REPLACE ECM (SEE REPLACEMENT
)
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
CIRCUIT DESCRIPTION
When the cruise control ECU (distance control ECU) detects that the wipers are operating, the dynamic laser
cruise control system will be cancelled.
HINT:
A wiper switch si
gnal is sent to the distance control ECU via CAN and BEAN. Therefore if there are any
ItemMeasurement Item / Display
(Range)Normal ConditionDiagnostic
Note
CCS READY MCruise control system standby
condition (Main CPU) / ON or OFFON <=> OFF: Change ON/OFF
each time Main SW is pushed.*1
CCS READY SCruise control system standby
condition (Sub CPU) / ON or OFFON <=> OFF: Change ON/OFF
each time Main SW is pushed.*1
CCS
INDICATOR MCruise indicator signal (Main CPU) /
ON or OFFON: "CCS READY" ON OFF:
"CCS READY" OFF*2
CCS
INDICATOR SCruise indicator signal (Sub CPU) /
ON or OFFON: "CCS READY" ON OFF:
"CCS READY" OFF*2

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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
1.CHECK HARNESS AND CONNECTOR (TC of DLC3 - ECM)
a. Disconnect the E2 connector from the ECM.
b. Measure the resistance according to the value(s) in the table below.
Standard:
ECM CONNECTOR TERMINALS RESISTANCE SPECIFICATION
Fig. 85: Identifying DLC3 Connector (TC) Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Tester connectionConditionSpecified condition
TC (E2-3) - TC (D1 - 13)AlwaysBelow 1 ohms

Fig. 86: Disconnecting E2 Connector From ECM
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (DLC3 - ECM)
OK: Go To Next Step.
2.CHECK HARNESS AND CONNECTOR (CG of DLC3 - BODY GROUND)
a. Measure the resistance according to the value(s) in the table below.
Standard:
ECM CONNECTOR TERMINALS RESISTANCE SPECIFICATION
Fig. 87: Identifying DLC3 Connector (CG) Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (DLC3 - BODY GROUND)
Tester connectionConditionSpecified condition
CG (D1-4) - Body groundAlwaysBelow 1 ohms