2003 LEXUS LS430 ignition

Fig. 58: Disconnecting Laser Sensor Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: Go To Next Step.
2.INSPECT LASER SENSOR
a. Reconnect the laser sensor connector.
b. Measure the voltage according to the value(s) in the table below.
Standard:
LASER SENSOR TERMINALS VOLTAGE SPECIFICATION
Tester connectionConditionSpecified value
L1-5 (IGB) - Body groundIgnition SW ON10 to 14 V

Fig. 59: Identifying Laser Sensor Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
c. Check the signal waveform between terminal LRDD (L1-3) of the laser sensor and body ground.
OK:
A waveform similar to that in the illustration to the left is output.
HINT:
Gauge set: 1 V/DIV, 2 ms/DIV
Condition: Ignition switch ON
NG: REPLACE LASER SENSOR (SEE REPLACEMENT
)

Fig. 64: Disconnecting Laser Sensor Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE WIRE HARNESS OR CONNECTOR
OK: Go To Next Step.
2.INSPECT CRUISE CONTROL ECU ASSY (DISTANCE CONTROL ECU)
a. Reconnect the cruise control ECU (distance control ECU) connector.
b. Turn the ignition switch to the ON position.
c. Measure the voltage according to the value(s) in the table below.
Standard:
CRUISE CONTROL ECU TERMINALS VOLTAGE SPECIFICATION
Tester connectionConditionSpecified value
D2-13 (IGB) - Body groundIgnition SW ON10 to 14 V

Fig. 65: Identifying Cruise Control ECU Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
d. Check the signal waveform between terminal LRRD (D2-23) of the cruise control ECU (distance
control ECU) and body ground.
OK:
A waveform similar to that in the illustration to the left is output.
HINT:
Gauge set: 2 V/DIV, 5 ms/DIV
Condition: Ignition switch ON
NG: REPLACE CRUISE CONTROL ECU ASSY (SEE REPLACEMENT
)

c. Measure the resistance according to the value(s) in the table below.
Standard:
CRUISE CONTROL ECU TERMINALS RESISTANCE SPECIFICATION
NG: REPAIR OR REPLACE WIRE HARNESS OR CONNECTOR
Fig. 70: Disconnecting Cruise Control ECU (Distance Control ECU) Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
Tester connectionConditionSpecified value
D2-1 (+B) - Body groundIgnition SW ON10 to 14 V
Tester connectionConditionSpecified value
D2-10 (SGND) - Body groundAlwaysBelow 1 ohms
D2-12 (GND) - Body groundAlwaysBelow 1 ohms

Fig. 71: Wiring Diagram - Laser Sensor Power Source Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT LASER SENSOR
a. Disconnect the laser sensor connector.
b. Measure the voltage according to the value(s) in the table below.
Standard:
LASER SENSOR CONNECTOR TERMINALS VOLTAGE SPECIFICATION
Tester connectionConditionSpecified value
L1-5 (IGB) - Body groundIgnition SW ON10 to 14 V

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-

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.-