2003 LEXUS LS430 turn signal

HINT:
*3 is OK, but *1 is NG --> ECM failure
*1 is OK, but *2 is NG --> DTC output or ECM failure
*3 is OK, but CRUISE main indicator light does not come on --> Indicator, W/H, or ECM failure
MULTI-INFORMATION DISPLAY CONTROL SWITCH (STEERING PAD SWITCH
MODULATOR):
DATA LIST (MULTI-INFORMATION DISPLAY CONTROL SWITCH (STEERING PAD
SWITCH MODULATOR))
2.ACTIVE TEST
HINT:
Performing the ACTIVE TEST using the hand-held tester allows components such as the relay, VSV, and
actuator to operate without parts removal. Performing the ACTIVE TEST as the first step of
troubleshooting is one way to shorten labor time.
It is possible to display the DATA LIST during the ACTIVE TEST.
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, perform the "ACTIVE TEST".
HINT:
The ignition switch must be turned to the ON position to proceed to the ACTIVE TEST using the hand-
held tester.
COMBINATION METER ASSY:
ACTIVE TEST DETAIL (COMBINATION METER ASSY)
VSC FAIL SAFEVSC fail-safe flag/ON or
OFF--
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.-
ItemVehicle Condition / Test DetailsDiagnostic Note
CRUISE INDIC"CRUISE" indicator is ON / OFF-

CIRCUIT DESCRIPTION
See CIRCUIT DESCRIPTION
.
Fig. 42: DTC P0500 And P0503 Problem Symptom Diagnostic Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM
See WIRING DIAGRAM
.
INSPECTION PROCEDURE
See INSPECTION PROCEDURE
.
CIRCUIT DESCRIPTION
When the brake pedal is depressed, the stop lamp switch assy sends a signal to the ECM. When the ECM
receives this signal, it cancels the cruise control.
The fail-safe function operates to enable normal driving even if there is a malfunction in the stop lamp signal
circuit.
The cancel condition occurs when positive battery voltage is applied to terminal STP.
When the brake is applied, battery positive voltage is normally applied to terminal STP of the ECM through the
STOP fuse and the stop lamp switch ass
y, and the ECM turns the cruise control off.

b. Turn the ignition switch to the ON position, and turn the hand-held tester main switch on.
c. Select the item "STP LIGHT SW M", "STP LIGHT SW S1" or "STP LIGHT SW S2" in the DATA
LIST, and read its value displayed on the hand-held tester.
d. Check that the stop lamp comes on when the brake pedal is depressed, and goes off when the brake
pedal is released.
CC (ECM):
DATA LIST (CC (ECM))
OK: When brake pedal operation is performed the standard values will be above.
NG: Go to step 2
OK: REPLACE ECM (SEE REPLACEMENT
)
2.INSPECT STOP LAMP SWITCH ASSY
a. Disconnect the stop lamp switch assy connector.
b. Measure the resistance according to the value(s) in the table below.
Standard:
STOP LAMP SWITCH TERMINALS RESISTANCE SPECIFICATION
NG: REPLACE STOP LAMP SWITCH ASSY
ItemMeasurement Item / Display
(Range)Normal ConditionDiagnostic
Note
STP LIGHT
SW MStop lamp SW signal (Main
CPU) / ON or OFFON: Brake pedal depressed OFF:
Brake pedal released-
STP LIGHT
SW S1Stop lamp SW signal (Sub CPU) /
ON or OFFON: Brake pedal depressed OFF:
Brake pedal released-
STP LIGHT
SW S2Stop lamp SW signal (Sub CPU) /
ON or OFFON: Brake pedal depressed OFF:
Brake pedal released-
Switch conditionTester connectionSpecified value
Switch pin free1 - 2Below 1 ohms
Switch pin free3 - 410 kohms or higher
Switch pin pushed in1 - 210 kohms or higher
Switch pin pushed in3 - 4Below 1 ohms

OK: REPLACE DRIVER SIDE J/B
CIRCUIT DESCRIPTION
This DTC indicates a malfunction in the ECM.
HINT:
The ECM receives signals from each sensor to control all the functions of the cruise control with the
microcomputer.
When a malfunction is detected, fail-safe remains on until the ignition switch is turned off.
DTC P0607 PROBLEM SYMPTOM DIAGNOSTIC
INSPECTION PROCEDURE
1.REPLACE ECM (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The distance control ECU receives information about the area in front of the vehicle from the laser sensor and
then sends a brake control demand signal (deceleration demand) and diagnosis signals, such as laser sensor
grime or laser sensor malfunction, to the ECM.
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

1.GO TO CAN COMMUNICATION SYSTEM (SEE HOW TO PROCEED WITH
TROUBLESHOOTING )
CIRCUIT DESCRIPTION
In the dynamic laser cruise control system, the ECM and the distance control ECU communicate with one
another to control the system based on some designation information. If the designation information of the
ECM and distance control ECU is different from each other, this DTC is recorded.
DTC P1617 PROBLEM SYMPTOM DIAGNOSTIC
INSPECTION PROCEDURE
1.CONFIRM THE DESIGNATION INFORMATION
a. If this DTC is output, confirm the designation information by following the procedures below.
1. Turn the ignition switch to the ON position.
2. Push the ON-OFF button of the cruise main switch on.
3. With the brake pedal depressed, push the cruise control main switch to RES/ACC 3 times
within 3 seconds. Check that the VSC buzzer sounds at this time.
If the light control switch is turned on by mistake, readjust the optical axis (refer to
ADJUSTMENT
for optical axis adjustment).
4. Clear the DTC and then recheck for DTCs.
OK: DTC is not output.
HINT:
If DTC P1617 is still output after performing the above procedures, replace the distance control ECU.
If the DTC P1617 is still output after replacing the distance control ECU, replace the ECM.
DTC No.DTC Detecting ConditionTrouble Area
P1617While the dynamic laser cruise control is either
<005300550048005300440055004c0051004a00030049005200550003005200530048005500440057004c005200510003005200550003005200530048005500440057004c0051004a000f0003004c004900030057004b00480003004700480056004c004a00
5100440057004c005200510003[
signal from the ECM and the designation return signal
from the distance control ECU do not match one another
for a certain amount of time or more, the ECM records
this trouble code.Cruise control ECU
(Distance control ECU)

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.-

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