cruise control LEXUS LS430 2003 Factory Owner's Manual

hand-held tester to the DLC3, turned the ignition switch to the ON position and operated the tester,
there is a problem on either the vehicle side or the tool side.
If communication is normal when the tool is connected to another vehicle, inspect the DLC3
on the original vehicle.
If communication is still impossible when the tool is connected to another vehicle, the
problem is probably in the tool itself, so consult the Service Department listed in the tool's
instruction manual.
3.CHECK THE INDICATOR
a. Turn the ignition switch to the ON position.
b. Check that the CRUISE main indicator light comes on when the cruise control main switch ON-
OFF button is push on, and that the indicator light goes off when the ON-OFF button is pushed off.
Fig. 13: Identifying CRUISE Main Indicator Light

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HINT:
If there is a problem with the indicator, inspect the CRUISE MAIN INDICATOR LIGHT CIRCUIT
.
HINT:

If a malfunction occurs in the vehicle speed sensors, stop lamp switch assy, or other related parts during
cruise control driving, the ECM actuates AUTO CANCEL of the cruise control and then the CRUISE
main indicator light starts to blink, informing the driver of the malfunction. At the same time, data of the
malfunction is stored as a diagnostic trouble code (DTC).
Fig. 14: Identifying Blinking Pattern Of CRUISE Main Indicator Light

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1.DTC CHECK
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. Read the DTCs on the tester screen.
2.DTC CLEAR

Fig. 15: Connecting Hand-Held Tester To DLC3
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. Clear the DTCs following the prompts on the tester screen.
1.If the following conditions are detected while the cruise control is in operation, the system clears the
stored vehicle speed in the ECM and cancels the cruise control operation.

Fig. 16: Fail-Safe Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.DATA LIST
a. While the hand-held tester is connected to the DLC3 and with the ignition switch turned to the ON
position, the CRUISE CONTROL data list can be displayed. Follow the prompts on the tester
screen to access the data list.
DATA LIST (CC (ECM))
Item
Measurement Item / Display
(Range)
Normal ConditionDiagnostic Note
VEHICLE SPDVehicle speed / min.: 0 km/h (0
mph), max.: 255 km/h (158
mph)Actual vehicle speed-
MEMORY SPDCruise control memorized
speed / min.: 0 km/h (0 mph),
max.: 255 km/h (158 mph)Actual stored vehicle speed-
THROTTLERequired throttle opening angle /
min.: 0°, max.: 125°Actual required throttle opening-
CRUISE CTRLCruise control system active
condition / ON or OFFON: Cruise control activated
OFF: Cruise control inactivated-
MAIN SW
(MAIN)Main SW signal (Main CPU) /
ON or OFFON: Main SW ON (Pushed on)
OFF: Main SW OFF (Pushed
off)"3"
MAIN SW (SUB)Main SW signal (Sub CPU) /
ON or OFFON: Main SW ON (Pushed on)
OFF: Main SW OFF (Pushed
off)"3"
CCS READY MCruise control system standby
condition (Main CPU) / ON or
OFFON --> OFF: Change ON/OFF
each time Main SW is pushed in."1"

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 indicator not turn on --> CRUISE MAIN indicator or wire harness or ECM failure
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:
CCS READY SCruise control system standby
condition (Sub CPU) / ON or
OFFON --> OFF: Change ON/OFF
each time Main SW is pushed in."1"
CCS INDICATOR
MCruise indicator signal (Main
CPU) /ON or OFFON: "CCS READY" ON OFF:
"CCS READY" OFF"2"
CCS
INDICATORSCruise indicator signal (Sub
CPU) /ON or OFFON: "CCS READY" ON OFF:
"CCS READY" OFF"2"
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 SW OFF-
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 light SW signal (Sub
CPU) / ON or OFFON: Brake pedal depressed OFF:
Brake pedal released-
SHIFT D POSPNP SW signal (D position) /
ON or OFFON: Shift D position OFF:
Except shift D position-

Fig. 18: 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.
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 assy, and the ECM turns the cruise control off.
Fig. 19: DTC P0571 Problem Symptom Diagnostic Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM

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

Fig. 26: Wiring Diagram - Cruise Control Switch Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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. Accordin
g to the display on the tester, read the "DATA LIST".

Fig. 27: Identifying Cruise Control Main Switch Positions
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HAND-HELD TESTER VALUE (ECM)
OK: When cruise control main switch operation is performed the standard values will be above.
RESULT DETAIL
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 (Main
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-

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

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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