2003 LEXUS LS430 ignition

1.DESCRIPTION
The ECU controls the cruise control system of the vehicle. The data and DTCs relating to the cruise
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4b004c0046004f004800110003002c004900030048004c0057[her DTC or CRUISE OK is not displayed
in the multi-information display on the combination meter when checking for DTCs, there may be a
problem with the combination meter or the CAN communication and multiplex communication system.
Use the hand-held tester to check and solve the problem.
2.CHECK THE DLC3
a. The vehicle's ECM uses ISO 9141-2 for communication. The terminal arrangement of the DLC3
complies with SAE J1962 and matches the ISO 9141-2 format.
Symbols
(Terminals
No.)Wiring
ColorTerminal
DescriptionConditionSpecified Condition
TC - E1 (E2-3
- E6-7)P-B -
BRGroundIgnition switch ON --> Connect
terminals TC and CG of DLC310 to 14 V --> Below
1 V
STP - E1 (E2-
4 - E6-7)G-O -
BRStop lamp signalIgnition switch ON Depress brake
pedal --> Release brake pedal10 to 14 V --> Below
1 V
CCS - E1 (E2-
31 - E6-7)W-L -
BRCruise control
main switch
circuitIgnition switch ON CANCEL switch
hold ON SET/COAST switch hold ON
RES/ACC switch hold ON MAIN
switch hold ON10 to 14 V 6.6 to 10.1
V 4.5 to 7.1 V 2.3 to
4.0 V Below 1 V
ST1 - - E1
(E3-8 - E6-7)V-Y -
BRStop lamp signalIgnition switch ON Depress brake
pedal --> Release brake pedalBelow 1 V --> 10 to
14V

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

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

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

The ignition switch must be turned to the ON position to proceed ACTIVE TEST using the hand-held
tester.
ACTIVE TEST DETAIL (COMBINATION METER ASSY)
HINT:
If a trouble code is displayed during the DTC check, check the circuit listed for that code. For details of each
code, refer to chart.
DIAGNOSTIC TROUBLE CODE CHART
Fig. 17: Diagnostic Trouble Code Information Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
CIRCUIT DESCRIPTION
See CIRCUIT DESCRIPTION
.
ItemVehicle Condition / Test DetailsDiagnostic Note
CRUISE INDIC"CRUISE" indicator is ON / OFF-
DTCDescription
DTC P0500 VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION
DTC P0503 VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION
DTC P0571 STOP LIGHT SWITCH CIRCUIT MALFUNCTION
DTC P0607 INPUT SIGNAL CIRCUIT MALFUNCTION

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.
HAND-HELD TESTER VALUE (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.
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