2003 LEXUS LS430 Identifying ac

Fig. 22: Identifying Stop Lamp Switch Connector
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OK: Go to next step
4.INSPECT ECM
a. Reconnect the stop lamp switch connector.
b. Disconnect the E2 and E3 connectors from the ECM.
c. Turn the ignition switch to the ON position.
d. Measure the voltage according to the value(s) in the table below.
ECM CONNECTOR TERMINALS VOLTAGE RESISTANCE SPECIFICATION
RESULT DETAIL
Pedal conditionTester connectionSpecification
DepressedE2-4 (STP) - Body ground10 to 14 V
ReleasedE2-4 (STP) - Body groundBelow 1 V
DepressedE3-8 (ST1-) - Body groundBelow 1 V
ReleasedE3-8 (ST1-) - Body ground10 to 14 V

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A: REPLACE ECM (SEE REPLACEMENT
)
5.INSPECT DRIVER SIDE J/B
a. Measure the voltage according to the value(s) in the table below.
Fig. 24: Identifying Driver Side Junction Block ECU Connectors

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DRIVER SIDE JUNCTION BLOCK ECU TERMINALS VOLTAGE SPECIFICATION
NG: Go to step 6
OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVER SIDE J/B ECU - ECM)
6.INSPECT DRIVER SIDE J/B
Pedal conditionTester connectionSpecification
DepressedD3-12 (STPO) - Body ground10 to 14 V
ReleasedD3-12 (STPO) - Body groundBelow 1 V

a. Measure the voltage according to the value(s) in the table below.
Fig. 25: Identifying Driver Side Junction Block ECU Connectors

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DRIVER SIDE JUNCTION BLOCK ECU TERMINALS VOLTAGE SPECIFICATION
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LAMP SWITCH - DRIVER
SIDE J/B ECU)
OK: REPLACE DRIVER SIDE J/B
CIRCUIT DESCRIPTION
Pedal conditionTester connectionSpecification
DepressedD3-12 (STPI) - Body ground10 to 14 V
ReleasedD3-12 (STPI) - Body groundBelow 1 V

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-

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.
DLC3 CONNECTOR TERMINALS RESISTANCE SPECIFICATION
Fig. 33: Identifying DLC3 Connector Terminals

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Tester connectionConditionSpecified condition
TC (E2-3) - TC (D1 - 13)AlwaysBelow 1 ohms

Fig. 34: Disconnecting E2 Connector From ECM
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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.
DLC3 CONNECTOR TERMINALS RESISTANCE SPECIFICATION
Fig. 35: Identifying DLC3 Connector (CG) Terminals

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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (DLC3 - BODY GROUND)
OK: Go to next step
Tester connectionConditionSpecified condition
CG (D1-4) - Body groundAlwaysBelow 1 ohms

3.CHECK HARNESS AND CONNECTOR (TC of DLC3 - BODY GROUND)
a. Measure the resistance according to the value(s) in the table below.
DLC3 CONNECTOR TERMINALS RESISTANCE SPECIFICATION
NG: REPAIR OR REPLACE WIRE HARNESS AND EACH ECU
Fig. 36: Identifying DLC3 Connector (TC) Terminals

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OK: REPLACE ECM (SEE REPLACEMENT
)
Tester connectionConditionSpecified condition
TC (D1-13) - Body groundAlways10 kohms or higher

Fig. 14: Identifying CRUISE Main Indicator
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11. Press the "ENTER" key.
12. Confirm the current value of the laser beam. (The default reading is 6.3° when the reflector position
is out of ran
ge.)