2003 LEXUS LS430 Identifying ac

Fig. 65: Identifying Cruise Control ECU Terminals
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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
)

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

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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-

Fig. 80: Identifying Spiral Cable Sub-Assy Connector
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NG: REPLACE SPIRAL CABLE SUB-ASSY (SEE REPLACEMENT
)

OK: Go To Next Step.
4.CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSY - ECM)
a. Measure the resistance according to the value(s) in the table below.
Standard:
SPIRAL CABLE SUB-ASSY AND ECM TERMINALS RESISTANCE SPECIFICATION
Fig. 81: Identifying Spiral Cable Sub
-Assy Connectors
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Tester connectionConditionSpecified value
C13-2 - E2-31 (CCS)AlwaysBelow 1 ohms
C13-4 - E3-20 (CCHG)AlwaysBelow 1 ohms
C13-2 - Body groundAlways10 kohms or higher
C13-4 - Body groundAlways10 kohms or higher

Fig. 82: Disconnecting ECM Connector Terminals
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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go To Next Step.
5.CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSY - BODY GROUND)
a. Measure the resistance according to the value(s) in the table below.
Standard:
SPIRAL CABLE SUB-ASSY CONNECTOR TERMINALS RESISTANCE
SPECIFICATION
Fig. 83: Identifying Spiral Cable Sub
-Assy Connectors
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Tester connectionConditionSpecified value
C13-3 - Body groundAlwaysBelow 1 ohms

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HINT:
When a particular warning light stays blinking, a ground short in the wiring of terminal TC of the DLC3 or an
internal ground short in the relevant ECU is suspected.
INSPECTION PROCEDURE
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.
Standard:
ECM CONNECTOR TERMINALS RESISTANCE SPECIFICATION
Fig. 85: Identifying DLC3 Connector (TC) Terminals

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

Fig. 86: 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.
Standard:
ECM CONNECTOR TERMINALS RESISTANCE SPECIFICATION
Fig. 87: Identifying DLC3 Connector (CG) Terminals

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

OK: Go To Next Step.
3.CHECK HARNESS AND CONNECTOR (TC of DLC3 - BODY GROUND)
a. Measure the resistance according to the value(s) in the table below.
Standard:
ECM CONNECTOR TERMINALS RESISTANCE SPECIFICATION
Fig. 88: Identifying DLC3 Connector (TC) Terminals

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NG: REPAIR OR REPLACE WIRE HARNESS AND EACH ECU
OK: REPLACE ECM (SEE REPLACEMENT
)
Tester connectionConditionSpecified condition
TC (D1-13) - Body groundAlways10 kohms or higher