2003 LEXUS LS430 Identifying ac

2.CHECK TRANSPONDER KEY ECU ASSY
Fig. 13: Identifying T9 ECU Connector Terminals

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a. Disconnect the T9 ECU connector.
b. Measure the voltage and resistance of the wire harness side connector.
Standard:
TRANSPONDER KEY ECU - VOLTAGE TABLE
Symbols
(Terminal No.)Wiring
ColorTerminal
DescriptionConditionSpecified Condition
AGND (T9-13) - V - Body GroundAlwaysBelow 1 ohms

Fig. 14: Identifying Waveform 1 Graph
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WAVEFORM 1 REFERENCE TABLE
Waveform 2 (Reference):
TerminalTXCT - GND
Tool Setting5 V/DIV., 20 ms/DIV.
ConditionIgnition switch OFF --> ON

Fig. 15: Identifying Waveform 2 Graph
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WAVEFORM 2 REFERENCE TABLE
Waveform 3 (Reference):
TerminalCODE - GND
Tool Setting10 V/DIV., 20 ms/DIV.
ConditionIgnition switch OFF --> ON

Fig. 16: Identifying Waveform 3 Graph
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WAVEFORM 3 REFERENCE TABLE
Waveform 4 (Reference):
TerminalEFIO - GND
Tool Setting10 V/DIV., 500 ms/DIV.
ConditionIgnition switch OFF --> ON

Fig. 17: Identifying Waveform 4 Graph
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WAVEFORM 4 REFERENCE TABLE
3.CHECK ECM
TerminalEFII - GND
Tool Setting10 V/DIV., 500 ms/DIV.
ConditionIgnition switch OFF --> ON

Fig. 18: Identifying ECM Connectors
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a. Disconnect the E2 and E4 ECM connectors.
b. Measure the voltage and resistance of the wire harness side connectors.
Standard:
ECM CONNECTORS - REFERENCE TABLE
If the result is not as specified, there may be a malfunction on the wire harness side.
c. Inspect using an oscilloscope.
Waveform 1 (Reference):
Symbols
(Terminal No.)Wiring
ColorTerminal
DescriptionConditionSpecified
Condition
IMI (E2-6) -
E01 (E4-2)GR-G - W-
BTransponder key
ECU input signalNo key in ignition key
cylinder --> Key insertedPulse generation
(see waveform 1)
IMO (E2-7) -
E01 (E4-2)GR-R - W-
BTransponder key
ECU output signalNo key in ignition key
cylinder --> Key insertedPulse generation
(see waveform 2)
E01 (E4-2) -
Body groundW-B - Body
groundGroundAlwaysBelow 1 ohms

Fig. 19: Identifying Waveform 1 Graph
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WAVEFORM 1 REFERENCE TABLE
Waveform 2 (Reference):
TerminalIMI - GND
Tool Setting10 V/DIV., 500 ms/DIV.
ConditionNo key in ignition key cylinder --> Key inserted

Fig. 20: Identifying Waveform 2 Graph
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WAVEFORM 2 REFERENCE TABLE
1.DESCRIPTION
a. The ECM controls the vehicle's immobilizer system functions. Immobilizer system data and the
Diagnostic Trouble Codes (DTCs) can be read through the vehicle's Data Link Connector 3
(DLC3). In some cases, a malfunction may be occurring in the immobilizer system even though the
security indicator lamp is not illuminated. When the system seems to be malfunctioning, use the
hand-held tester to check for malfunctions and perform repairs.
2.CHECK DLC3
HINT:
TerminalIMO - GND
Tool Setting10 V/DIV., 500 ms/DIV.
ConditionNo key in ignition key cylinder --> Key inserted