LEXUS LS430 2003 Factory Repair Manual

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

If the result is not as specified, there may be a malfunction on the wire harness side.
c. Reconnect the T9 ECU connector.
d. Measure the voltage of the connector.
Standard:
TRANSPONDER KEY ECU - VOLTAGE TABLE
If the result is not as specified, the ECU may have a malfunction.
e. Inspect using an oscilloscope.
Waveform 1 (Reference):
Body groundground
CPUB (T9-1) -
GND (T9-14)V-Y - W-BBatteryAlways10 to 14V
IG2 (T9-2) -
AGND (T9-13)B-VIgnition switchIgnition switch OFF -->
ON0V --> 10 to 14V
KSW (T9-3) -
AGND (T9-13)LG-B - VUnlock warning
switchNo key in ignition key
cylinder --> Key inserted10 kohms or higher --
> Below 1 ohms
Symbols
(Terminal No.)Wiring
ColorTerminal DescriptionConditionSpecified
Condition
KSW (T9-3) -
AGND (T9-13)LG-B - VUnlock warning switch
No key in ignition key
cylinder --> Key
inserted
10 to 14V 0V
VC5 (T9-9) -
AGND (T9-13)O - VPower sourceIgnition switch OFF --
> ON0 V --> 4.6 to
5.4V
TXCT (T9-12) -
AGND (T9-13)L-B - VTransponder key amplifier
communication signalIgnition switch OFF --
> ONPulse generation
(see waveform 1)
CODE (T9-10) -
AGND (T9-13)R-W - VTransponder key amplifier
communication signalIgnition switch OFF --
> ONPulse generation
(see waveform 2)
EFIO (T9-6) -
AGND (T9-13)B-Y - VECM output signalIgnition switch OFF --
> ONPulse generation
(see waveform 3)
EFII (T9-7) -
AGND (T9-13)GR-R - VECM input signalIgnition switch OFF --
> ONPulse generation
(see waveform 4)

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

The vehicle uses the ISO 15765-4 communication protocol. The terminal arrangement of the DLC3
complies with SAE J1962 and matches the ISO 15765-4 format.
Fig. 21: Identifying DLC3 Connector Terminals

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DLC3 - REFERENCE TABLE
If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and
connector.
HINT:
Connect the cable of the han
d-held tester (with CAN VIM) to the DLC3, turn the ignition switch ON and
Symbols (Terminals No.)Terminal DescriptionConditionSpecified condition
SIL (7) - SG (5)Bus "+" lineDuring transmissionPulse generation
CG (4) - Body groundChassis groundAlwaysBelow 1 ohms
SG (5) - Body groundSignal groundAlwaysBelow 1 ohms
BAT (16) - Body groundBattery positiveAlways11 to 14V