Identifying condition LEXUS LS430 2003 Factory Repair Manual

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

Fig. 31: Identifying U7 Switch Connector Terminals
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Standard:
UNLOCK WARNING SWITCH - BODY GROUND - RESISTANCE TABLE
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
Tester connectionSpecified condition
U7-1 - Body groundBelow 1 ohms

Fig. 32: Identifying U7 Switch And T9 ECU Connector Terminals
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Standard:
TRANSPONDER KEY ECU - UNLOCK WARNING SWITCH - RESISTANCE TABLE
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: REPLACE TRANSPONDER KEY ECU ASSY
CIRCUIT DESCRIPTION
This DTC is output when: 1) during the key code registration, a key malfunction occurs; or 2) the key code was
unable to be registered properly. Follow the inspection procedure below.
DTC REFERENCE TABLE
INSPECTION PROCEDURE
1.RE-REGISTER KEY
a. Delete the DTC (see DTC CHECK/CLEAR
).
b. Re-register the key (see REGISTRATION
), and check that the engine starts with the key.
OK: Engine starts.
NG: REPLACE KEY
OK: NORMAL (INSPECTION FINISHED)
CIRCUIT DESCRIPTION
This DTC is output when a key with an incomplete key code is inserted into the ignition key cylinder.
DTC REFERENCE TABLE
Tester connectionSpecified condition
T9-3 (KSW) - U7-2Below 1ohms
DTC No.DTC Detection ConditionTrouble Area
B2793Transponder chip malfunctionKey
DTC No.DTC Detection ConditionTrouble Area
B2794Key with incomplete key code is insertedKey

Fig. 36: Identifying T9 ECU And T8 Amplifier Connector Terminals
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Standard:
TRANSPONDER KEY ECU - TRANSPONDER KEY AMPLIFIER - RESISTANCE TABLE
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: Go to next step
4.CHECK OPERATION OF TRANSPONDER KEY AMPLIFIER
a. After replacing the transponder key amplifier with a normally functioning amplifier, check that the
engine starts.
OK: Engine starts.
NG: REPLACE TRANSPONDER KEY ECU ASSY
OK: END
CIRCUIT DESCRIPTION
This DTC is output when a communication error occurs between the transponder key amplifier and transponder
key ECU. Some possible reasons for the communication error are: 1) 2 or more ignition keys are positioned too
close together, or 2) noise is occurring in the communication line. Follow the inspection procedure below.
Fig. 37: DTC Reference Chart

Tester connectionSpecified condition
T9-9 (VC5) - T8-1 (+B)Below 1ohms
T9-10 (CODE) - T8-4 (CODE)Below 1ohms
T9-12 (TXCT) - T8-5 (TXCT)Below 1 ohms
T9-13 (AGND) - T8-7 (GND)Below 1 ohms
T9-9 (VC5) or T8-1 (+B) - Body ground10 kohms or higher
T9-10 (CODE) or T8-4 (CODE) - Body ground10 kohms or higher
T9-12 (TXCT) or T8-5 (TXCT) - Body ground10 kohms or higher
T9-13 (AGND) or T8-7 (GND) - Body ground10 kohms or higher