2003 LEXUS LS430 immobilizer

a. When adding master keys and sub-keys (additional registration).
1. Register the key code (immobilizer code) in the transponder key ECU.
CODE REGISTRATION TABLE (ADDITIONAL REGISTRATION)
b. When replacing the transponder key ECU (new registration).
1. Register the key code (immobilizer code) in the transponder key ECU.
CODE REGISTRATION TABLE (IMMOBILIZER CODE)
2. Register the ECU COMMUNICATION ID between the ECM and the transponder key ECU.
CODE REGISTRATION TABLE (ECU COMMUNICATION ID)
c. When replacing the ECM.
1. Register the ECU COMMUNICATION ID between the ECM and the transponder key ECU.
CODE REGISTRATION TABLE (REPLACING ECM)
d. Erasure of key code.
1. Erase the key code.
CODE REGISTRATION TABLE (ERASING KEY CODE)
2.KEY REGISTRATION IN AUTOMATIC REGISTRATION (NEW REGISTRATION)
a. When an ignition key is inserted into the ignition key cylinder, the key code (immobilizer code)
registration is automatic. In this mode, a maximum of 4 key codes for 3 master keys and 1 sub-key
can be registered. Any order of registration for the master keys and sub-key is fine because the
transponder key ECU can distinguish between different types of keys.
HINT:
When a new transponder key ECU is installed, key codes (immobilizer codes) must be
Target ECUSee Step
Transponder key ECU3
Target ECUSee Step
Transponder key ECU2
Target ECUSee Step
ECM5
Target ECUSee Step
Transponder key ECU5
Target ECUSee Step
Transponder key ECU4

When the immobilizer system is operating normally and the key is pulled out, the security
indicator blinks continuously.
If the key code registration has failed in automatic key code registration mode, code 2-1 will
be output from the security indicator. Trying to re-register an already registered key will
cause code 2-2 to be output when the key is inserted. If the number of registered key codes
exceeds the limit, code 2-3 will be output from the security indicator. The output details are
shown below.
Security Indicator

Fig. 6: Identifying Security Indicator Output Codes
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
b. Finish the automatic key code registration mode.
HINT:
The automatic key code registration mode can be forced to end when at least 1 key code
(immobilizer code) for the master key has been registered.

Fig. 7: Automatic Key Code Registration Flowchart (Additional Registration)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
A brief outline of procedures for key code registration is shown in this information. For more
detailed information, please refer to the hand-held tester screen's instructions.
When the immobilizer system is operating normally and the key is pulled out, the security
indicator blinks continuously.
If the key code registration has failed in automatic key code registration mode, code 2-1 will
be output from the security indicator. Trying to re-register an already registered key will
cause code 2-2 to be output when the key is inserted. If the number of registered key codes
exceeds the limit, code 2-3 will be output from the security indicator. The output details are
shown in step 2 (new re
gistration).

4.ERASURE OF KEY CODE
a. Erase key codes using the hand-held tester.
HINT:
All key codes are erased except for the master key, which is used for erasing the key codes.
In order to use a key whose code has been erased, a new key code must be registered.
Registration will be cancelled if each step is not completed within the specified time.
Erasing Key Code
Fig. 8: Erasing Key Code Flowchart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
A brief outline of procedures for key code erasure is shown in this information. For more
detailed information, please refer to the hand-held tester screen's instructions.
When the immobilizer system is operating normally and the key is pulled out, the security
indicator blinks continuously.
5.ECU COMMUNICATION ID REGISTRATION

Fig. 20: Identifying Waveform 2 Graph
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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

1.DATA LIST
HINT:
Using the hand-held tester's DATA LIST allows switch, sensor, actuator and other item values to be read
without removing any parts. Reading the DATA LIST early in troubleshooting is one way to save time.
a. Connect the hand-held tester to the Controller Area Network Vehicle Interface Module (CAN
VIM). Then connect the CAN VIM to the DLC3.
b. Turn the ignition switch ON.
c. Read the DATA LIST.
Transponder key ECU assy:
TRANSPONDER KEY ECU ASSY - DATA LIST
Theft warning ECU assy:
Item
Measurement Item/ Display
(Range)
Normal Condition
KEY SWUnlock warning switch signal/
ON or OFFON: Key is in ignition key
cylinder OFF: No key is in
ignition key cylinder
IMMOBILIZERImmobilizer system status/ SET or
UNSETUNSET: Ignition switch ON
SET: Without key
RESPONSETransponder chip data/ NG or OKNG: Data error OK: Data OK
FRAMETransponder chip data/ NG or OKNG: Data error OK: Data OK
SERIAL NUMBERTransponder chip data/ NG or OKNG: Data error OK: Data OK
ENCRYPT CODETransponder chip data/ NG or OKNG: Data error OK: Data OK
STATUSTransponder chip data/ NG or OKNG: Data error OK: Data OK
BCCTransponder chip signal/ NG or
OKNG: Incorrect data sending OK:
Correct data sending
SUB KEYSub-key code signal/ NOMATCH
or MATCHNOMATCH: Unmatched sub-key
code is sent MATCH: Sub-key
code is sent
MASTER KEYMaster key code signal/
NOMATCH or MATCHNOMATCH: Unmatched Master
key code is sent MATCH: Master
key code is sent
REGIST SUB CODENumber of registered sub-
key/min. 0, max. 15Number of registered sub-key
REGIST MAS CODENumber of registered master
key/min. 0, max. 15Number of registered master key
REG CODE SPACEMemory space for key codes
registration/ NOT FULL or FULLNOT FULL: Possible to register
more key codes FULL: Cannot
register any more key codes

Fig. 24: Theft Warning ECU Assy Data List
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2.ACTIVE TEST
HINT:
Performing the hand-held tester's ACTIVE TEST allows relay, VSV, actuator and other items to be
operated without removing any parts. Performing the ACTIVE TEST early in troubleshooting is one way
to save time. The DATA LIST can be displayed during the ACTIVE TEST.
a. Connect the hand-held tester (with CAN VIM) to the DLC3.
b. Turn the ignition switch ON.
c. Perform the ACTIVE TEST by following the directions on the tester screen.
Transponder key ECU assy:
TRANSPONDER KEY ECU ASSY - ACTIVE TEST
DIAGNOSTIC TROUBLE CODE CHART
1.TRANSPONDER KEY ECU DTC CHART
ItemTester Details
SECURITY INDICTurn security indicator ON/OFF
DTCDescription
DTC B2780PUSH SWITCH/KEY UNLOCK WARNING
SWITCH MALFUNCTION
DTC B2793TRANSPONDER CHIP MALFUNCTION
DTC B2794UNMATCHED ENCRYPTION CODE
DTC B2795UNMATCHED KEY CODE
DTC B2796, DTC B2798NO COMMUNICATION IN IMMOBILIZER
SYSTEM
DTC B2797COMMUNICATION MALFUNCTION NO.1
DTC B2799ENGINE IMMOBILIZER SYSTEM
MALFUNCTION