2003 LEXUS LS430 lock

Fig. 43: Engine Immobilizer System Malfunction - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.CHECK WIRE HARNESS (STEERING LOCK ECU - ECM)
a. Disconnect the S46 ECU connector.
b. Disconnect the E2 ECM connector
c. Measure the resistance of the wire harness side connectors.
Standard:
STEERING LOCK ECU - ECM - RESISTANCE TABLE
Tester connectionSpecified condition
S46-13 (EFIO) - E2-6 (IMI)Below 1 ohms
S46-4 (EFII) - E2-7 (IMO)Below 1 ohms
S46-13 (EFIO) or E2-6 (IMI) - Body ground10 kohms or higher
S46-4 (EFII) or E2-7 (IMO) - Body ground10 kohms or higher

Fig. 44: Checking Wire Harness (Steering Lock ECU -ECM)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: REPLACE ECM
CIRCUIT DESCRIPTION
This circuit provides power to operate the steering lock ECU.
WIRING DIAGRAM
Fig. 45: ECU Power Source Circuit
- Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT FUSE (MPX-B1, AM2, STR LOCK, D/C CUT)
a. Remove the MPX-B1, AM2 and STR LOCK fuses from the passenger side J/B.
b. Remove the D/C CUT fuse from the FL block.
c. Measure the resistance of the fuse.
Standard: Below 1 ohms
NG: REPLACE FUSE
OK: Go to next step
2.CHECK WIRE HARNESS (STEERING LOCK ECU - BATTERY AND BODY GROUND)
a. Disconnect the S46 ECU connector.
b. Measure the resistance and voltage of the wire harness side connector.
Standard:
STEERING LOCK ECU - BATTERY AND BODY GROUND - RESISTANCE TABLE
Tester connectionConditionSpecified condition
S46-1 (CPUB) - Body groundAlways10 to 14 V
S46-2 (IG2) - Body groundIgnition switch OFF -> ON0 V -> 10 to 14 V
S46-10 (+B) - Body groundAlways10 to 14 V
S46-9 (GND) - Body groundAlwaysBelow 1 ohms

Fig. 46: Checking Wire Harness (Steering Lock ECU - Battery & Body Ground)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: REPLACE STEERING LOCK ECU

Fig. 2: Identifying Engine Immobilizer System Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.ENGINE IMMOBILIZER SYSTEM DESCRIPTION
The engine immobilizer system is designed to prevent the vehicle from being stolen. This system uses a
transponder key ECU that stores the key codes of authorized ignition keys. If an attempt is made to start
the engine using an unauthorized key, the ECU sends a signal to the ECM to prohibit fuel delivery and
ignition, effectively disabling the engine.
2.FUNCTION OF MAIN COMPONENT
COMPONENT FUNCTION TABLE
3.SYSTEM FUNCTION
When the transponder key ECU detects that the unlock warning switch is ON, the ECU provides current
to the transponder ke
y coil and produces a faint electric wave. A transponder chip in the key grip and
ComponentOutline
Transponder key
coil/amplifierWhen key is inserted in ignition key cylinder, key coil receives key's code. Then
amplifier amplifies ID code and outputs it to transponder key ECU.
Unlock warning
switchDetects if key is in ignition key cylinder and outputs results to transponder key
ECU.
ECM
Through SFI communication, ECM receives ID verification results from
transponder key ECU. ECM also verifies ECUs. Then judgement of whether or not
to immobilize engine is made.
Security indicatorDepending on operation of theft warning ECU (theft deterrent ECU), interior
security indicator lamp illuminates or starts blinking.

Transponder key ECU assy:
Fig. 3: Transponder Key ECU Assy Data List

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: "ON" (Key is in ignition key cylinder) appears on the screen.
NG: See DTC B2780 PUSH SWITCH/KEY UNLOCK WARNING SWITCH MALFUNCTION
)
OK: Go to next step
6.See PROBLEM SYMPTOMS TABLE
)
a. If the fault is not listed on the problem symptoms table, proceed to A.
b. If the fault is listed on the problem symptoms table, proceed to B.
B: Go to step 8
A: Go to next step
7.OVERALL ANALYSIS AND TROUBLESHOOTING
a. DATA LIST/ACTIVE TEST (see DATA LIST/ACTIVE TEST
)
1. Inspection with the hand-held tester (DATA LIST)
2. Inspection with the hand-held tester (ACTIVE TEST)
b. See TERMINALS OF ECU
)
8.ADJUST, REPAIR OR REPLACE
9.CONFIRMATION TEST
END

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)

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