2003 LEXUS LS430 lock

Fig. 3: System Diagram (W/ Smart Key System)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
COMMUNICATION LINE REFERENCE
1.FUNCTION OF COMPONENT
SenderReceiverSignalCommunication
Line
Steering Lock
ECUMeter ECUBuzzer Sound SignalBEAN
Driver Door ECUSteering Lock
ECUFront Door Courtesy Switch Signal (Driver
Side)BEAN

Fig. 4: Function Of Component
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2.KEY REMINDER WARNING SYSTEM FUNCTION
a. w/o Smart key system:
When the driver door is opened with the ignition switch in the ACC or LOCK position, this system
sounds a buzzer to warn the driver that the ignition key has not been removed from the ignition key
cylinder.
b. w/ Smart key system:
For the vehicles with the smart key system, with the ignition switch OFF and the smart key in the ignition
key cylinder, opening the driver door causes this system to sound a key reminder warning buzzer. This
system can also sound a key reminder warning buzzer when the smart key is not inserted into the ignition
key cylinder (smart key is in the driver's possession). For details, refer to the SMART KEY SYSTEM

section.
HINT:
Use this procedure to troubleshoot the key reminder warning system.
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1.VEHICLE BROUGHT TO WORKSHOP
2.CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK
3.INSPECT COMMUNICATION FUNCTION OF LARGE-SCALE MULTIPLEX
COMMUNICATION SYSTEM (BEAN)
a. Use the hand-held tester to check for normal function of the multiplex communication system.
1. (ECU not connected, communication line malfunctioning) Without code outputs, proceed to
A.
2. (ECU not connected, communication line malfunctioning) With code outputs, proceed to B.
B: Go to MULTIPLEX COMMUNICATION SECTION (See DIAGNOSTIC TROUBLE CODE
CHART )

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:
SPECIFIED CONDITION
If the result is not as specified, the ECU may have a malfunction.
2.CHECK STEERING LOCK ECU
KSW (T9-3) - GND
(T9-14)LG-B - W-BUnlock warning
switch input1: No key in
ignition key
cylinder --> 2: Key
inserted1: 10 kohms or
higher --> 2:
Below 1 ohms
Symbols
(Terminal No.)Wiring
ColorTerminal
DescriptionConditionSpecified
Condition
KSW (T9-3) - GND
(T9-14)LG-B - W-
BUnlock warning
switch input1: No key in ignition key
cylinder --> 2: Key inserted1: 10 to 14V -->
2:0 V

Fig. 8: Identifying Terminals Of Steering Lock ECU
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Disconnect the S46 ECU connector.
b. Measure the voltage and resistance of the wire harness side connector.
Standard:
SPECIFIED CONDITION
Symbols
(Terminal No.)Wiring
ColorTerminal
DescriptionConditionSpecified Condition
CPUB (S46-1) -
Body groundV-Y - Body
ground+B (CPUB)
Power supplyAlways10 to 14V
+B (S46-10)-
Body groundR-L - Body
ground+B Power supplyAlways10 to 14V
LG-B -1: No key in starter

If the result is not as specified, there may be a malfunction on the wire harness side.
c. Reconnect the S46 ECU connector.
d. Measure the voltage of the connector.
Standard:
SPECIFIED CONDITION
If the result is not as specified, the ECU may have a malfunction.
3.CHECK DRIVER DOOR ECU
Fig. 9: Identifying Terminals Of Driver Door ECU

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Disconnect the D25 ECU connector.
b. Measure the voltage and resistance of the wire harness side connector.
KSW (S46-12) -
Body groundBody
groundUnlock warning
switch inputswitch --> 2: Key
inserted1: 10 kohms or higher
--> 2: Below 1 ohms
PUSH (S46-11)-
Body groundP-B -Body
groundPush switch input
1: No key in starter
switch --> 2: Key
inserted1: 10 kohms or higher
--> 2: Below 1 ohms
GND (S46-9) -
Body groundW-B -Body
groundGroundAlwaysBelow 1ohms
Symbols (Terminal
No.)Wiring
ColorTerminal
DescriptionConditionSpecified
Condition
KSW (S46-12) -
GND (S46-9)LG-B - W-
BUnlock warning
switch input1: No key in ignition cylinder -
-> 2: Key inserted1: 10 to 14V -->
2: 0V
PUSH (S46-11) -
GND (S46-9)P-B - W-BPush switch input1: No key in ignition cylinder -
-> 2: Key inserted1: 10 to 14V -->
2:0V

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 (with CAN VIM) to the DLC3.
b. Turn the ignition switch ON.
c. Read the DATA LIST on the tester's screen.
Driver door ECU:
Fig. 11: DATA LIST
- Driver Door ECU
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Transponder key ECU (w/o Smart key system):
Fig. 12: DATA LIST
- Transponder Key ECU (w/o Smart Key System)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Steering lock ECU (w/ Smart key system):
Fig. 13: DATA LIST
- Steering Lock ECU (w/ Smart Key System)
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 removin
g any parts. Performing the ACTIVE TEST early in troubleshooting is one way

Fig. 14: Wiring Diagram - Driver Door ECU Power Source Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT FUSE (MPX-IG, AM1, D DOOR, MPX-B1, D/C CUT)
a. Remove the MPX-IG and AM1 fuses from the driver side J/B.
b. Remove the D DOOR and MPX-B1 fuses from the passenger side J/B.
c. Remove the D/C CUT fuse from the FL block assy.
d. Measure the resistance.

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS
TABLE
1.CHECK KEY REMINDER WARNING SYSTEM
a. Check that the key reminder warning buzzer sounds.
1. Close the driver side door, insert the key into the ignition key cylinder and then turn the key
to the LOCK or ACC position.
2. Open the driver side door and check that the buzzer sounds intermittently.
b. Check that the key reminder warning buzzer stops.
1. Check that the buzzer stops sounding if any of the following operations is performed while
the buzzer is sounding:
Close the driver side door (front door courtesy lamp switch is off).
Turn the ignition switch ON.
Pull out the key from the ignition key cylinder.
1.INSPECT UNLOCK WARNING SWITCH ASSY
a. Remove the unlock warning switch.
b. Measure the resistance of the switch.
Standard:
SPECIFIED CONDITION
If the result is not as specified, replace the switch ass
y.
Tester ConnectionSwitch ConditionSpecified Condition
1 -2Not pushed10 kohms or higher
1 -2PushedBelow 1 ohms