2003 LEXUS LS430 key

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 )

Fig. 5: Customer Problem Analysis Check Sheet
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
The following items can be customized.
Meter ECU:
CUSTOMIZE PARAMETERS
Display (Item)DefaultContentsSetting
KEY REMND
VOLUMLARGEFunction that changes key reminder
buzzer's volumeLARGE/MEDIUM/SMALL

Fig. 6: Problem Symptoms Table
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.CHECK TRANSPONDER KEY ECU ASSY
KEY REMND
SOUNDNORMALFunction that changes key reminder
buzzer's frequencyNORMAL/FAST/SLOW/0s

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

Standard:
SPECIFIED CONDITION
If the result is not as specified, there may be a malfunction on the wire harness side.
1.DESCRIPTION
Key reminder warning system data can be read in the Data Link Connector 3 (DLC3) of the vehicle.
When the system seems to be malfunctioning, use the hand-held tester to check for malfunctions and
perform repairs.
2.CHECK DLC3
The vehicle's ECU uses the ISO 15765-4 communication protocol. The terminal arrangement of the
DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.
HINT:
Connect the cable of the hand-held tester (with CAN VIM) to the DLC3, turn the ignition switch ON and
attempt to use the hand-held tester. If the screen displays UNABLE TO CONNECT TO VEHICLE, a
problem exists in the vehicle side or the tester side.
If the communication is normal when the tester is connected to another vehicle, inspect the DLC3 on the
original vehicle. If the communication is still impossible when the tester is connected to another vehicle,
the problem is probably in the tester itself. Consult the Service Department listed in the tester's instruction
manual.
Symbols
(Terminal No.)Wiring
ColorTerminal
DescriptionConditionSpecified Condition
CPUB (D25-4) -
Body groundV-Y -Body
ground+B (CPUB) power
supplyAlways10 to 14V
SIG (D25-5) -
Body groundR-L -Body
ground+B (SIG) power
supplyIgnition switch 1: OFF
--> 2: ON1: Below 1 V --> 2: 10 to
14V
BDR (D25-6) -
Body groundR-Body
ground+B (BDR) power
supplyAlways10 to 14V
GND (D25-1) -
Body groundW-B -Body
groundGroundAlwaysBelow 1 ohms
CTY (D25-23) -
Body groundP-G -Body
groundDriver door courtesy
switch inputDriver door 1:
CLOSED --> 2: OPEN1: 10 kohms or higher --
> 2: Below 1 ohms

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