LEXUS LS430 2003 Factory Repair Manual

Fig. 2: Defogger System Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Communication Table
COMMUNICATION TABLE
1.GENERAL
The rear window defogger system's thin heater wires are attached to the inside of the rear window and
defog the window surface quickly. The indicator lamp illuminates while the system is operating. The
system automatically turns off after approximately 15 minutes.
2.FUNCTION OF MAIN COMPONENT
SenderReceiverSignalLine
Multi-display(1)A/C control assemblyRear defogger switch
signalBEAN
Center cluster integration
panel
(2)
A/C control assemblyRear defogger switch
signalBEAN/AVC-LAN
(1)w/ LEXUS navigation system
(2)w/o LEXUS navigation system

FUNCTION OF MAIN COMPONENT
3.DESCRIPTION
The LS430 has the rear defogger system with the following function.
DESCRIPTION
HINT:
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56005700480050001100030003[
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030018001100030003[
1.VEHICLE BROUGHT TO WORKSHOP
2.CUSTOMER PROBLEM ANALYSIS CHECK AND SYMPTOM CHECK (See CUSTOMER
PROBLEM ANALYSIS CHECK )
3.CHECK 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 SYSTEM (See DIAGNOSTIC TROUBLE CODE
CHART )
A: Go to next step
4.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.
ComponentOutline
DEFOG RelayReceives rear defogger activation request signals
from A/C control assembly and supplies power to
rear window defogger.
Rear Window DefoggerReceives power from DEFOG relay and heats
defogger wire.
FunctionOutline
Defogs the rear window surfaceReceives rear defogger activation request signals
from A/C control assembly and supplies power to
rear window defogger. Receives power from
DEFOG relay and heats defogger wire.

B: Go to step 6
A: Go to next step
5.OVERALL ANALYSIS AND TROUBLESHOOTING
a. DATA LIST/ACTIVE TEST (See DATA LIST/ACTIVE TEST
)
1. Inspection with the hand-held tester (ACTIVE TEST)
b. Terminals of ECU (See TERMINALS OF ECU
)
c. Inspection (see INSPECTION
)
6.ADJUST, REPAIR OR REPLACE
7.CONFIRMATION TEST
END

Fig. 3: Identifying Customer Problem Analysis Check Sheet
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig. 4: Problem Symptoms Table
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.CHECK A/C CONTROL ASSY (A/C ECU)
Fig. 5: Identifying A/C Control Assy Connector Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Disconnect the A11 ECU connector.
b. Measure the voltage and resistance of the wire harness side connector.
Standard:
A/C CONTROL ASSY - REFERENCE TABLE (DISCONNECTED)
Symbols Terminal Specified

If the result is not as specified, there may be a malfunction on the wire harness side.
c. Reconnect the A11 ECU connector.
d. Measure the voltage of the connector.
Standard:
A/C CONTROL ASSY - REFERENCE TABLE (RECONNECTED)
If the result is not as specified, the ECU may have a malfunction.
1.DESCRIPTION
a. Defogger system data and the Diagnostic Trouble Code (DTCs) can be read in the Data Link
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03005600480048005000560003005700520003004500480003[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.
(Terminal No.)Wiring ColorDescriptionConditionCondition
GND (A11-1) -
Body groundW-B - Body
groundGroundAlwaysBelow 1 ohms
IG (A11-9) - Body
groundLG-R - Body
groundIgnition power
supplyIgnition switch
turned OFF -> ONBelow 1 V -> 10 to
14 V
+B (A11-21) -
Body groundB-Y - Body
groundBattery power
supplyAlways10 to 14 V
Symbols
(Terminal No.)
Wiring Color
Terminal
Description
Condition
Specified
Condition
RDFGR (A11-8) -
GND (A11-1)W - W-BDEFOG relayIgnition switch
ON, Rear defogger
switch to OFF ->
ON10 to 14 V ->
Below 1 V
IG (A11-9) - GND
(A11-1)LG-R - W-BIgnition power
supplyIgnition switch
turned OFF -> ONBelow 1 V -> 10 to
14 V
+B (A11-21) -
GND (A11-1)B-Y - W-BBattery power
supplyAlways10 to 14 V

Fig. 6: Identifying DLC3 Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
DLC3 REFERENCE TABLE
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 the message UNABLE TO CONNECT TO
VEHICLE, there is a problem either with the vehicle or with the tester.
If communication is normal when the tester is connected to another vehicle, inspect the DLC3 on
the original vehicle.
If communication is still impossible when the tester is connected to another vehicle, the problem is
probabl
y in the tester itself. Consult the Service Department listed in the tester's instruction manual.
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 14 V

Fig. 7: Connecting Hand-Held Tester To DLC3
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
3.INSPECT BATTERY VOLTAGE
Standard: 11 to 14 V
If voltage is below 11 V, recharge the battery before proceeding.
1.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.
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.
A/C control assy:
A/C CONTROL ASSY - REFERENCE TABLE
CIRCUIT DESCRIPTION
When the defogger switch is turned on, a rear defogger activation request signal is input to the A/C control (A/C
ECU) from the multi-display
1 or center cluster integration panel2 . Then, the A/C control assembly outputs this
signal to the defogger relay (Marking: DEFOG) and the rear window defogger system is activated.
HINT:
1. w/ LEXUS navigation system
2. w/o LEXUS navigation system
WIRING DIAGRAM
ItemTest DetailsDiagnostic Note
DEFOGGER RLY-ROperate rear window defogger OFF/ON-

Fig. 8: Rear Window Defogger System - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT FUSE
a. Select the ACTIVE TEST, use the han
d-held tester to generate a control command, and then check

that the A/C control is turned on and off.
FUSE - REFERENCE TABLE
OK:
When OFF is selected on the hand-held tester, the rear defogger should turn off.
When ON is selected on the hand-held tester, the rear defogger should become active.
NG: Go to step 2
OK: REPLACE AIR CONDITIONER CONTROL ASSY AND IF DEFOGGER STILL DOES
NOT OPERATE, REPLACE MULTI-DISPLAY OR CLUSTER INTEGRATION PANEL
2.INSPECT FUSE (DEFOG, FR IG)
a. Remove the DEFOG H-fuse from the FL block.
b. Remove the FR IG fuse from the engine room R/B.
c. Measure the resistance of the fuse.
Standard: Below 1 ohms
NG: REPLACE FUSE
OK: Go to next step
3.CHECK WIRE HARNESS (DEFOG RELAY - BATTERY)
a. Remove the DEFOG relay from the engine room R/B No. 2.
b. Measure the voltage of the wire harness side connector.
Standard:
DEFOG RELAY - BATTERY - VOLTAGE TABLE
ItemTest DetailsDiagnostic Note
DEFOGGER RLY-ROperate rear window defogger
OFF/ON-
Tester ConnectionConditionSpecified Condition
R/B DEFOG relay terminal 1 -
Body groundIgnition switch ON10 to 14 V
R/B DEFOG relay terminal 5 -
Body groundAlways10 to 14 V