2003 LEXUS LS430 lumbar support

Fuel Lid Opener MotorOn left side of luggage compartment, behind left
rear fenderwell. See Fig. 19
.
Headlight Beam Level Control Actuator LHBehind left headlight. See Fig. 13 .
Headlight Beam Level Control Actuator RHBehind right headlight. See Fig. 13 .
Headlight Cleaner MotorBelow left headlight. See Fig. 13 .
Height Control CompressorOn right front of engine compartment. See Fig. 13 .
Luggage Compartment Door Closer MotorOn center rear of luggage compartment lid. See Fig.
28 .
Power Seat Module (Rear Passenger's RH Seat Slide
Control)Right side of rear seat. See Fig. 32 .
Power Seat Motor (Driver's Seat Cushion Control)Lower left side of driver's seat. See Fig. 31 .
Power Seat Motor (Driver's Seat Front Vertical
Control)Lower left side of driver's seat. See Fig. 31 .
Power Seat Motor (Driver's Seat Lifter Control)Lower right side of driver's seat bottom. See Fig.
31 .
Power Seat Motor (Driver's Seat Lumbar Support
Lower Side Control)Lower right side of driver's seat cushion. See Fig.
31 .
Power Seat Motor (Driver's Seat Lumbar Support
Upper Side Control)Upper right side of driver's seat back. See Fig. 31 .
Power Seat Motor (Driver's Seat Reclining Control)Lower left rear side of driver's seat bottom. See Fig.
31 .
Power Seat Motor (Driver's Seat Slide Control)In lower left side of driver's seat cushion. See Fig.
31 .
Power Seat Motor (Front Passenger's Seat Front
Vertical Control)In lower right side of front passenger's seat bottom.
See Fig. 31
.
Power Seat Motor (Front Passenger's Seat Head
Rest Control)In upper left side of front passenger's seat back. See
Fig. 31
.
Power Seat Motor (Front Passenger's Seat Lifter
Control)In lower left side of front passenger's seat bottom.
See Fig. 31
.
Power Seat Motor (Front Passenger's Seat Lumbar
Support Control)Lower left rear of front passenger seat cushion. See
Fig. 31
.
Power Seat Motor (Front Passenger's Seat Reclining
Control)Lower right side of front passenger's seat. See Fig.
31 .
Power Seat Motor (Front Passenger's Seat Slide
Control)Under passenger's seat cushion. See Fig. 31 .
Power Seat Motor (Rear Passenger's LH Seat Slide
Control)Left side of rear seat. See Fig. 32 .
Power Window Motor Front LHIn left front door. See Fig. 29 .
Power Window Motor Front RHIn right front door. See Fig. 29 .
Power Window Motor Rear LHIn left rear door. See Fig. 29 .
Power Window Motor Rear RHIn right rear door. See Fig. 29 .
Rear Blower MotorCenter rear of vehicle. See Fig. 29 .
Rear Damper Servo MotorRear center of luggage compartment. See Fig. 29 .

Fig. 4: Communication Table
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.FRONT POWER SEAT CONTROL SYSTEM DESCRIPTION
The power seat is standard equipment for the front seats and optional equipment for the rear seats.
On the LS430, a memory system for the driver seat is provided as standard equipment.
2.FUNCTION OF MAIN COMPONENT
The following functions are available.
MAIN COMPONENT FUNCTION
ComponentsFunction
Seat slide motorReceives signal from driver seat ECU, motor operates, and driver side's
seat slides forward and rearward.
Seat reclining motorReceives signal from driver seat ECU, motor operates, and driver side's
seat reclines forward and rearward.
Seat cushion slide motorReceives signal from driver seat ECU, motor operates, and driver side's
seat cushion slides.
Seat front vertical motorReceives signal from driver seat ECU, motor operates, and driver side's
seat front vertical raises and lowers.
Seat rear vertical motorReceives signal from driver seat ECU, motor operates, and driver side's
seat rear vertical raises and lowers.
Seat lumbar support upper
motorReceives signal from driver seat ECU, motor operates, and driver side's
seat lumbar support upper can be adjusted.
Seat lumbar support lower
motorReceives signal from driver seat ECU, motor operates, and driver side's
seat lumbar support lower can be adjusted.
Seat headrest height motorReceives signal from driver seat ECU, motor operates, and driver side's

3.SYSTEM OPERATION
The front power seat's adjustment and position memory are shown in the chart below.
SYSTEM OPERATION
For the memory function, first, memory switch operation is transferred from the driver door ECU to the
driver seat ECU via the multiplex communication line. Then, either the seat position is recorded in
memory or a previously recorded seat position is recalled.
HINT:
Use this procedure to troubleshoot the front power seat control system with memory function.
<0037004b00480003004b0044005100470010004b0048004f0047000300570048005600570048005500030056004b00520058004f0047000300450048000300580056004800470003004c005100030056005700480053005600030016000300440051004700
030018001100030003[
1.VEHICLE BROUGHT TO WORKSHOP
2.CUSTOMER PROBLEM ANALYSIS CHECK AND PROBLEM SYMPTOM CHECK (SEE
CUSTOMER PROBLEM ANALYSIS CHECK
)
3.CHECK COMMUNICATION FUNCTION OF LARGE-SCALE MULTIPLEX
COMMUNICATION SYSTEM (BEAN)
seat headrest raises and lowers.
Seat position sensorIs built in each seat adjuster and sends seat position data to driver seat
ECU so that it can detect seat positions at all times.
Seat control switchBased on switches operated, seat adjuster signals are input into driver seat
ECU and seat is adjusted accordingly. Lumbar support adjustments are
also done.
Set switch Memory switchWhen set switch and memory switch are pressed simultaneously, SET, 1, 2
or 3 switch is input to driver door ECU and driver side's seat position is
recorded. Then, when memory switch is pressed, SET, 1, 2 or 3 switch is
input to driver door ECU and driver side's seat position changes according
to memory.
Seat Adjustment FunctionDriverFront Passenger
Fore-and-Aft SlidePower and memoryPower
RecliningPower and memoryPower
Cushion SlidePower and memory-
Front Vertical HeightPower and memoryPower
Rear VerticalPower and memoryPower
Dual Lumbar SupportPower-
Single Lumbar Support-Manual
Headrest Fore-and-AftManualManual
Headrest HeightPower and memoryPower

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.
Driver seat ECU:
DRIVER SEAT ECU - ACTIVE TEST
CIRCUIT DESCRIPTION
This circuit provides power to operate the driver seat ECU.
This driver seat ECU is built into this power seat switch. The lumbar support switch and the seat cushion switch
are separate from the power seat switch.
WIRING DIAGRAM
ItemTest DetailsDiagnostic Note
RECLININGTest detail: reclining operation FRONT/REAR Vehicle
condition: stopped-
F VERTICALTest detail: front vertical operation UP/DOWN Vehicle
condition: stopped-
LIFTERTest detail: lifter operation UP/DOWN Vehicle condition:
stopped-
SLIDETest detail: sliding operation UP/DOWN Vehicle condition:
stopped-
HEADRESTTest detail: headrest operation UP/DOWN Vehicle condition:
stopped-
CUSHIONTest detail: cushion length operation FRONT/REAR Vehicle
condition: stopped-

Fig. 27: Identifying D28 Driver Seat ECU Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
A: REPLACE FRONT SEAT HEADREST ADJUSTER
B: REPLACE FRONT POWER SEAT ADJUSTER
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS
TABLE
CIRCUIT DESCRIPTION
Pressing the lumbar switch activates the lumbar support motor.
Because the lumbar support switch is not connected to the driver seat ECU, pressing this switch does not
operate ECU operations such as the memory function.
WIRING DIAGRAM

Fig. 28: Lumbar Support Switch Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT LUMBAR SUPPORT SWITCH
a. Remove the lumbar support switch.
b. Measure the resistance.
Standard:
Upper side control
TESTER CONNECTION AND SPECIFIED CONDITION

Fig. 29: Identifying Lumbar Support Switch Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE LUMBAR SUPPORT SWITCH
OK: GO TO NEXT STEP
2.INSPECT POWER SEAT MOTOR (SEE INSPECTION
)
NG: REPLACE POWER SEAT MOTOR
OK: GO TO NEXT STEP
3.CHECK WIRE HARNESS (LUMBAR SUPPORT SWITCH - POWER SEAT MOTOR AND
BODY GROUND)
a. Disconnect the P23 switch, connector.
b. Disconnect the P30 and P31 motor connectors.
c. Measure the resistance and voltage of the wire harness side connectors.
Standard:
TESTER CONNECTION AND SPECIFIED CONDITION
Tester connectionSpecified condition
P23-1 (H) - P31-1Below 1 ohms
P23-4 (R) - P31-2Below 1 ohms
P23-2 (H1) - P30-2Below 1 ohms
P23-3 (R1) - P30-1Below 1 ohms
P23-6 (E) - Body groundBelow 1 ohms
P23-5 (B) - P23-6 (E)10 to 14 V

Fig. 30: Identifying P23 Lumbar Support Switch Connector Terminals And P30,P31 Power Seat
Motor Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR AND REPLACE HARNESS AND CONNECTOR