2003 LEXUS LS430 Rear suspension

Fig. 46: Identifying Height Control Sensor Rear LH Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
B: REPLACE HEIGHT CONTROL SENSOR SUB-ASSY FRONT RH (SEE REPLACEMENT
)
C: REPLACE HEIGHT CONTROL SENSOR SUB-ASSY FRONT LH (SEE REPLACEMENT
)
D: REPLACE HEIGHT CONTROL SENSOR SUB-ASSY REAR RH (SEE REPLACEMENT
)
E: REPLACE HEIGHT CONTROL SENSOR SUB-ASSY REAR LH (SEE REPLACEMENT
)
A: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)

Acceleration value must change.
RESULT DESCRIPTION
B: Go to step 2
C: Go to step 3
D: REPLACE LEFT FRONT ACCELERATION SENSOR
HINT:
For the left front acceleration sensor failure, replace the suspension control ECU.
A: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
2.INSPECT HEIGHT CONTROL SENSOR SUB-ASSY FRONT RH
a. Remove the height control sensor sub-assy front RH.
b. Connect 3 dry batteries of 1.5 V in series.
c. Connect terminal 1 (SHB) to the batteries' positive (+) terminal, and terminal 4 (SHG) to the
batteries' negative (-) terminal, then apply voltage of approximately 4.5 V between terminals 4
(SHG) and 3 (SGFR) for the following conditions.
SENSOR CONDITION AND VOLTAGE SPECIFICATIONS
OKA
NG (right front acceleration sensor)B
NG (rear acceleration sensor)C
NG (left front acceleration sensor)D
Sensor conditionVoltage
Sensor stationaryApprox. 2.3 V
Sensor vibrating verticallyChange between approx. 1.0 to 4.0 V

Fig. 59: Identifying Absorber Control Actuator Rear LH Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE ABSORBER CONTROL ACTUATOR
OK:Go to next step
3.CHECK HARNESS AND CONNECTOR (ABSORBER CONTROL ACTUATOR - SUSPENSION
CONTROL ECU) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Disconnect the air suspension ECU A21 or A22 connector.
b. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT RH)
Tester ConnectionSpecified Condition
A21-1 (FAR+) - S6-2 (FAR+)Below 1 ohms
A21-2 (FAR-) - S6-5 (FAR-)Below 1 ohms
A21-3 (FBR+) - S6-1 (FBR+)Below 1 ohms
A21-4 (FBR-) - S6-4 (FBR-)Below 1 ohms
A21-1 (FAR+) - Body ground10 Kohms or higher

Fig. 67: Identifying Absorber Control Actuator Rear LH Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The exhaust solenoid discharges high pressure air from the system by opening the solenoid valve according to
the si
gnal from the suspension control ECU.

CIRCUIT DESCRIPTION
FRONT HEIGHT CONTROL SOLENOID VALVE:
The height control valve sub-assy No. 1 (front height control solenoid valve) independently opens and closes
paths to the pneumatic cylinder for the front wheel side by receiving signals from the suspension control ECU.
HINT:
The right left solenoid valves are integrated and mounted on front side.
REAR HEIGHT CONTROL SOLENOID VALVE:
The height control valve sub-assy No. 2 (rear height control solenoid valve) independently opens and closes
paths to the pneumatic cylinder for the rear wheel side by receiving signals from the suspension control ECU.
HINT:
The right left solenoid valves are integrated and mounted on rear side.
Fig. 74: DTC C1737 And DTC C1740 Detecting Condition And Trouble Area

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM

POWER SOURCE CIRCUIT ) is displayed, carry out the necessary inspection. If they are output at the
same time, carry out the necessary inspection for DTC C1774 first.
NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE
OK:Go to next step
2.PERFORM ACTIVE TEST BY HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position and turn the hand-held tester main switch on.
c. Select the item below in the ACTIVE TEST and operate it with the hand-held tester.
VEHICLE CONDITION / TEST DETAILS
d. Check the operation sound of the height control solenoid valve when the solenoid is turned on
through the ACTIVE TEST.
OK:
An operation sound is heard 1 second after the height control solenoid valve is turned on.
NG: Go to step 3
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
3.INSPECT HEIGHT CONTROL SOLENOID VALVE
HEIGHT CONTROL SOLENOID VALVE FRONT:
a. Disconnect the height control solenoid valve connector.
b. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (RH)
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (LH)
ItemVehicle Condition / Test DetailsDiagnostic Note
FR SOLTurn OFF right front solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
FL SOLTurn OFF left front solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
RR SOLTurn OFF right rear solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
RL SOLTurn OFF left rear solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
Tester ConnectionSpecified Condition
2 (GND) - 3 (SLFR)10 to 14 ohms

Fig. 79: Identifying Height Control Solenoid Valve Rear LH Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK:
It should make an operating sound (click).
RESULT DESCRIPTION
HINT:
When a malfunction is found in the rear solenoid valve, replace the height control valve sub-assy No. 2.
B: REPLACE HEIGHT CONTROL VALVE SUB-ASSY NO. 1 (SEE REPLACEMENT
)
C: REPLACE HEIGHT CONTROL VALVE SUB-ASSY NO. 2 (SEE REPLACEMENT
)
A:Go to next step
4.CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - HEIGHT
OKA
NGC

CONTROL SOLENOID VALVE) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE)
a. Disconnect the suspension control ECU A20 or A21 connector.
b. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT
RH)
Fig. 80: Identifying Suspension Control ECU Connector Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT
LH)
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (REAR RH)
Tester ConnectionSpecified Condition
A20-16 (SLFR) - F3-3 (RH+)Below 1 ohms
A20-16 (SLFR) - Body ground10 Kohms or higher
Tester ConnectionSpecified Condition
A20-17 (SLFL) - F3-1 (LH+)Below 1 ohms
A20-17 (SLFL) - Body ground10 Kohms or higher